Dynamic Pressure Monitoring And Adjustments Based On Pump Flow Characteristics

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims the benefit of and priority of U.S. Provisional Patent Application Ser. No. 63/699,925, filed Sep. 27, 2024, the contents of which are incorporated by reference herein.

BACKGROUND

Field of the Disclosure

[0002]The present subject matter relates to control of a pneumatic pump. More particularly, the present subject matter relates to use of signals from a capacitive sensor to dynamically adjust the pressure applied by a pneumatic pump of a fluid processing device.

Description of Related Art

[0003]The use of pneumatic pumps in medical devices is well-established and common in multiple devices. By utilizing a controller, a system can modulate the pressure that is exerted on a pump chamber to induce fluid flow. The basic premise of a pneumatic pumping system is that a vacuum (negative pressure) is exerted onto a pumping chamber to pull back a flexible diaphragm or membrane of the pumping chamber and allow fluid to enter. Conversely, to empty the chamber, a positive pressure is applied, moving the flexible diaphragm or membrane toward and into the chamber and forcing fluid out of the chamber and into an associated fluid pathway. Current methods of controlling the pneumatics required to operate a pump involve statically setting pressures to the highest levels potentially required or setting pressures to levels which have been shown to perform well across a majority of procedures. In instances where the pressure is not sufficient to induce adequate fluid flow, an alert is generated and the procedure will typically be terminated.

[0004]Depending on the fluid viscosity, the fluid flow/pressure in associated fluid pathways, or other sources of restriction (e.g., donor vein issues, kinks, etc.), the flow of fluid into and/or out of the pumping chamber may be compromised. In order to detect any such irregularities, the operation of a pneumatic pump may be monitored by an associated sensor, with differently configured sensors possibly being employed to assist in pump control. One type of sensor that may be used to monitor operation of a pneumatic pump is a capacitive sensor, which measures whether the pump fills correctly (indicating that there is no upstream restriction) and empties correctly (indicating that there is no downstream restriction). One such system employing pneumatic pumps and capacitive sensors is described in U.S. Patent Application Publication No. 2006/0161092, which is hereby incorporated herein by reference.

[0005]When an upstream restriction is detected, the current methodology is to increase the amount of time the pumping chamber remains open (i.e., the time during which a vacuum or negative pressure is applied to a flexible diaphragm or membrane of the chamber) to allow for more fluid to flow in over time, or to calculate the volume believed to be moved by the pump (i.e., the stroke volume) as being less than normal. However, one possible drawback of each of these methods is severely limiting the maximum rate at which the pump can operate.

[0006]Rather than increasing the amount of time that the pumping chamber remains open or adjusting the stroke volume, an alternative approach is to apply a stronger vacuum or negative pressure to the flexible diaphragm or membrane of the pumping chamber, thus creating a stronger pull-in force into the chamber, which has been shown to allow for a faster fill without compromising the maximum rate. However, one potential drawback of such an approach is the risk of possibly creating larger than necessary shear stresses, which could be detrimental to the procedure/products (e.g., red blood cells).

[0007]As for downstream restrictions, when one is detected, the current methodology is to increase the amount of time that the pumping chamber remains closed (i.e., the time during which a positive pressure is applied to a flexible diaphragm or membrane of the chamber) to allow for more fluid to flow out over time, or to calculate the volume believed to be moved by the pump (i.e., the stroke volume) as being less than normal. As with the conventional responses to detection of an upstream restriction, one possible drawback of each of these methods is severely limiting the maximum rate at which the pump can operate.

[0008]Rather than increasing the amount of time that the pumping chamber remains closed or adjusting the stroke volume, an alternative approach is to apply a stronger positive pressure to the flexible diaphragm or membrane of the pumping chamber, thus creating a stronger push-out force into the chamber, which has been shown to allow for a faster empty without compromising the maximum rate. However, one potential drawback of such an approach is the risk of possibly creating larger than necessary shear stresses, which could be detrimental to the procedure/products (e.g., red blood cells).

[0009]As none of the above approaches is without significant disadvantages, it would be advantageous to provide an approach to controlling operation of a pneumatic pump that avoids the drawbacks of conventional approaches.

SUMMARY

[0010]There are several aspects of the present subject matter which may be embodied separately or together in the devices and methods described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately as set forth in the claims appended hereto.

[0011]In one aspect, a fluid processing device is provided for use in combination with a fluid flow circuit comprising a pump chamber including a flexible diaphragm and an electrode. The fluid processing device includes a controller programmed to execute a fluid flow procedure, a pneumatic pump, and a capacitive sensor. The pneumatic pump is operatively coupled to the controller and configured to be actuated by the controller during the fluid flow procedure to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey the fluid out of the pump chamber. The capacitive sensor is operatively coupled to the controller, configured to be electrically coupled to the electrode of the pump chamber, and configured to transmit an inflow signal to the controller that is indicative of an inflow volume of the fluid that has been drawn into the pump chamber while the pneumatic pump is applying negative pressure to the flexible diaphragm of the pump chamber during the inflow duration. The controller is programmed to actuate the pneumatic pump to apply an initial negative pressure to the flexible diaphragm of the pump chamber for the inflow duration when first applying negative pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure, with the initial negative pressure being selected to be a minimum negative pressure at which a complete fill of the pump chamber is expected be achieved when negative pressure is being applied to the flexible diaphragm of the pump chamber during the inflow duration. The controller determines whether a complete fill of the pump chamber has been achieved during application of the initial negative pressure to the flexible diaphragm of the pump chamber during the inflow duration based at least in part on the inflow signal and, upon determining that a complete fill of the pump chamber has not been achieved, actuates the pneumatic pump to apply a second negative pressure that is greater than the initial negative pressure to the flexible diaphragm of the pump chamber for the inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure.

[0012]In another aspect, a controller-implemented method is provided for executing a fluid flow procedure using a fluid flow circuit having a pump chamber including a flexible diaphragm and an electrode. The method includes actuating a pneumatic pump to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey the fluid out of the pump chamber. The pneumatic pump is actuated to apply an initial negative pressure to the flexible diaphragm of the pump chamber for the inflow duration when first applying negative pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure, with the initial negative pressure being selected to be a minimum negative pressure at which a complete fill of the pump chamber is expected be achieved when negative pressure is being applied to the flexible diaphragm of the pump chamber during the inflow duration. An inflow signal is received from a capacitive sensor electrically coupled to the electrode of the pump chamber that is indicative of an inflow volume of the fluid that has been drawn into the pump chamber while the pneumatic pump is applying negative pressure to the flexible diaphragm of the pump chamber during the inflow duration. It is then determined whether a complete fill of the pump chamber has been achieved during application of the initial negative pressure to the flexible diaphragm of the pump chamber during the inflow duration, based at least in part on the inflow signal. Upon determining that a complete fill of the pump chamber has not been achieved, the pneumatic pump is actuated to apply a second negative pressure that is greater than the initial negative pressure to the flexible diaphragm of the pump chamber for the inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure.

[0013]In yet another aspect, a fluid processing device is provided for use in combination with a fluid flow circuit comprising a pump chamber including a flexible diaphragm and an electrode. The fluid processing device includes a controller programmed to execute a fluid flow procedure, a pneumatic pump, and a capacitive sensor. The pneumatic pump is operatively coupled to the controller and configured to be actuated by the controller during the fluid flow procedure to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey the fluid out of the pump chamber. The capacitive sensor is operatively coupled to the controller, configured to be electrically coupled to the electrode of the pump chamber, and configured to transmit an outflow signal to the controller that is indicative of an outflow volume of the fluid that has been conveyed out of the pump chamber while the pneumatic pump is applying positive pressure to the flexible diaphragm of the pump chamber during the outflow duration. The controller is programmed to actuate the pneumatic pump to apply an initial positive pressure to the flexible diaphragm of the pump chamber for the outflow duration when first applying positive pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure, with the initial positive pressure being selected to be a minimum positive pressure at which a complete empty of the pump chamber is expected be achieved when positive pressure is being applied to the flexible diaphragm of the pump chamber during the outflow duration. The controller determines whether a complete empty of the pump chamber has been achieved during application of the initial positive pressure to the flexible diaphragm of the pump chamber during the outflow duration based at least in part on the outflow signal and, upon determining that a complete empty of the pump chamber has not been achieved, actuates the pneumatic pump to apply a second positive pressure that is greater than the initial positive pressure to the flexible diaphragm of the pump chamber for the outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure.

[0014]In another aspect, a controller-implemented method is provided for executing a fluid flow procedure using a fluid flow circuit having a pump chamber including a flexible diaphragm and an electrode. The method includes actuating a pneumatic pump to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey the fluid out of the pump chamber. The pneumatic pump is actuated to apply an initial positive pressure to the flexible diaphragm of the pump chamber for the outflow duration when first applying positive pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure, with the initial positive pressure being selected to be a minimum positive pressure at which a complete empty of the pump chamber is expected be achieved when positive pressure is being applied to the flexible diaphragm of the pump chamber during the outflow duration. An outflow signal is received from a capacitive sensor electrically coupled to the electrode of the pump chamber that is indicative of an outflow volume of the fluid that has been conveyed out of the pump chamber while the pneumatic pump is applying positive pressure to the flexible diaphragm of the pump chamber during the outflow duration. It is then determined whether a complete empty of the pump chamber has been achieved during application of the initial positive pressure to the flexible diaphragm of the pump chamber during the outflow duration, based at least in part on the outflow signal. Upon determining that a complete empty of the pump chamber has not been achieved, the pneumatic pump is actuated to apply a second positive pressure that is greater than the initial positive pressure to the flexible diaphragm of the pump chamber for the outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during the fluid flow procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a perspective view of an exemplary fluid processing device that comprises a component of a fluid processing system according to an aspect of the present disclosure;

[0016]FIG. 2 is a schematic view of an exemplary disposable fluid flow circuit that may be mounted to the fluid processing device of FIG. 1 to complete a fluid processing system according to an aspect of the present disclosure;

[0017]FIG. 3 is a top plan view of an exemplary cassette of the fluid flow circuit of FIG. 2, which can be actuated to perform a variety of different fluid processing procedures in association with the fluid processing device shown in FIG. 1;

[0018]FIG. 4 is a schematic view of portions of a cassette station of the fluid processing device of FIG. 1 and the cassette of FIG. 3; and

[0019]FIG. 5 is a schematic view of the fluid flow circuit of FIG. 2 mounted on the fluid processing device of FIG. 1, showing the system carrying out a fluid processing procedure.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0020]The embodiments disclosed herein are for the purpose of providing an exemplary description of the present subject matter. They are, however, only exemplary, and the present subject matter may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting the subject matter as defined in the accompanying claims.

[0021]FIGS. 1-5 show components of a fluid processing system that embodies various aspects of the present subject matter. Use of the system for separating blood into two or more components and collecting at least one of the components will be described herein, though it should be understood that systems according to the present disclosure can be used for processing a variety of fluids, which may include bodily fluids and non-bodily fluids.

[0022]Generally speaking, the system includes two principal components, a durable and reusable fluid processing device 10 (FIG. 1) and a disposable fluid flow circuit 12 (FIG. 2). The illustrated fluid processing device 10 includes a spinning membrane separator drive unit 14, a centrifuge or centrifugal separator 16, additional components that control fluid flow through the disposable flow circuit 12, and a controller 18, which governs the operation of the other components of the fluid processing device 10 to perform a fluid processing procedure. A fluid processing device 10 of the type shown in FIG. 1 is described in greater detail in PCT Patent Application Publication No. WO 2018/053217 A1, which is hereby incorporated herein by reference. While the principles described herein may be employed when using the fluid processing device 10 of FIG. 1, it should be understood that these same principles may be applied to other fluid processing devices, including devices employing single separation technologies or approaches.

I. The Durable Fluid Processing Device

[0023]The fluid processing device 10 (FIG. 1) is configured as a durable item that is capable of long-term use. It should be understood that the fluid processing device 10 of FIG. 1 is merely exemplary of one possible configuration and that fluid processing devices according to the present disclosure may be differently configured.

