Abstract: A pressure cuff draw mode enhancement system for a blood fractionation system having a single-lumen phlebotomy needle, a flow-through plasma separation filter, and an in-process fluid reservoir, includes a pressure cuff in operative association with the donor. During an initial draw cycle of the system whole blood is pumped by an inlet pump through the filter to the in-process reservoir. When a predetermined volume of filtered plasma-deficient blood has been collected in the reservoir, as sensed by the weight of the reservoir, the system reverts to a return cycle wherein a portion of the plasma-deficient blood in the reservoir is pumped back to the phlebotomy needle by a return pump. Depending on the relative operating rates of the inlet and return pumps, an operator-controllable portion of the plasma-deficient blood from the in-process reservoir is returned to the donor through the phlebotomy needle, and the remaining portion is recirculated through the filter.

Abstract: A monitoring system for monitoring trans-membrane pressure in plasmapheresis apparatus utilizing a microporous membrane type filter includes first and second pressure-to-frequency transducer circuits for developing signals frequency-indicative of the inlet and outlet pressures of the filter. The signals are digitally compared in a pulse subtraction circuit to produce an output signal frequency-indicative of trans-membrane pressure. The output signal is applied to a periodically reset display counter to develop a digital readout of trans-membrane pressure. Porous filter elements in the flow system and in the inlet port of each transducer isolate bacteria within the flow system, prevent contamination of the transducers, and provide a time constant for each transducer which prevents transient flow variations in the system from causing erroneous trans-membrane pressure readings.

Abstract: An apparatus for separating and collecting plasma from whole blood includes a collection rate monitoring system which provides a digital display of the rate of plasma collection per minute. A transducer circuit within the system develops an electrical signal frequency-dependent on the weight of the collected plasma. The frequency of this signal over a present measurement interval is periodically compared with the frequency of the signal over a preceding measurement interval to develop a signal indicative of the volume of plasma collected during the interval. This signal is combined in a shift register with signals developed over a plurality of immediately preceding measurement intervals, which, taken with the present interval, comprise a one minute period, to develop at the end of each interval an output signal indicative of the total units of plasma collected over the previous minute.

Abstract: A disposable prepackaged fluid processing module includes an integral housing wherein fluid containers, tubing segments, and other components required in processing a fluid are contained. Fluid communication between the containers, components and tubing segments is provided by a fluid circuit formed by a panel of the housing, and an overlying fluid-impermeable flexible sheet member. The fluid circuit includes pump and valve elements which operate in response to pressures applied to the sheet member. Upon installation of the system in a related actuator apparatus pneumatic actuator ports apply pressures to the pump and valve elements to circulate fluid through the fluid circuit.

Abstract: A fluid processing apparatus for use in conjunction with a prepackaged disposable fluid processing module of the type which includes an integral housing wherein fluid containers, tubing segments, and other components required in processing a fluid are contained, and wherein fluid communication between the containers, components and tubing segments is provided by a fluid circuit formed within the housing by a first relatively inflexible fluid-impervious sheet member and a second relatively flexible fluid-impermeable sheet member. The fluid circuit includes pump and valve elements which operate in response to pressures applied to the second sheet member. Upon installation of the system in the processing apparatus pneumatic actuator ports apply pressures to the second sheet member through access apertures in the housing to circulate fluid through the fluid circuit.

Abstract: A fluid processing apparatus for use in conjunction with a disposable fluid processing module of the type which includes an integral housing wherein fluid containers, tubing segments, and other components required in processing a fluid are contained, and wherein fluid communication between the containers, components and tubing segments is provided by a fluid circuit formed by a panel of the housing, and an overlying fluid-impermeable flexible sheet member. The processing apparatus includes an actuator station for receiving the module housing, and pneumatic actuator ports which apply pressures to pump and valve elements in the fluid circuit to circulate fluid through the system.

Abstract: An apparatus for separating and collecting plasma from whole blood includes a volume monitoring system which provides a continuous display of the volume of plasma collected. A transducer circuit within the system develops an electrical signal frequency-dependent on the weight of the collected plasma. The frequency of this signal over a present measurement interval is periodically compared with the frequency of the signal over a preceding measurement interval to develop a difference signal. If the difference is determined to be positive and less than a predetermined maximum collection rate so as to constitute a valid collection increment, the difference is cumulatively added to previous collection increments in a cumulative display counter to provide a collected volume display, and the frequency of the present measurement interval is taken as a frequency of the preceding measurement interval for the next comparison.