[0024]In the illustrated embodiment, the fluid processing device 10 is embodied in a single housing or case 20. The illustrated case 20 includes a generally horizontal portion 22 (which may include an inclined or angled face or upper surface for enhanced visibility and ergonomics) and a generally vertical portion 24. The spinning membrane separator drive unit 14 and the centrifugal separator 16 are shown as being incorporated into the generally horizontal portion 22 of the case 20, while the controller 18 is shown as being incorporated into the generally vertical portion 24.

A. Spinning Membrane Separator Drive Unit

[0025]The fluid processing device 10 includes a spinner support or spinning membrane separator drive unit 14 for accommodating a generally cylindrical spinning membrane separator 26 of the fluid flow circuit 12. U.S. Pat. No. 5,194,145 (which is hereby incorporated herein by reference) describes an exemplary spinning membrane separator drive unit that would be suitable for incorporation into the fluid processing device 10, but it should be understood that the spinning membrane separator drive unit 14 may be differently configured without departing from the scope of the present disclosure.

[0026]The illustrated spinning membrane separator drive unit 14 has a base 28 configured to receive a lower portion of the spinning membrane separator 26 and an upper end cap 30 to receive an upper portion of the spinning membrane separator 26. Preferably, the upper end cap 30 is positioned directly above the base 28 to orient a spinning membrane separator 26 received by the spinning membrane separator drive unit 14 vertically and to define a vertical axis about which the spinning membrane separator 26 is spun. While it may be advantageous for the spinning membrane separator drive unit 14 to vertically orient a spinning membrane separator 26, it is also within the scope of the present disclosure for the spinning membrane separator 26 to be differently oriented when mounted to the fluid processing device 10.

[0027]In one embodiment, one of the base 28 and upper end cap 30 of the spinning membrane separator drive unit 14 is movable with respect to the other, which may allow differently sized spinning membrane separators 26 to be received by the spinning membrane separator drive unit 14. For example, the upper end cap 30 may be translated vertically with respect to the base 28 and locked in a plurality of different positions, with each locking position corresponding to a differently sized spinning membrane separator 26.

[0028]At least one of the base 28 and the upper end cap 30 is configured to spin one or more components of the spinning membrane separator 26 about the axis defined by the spinning membrane separator drive unit 14. The mechanism by which the spinning membrane separator drive unit 14 spins one or more components of the spinning membrane separator 26 may vary without departing from the scope of the present disclosure. In one embodiment, a component of the spinning membrane separator 26 to be spun includes at least one element configured to be acted upon by a magnet (e.g., a metallic material), while the spinning membrane separator drive unit 14 includes a magnet (e.g., a series of magnetic coils or semi-circular arcs). By modulating the magnetic field acting upon the aforementioned element of the spinning membrane separator 26, the component or components of the spinning membrane separator 26 may be made to spin in different directions and at varying speeds. In other embodiments, different mechanisms may be employed to spin the component or components of the spinning membrane separator 26.

[0029]Regardless of the mechanism by which the spinning membrane separator drive unit 14 spins the component or components of the spinning membrane separator 26, the component or components of the spinning membrane separator 26 is/are preferably spun at a speed that is sufficient to create Taylor vortices in a gap between the spinning component and a stationary component of the spinning membrane separator 26 (or a component that spins at a different speed). Fluid to be separated within the spinning membrane separator 26 flows through this gap, and filtration may be dramatically improved by the creation of Taylor vortices.

B. Centrifugal Separator

[0030]As for the centrifugal separator 16, it includes a centrifuge compartment 32 that receives a centrifugal separation chamber 36 of the fluid flow circuit 12, as well as other components of the centrifugal separator 16. Further details as to the configuration and operation of an exemplary centrifugal separator are set forth in PCT Patent Application Publication No. WO 2018/053217 A1.

[0031]Fluid (e.g., anticoagulated whole blood) is introduced into the centrifugal separation chamber 36 by an umbilicus, with the fluid being separated into a layer of less dense components (e.g., platelet-rich plasma, in the case of blood being separated) and a layer of more dense components (e.g., packed red blood cells) within the centrifugal separation chamber 36 as a result of centrifugal forces as it rotates. Components of an interface monitoring system may be positioned within the centrifuge compartment 32 to oversee separation of fluid within the centrifugal separation chamber 36. The interface monitoring system may include a light source 50 and a light detector 52, which is positioned and oriented to receive at least a portion of the light emitted by the light source 50.

[0032]The orientation of the various components of the interface monitoring system depends at least in part on the particular configuration of the centrifugal separation chamber 36. In general, though, the light source 50 emits a light beam (e.g., a laser light beam) through the separated fluid components within the centrifugal separation chamber 36 (which may be formed of a material that substantially transmits the light or at least a particular wavelength of the light without absorbing it). A portion of the light reaches the light detector 52, which transmits a signal to the controller 18 that is indicative of the location of an interface between the separated fluid components. If the controller 18 determines that the interface is in the wrong location (which can affect the separation efficiency of the centrifugal separator 16 and/or the quality of the separated fluid components), then it can issue commands to the appropriate components of the fluid processing device 10 to modify their operation so as to move the interface to the proper location.

C. Other Components of the Fluid Processing Device

[0033]In addition to the spinning membrane separator drive unit 14 and the centrifugal separator 16, the fluid processing device 10 may include other components compactly arranged to aid fluid processing.

[0034]The generally horizontal portion 22 of the case 20 of the illustrated fluid processing device 10 includes a cassette station 54, which accommodates a flow control cassette 48 of the fluid flow circuit 12. An exemplary flow control cassette 48 (which will be described in greater detail herein) is shown in FIG. 3, while FIG. 4 shows a portion of the flow control cassette 48 being received by the cassette station 54. In one embodiment, the cassette station 54 is similarly configured to the pneumatic-actuated pump and valve station described in U.S. Patent Application Publication No. 2006/0161092. The illustrated cassette station 54 includes a plurality of clamps or valves V1-V9 (FIG. 1), which move between a plurality of positions (e.g., between a retracted or lowered position and an actuated or raised position) to selectively contact or otherwise interact with corresponding valve stations C1-C9 of the flow control cassette 48 of the fluid flow circuit 12 (FIG. 3). Depending on the configuration of the fluid flow circuit 12, its cassette 48 may not include a valve station C1-C9 for each valve V1-V9 of the cassette station 54, in which case fewer than all of the valves V1-V9 will be used in a fluid processing procedure.

[0035]In the actuated position, a valve V1-V9 engages the associated valve station C1-C9 to prevent fluid flow through that valve station C1-C9 (e.g., by closing one or more ports associated with the valve station C1-C9, thereby preventing fluid flow through that port or ports). In the retracted position, a valve V1-V9 is disengaged from the associated valve station C1-C9 (or less forcefully contacts the associated valve station C1-C9 than when in the actuated position) to allow fluid flow through that valve station C1-C9 (e.g., by opening one or more ports associated with the valve station C1-C9, thereby allowing fluid flow through that port or ports). Additional clamps or valves V10 and V11 may be positioned outside of the cassette station 54 to interact with portions of valve stations C10 and C11 (which may be lengths of tubing) of the fluid flow circuit 12 to selectively allow and prevent fluid flow therethrough. The valves V1-V9 and corresponding valve stations C1-C9 of the cassette station 54 and cassette 48 may be differently configured and operate differently from the valves V10 and V11 and the valve stations C10 and C11 that are spaced away from the cassette station 54.

[0036]The cassette station 54 may be provided with additional components, such as pressure sensors A1-A4, which interact with sensor stations S1-S4 of the cassette 48 to monitor the pressure at various locations of the fluid flow circuit 12. For example, if the fluid source is a human donor, one or more of the pressure sensors A1-A4 may be configured to monitor the pressure of the donor's vein during blood draw and return. Other pressure sensors A1-A4 may monitor the pressure of the spinning membrane separator 26 and the centrifugal separation chamber 36. The controller 18 may receive signals from the pressure sensors A1-A4 that are indicative of the pressure within the fluid flow circuit 12 and, if a signal indicates a low-or high-pressure condition, the controller 18 may initiate an alarm or error condition to alert an operator to the condition and/or to attempt to bring the pressure to an acceptable level without operator intervention.

[0037]The fluid processing device 10 may also include a plurality of pumps P1-P6 (which may be collectively referred to as a pump assembly or pump system) to cause fluid to flow through the fluid flow circuit 12. The pumps P1-P6 may be differently or similarly configured and/or function similarly or differently from each other. In the illustrated embodiment, the pumps P1-P6 are configured as pneumatic pumps, which may be generally configured as described in U.S. Patent Application Publication No. 2006/0161092. An actuator of each pump P1-P6 is controlled by the controller 18 to alternately apply positive and negative pressures to a flexible membrane or diaphragm 64 of a different pump chamber T1-T6 defined by the flow control cassette 48 (FIG. 4) so as to cause fluid to flow through a portion of the fluid flow circuit 12. The configurations and operation of the pump system and the controller 18 will be described in greater detail herein.

[0038]The illustrated fluid processing device 10 also includes a spinner inlet sensor M1 for determining one or more properties of a fluid flowing into a spinning membrane separator 26 mounted within the spinning membrane separator drive unit 14. If the fluid flowing into the spinning membrane separator 26 is whole blood (which may include anticoagulated whole blood), the spinner inlet sensor M1 may be configured to determine the hematocrit of the blood flowing into the spinning membrane separator 26. If the fluid flowing into the spinning membrane separator 26 is platelet-rich plasma, the spinner inlet sensor M1 may be configured to determine the platelet concentration of platelet-rich plasma flowing into the spinning membrane separator 26. The spinner inlet sensor M1 may detect the one or more properties of a fluid by optically monitoring the fluid as it flows through tubing of the fluid flow circuit 12, or by any other suitable approach. The controller 18 may receive signals from the spinner inlet sensor M1 that are indicative of the one or more properties of fluid flowing into the spinning membrane separator 26 and use the signals to optimize the fluid processing procedure based upon that property or properties. If the property or properties is/are outside of an acceptable range, then the controller 18 may initiate an alarm or error condition to alert an operator to the condition. A suitable device and method for monitoring hematocrit and/or platelet concentration is described in U.S. Pat. No. 6,419,822 (which is hereby incorporated herein by reference), but it should be understood that a different approach may also be employed for monitoring one or more properties of a fluid or fluid component flowing into the spinning membrane separator 26.

[0039]The illustrated fluid processing device 10 further includes a spinner outlet sensor M2, which accommodates tubing of the fluid flow circuit 12 that flows a separated fluid component out of the spinning membrane separator 26. The spinner outlet sensor M2 monitors the separated fluid component to determine one or more properties thereof, and may do so by optically monitoring the separated fluid component as it flows through the tubing or by any other suitable approach. In one embodiment, separated plasma flows through the tubing, in which case the spinner outlet sensor M2 may be configured to determine the amount of cellular blood components in the plasma and/or whether the plasma is hemolytic and/or lipemic. This may be done using an optical monitor of the type described in U.S. Pat. No. 8,556,793 (which is hereby incorporated herein by reference) that measures the optical density of the fluid in the associated tubing, or by any other suitable device and/or method.

[0040]The illustrated fluid processing device also includes an air detector M3 (e.g., an ultrasonic bubble detector), which accommodates tubing of the fluid flow circuit 12 that flows fluid to a recipient. It may be advantageous to prevent air from reaching the recipient, whether a human recipient (e.g., the same human that serves as the blood source) or a non-human recipient (e.g., a storage bag or container), so the air detector M3 may transmit signals to the controller 18 that are indicative of the presence or absence of air in the tubing. If the signal is indicative of air being present in the tubing, the controller 18 may initiate an alarm or error condition to alert an operator to the condition and/or to take corrective action to prevent the air from reaching the recipient (e.g., by reversing the flow of fluid through the tubing or diverting flow to a vent location).

[0041]The generally vertical portion 24 of the case 20 may include a plurality of volume measurement systems W1-W6 (six are shown, but more or fewer may be provided), each configured to be associated with one or more fluid containers F1-F7 of the fluid flow circuit 12 (FIGS. 2 and 5). Each volume measurement system W1-W6 is configured to work in combination with the controller 18 to measure a current volume of fluid within an associated fluid container F1-F7 and to calculate a change in that volume between two or more points in time. The individual volume measurement systems W1-W6 may be variously configured without departing from the scope of the present disclosure, which may include two or more of the volume measurement systems W1-W6 being differently configured. In one exemplary embodiment, a volume measurement system W1-W6 may be configured as or include a weight scale configured to support and measure the weight of a fluid within an associated fluid container F1-F7 (with the measured weight being converted to a volume by a component of the volume measurement system W1-W6 or by the controller 18). In another exemplary embodiment, a volume measurement system W1-W6 may include one or more sensors configured to detect a volume and/or a change in volume of a fluid within an associated fluid container F1-F7. Volume measurement systems including additional components (e.g., both a weight scale and a sensor) and/or alternative components may also be employed without departing from the scope of the present disclosure.

[0042]Regardless of its particular configuration, each volume measurement system W1-W6 may transmit to the controller 18 a signal that is indicative of the volume of the fluid within the associated container F1-F7 to track the change of volume during the course of a procedure. This allows the controller 18 to process the incremental volume changes to derive fluid processing volumes and flow rates and subsequently generate signals to control processing events based, at least in part, upon the derived processing volumes. For example, the controller 18 may diagnose leaks and obstructions in the fluid flow circuit 12 and alert an operator.

[0043]The illustrated case 20 is also provided with a plurality of hooks or supports H1 and H2 that may support various components of the fluid flow circuit 12 or other suitably sized and configured objects.

D. Controller

[0044]According to an aspect of the present disclosure, the fluid processing device 10 includes a controller 18, which is suitably configured and/or programmed to control operation of the fluid processing device 10. In one embodiment, the controller 18 comprises a main processing unit (MPU), which can comprise, e.g., a Pentium™ type microprocessor made by Intel Corporation, although other types of conventional microprocessors can be used. In one embodiment, the controller 18 may be mounted inside the generally vertical portion 24 of the case 20, adjacent to or incorporated into an operator interface station (e.g., a touchscreen). In other embodiments, the controller 18 and operator interface station may be associated with the generally horizontal portion 22 or may be incorporated into a separate device that is connected (either physically, by a cable or the like, or wirelessly) to the fluid processing device 10.

[0045]The controller 18 is configured and/or programmed to execute at least one fluid processing procedure but, more advantageously, is configured and/or programmed to execute a variety of different fluid processing procedures. For example, the controller 18 may be configured and/or programmed to carry out one or more of the following: a double unit red blood cell collection procedure, a plasma collection procedure, a plasma/red blood cell collection procedure, a red blood cell/platelet/plasma collection procedure, a platelet collection procedure, and a platelet/plasma collection procedure.

[0046]More particularly, in carrying out these fluid processing procedures, the controller 18 is configured and/or programmed to control one or more of the following tasks: drawing fluid into a fluid flow circuit 12 mounted to the fluid processing device 10, conveying fluid through the fluid flow circuit 12 to a location for separation (i.e., into a spinning membrane separator 26 or centrifugal separation chamber 36 of the fluid flow circuit 12), separating the fluid into two or more components as desired, and conveying the separated components into storage containers, to a second location for further separation (e.g., into whichever of the spinning membrane separator 26 and centrifugal separation chamber 36 that was not used in the initial separation stage), or to a recipient (which may be a source from which the fluid was originally drawn).

[0047]This may include instructing the spinning membrane separator drive unit 14 and/or the centrifugal separator 16 to operate at a particular rotational speed and instructing a pump P1-P6 to apply a particular (positive or negative) pressure to a flexible membrane or diaphragm 64 of an associated pump chamber T1-T6 of the cassette 48 for a particular duration to convey fluid through a portion of the fluid flow circuit 12 at a particular flow rate. Hence, while it may be described herein that a particular component of the fluid processing device 10 (e.g., the spinning membrane separator drive unit 14 or the centrifugal separator 16) performs a particular function, it should be understood that that component is being controlled by the controller 18 to perform that function.

[0048]Before, during, and after a procedure, the controller 18 may receive signals from various components of the fluid processing device 10 (e.g., the pressure sensors A1-A4) to monitor various aspects of the operation of the fluid processing device 10 and characteristics of the fluid and separated fluid components as they flow through the fluid flow circuit 12. If the operation of any of the components and/or one or more characteristics of the fluid or separated fluid components is outside of an acceptable range, then the controller 18 may initiate an alarm or error condition to alert the operator and/or take action to attempt to correct the condition. The appropriate corrective action will depend upon the particular error condition and may include action that is carried out with or without the involvement of an operator.

[0049]For example, the controller 18 may include an interface control module, which receives signals from the light detector 52 of the interface monitoring system.

[0050]The signals that the controller 18 receives from the light detector 52 are indicative of the location of an interface between the separated fluid components within the centrifugal separation chamber 36. If the controller 18 determines that the interface is in the wrong location, then it can issue commands to the appropriate components of the fluid processing device 10 to modify their operation so as to move the interface to the proper location. For example, the controller 18 may instruct one of the pumps P1-P6 to cause fluid to flow into the centrifugal separation chamber 36 at a different rate and/or for a separated fluid component to be removed from the centrifugal separation chamber 36 at a different rate and/or for the centrifugal separation chamber 36 to be spun at a different speed by the centrifugal separator 16.

[0051]If provided, an operator interface station associated with the controller 18 allows the operator to view on a screen or display (in alpha-numeric format and/or as graphical images) information regarding the operation of the system. The operator interface station also allows the operator to select applications to be executed by the controller 18, as well as to change certain functions and performance criteria of the system. If configured as a touchscreen, the screen of the operator interface station can receive input from an operator via touch-activation. Otherwise, if the screen is not a touchscreen, then the operator interface station may receive input from an operator via a separate input device, such as a computer mouse or keyboard. It is also within the scope of the present disclosure for the operator interface station to receive input from both a touchscreen and a separate input device, such as a keypad.

II. The Disposable Fluid Flow Circuit

[0052]As for the fluid flow circuit or flow set 12 (FIG. 2), it is intended to be a sterile, single use, disposable item. Before beginning a given fluid processing procedure, the operator mounts various components of the fluid flow circuit 12 to the case 20 in association with the fluid processing device 10. The controller 18 implements the procedure based upon preset protocols, taking into account other input from the operator. Upon completing the procedure, the operator removes the fluid flow circuit 12 from association with the fluid processing device 10. The portions of the fluid flow circuit 12 holding the collected fluid component or components (e.g., collection containers or bags) are removed from the case 20 and retained for storage, transfusion, or further processing. The remainder of the fluid flow circuit 12 is removed from the case 20 and discarded.

[0053]In the illustrated embodiment, the fluid flow circuit 12 includes a cassette 48 (FIG. 3), to which the other components of the fluid flow circuit 12 are connected by flexible tubing. The other components may include a plurality of fluid containers F1-F7. In the context of the present disclosure, these containers include an anticoagulant container F1, a saline container F2, an in-process container F3, a return container F4, a plasma collection container F5, a platelet collection container F6, and an (optional) additive container F7. The illustrated flow circuit 12 further includes one or more fluid source access devices (e.g., a connector for accessing blood within a fluid container or a phlebotomy needle), a spinning membrane separator 26 and a centrifugal separation chamber 36.

[0054]The flow control cassette 48 provides a centralized, programmable, integrated platform for all the pumping and many of the valving functions required for a given fluid processing procedure. In one embodiment, the cassette 48 is similarly configured to the cassette of U.S. Patent Application Publication No. 2006/0161092, but is adapted to include the various stations and flow paths required to carry out the fluid processing procedures implemented by the fluid processing system.

[0055]In use, the cassette 48 is mounted to the cassette station 54 of the fluid processing device 10, with a flexible membrane or diaphragm 64 of the cassette 48 placed into contact with the cassette station 54. The flexible diaphragm 64 overlays an array of interior cavities formed by the body of the cassette 48. The different interior cavities define sensor stations S1-S4, valve stations C1-C9, pump stations T1-T6, and a plurality of flow paths. The side of the cassette 48 opposite the flexible diaphragm 64 may be sealed by another flexible diaphragm or by a rigid cover, thereby sealing fluid flow through the cassette 48 from the outside environment.

[0056]Each sensor station S1-S4 is aligned with an associated pressure sensor A1-A4 of the cassette station 54, with each pressure sensor A1-A4 being capable of monitoring the pressure within the associated sensor station S1-S4. Each valve station C1-C9 is aligned with an associated valve V1-V9 and may define one or more ports that allow for fluid communication between the valve station C1-C9 and another interior cavity of the cassette 48 (e.g., a flow path). As described above, each valve V1-V9 is movable under command of the controller 18 to move between a plurality of positions (e.g., between a retracted or lowered position and an actuated or raised position) to selectively contact the valve stations C1-C9 of the cassette 48. In the actuated position, a valve V1-V9 engages the associated valve station C1-C9 to close one or more of its ports to prevent fluid flow therethrough. In the retracted position, a valve V1-V9 is disengaged from the associated valve station C1-C9 (or less forcefully contacts the associated valve station C1-C9 than when in the actuated position) to open one or more ports associated with the valve station C1-C9, thereby allowing fluid flow therethrough.

[0057]As described above, the cassette 48 defines a plurality of pump chambers T1-T6, with each pump chamber interacting with a different one of the pneumatic pumps P1-P6 of the cassette station 54 of the fluid processing device 10. The different pumps P1-P6 may interact with the pump stations T1-T6 of the cassette 48 to perform different tasks during a procedure, but in the context of the present disclosure, a different one of the pumps P1-P6 may be configured to serve as an anticoagulant pump P1, a source pump P2, a centrifuge pump P3, an outlet pump P4, a recirculation pump P5, and a plasma pump P6.

[0058]Various lengths of tubing extend from the side surface of the cassette 48 to connect to the other components of the fluid flow circuit 12, such as the various fluid containers F1-F7, the spinning membrane separator 26, and the centrifugal separation chamber 36. The tubing connected to the centrifugal separator chamber 36 (which includes one inlet tube and two outlet tubes) may be aggregated into an umbilicus.

[0059]Various additional components may be incorporated into the tubing leading out of the cassette 48 or into one of the cavities of the cassette 48. For example, as shown in FIG. 2, a manual clamp 56 may be associated with a line or lines leading to the fluid source, a return line filter 58 (e.g., a microaggregate filter) may be associated with a line leading to a fluid recipient, and/or an air trap 62 may be positioned on a line upstream of the centrifugal separation chamber 36.

III. Exemplary Fluid Processing Procedure

[0060]An exemplary fluid processing procedure according to the present disclosure will now be described. In the exemplary procedure, blood is separated via centrifugation into packed red blood cells and platelet-rich plasma, with a portion of the platelet-rich plasma being recirculated back through a centrifugal separation chamber and another portion being separated into platelet concentrate and platelet-poor plasma until a target volume of platelets has been collected. It should be understood that the below-described procedure is merely exemplary and that the principles described herein may be practiced in combination with other fluid processing procedures (e.g., procedures in which platelet-poor plasma is recirculated through a centrifugal separation chamber during blood separation) without departing from the scope of the present disclosure.

[0061]Prior to processing, an operator selects the desired protocol (e.g., using an operator interface station, if provided), which informs the controller 18 of the manner in which it is to control the other components of the fluid processing device 10 during the procedure. This may include first selecting one of a plurality of possible procedures that the system is capable of executing and then, after selecting the nature of the procedure, selecting one or more parameters to be in effect during the procedure. For example, this may include selecting a platelet collection procedure from among a variety of blood separation procedures and then selecting a total volume of blood to be processed or a target volume of platelets to be collected during the procedure. If the fluid source is a living source (e.g., a donor or patient), the operator may proceed to enter various parameters, such as the sex/height/weight of the source. In one embodiment, the operator may also enter one or more characteristics of the fluid to be processed, such as a platelet pre-count.