Abstract: An apparatus for the continuous flow fractionation of whole blood incorporates motor driven whole blood, anticoagulant and replacement pumps, negative and positive pressure monitors, and a dual bubble detector which function in conjunction with a disposable single-use flow system and a hollow fiber filter to separate and collect plasma from whole blood. Operation of the pump motors, pressure monitors and bubble detector is controlled by a control circuit within the apparatus to provide one of several operator-selected operating modes, including run, prime and reinfuse modes. The control circuit provides an alarm which can be cancelled by the operator when certain system parameters fall outside of normal operating limits, and interrupts operation of the pumps when the parameters exceed maximum limits. A failsafe circuit independent of the control circuits interrupts power to the pump motors in the event the motors do not stop upon detection of a bubble or fluid absence in the flow system.

Abstract: A flow control system, for example for blood plasma or other medical fluids, comprises a plurality of flexible, collapsible flow conduits for the selective and aseptic transfer of fluids between various locations through said conduits. Switching means are provided for selectively collapsing a plurality of separate sections of the conduit to block fluid flow therethrough, to selectively define specific and variable fluid flow paths in the flow conduit. In accordance with this invention, the switching means defines a cam plate, which in turn defines a generally flat face positioned adjacent portions of the flow conduit. Pivot means are provided causing the cam plate to be rotatable about an axis normal to the flat face. Also, a cam connecting system is disclosed, to adapt it to pass through an openable door.

Abstract: A flow control device includes a first member and a second member which has a movable portion. The first member accommodates the attachment of a length of flexible conduit. The second member can be positioned on the first member to sandwich the secured conduit between the first member and the movable portion of the second member. When in this position, displacement of the movable portion serves to selectively pinch close the secured conduit between the movable portion and the first member. Fluid flow through the conduit can thus be conveniently controlled. The device is extremely adaptable and can be readily incorporated into virtually any fluid system which requires complex, repetitive valving functions, such as those associated with a plasmapheresis assembly.

Abstract: A method and apparatus are described for obtaining a desired rate of plasma collection from a membrane plasmapheresis filter having a blood inlet, a blood outlet, a plasma outlet, outer members and a pair of spaced microporous filter membranes defining a blood flow path. A holder is provided for the filter having means for applying pressure against the outer members. The blood pressure at the blood inlet is sensed during plasmapheresis and variable amounts of pressure are applied against the outer members at an angular direction with respect to the membranes. In this manner, the blood flow path gap between the membranes is controlled in accordance with a desired blood pressure adjacent the blood inlet.

Abstract: A system is provided for detecting the absence of liquid in a liquid chamber. A signal is transmitted through a liquid chamber and a signal is provided in response to the amplitude of the received signal. A receiving transducer receives an AC signal which is amplified and fed to a DC control circuit. A reference voltage is provided to one input of a comparator and the output of the DC control circuit is fed to the other input of the comparator. The comparator output provides the liquid absence signal if the difference between the reference voltage and the DC control circuit output voltage is less than a predetermined value.

Abstract: A liquid presence detector having a light-transmissive chamber for the liquid to be detected. A light emitting diode is positioned outside of the chamber for transmitting light through the chamber and a photosensitive transistor is positioned for receiving the light that has been transmitted through the chamber. The light emitting diode is located at a distance from the chamber that is equal to the focal point of a lens that is created by the chamber and liquid when the liquid is present. The photosensitive transistor output voltage is compared with a reference voltage and an output signal is provided in response to a predetermined difference between the detector output voltage and the reference voltage.

Abstract: An apparatus for warming blood and other parenteral fluids as they are infused through a disposable flow system includes a pair of heating elements which heat the blood as it passes through a warming bag provided in the flow system. The heating elements are recurringly switched on and off with a duty cycle dependent on both the temperature of the blood at the output of the warming bag and the temperature differential between the output and input of the bag to maintain the blood at a predetermined temperature independent of flow rate. A digital display and monitoring circuit provides a highly accurate digital indication of blood temperature and interrupts the application of power to the heating elements in the event the temperature exceeds a predetermined maximum level.

Abstract: Photometric apparatus and method for determining the absorbance ratio, in a sample, of two different wavelength lights. A first light is given a reference intensity and is passed through the sample. A second light is passed through the sample and its intensity is varied so that the intensity of the second light that has passed through the sample is equal to the intensity of the first light that has passed through the sample. When these intensities are equal, the intensity of the second light is detected in a state wherein it has not passed through the sample, resulting in an equivalent to the ratio of the absorbance in the sample of the second light and the first light.

Abstract: Process and apparatus for weighing material being collected. In the illustrative embodiment, plasma that has been separated from whole blood is collected. The tare weight is sensed and the weight of the material being collected is sensed. Pulses are provided in frequency proportion to the sensed weight. The tare weight pulses are counted and stored. A net weight counter is set with a predetermined count corresponding to the maximum amount of plasma to be collected. A measure weight signal reverses the tare weight count with the net weight counter being inhibited until the tare weight count reversal has been completed. Once the tare weight count reversal is completed, the net weight counter is operative to count the sensed weight pulses. A completion signal is provided when the predetermined count has been decremented to zero.