[0062]If there are any fluid containers (e.g., a platelet additive solution container) that are not integrally formed with the fluid flow circuit 12, they may be connected to the fluid flow circuit 12 (e.g., by piercing a septum of a tube of the fluid flow circuit 12 or via a luer connector), with the fluid flow circuit 12 then being mounted to the fluid processing device 10 (including the fluid containers F1-F7 being associated with the volume measurement systems W1-W6, as appropriate). In one exemplary embodiment, each volume measurement system W1-W6 includes a weight scale associated with a hook from which a fluid container may be hung. In another exemplary embodiment, at least one of the volume measurement systems W1-W6 includes a weight scale associated with a horizontal platform or surface, with a container being placed onto the platform or surface for support while the weight scale sends signals indicative of the weight of the container (and its contents) to be sent to the controller 18 throughout the course of a procedure. In other embodiments, a fluid container may be associated with a volume measurement system omitting a weight scale, but including other means for measuring the volume of fluid within the container (e.g., one or more sensors).

[0063]An integrity check of the fluid flow circuit 12 may be executed by the controller 18 to ensure that the various components are properly connected and functioning. Following a successful integrity check, the fluid source is connected to the fluid flow circuit 12 (e.g., by connecting to a container of previously collected fluid or by phlebotomizing a donor), and the fluid flow circuit 12 may be primed (e.g., using saline pumped from a saline container F2 by operation of one or more of the pumps P1-P6 of the fluid processing device 10).

[0064]After the fluid flow circuit 12 has been primed, fluid processing may begin. In a first phase of an exemplary platelet collection procedure (FIG. 5), blood is drawn into the fluid flow circuit 12 from a blood source. If the blood source is a donor, then blood may be drawn into the fluid flow circuit 12 through a single needle that is connected to the cassette by line L1. Line L1 may include a manual clamp 56 that may initially be in a closed position to prevent fluid flow through line L1. When processing is to begin, an operator may move the manual clamp 56 from its closed position to an open position to allow fluid flow through line L1.

[0065]The blood is drawn into line L1 by the source pump P2 of the fluid processing device 10. Anticoagulant from the anticoagulant container F1 may be drawn through line L2 under action of the anticoagulant pump P1 and added to the blood at a junction of lines L1 and L2.

[0066]In the illustrated embodiment, valve V10 is open to allow anticoagulated blood to flow through line L3 and a cassette sensor station associated with pressure sensor A1, while valve V11 is closed to prevent fluid flow through line L4. If the blood source is a living body (e.g., a donor), the pressure sensor A1 may communicate with the controller 18 to monitor the pressure within the vein of the blood source.

[0067]The cassette includes two valve stations downstream of the source pump P2, with valve V2 being closed to prevent flow through line L5 and valve V1 being open to allow flow through line L6. A portion of the blood is directed through line L7 and a cassette sensor station associated with pressure sensor A3 to the in-process container F3 and the remainder is directed through line L8 toward the centrifuge pump P3, which controls the amount of blood that is directed to the centrifugal separation chamber 36 instead of the in-process container F3. In particular, the flow rate of the source pump P2 is greater than the flow rate of the centrifuge pump P3, with the difference therebetween being equal to the flow rate of blood into the in-process container F3. The flow rates may be selected such that the in-process container F3 is partially or entirely filled with blood at the end of the draw phase.

[0068]The blood pumped through line L8 by the centrifuge pump P3 passes through line L9, an air trap 62, and a cassette sensor station associated with pressure sensor A2 (which works in combination with the controller 18 of the fluid processing device 10 to monitor the pressure in the centrifugal separation chamber 36) before reaching the centrifugal separation chamber 36 of the fluid flow circuit 12. The centrifugal separator 16 of the fluid processing device 10 manipulates the centrifugal separation chamber 36 to separate the blood in the centrifugal separation chamber 36 into platelet-rich plasma and packed red blood cells. In one embodiment, the centrifugal separation chamber 36 is rotated nominally at 4,500 rpm, but the particular rotational speed may vary depending on the flow rates of fluids into and out of the centrifugal separation chamber 36.

[0069]The packed red blood cells exit the centrifugal separation chamber 36 via line L10 and flow through line L11 into the return container F4. Platelet-rich plasma is drawn out of the centrifugal separation chamber 36 via line L12 by the combined operation of the recirculation and outlet pumps P5 and P4 of the fluid processing device 10. The platelet-rich plasma travels through line L12 until it reaches a junction, which splits into lines L13 and L14. The recirculation pump P5 is associated with line L13 and redirects a portion of the platelet-rich plasma to a junction, where it mixes with blood in line L8 that is being conveyed into the centrifugal separation chamber 36 by the centrifuge pump P3. Recirculating a portion of the platelet-rich plasma into the centrifugal separation chamber 36 with inflowing blood decreases the hematocrit of the blood entering the centrifugal separation chamber 36, which may improve separation efficiency. By such an arrangement, the flow rate of the fluid entering the centrifugal separation chamber 36 is equal to the sum of the flow rates of the centrifuge pump P3 and the recirculation pump P5. As the platelet-rich plasma drawn out of the centrifugal separation chamber 36 into line L13 by the recirculation pump P5 is immediately added back into the centrifugal separation chamber 36, the bulk or net platelet-rich plasma flow rate out of the centrifugal separation chamber 36 is equal to the flow rate of the outlet pump P4.

[0070]Line L14 ends at a junction, where it joins with lines L15 and L16. Valve V6 is closed to prevent fluid flow through line L16, thereby directing the separated platelet-rich plasma to the spinning membrane separator 26 via line L15. Before reaching the spinning membrane separator 26, the portion of the platelet-rich plasma conveyed through line L15 passes the spinner inlet sensor M1 and a cassette sensor station associated with pressure sensor A4. The spinner inlet sensor M1 may detect the concentration of platelets in the platelet-rich plasma entering the spinning membrane separator 26, while the pressure sensor A4 may monitor the pressure of the spinning membrane separator 26.

[0071]While valve V6 is shown in FIG. 5 as being closed, it may be selectively opened to divert all or a portion of the platelet-rich plasma from line L14 into and through line L16 and to the return container F4, if necessary. An example would be at the start of a procedure when separation is initializing and platelets are not yet exiting the centrifugal separation chamber 36, in which case the fluid conveyed through line L14 by the outlet pump P4 could be diverted to the return container F4.

[0072]The spinning membrane separator drive unit 14 of the fluid processing device 10 manipulates the spinning membrane separator 26 to separate the platelet-rich plasma into platelet-poor plasma (“plasma”) and platelet concentrate (“platelets”). Plasma is pumped out of the spinning membrane separator 26 via line L17 by the plasma pump P6 of the fluid processing device 10. Valves V5, V6, V8, and V9 are closed to direct the separated plasma along line L18, through valve V4, and into the return container F4 (with the separated red blood cells). On the way to the return container F4, the plasma passes through spinner outlet sensor M2, which may cooperate with the controller 18 to determine one or more characteristics of the plasma, such as the amount of cellular blood components in the plasma and/or whether the plasma is hemolytic and/or lipemic.

[0073]The platelet concentrate is conveyed out of the spinning membrane separator 26 via line L19. There is no pump associated with line L19, so instead the flow rate at which the platelets exit the spinning membrane separator 26 is equal to the difference between the flow rates of the outlet pump P4 and plasma pump P6. Valve V8 is closed to prevent fluid flow through the line L20, thereby directing the flow of platelets along line L19, through valve V7, and into the platelet collection container F6. Valve V8 may be selectively opened to allow fluid flow through line L20 and to a junction, where it joins the plasma flowing through line L18 to the return container F4, if necessary.

[0074]Depending on the volume of platelets to be collected, the draw stage of FIG. 5 may be repeated, with draw stages being alternated with return stages in which blood from the in-process container F3 is separated in the centrifugal separation chamber 36 while previously collected blood components in the return container F4 are returned to the blood source. During such return stages, the separated red blood cells and platelet-rich plasma may be variously routed through the fluid flow circuit 12, typically with an additional volume of platelets being collected in the platelet collection container F6 after being separated from platelet-poor plasma in the spinning membrane separator 26 (as during the draw stage of FIG. 5). A platelet additive solution from the additive container F7 may be added to the collected platelets in the platelet collection container F6 before ending the procedure.

IV. Pump Control

[0075]As described above, in the illustrated embodiment, the pumps P1-P6 are configured as pneumatic pumps, with an actuator of each pump P1-P6 being selectively controlled by the controller 18 to alternately apply positive and negative pressures to a flexible membrane or diaphragm 64 of a different pump chamber T1-T6 defined by the flow control cassette 48 to cause fluid (which may be either an intact fluid, such as whole blood, or a separated fluid component, such as platelet-poor plasma) to flow through a portion of the fluid flow circuit 12. More particularly, a pump P1-P6 is actuated by the controller 18 to apply a vacuum or negative pressure to the flexible diaphragm 64 overlaying an associated pump chamber T1-T6 in order to draw fluid from an adjacent cavity of the cassette 48 (e.g., an upstream fluid flow path) into the pump chamber T1-T6 and is then actuated by the controller 18 to apply a positive pressure to the flexible diaphragm 64 in order to convey fluid from the pump chamber T1-T6 to an adjacent cavity of the cassette 48 (e.g., a downstream fluid flow path).

[0076]When no pressure is being applied to the diaphragm 64 by a pump P1-P6, the diaphragm 64 will tend to lay substantially flat over the pump chamber T1-T6 that is aligned with the pump P1-P6, which corresponds to a horizontal arrangement in the orientation of FIG. 4. When a vacuum or negative pressure is applied to the diaphragm 64 by one of the pumps P1-P6, the diaphragm 64 is pulled away from the pump chamber T1-T6 aligned with the pump P1-P6 (to the “inflow” state shown in FIG. 4 in solid lines), which draws fluid into the pump chamber T1-T6. When a positive pressure is applied to the diaphragm 64 by one of the pumps P1-P6, the diaphragm 64 is advanced into the pump chamber T1-T6 aligned with the pump P1-P6 (to the “outflow” state shown in broken lines in FIG. 4), which conveys fluid out of the pump chamber T1-T6.

[0077]When the pump system is operating as intended, applying a vacuum or negative pressure to the region of the diaphragm 64 overlaying a pump chamber T1-T6 for a predetermined amount of time (which amount of time is referred to herein as an “inflow duration”) will result in a complete fill of that pump chamber T1-T6. As used herein, the term “complete fill” refers to a target volume of a fluid having been drawn into a pump chamber T1-T6 by application of a vacuum or negative pressure for a predetermined amount of time (which amount of time is referred to herein as an “inflow duration” and corresponds to the time required to complete one suction stroke). In one embodiment, the target volume drawn into the pump chamber T1-T6 in a “complete fill” may correspond to a particular percentage of the volume defined by the pump chamber T1-T6 (e.g., with a “complete fill” being achieved when a volume of fluid corresponding to at least 95% of the volume of the pump chamber T1-T6 has been drawn into the pump chamber T1-T6), with the exact target volume depending on any of a number of factors, including the configuration of the pump chamber T1-T6 and the magnitude of the vacuum or negative pressure being applied to the portion of the diaphragm 64 overlaying the pump chamber T1-T6.

[0078]Similarly, when the pump system is operating as intended, applying a positive pressure to the region of the diaphragm 64 overlaying a pump chamber T1-T6 for a predetermined amount of time (which amount of time is referred to herein as an “outflow duration” and corresponds to the time required to complete one delivery stroke) will result in a complete empty of that pump chamber T1-T6. As used herein, the term “complete empty” refers to a target volume of a fluid having been conveyed out of a pump chamber T1-T6 by (or a target volume of fluid remaining within the pump chamber T1-T6 after) application of a positive pressure to the region of the diaphragm 64 overlaying the pump chamber T1-T6 for a predetermined amount of time (which amount of time is referred to herein as an “outflow duration”). In one embodiment, the target volume of fluid that is removed from the pump chamber T1-T6 in a “complete empty” may correspond to the volume of fluid contained within the pump chamber T1-T6 immediately prior to positive pressure being applied to the diaphragm 64, with a “complete empty” being achieved when all of the fluid in the pump chamber T1-T6 has been conveyed out of the pump chamber T1-T6, leaving the pump chamber T1-T6 completely empty of the fluid. In other embodiments, a “complete empty” may be considered to have been achieved when no more than a certain volume of fluid remains within the pump chamber T1-T6 after application of positive pressure to the diaphragm 64 for the outflow duration.

[0079]When there is a flow restriction present, application of a vacuum or negative pressure having a certain strength to the region of the diaphragm 64 overlaying a particular pump chamber T1-T6 for the inflow duration may not result in a complete fill of that pump chamber T1-T6 when a vacuum or negative pressure having that strength should otherwise result in a complete fill. In such a situation, less fluid will be drawn into the pump chamber T1-T6 than would be expected for the vacuum or negative pressure being applied during the inflow duration. Similarly, when a pump flow restriction is present, application of a positive pressure having a certain strength to the region of the diaphragm 64 overlaying a particular pump chamber T1-T6 for the outflow duration may not result in a complete empty of that pump chamber T1-T6 when a positive pressure having that strength should otherwise result in a complete empty. In such a situation, less fluid will be conveyed out of the pump chamber T1-T6 than would be expected for the positive pressure being applied during the outflow duration.

[0080]According to an aspect of the present disclosure, the controller 18 is programmed to determine whether a complete fill has been achieved by application of a vacuum or negative pressure to the region of the diaphragm 64 overlaying a particular pump chamber T1-T6 for the inflow duration and to determine whether a complete empty has been achieved by application of a positive pressure to the region of the diaphragm 64 overlaying a particular pump chamber T1-T6 for the outflow duration. While it may be advantageous for the controller 18 to be programmed to assess both a complete fill and a complete empty (and to adjust operation of the pump system in response to an incomplete fill and/or an incomplete empty, as will be described in greater detail), it is within the scope of the present disclosure for the controller 18 to be programmed to assess only one of a complete fill and a complete empty (and to adjust operation of the pump system in response to a failure to achieve whichever condition that the controller 18 is programmed to monitor).

[0081]The controller 18 may assess a complete fill and/or a complete empty of a pump chamber T1-T6 by acting in combination with an electrode 66 of the pump chamber T1-T6 and a capacitive sensor 68 of the cassette station 54 (along with a current source 70 of the fluid processing device 10 that supplies current to the electrode 66). As shown in FIG. 4, the electrode 66 is at least partially positioned within the pump chamber T1-T6 so as to allow the electrode 66 to come into contact with a fluid positioned within the pump chamber T1-T6. The electrode 66 is configured and oriented to be electrically coupled to an associated capacitive sensor 68 when the flow control cassette 48 is mounted to the cassette station 54, with the capacitive sensor 68 being operatively coupled to the controller 18. The particular configurations of the electrode 66 and the capacitive sensor 68 may vary without departing from the scope of the present disclosure (provided that each is suitably configured to work in combination with the other), with each electrode 66 and each capacitive sensor 68 being conventionally configured in one exemplary embodiment.

[0082]The electrode 66 and the capacitive sensor 68 may operate in a conventional fashion (e.g., as described in U.S. Patent Application Publication No. 2006/0161092), with the passage of current through each electrode 66 creating an electrical field within the associate pump chamber T1-T6. The alternating deflection of the region of the diaphragm 64 overlaying the pump chamber T1-T6 to draw fluid into and expel fluid from the pump chamber T1-T6 changes the electrical field, resulting in a change in total capacitance of the circuit through the electrode 66. In particular, capacitance increases as fluid is draw into the pump chamber T1-T6, while capacitance decreases as fluid is expelled from the pump chamber T1-T6.

[0083]Signals transmitted from each capacitive sensor 68 to the controller 18 reflect the capacitance for the associated electrode 66 and, thus, the volume of fluid contained within the pump chamber T1-T6 associated with that electrode 66 at the time that the signal was transmitted. Signals transmitted from a capacitive sensor 68 to the controller 18 at times that reflect the volume of fluid within an associated pump chamber T1-T6 after application of a vacuum or negative pressure to the region of the diaphragm 64 overlaying the pump chamber T1-T6 for the inflow duration are referred to herein as “inflow signals. ” Similarly, signals transmitted from a capacitive sensor 68 to the controller 18 at times that reflect the volume of fluid remaining within an associated pump chamber T1-T6 after application of a positive pressure to the region of the diaphragm 64 overlaying the pump chamber T1-T6 for the outflow duration are referred to herein as “outflow signals.” A capacitance signal will have a relatively high signal magnitude or voltage when the monitored pump chamber T1-T6 is filled with fluid (with the diaphragm 64 being in the state or position shown in solid lines in FIG. 4) and a relatively low signal magnitude or voltage when the monitored pump chamber T1-T6 is empty of fluid (with the diaphragm 64 being in the state or position shown in broken lines in FIG. 4), with there being a range of intermediate signal magnitudes or voltages when an intermediate volume of fluid is present within the monitored pump chamber T1-T6 (with the diaphragm 64 occupying a position between the two positions illustrated in FIG. 4).

[0084]Thus, an inflow signal having a maximum magnitude or voltage will be indicative of a complete fill and allow the controller 18 to determine that a complete fill has been achieved, while an inflow signal having a lower magnitude or voltage will be indicative of an incomplete fill and allow the controller 18 to determine that a complete fill has not been achieved. Similarly, an outflow signal having a minimum magnitude or voltage (possibly including a voltage or magnitude of zero) will be indicative of a complete empty and allow the controller 18 to determine that a complete empty has been achieved, while an outflow signal having a greater magnitude or voltage will be indicative of an incomplete empty and allow the controller 18 to determine that a complete empty has not been achieved.

[0085]When an inflow signal indicates that a complete fill has not been achieved by application of a vacuum or negative pressure having a particular strength for the inflow duration, the controller 18 may calculate a vacuum or negative pressure strength (which will be greater than the vacuum or negative pressure most recently applied) that would need to be applied for the same inflow duration in order to achieve a complete fill. The controller 18 may calculate such an adjusted vacuum or negative pressure strength according to any suitable approach without departing from the scope of the present disclosure. Similarly, when an outflow signal indicates that a complete empty has not been achieved by application of a positive pressure having a particular strength for the outflow duration, the controller 18 may calculate a positive pressure strength (which will be greater than the positive pressure most recently applied) that would need to be applied for the same outflow duration in order to achieve a complete empty. The controller 18 may calculate such an adjusted positive pressure strength according to any suitable approach without departing from the scope of the present disclosure.

[0086]According to one embodiment of the present disclosure, the controller 18 is programmed to implement a protocol that is calculated to dynamically determine and then apply the minimum (or weakest) vacuum or negative pressure that is capable of achieving a complete fill of a pump chamber T1-T6 when that vacuum or negative pressure is applied for a fixed or constant inflow duration (which protocol may be referred to herein as an “inflow protocol”). According to another embodiment of the present disclosure, the controller 18 is programmed to implement a protocol that is calculated to dynamically determine and then apply the minimum (or weakest) positive pressure that is capable of achieving a complete empty of a pump chamber T1-T6 when that positive pressure is applied for a fixed or constant outflow duration (which protocol may be referred to herein as an “outflow protocol”). According to yet another embodiment of the present disclosure, the controller 18 is programmed to implement both an inflow protocol and an outflow protocol.

[0087]Before considering particular inflow and outflow protocols, it should be understood that a fluid processing procedure may include a particular pump P1-P6 and associated pump chamber T1-T6 being used to pump different fluids during different stages of the procedure. For example, in an exemplary blood separation procedure, a given pump/pump chamber pair may be used for the flow of saline during a priming stage of the procedure, for the flow of whole blood during a blood separation stage of the procedure, and for the flow of a blood component storage solution during a post-separation stage of the procedure. Different fluids may require different pumping pressures, such that an inflow and/or outflow protocol executed for a particular pump/pump chamber pair while pumping saline may not be applicable when the same pump/pump chamber pair is later used during the same procedure to pump whole blood. Thus, it should be understood that the controller 18 may execute an inflow and/or outflow protocol multiple times for a given pump/pump chamber pair during a fluid processing procedure, with a new inflow and/or outflow protocol being initiated for each fluid being pumped using that pump/pump chamber pair. Accordingly, as used herein, the term “fluid flow procedure” should be understood as referring to a particular fluid being pumped using a given pump/pump chamber pair, with a new “fluid flow procedure” (and inflow and/or outflow protocol) beginning when a different fluid is being pumped using that same pump/pump chamber pair. Indeed, multiple inflow and/or outflow protocols may be implemented for a given pump/pump chamber pair during a multi-stage fluid processing procedure, with each inflow protocol having the same or different settings (e.g., different pumping pressure levels) and with each outflow protocol having the same or different settings.

[0088]Turning now to an inflow protocol, in one embodiment, it begins with the controller 18 actuating a pump P1-P6 to apply an initial vacuum or negative pressure to a region of a diaphragm 64 overlaying a pump chamber T1-T6 aligned with the pump P1-P6 for an inflow duration when first applying a vacuum or negative pressure to that region of the diaphragm 64 during a fluid flow procedure. The initial vacuum or negative pressure is selected to be a minimum or weakest vacuum or negative pressure at which a complete fill of the pump chamber T1-T6 is expected to be achieved when that vacuum or negative pressure has been applied to that region of the diaphragm 64 for the inflow duration and assumes there to be no flow restriction that would affect the ability of the pump system to achieve a compete fill. The strength or magnitude of the initial vacuum or negative pressure may be empirically or theoretically calculated according to any suitable approach without departing from the scope of the present disclosure and may vary from system to system and from procedure to procedure for a given system.

[0089]After the fluid flow procedure has begun and the pump system has been actuated to apply the initial vacuum or negative pressure to the diaphragm 64 for the inflow duration, the capacitive sensor 68 will transmit an inflow signal to the controller 18, with the controller 18 assessing the inflow signal to determine whether a complete fill has been achieved, as described above. When the controller 18 determines that a complete fill has not been achieved, it may then actuate the pump system to apply a second or increased vacuum or negative pressure (which is stronger than the initial vacuum or negative pressure) to the same region of the diaphragm 64 for the same inflow duration when next applying a vacuum or negative pressure to that region of the diaphragm 64. The magnitude of the increase in strength of the vacuum or negative pressure may vary without departing from the scope of the present disclosure. For example, in one embodiment, the controller 18 may be programmed to increase the strength of the applied vacuum or negative pressure by a predetermined increment. In another embodiment, the controller 18 may instead be programmed to calculate a vacuum or negative pressure strength that would need to be applied for the same inflow duration in order to achieve a complete fill (as described above) and then actuate the pump system to apply an increased vacuum or negative pressure having that strength for the same inflow duration when next applying a vacuum or negative pressure to the same region of the diaphragm 64.

[0090]Once the second or increased vacuum or negative pressure has been applied to the same region of the diaphragm 64 for the same inflow duration, the controller 18 will assess the inflow signal from the capacitive sensor 68 to determine whether application of the second or increased vacuum or negative pressure has been successful in achieving a complete fill. If not, the controller 18 may proceed to repeat the alternating steps of actuating the pump system to apply a further increased vacuum or negative pressure (that is greater or stronger than the most recently applied vacuum or negative pressure) to the same region of the diaphragm 64 for the same inflow duration and analyzing the inflow signal resulting from the application of that vacuum or negative pressure to determine whether a complete fill has been achieved, with the steps being repeated until the controller 18 receives an inflow signal indicating that a complete fill has been achieved. In one embodiment, the controller 18 may be programmed with a maximum vacuum or negative pressure that can be applied to a region of the diaphragm 64 by the pump system (which may be the maximum vacuum or negative pressure that the pump system is capable of generating or may be some lesser value). In such an embodiment, if the controller 18 determines that the inflow signal indicates that application of a vacuum or negative pressure having a greater strength than the maximum value is required, the controller 18 may generate an alert or alarm and (rather than implementing the change in applied pressure indicated by the inflow signal) either pause the procedure or change the applied vacuum or negative pressure to the designated maximum value.

[0091]When the controller 18 determines that a complete fill has been achieved (whether by use of the initial vacuum or negative pressure or the second vacuum or negative pressure or some other increased vacuum or negative pressure), the controller 18 may continue controlling the pump system to apply the same vacuum or negative pressure to the same region of the diaphragm 64 for the same inflow duration when next applying a vacuum or negative pressure to that region of the diaphragm 64.

[0092]According to such an approach, the controller 18 may continue controlling the pump system to apply the same vacuum or negative pressure to the same region of the diaphragm 64 for the same inflow duration whenever subsequently applying a vacuum or negative pressure to that region of the diaphragm 64 for the remainder of the fluid flow procedure, provided that inflow signals from the capacitive sensor 68 continue to indicate that complete fills are being achieved. If an inflow signal were to indicate that a complete fill has not been achieved (e.g., if a flow restriction has arisen), the controller 18 may proceed according to the above-described approach to increasing the strength of the applied vacuum or negative pressure until receiving a signal indicating that a complete fill has been achieved.

[0093]Alternatively, rather than applying the same vacuum or negative pressure for the remainder of the fluid flow procedure, the controller 18 may instead continue controlling the pump system to apply the most recently applied vacuum or negative pressure to the same region of the diaphragm 64 for the same inflow duration whenever subsequently applying a vacuum or negative pressure to that region of the diaphragm 64 for only a predetermined amount of time or predetermined volume of fluid pumped (provided that inflow signals from the capacitive sensor 68 continue to indicate that complete fills are being achieved). Once that predetermined amount of time or predetermined volume of fluid pumped has been completed, the controller 18 may actuate the pump system to apply a decreased vacuum or negative pressure (which is weaker than the vacuum or negative pressure most recently applied) to the same region of the diaphragm 64 for the same inflow duration when next applying a vacuum or negative pressure to that region of the diaphragm 64. This may be understood as an attempt to determine whether a weaker vacuum or negative pressure may be capable of achieving a complete fill, which may be possible if a previous flow restriction has been resolved. If the controller 18 is programmed to implement a predetermined amount of time or a predetermined volume of fluid pumped, that value may remain the same for an entire fluid flow procedure or may be changed during a fluid flow procedure, with any change either being pre-programmed into the controller 18 or with the controller 18 being programmed to determine the nature of the change to be made (which may be based on any possible factors without departing from the scope of the present disclosure).

[0094]Once the decreased vacuum or negative pressure has been applied, the controller 18 the capacitive sensor 68 will transmit an inflow signal to the controller 18, with the controller 18 assessing the inflow signal to determine whether a complete fill has been achieved using the decreased vacuum or negative pressure. When the controller 18 determines that a complete fill has been achieved, the controller 18 may continue actuating the pump system to apply the same decreased vacuum or negative pressure to the same region of the diaphragm 64 for the same inflow duration when next applying a vacuum or negative pressure to that region of the diaphragm 64 for the remainder of the fluid flow procedure or for a predetermined time period (as described above). Alternatively, as long as inflow signals from the capacitive sensor 68 continue being indicative of complete fills, the controller 18 may proceed to actuate the pump system to apply further decreased vacuum or negative pressure to the same region of the diaphragm 64 for the same inflow duration.

[0095]However, once the controller 18 receives an inflow signal indicating that a complete fill has not been achieved using a decreased vacuum or negative pressure, it may then actuate the pump system to apply an increased vacuum or negative pressure (which is stronger than the vacuum or negative pressure most recently applied) to the same region of the diaphragm 64 for the same inflow duration, with the strength of the vacuum or negative pressure being increased (according to the above-described approach) until the controller 18 receives an inflow signal that is indicative of a complete fill. By implementing such a protocol, the controller 18 is able to dynamically determine the minimum or weakest vacuum or negative pressure that may be applied in order to achieve a complete fill.

[0096]According to another alternative response to detection of a complete fill, rather than continuing to apply the most recently applied vacuum or negative pressure for the same inflow duration when subsequently applying a vacuum or negative pressure to the same region of the diaphragm 64 for a predetermined time period or predetermined volume of fluid pumped, the controller 18 may be programmed to instead immediately control the pump system to apply a decreased vacuum or negative pressure for the same duration when next applying a vacuum or negative pressure to the same region of the diaphragm 64. Such an approach may be understood as being a more aggressive attempt to determine whether application of the decreased vacuum or negative pressure would be sufficient to achieve a complete fill. If fluid flow stability is prioritized, it may be preferred to maintain the applied vacuum or negative pressure at the same level for a predetermined amount of time or a predetermined volume of fluid pumped before decreasing it, whereas it may be preferred to immediately decrease the applied vacuum or negative pressure if it is instead a priority to determine the weakest vacuum or negative pressure that may be applied to achieve a complete fill.

[0097]If the inflow protocol does include vacuum or negative pressure strength being decreased sometime after a complete fill has been achieved, such a step may be executed by the controller 18 continuously throughout a fluid flow procedure. Alternatively, the controller 18 may be programmed to execute such a step a predetermined number of times during a fluid flow procedure (e.g., on a periodic or rolling basis throughout a procedure), including being done only once. In one embodiment, the controller 18 may be programmed to execute such a step one time for each fluid that is pumped using a particular pump P1-P6 and associated pump chamber T1-T6 during a multi-stage fluid processing procedure, such as the step being executed once for the flow of saline during a priming stage of the procedure, once for the flow of whole blood during a blood separation stage of the procedure, and once for the flow of a blood component storage solution during a post-separation stage of the procedure. As explained above, the pumping of each different fluid by a particular pump/pump chamber pair may be understood as the execution of a different “fluid flow procedure” (each with its own inflow protocol being implemented), such that this approach may be understood as the step being executed once for each fluid flow procedure of the multi-stage fluid processing procedure.

[0098]Regardless of how exactly the inflow protocol is implemented, it will be seen that the overall effect is for the controller 18 to start by actuating the pump system to apply a relatively weak vacuum or negative pressure to a region of the diaphragm 64 (though one that is calculated to achieve a complete fill of a pump chamber T1-T6 aligned with that region of the diaphragm 64), with the controller 18 dynamically determining whether a complete fill has been achieved and dynamically adjusting the strength of the applied vacuum or negative pressure (without changing the inflow duration) until arriving at a strength that is just enough to achieve a complete fill. Even after a complete fill has been achieved, the controller 18 may reduce the strength of the applied vacuum or negative pressure (without changing the inflow duration) to determine whether a weaker vacuum or negative pressure may be appropriate and effective to achieve a complete fill (e.g., if a previous flow restriction has been resolved). The benefits of applying the weakest viable vacuum or negative pressure include less wear on mechanical components, less need to run noisy compressors continuously, minimization of the wear and tear on the diaphragm 64, improved donor/patient comfort (when the inflow protocol is applied to a pump drawing blood from the vein of a donor or patient), and increased speed without an increased risk of damaging fluid components (e.g., red blood cells or platelets) during the fluid flow procedure.

[0099]Turning now to an outflow protocol, in one embodiment, it begins with the controller 18 actuating a pump P1-P6 to apply an initial positive pressure to a region of a diaphragm 64 overlaying a pump chamber T1-T6 aligned with the pump P1-P6 for an outflow duration when first applying a positive pressure to that region of the diaphragm 64 during a fluid flow procedure. The initial positive pressure is selected to be a minimum or weakest positive pressure at which a complete empty of the pump chamber T1-T6 is expected to be achieved when that positive pressure has been applied to that region of the diaphragm 64 for the outflow duration and assumes there to be no flow restriction that would affect the ability of the pump system to achieve a compete empty. The strength or magnitude of the initial positive pressure may be empirically or theoretically calculated according to any suitable approach without departing from the scope of the present disclosure and may vary from system to system and from procedure to procedure for a given system.

[0100]After the fluid flow procedure has begun and the pump system has been actuated to apply the initial positive pressure to the diaphragm 64 for the outflow duration, the capacitive sensor 68 will transmit an outflow signal to the controller 18, with the controller 18 assessing the outflow signal to determine whether a complete empty has been achieved, as described above. When the controller 18 determines that a complete empty has not been achieved, it may then actuate the pump system to apply a second or increased positive pressure (which is stronger than the initial positive pressure) to the same region of the diaphragm 64 for the same outflow duration when next applying a positive pressure to that region of the diaphragm 64. The magnitude of the increase in strength of the positive pressure may vary without departing from the scope of the present disclosure. For example, in one embodiment, the controller 18 may be programmed to increase the strength of the applied positive pressure by a predetermined increment. In another embodiment, the controller 18 may instead be programmed to calculate a positive pressure strength that would need to be applied for the same outflow duration in order to achieve a complete empty (as described above) and then actuate the pump system to apply an increased positive pressure having that strength for the same outflow duration when next applying a positive pressure to the same region of the diaphragm 64.

[0101]Once the second or increased positive pressure has been applied to the same region of the diaphragm 64 for the same outflow duration, the controller 18 will assess the outflow signal from the capacitive sensor 68 to determine whether application of the second or increased positive pressure has been successful in achieving a complete empty. If not, the controller 18 may proceed to repeat the alternating steps of actuating the pump system to apply a further increased positive pressure (that is greater or stronger than the most recently applied positive pressure) to the same region of the diaphragm 64 for the same outflow duration and analyzing the outflow signal resulting from the application of that positive pressure to determine whether a complete empty has been achieved, with the steps being repeated until the controller 18 receives an outflow signal indicating that a complete empty has been achieved. In one embodiment, the controller 18 may be programmed with a maximum positive pressure that can be applied to a region of the diaphragm 64 by the pump system (which may be the maximum positive pressure that the pump system is capable of generating or may be some lesser value). In such an embodiment, if the controller 18 determines that the outflow signal indicates that application of a positive pressure having a greater strength than the maximum value is required, the controller 18 may generate an alert or alarm and (rather than implementing the change in applied pressure indicated by the outflow signal) either pause the procedure or change the applied positive pressure to the designated maximum value.

[0102]When the controller 18 determines that a complete empty has been achieved (whether by use of the initial positive pressure or the second positive pressure or some other increased positive pressure), the controller 18 may continue controlling the pump system to apply the same positive pressure to the same region of the diaphragm 64 for the same outflow duration when next applying a positive pressure to that region of the diaphragm 64. According to such an approach, the controller 18 may continue controlling the pump system to apply the same positive pressure to the same region of the diaphragm 64 for the same outflow duration whenever subsequently applying a positive pressure to that region of the diaphragm 64 for the remainder of the fluid flow procedure, provided that outflow signals from the capacitive sensor 68 continue to indicate that complete empties are being achieved. If an outflow signal were to indicate that a complete empty has not been achieved (e.g., if a flow restriction has arisen), the controller 18 may proceed according to the above-described approach to increasing the strength of the applied positive pressure until receiving a signal indicating that a complete empty has been achieved.

[0103]Alternatively, rather than applying the same positive pressure for the remainder of the fluid flow procedure, the controller 18 may instead continue controlling the pump system to apply the most recently applied positive pressure to the same region of the diaphragm 64 for the same outflow duration whenever subsequently applying a positive pressure to that region of the diaphragm 64 for only a predetermined amount of time or predetermined volume of fluid pumped (provided that outflow signals from the capacitive sensor 68 continue to indicate that complete empties are being achieved). Once that predetermined amount of time or predetermined volume of fluid pumped has been completed, the controller 18 may actuate the pump system to apply a decreased positive pressure (which is weaker than the positive pressure most recently applied) to the same region of the diaphragm 64 for the same outflow duration when next applying a positive pressure to that region of the diaphragm 64. This may be understood as an attempt to determine whether a weaker positive pressure may be capable of achieving a complete empty, which may be possible if a previous flow restriction has been resolved. If the controller 18 is programmed to implement a predetermined amount of time or a predetermined volume of fluid pumped, that value may remain the same for an entire fluid flow procedure or may be changed during a fluid flow procedure, with any change either being pre-programmed into the controller 18 or with the controller 18 being programmed to determine the nature of the change to be made (which may be based on any possible factors without departing from the scope of the present disclosure).

[0104]Once the decreased positive pressure has been applied, the controller 18 the capacitive sensor 68 will transmit an outflow signal to the controller 18, with the controller 18 assessing the outflow signal to determine whether a complete empty has been achieved using the decreased positive pressure. When the controller 18 determines that a complete empty has been achieved, the controller 18 may continue actuating the pump system to apply the same decreased positive pressure to the same region of the diaphragm 64 for the same outflow duration when next applying a positive pressure to that region of the diaphragm 64 for the remainder of the fluid flow procedure or for a predetermined time period (as described above). Alternatively, as long as outflow signals from the capacitive sensor 68 continue being indicative of complete empties, the controller 18 may proceed to actuate the pump system to apply further decreased positive pressure to the same region of the diaphragm 64 for the same outflow duration.

[0105]However, once the controller 18 receives an outflow signal indicating that a complete empty has not been achieved using a decreased positive pressure, it may then actuate the pump system to apply an increased positive pressure (which is stronger than the positive pressure most recently applied) to the same region of the diaphragm 64 for the same outflow duration, with the strength of the positive pressure being increased (according to the above-described approach) until the controller 18 receives an outflow signal that is indicative of a complete empty. By implementing such a protocol, the controller 18 is able to dynamically determine the minimum or weakest positive pressure that may be applied in order to achieve a complete empty.

[0106]According to another alternative response to detection of a complete empty, rather than continuing to apply the most recently applied positive pressure for the same outflow duration when subsequently applying a positive pressure to the same region of the diaphragm 64 for a predetermined time period or predetermined volume of fluid pumped, the controller 18 may be programmed to instead immediately control the pump system to apply a decreased positive pressure for the same duration when next applying a positive pressure to the same region of the diaphragm 64. Such an approach may be understood as being a more aggressive attempt to determine whether application of the decreased positive pressure would be sufficient to achieve a complete empty. If fluid flow stability is prioritized, it may be preferred to maintain the applied positive pressure at the same level for a predetermined amount of time or a predetermined volume of fluid pumped before decreasing it, whereas it may be preferred to immediately decrease the applied positive pressure if it is instead a priority to determine the weakest positive pressure that may be applied to achieve a complete empty.

[0107]If the outflow protocol does include a positive pressure strength being decreased sometime after a complete empty has been achieved, such a step may be executed by the controller 18 continuously throughout a fluid flow procedure. Alternatively, the controller 18 may be programmed to execute such a step a predetermined number of times during a fluid flow procedure (e.g., on a periodic or rolling basis throughout a procedure), including being done only once. In one embodiment, the controller 18 may be programmed to execute such a step one time for each fluid that is pumped using a particular pump P1-P6 and associated pump chamber T1-T6 during a multi-stage fluid processing procedure, such as the step being executed once for the flow of saline during a priming stage of the procedure, once for the flow of whole blood during a blood separation stage of the procedure, and once for the flow of a blood component storage solution during a post-separation stage of the procedure. As explained above, the pumping of each different fluid by a particular pump/pump chamber pair may be understood as the execution of a different “fluid flow procedure” (each with its own outflow protocol being implemented), such that this approach may be understood as the step being executed once for each fluid flow procedure of the multi-stage fluid processing procedure.

[0108]Regardless of how exactly the outflow protocol is implemented, it will be seen that the overall effect is for the controller 18 to start by actuating the pump system to apply a relatively weak positive pressure to a region of the diaphragm 64 (though one that is calculated to achieve a complete empty of a pump chamber T1-T6 aligned with that region of the diaphragm 64), with the controller 18 dynamically determining whether a complete empty has been achieved and dynamically adjusting the strength of the applied positive pressure (without changing the outflow duration) until arriving at a strength that is just enough to achieve a complete empty. Even after a complete empty has been achieved, the controller 18 may reduce the strength of the applied positive pressure (without changing the outflow duration) to determine whether a weaker positive pressure may be appropriate and effective to achieve a complete empty (e.g., if a previous flow restriction has been resolved). As described above with regard to an inflow protocol, the benefits of applying the weakest viable positive pressure include less wear on mechanical components, less need to run noisy compressors continuously, minimization of the wear and tear on the diaphragm 64, improved donor/patient comfort (when the outflow protocol is applied to a pump conveying a fluid to a donor or patient), and increased speed without an increased risk of damaging fluid components (e.g., red blood cells or platelets) during the fluid flow procedure.

V. Aspects

[0109]Aspect 1. A fluid processing device for use in combination with a fluid flow circuit comprising a pump chamber including a flexible diaphragm and an electrode, the fluid processing device comprising: a controller programmed to execute a fluid flow procedure; a pneumatic pump operatively coupled to the controller and configured to be actuated by the controller during the fluid flow procedure to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey said fluid out of the pump chamber; and a capacitive sensor operatively coupled to the controller, configured to be electrically coupled to the electrode of the pump chamber, and configured to transmit an inflow signal to the controller that is indicative of an inflow volume of the fluid that has been drawn into the pump chamber while the pneumatic pump is applying negative pressure to the flexible diaphragm of the pump chamber during said inflow duration, wherein the controller is programmed to actuate the pneumatic pump to apply an initial negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when first applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with said initial negative pressure being selected to be a minimum negative pressure at which a complete fill of the pump chamber is expected be achieved when negative pressure is being applied to the flexible diaphragm of the pump chamber during said inflow duration, determine whether a complete fill of the pump chamber has been achieved during application of said initial negative pressure to the flexible diaphragm of the pump chamber during said inflow duration based at least in part on said inflow signal, and upon determining that a complete fill of the pump chamber has not been achieved during application of said initial negative pressure to the flexible diaphragm of the pump chamber during said inflow duration, actuate the pneumatic pump to apply a second negative pressure that is greater than the initial negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0110]Aspect 2. The fluid processing device of Aspect 1, wherein said second negative pressure is greater than the initial negative pressure by a predetermined increment.

[0111]Aspect 3. The fluid processing device of Aspect 1, wherein the controller is further programmed to, upon determining that a complete fill of the pump chamber has not been achieved during application of said initial negative pressure to the flexible diaphragm of the pump chamber during said inflow duration, determine a negative pressure required to be applied to the flexible diaphragm of the pump chamber during said inflow duration so as to achieve a complete fill of the pump chamber, and said second negative pressure is selected to be equal to said negative pressure required to be applied to the flexible diaphragm of the pump chamber during said inflow duration so as to achieve a complete fill of the pump chamber.

[0112]Aspect 4. The fluid processing device of any one of the preceding Aspects, wherein the controller is further programmed to: (a) determine whether a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, (b) upon determining that the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber, actuate the pneumatic pump to apply an increased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased negative pressure being greater than the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, and (c) repeat (a) and (b) until determining that the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber.

[0113]Aspect 5. The fluid processing device of any one of the preceding Aspects, wherein the controller is further programmed to, upon determining that a complete fill of the pump chamber has been achieved during application of a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, continue to actuate the pneumatic pump to apply the negative pressure most recently applied to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0114]Aspect 6. The fluid processing device of any one of the preceding Aspects, wherein the controller is further programmed to, upon determining that a complete fill of the pump chamber has been achieved during application of a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, continue to actuate the pneumatic pump to apply the negative pressure most recently applied to the flexible diaphragm of the pump chamber for said inflow duration whenever subsequently applying negative pressure to the flexible diaphragm of the pump chamber until the fluid flow procedure has been completed.

[0115]Aspect 7. The fluid processing device of any one of Aspects 1-5, wherein the controller is further programmed to, upon determining that a complete fill of the pump chamber has been achieved during application of a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, continue to actuate the pneumatic pump to apply the negative pressure most recently applied to the flexible diaphragm of the pump chamber for said inflow duration whenever subsequently applying negative pressure to the flexible diaphragm of the pump chamber for a predetermined amount of time or for a predetermined volume of fluid pumped during the fluid flow procedure.

[0116]Aspect 8. The fluid processing device of Aspect 7, wherein the controller is further programmed to: (d) determine whether said predetermined amount of time or said predetermined volume of fluid pumped has been completed and, upon determining that said predetermined amount of time or said predetermined volume of fluid pumped has been completed, (e) actuate the pneumatic pump to apply a decreased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased negative pressure being lower than the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration.

[0117]Aspect 9. The fluid processing device of Aspect 8, wherein the controller is further programmed to: (f) determine whether a decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, and (g) repeat (e) and (f) until determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber and, upon determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber, actuate the pneumatic pump to apply an increased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased negative pressure being greater than the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration.

[0118]Aspect 10. The fluid processing device of any one of Aspects 1-4, wherein the controller is further programmed to: (d) determine whether a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber and, upon determining that the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, (e) actuate the pneumatic pump to apply a decreased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased negative pressure being lower than the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, (f) determine whether a decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, and (g) repeat (e) and (f) until determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber and, upon determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber, actuate the pneumatic pump to apply an increased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased negative pressure being greater than the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration.

[0119]Aspect 11. The fluid processing device of any one of the preceding Aspects, wherein the controller is further programmed to execute a multi-stage fluid processing procedure in which different fluids are pumped through the pump chamber by the pneumatic pump during at least two of the stages of the fluid processing procedure, and execute a separate fluid flow procedure for at least two of said different fluids.

[0120]Aspect 12. A controller-implemented method of executing a fluid flow procedure using a fluid flow circuit comprising a pump chamber including a flexible diaphragm and an electrode, the method comprising: actuating a pneumatic pump to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey said fluid out of the pump chamber, wherein the pneumatic pump is actuated to apply an initial negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when first applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with said initial negative pressure being selected to be a minimum negative pressure at which a complete fill of the pump chamber is expected be achieved when negative pressure is being applied to the flexible diaphragm of the pump chamber during said inflow duration; receiving an inflow signal from a capacitive sensor electrically coupled to the electrode of the pump chamber that is indicative of an inflow volume of the fluid that has been drawn into the pump chamber while the pneumatic pump is applying negative pressure to the flexible diaphragm of the pump chamber during said inflow duration; determining whether a complete fill of the pump chamber has been achieved during application of said initial negative pressure to the flexible diaphragm of the pump chamber during said inflow duration based at least in part on said inflow signal; and upon determining that a complete fill of the pump chamber has not been achieved during application of said initial negative pressure to the flexible diaphragm of the pump chamber during said inflow duration, actuating the pneumatic pump to apply a second negative pressure that is greater than the initial negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0121]Aspect 13. The method of Aspect 12, wherein said second negative pressure is greater than the initial negative pressure by a predetermined increment.

[0122]Aspect 14. The method of Aspect 12, further comprising, upon determining that a complete fill of the pump chamber has not been achieved during application of said initial negative pressure to the flexible diaphragm of the pump chamber during said inflow duration, determining a negative pressure required to be applied to the flexible diaphragm of the pump chamber during said inflow duration so as to achieve a complete fill of the pump chamber, wherein said second negative pressure is selected to be equal to said negative pressure required to be applied to the flexible diaphragm of the pump chamber during said inflow duration so as to achieve a complete fill of the pump chamber.

[0123]Aspect 15. The method of any one of Aspects 12-14, further comprising: (a) determining whether a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, (b) upon determining that the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber, actuating the pneumatic pump to apply an increased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased negative pressure being greater than the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, and (c) repeating (a) and (b) until determining that the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber.

[0124]Aspect 16. The method of any one of Aspects 12-15, further comprising, upon determining that a complete fill of the pump chamber has been achieved during application of a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, continuing to actuate the pneumatic pump to apply the negative pressure most recently applied to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0125]Aspect 17. The method of any one of Aspects 12-16, further comprising, upon determining that a complete fill of the pump chamber has been achieved during application of a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, continuing to actuate the pneumatic pump to apply the negative pressure most recently applied to the flexible diaphragm of the pump chamber for said inflow duration whenever subsequently applying negative pressure to the flexible diaphragm of the pump chamber until the fluid flow procedure has been completed.

[0126]Aspect 18. The method of any one of Aspects 12-16, further comprising, upon determining that a complete fill of the pump chamber has been achieved during application of a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, continuing to actuate the pneumatic pump to apply the negative pressure most recently applied to the flexible diaphragm of the pump chamber for said inflow duration whenever subsequently applying negative pressure to the flexible diaphragm of the pump chamber for a predetermined amount of time or for a predetermined volume of fluid pumped during the fluid flow procedure.

[0127]Aspect 19. The method of Aspect 18, further comprising: (d) determining whether said predetermined amount of time or said predetermined volume of fluid pumped has been completed and, upon determining that said predetermined amount of time or said predetermined volume of fluid pumped has been completed, (e) actuating the pneumatic pump to apply a decreased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased negative pressure being lower than the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration.

[0128]Aspect 20. The method of Aspect 19, further comprising: (f) determining whether a decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, and (g) repeating (e) and (f) until determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber and, upon determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber, actuating the pneumatic pump to apply an increased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased negative pressure being greater than the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration.

[0129]Aspect 21. The method of any one of Aspects 12-15, further comprising: (d) determining whether a negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber and, upon determining that the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, (e) actuating the pneumatic pump to apply a decreased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased negative pressure being lower than the negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration, (f) determining whether a decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has achieved a complete fill of the pump chamber, and (g) repeating (e) and (f) until determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber and, upon determining that the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration has not achieved a complete fill of the pump chamber, actuating the pneumatic pump to apply an increased negative pressure to the flexible diaphragm of the pump chamber for said inflow duration when next applying negative pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased negative pressure being greater than the decreased negative pressure most recently applied to the flexible diaphragm of the pump chamber during said inflow duration.

[0130]Aspect 22. The method of any one of Aspects 12-21, further comprising executing a multi-stage fluid processing procedure in which different fluids are pumped through the pump chamber by the pneumatic pump during at least two of the stages of the fluid processing procedure, wherein separate fluid flow procedures are executed for at least two of said different fluids.

[0131]Aspect 23. A fluid processing device for use in combination with a fluid flow circuit comprising a pump chamber including a flexible diaphragm and an electrode, the fluid processing device comprising: a controller programmed to execute a fluid flow procedure; a pneumatic pump operatively coupled to the controller and configured to be actuated by the controller during the fluid flow procedure to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey said fluid out of the pump chamber; and a capacitive sensor operatively coupled to the controller, configured to be electrically coupled to the electrode of the pump chamber, and configured to transmit an outflow signal to the controller that is indicative of an outflow volume of the fluid that has been conveyed out of the pump chamber while the pneumatic pump is applying positive pressure to the flexible diaphragm of the pump chamber during said outflow duration, wherein the controller is programmed to actuate the pneumatic pump to apply an initial positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when first applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with said initial positive pressure being selected to be a minimum positive pressure at which a complete empty of the pump chamber is expected be achieved when positive pressure is being applied to the flexible diaphragm of the pump chamber during said outflow duration, determine whether a complete empty of the pump chamber has been achieved during application of said initial positive pressure to the flexible diaphragm of the pump chamber during said outflow duration based at least in part on said outflow signal, and upon determining that a complete empty of the pump chamber has not been achieved during application of said initial positive pressure to the flexible diaphragm of the pump chamber during said outflow duration, actuate the pneumatic pump to apply a second positive pressure that is greater than the initial positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0132]Aspect 24. The fluid processing device of Aspect 23, wherein said second positive pressure is greater than the initial positive pressure by a predetermined increment.

[0133]Aspect 25. The fluid processing device of Aspect 23, wherein the controller is further programmed to, upon determining that a complete empty of the pump chamber has not been achieved during application of said initial positive pressure to the flexible diaphragm of the pump chamber during said outflow duration, determine a positive pressure required to be applied to the flexible diaphragm of the pump chamber during said outflow duration so as to achieve a complete empty of the pump chamber, and said second positive pressure is selected to be equal to said positive pressure required to be applied to the flexible diaphragm of the pump chamber during said outflow duration so as to achieve a complete empty of the pump chamber.

[0134]Aspect 26. The fluid processing device of any one of Aspects 23-25, wherein the controller is further programmed to: (a) determine whether a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, (b) upon determining that the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber, actuate the pneumatic pump to apply an increased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased positive pressure being greater than the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, and (c) repeat (a) and (b) until determining that the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber.

[0135]Aspect 27. The fluid processing device of any one of Aspects 23-26, wherein the controller is further programmed to, upon determining that a complete empty of the pump chamber has been achieved during application of a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, continue to actuate the pneumatic pump to apply the positive pressure most recently applied to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0136]Aspect 28. The fluid processing device of any one of Aspects 23-27, wherein the controller is further programmed to, upon determining that a complete empty of the pump chamber has been achieved during application of a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, continue to actuate the pneumatic pump to apply the positive pressure most recently applied to the flexible diaphragm of the pump chamber for said outflow duration whenever subsequently applying positive pressure to the flexible diaphragm of the pump chamber until the fluid flow procedure has been completed.

[0137]Aspect 29. The fluid processing device of any one of Aspects 23-27, wherein the controller is further programmed to, upon determining that a complete empty of the pump chamber has been achieved during application of a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, continue to actuate the pneumatic pump to apply the positive pressure most recently applied to the flexible diaphragm of the pump chamber for said outflow duration whenever subsequently applying positive pressure to the flexible diaphragm of the pump chamber for a predetermined amount of time or for a predetermined volume of fluid pumped during the fluid flow procedure.

[0138]Aspect 30. The fluid processing device of Aspect 29, wherein the controller is further programmed to: (d) determine whether said predetermined amount of time or said predetermined volume of fluid pumped has been completed and, upon determining that said predetermined amount of time or said predetermined volume of fluid pumped has been completed, (e) actuate the pneumatic pump to apply a decreased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased positive pressure being lower than the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration.

[0139]Aspect 31. The fluid processing device of Aspect 30, wherein the controller is further programmed to: (f) determine whether a decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, and (g) repeat (e) and (f) until determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber and, upon determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber, actuate the pneumatic pump to apply an increased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased positive pressure being greater than the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration.

[0140]Aspect 32. The fluid processing device of any one of Aspects 23-26, wherein the controller is further programmed to: (d) determine whether a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber and, upon determining that the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, (e) actuate the pneumatic pump to apply a decreased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased positive pressure being lower than the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, (f) determine whether a decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, and (g) repeat (e) and (f) until determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber and, upon determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber, actuate the pneumatic pump to apply an increased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased positive pressure being greater than the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration.

[0141]Aspect 33. The fluid processing device of any one of Aspects 23-32, wherein the controller is further programmed to execute a multi-stage fluid processing procedure in which different fluids are pumped through the pump chamber by the pneumatic pump during at least two of the stages of the fluid processing procedure, and execute a separate fluid flow procedure for at least two of said different fluids.

[0142]Aspect 34. A controller-implemented method of executing a fluid flow procedure using a fluid flow circuit comprising a pump chamber including a flexible diaphragm and an electrode, the method comprising: actuating a pneumatic pump to alternately apply negative pressure to the flexible diaphragm of the pump chamber for an inflow duration so as to draw a fluid into the pump chamber and apply positive pressure to the flexible diaphragm of the pump chamber for an outflow duration so as to convey said fluid out of the pump chamber, wherein the pneumatic pump is actuated to apply an initial positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when first applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with said initial positive pressure being selected to be a minimum positive pressure at which a complete empty of the pump chamber is expected be achieved when positive pressure is being applied to the flexible diaphragm of the pump chamber during said outflow duration; receiving an outflow signal from a capacitive sensor electrically coupled to the electrode of the pump chamber that is indicative of an outflow volume of the fluid that has been conveyed out of the pump chamber while the pneumatic pump is applying positive pressure to the flexible diaphragm of the pump chamber during said outflow duration; determining whether a complete empty of the pump chamber has been achieved during application of said initial positive pressure to the flexible diaphragm of the pump chamber during said outflow duration based at least in part on said outflow signal; and upon determining that a complete empty of the pump chamber has not been achieved during application of said initial positive pressure to the flexible diaphragm of the pump chamber during said outflow duration, actuating the pneumatic pump to apply a second positive pressure that is greater than the initial positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0143]Aspect 35. The method of Aspect 34, wherein said second positive pressure is greater than the initial positive pressure by a predetermined increment.

[0144]Aspect 36. The method of Aspect 34, further comprising, upon determining that a complete empty of the pump chamber has not been achieved during application of said initial positive pressure to the flexible diaphragm of the pump chamber during said outflow duration, determining a positive pressure required to be applied to the flexible diaphragm of the pump chamber during said outflow duration so as to achieve a complete empty of the pump chamber, wherein said second positive pressure is selected to be equal to said positive pressure required to be applied to the flexible diaphragm of the pump chamber during said outflow duration so as to achieve a complete empty of the pump chamber.

[0145]Aspect 37. The method of any one of Aspects 34-36, further comprising: (a) determining whether a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, (b) upon determining that the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber, actuating the pneumatic pump to apply an increased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased positive pressure being greater than the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, and (c) repeating (a) and (b) until determining that the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber.

[0146]Aspect 38. The method of any one of Aspects 34-37, further comprising, upon determining that a complete empty of the pump chamber has been achieved during application of a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, continuing to actuate the pneumatic pump to apply the positive pressure most recently applied to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure.

[0147]Aspect 39. The method of any one of Aspects 34-38, further comprising, upon determining that a complete empty of the pump chamber has been achieved during application of a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, continuing to actuate the pneumatic pump to apply the positive pressure most recently applied to the flexible diaphragm of the pump chamber for said outflow duration whenever subsequently applying positive pressure to the flexible diaphragm of the pump chamber until the fluid flow procedure has been completed.

[0148]Aspect 40. The method of any one of Aspects 34-38, further comprising, upon determining that a complete empty of the pump chamber has been achieved during application of a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, continuing to actuate the pneumatic pump to apply the positive pressure most recently applied to the flexible diaphragm of the pump chamber for said outflow duration whenever subsequently applying positive pressure to the flexible diaphragm of the pump chamber for a predetermined amount of time or for a predetermined volume of fluid pumped during the fluid flow procedure.

[0149]Aspect 41. The method of Aspect 40, further comprising: (d) determining whether said predetermined amount of time or said predetermined volume of fluid pumped has been completed and, upon determining that said predetermined amount of time or said predetermined volume of fluid pumped has been completed, (e) actuating the pneumatic pump to apply a decreased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased positive pressure being lower than the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration.

[0150]Aspect 42. The method of Aspect 41, further comprising: (f) determining whether a decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, and (g) repeating (e) and (f) until determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber and, upon determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber, actuating the pneumatic pump to apply an increased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased positive pressure being greater than the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration.

[0151]Aspect 43. The method of any one of Aspects 34-37, further comprising: (d) determining whether a positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber and, upon determining that the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, (e) actuating the pneumatic pump to apply a decreased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the decreased positive pressure being lower than the positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration, (f) determining whether a decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has achieved a complete empty of the pump chamber, and (g) repeating (e) and (f) until determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber and, upon determining that the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration has not achieved a complete empty of the pump chamber, actuating the pneumatic pump to apply an increased positive pressure to the flexible diaphragm of the pump chamber for said outflow duration when next applying positive pressure to the flexible diaphragm of the pump chamber during said fluid flow procedure, with the increased positive pressure being greater than the decreased positive pressure most recently applied to the flexible diaphragm of the pump chamber during said outflow duration.

[0152]Aspect 44. The method of any one of Aspects 34-43, further comprising executing a multi-stage fluid processing procedure in which different fluids are pumped through the pump chamber by the pneumatic pump during at least two of the stages of the fluid processing procedure, wherein separate fluid flow procedures are executed for at least two of said different fluids.

[0153]It will be understood that the embodiments described above are illustrative of some of the applications of the principles of the present subject matter. Numerous modifications may be made by those skilled in the art without departing from the spirit and scope of the claimed subject matter, including those combinations of features that are individually disclosed or claimed herein. For these reasons, the scope hereof is not limited to the above description but is as set forth in the following claims, and it is understood that claims may be directed to the features hereof, including as combinations of features that are individually disclosed or claimed herein.