Abstract: A speed control circuit for a DC motor includes a digital-to-analog (D/A) converter, a regulator/controller, and a control circuit which applies a compensating current to the DC motor that compensates for variations in loading applied to the motor. The regulator/controller compares a reference voltage provided by the D/A converter with a feedback signal provided by the motor to generate a signal to activate the control circuit, thus to supply a compensating current to the motor.

Abstract: A multi-lumen, multi-purpose cardiac catheter which incorporates optical filaments and an optical coupler for use with external apparatus for determining the oxygen concentration in the blood of a patient under critical care conditions, as well as incorporating therein a thermal element useable with a second external apparatus for measurement of continuous cardiac output. A thermal plug provides an interface between a temperature control apparatus and the thermal element to simply and accurately monitor and control the temperature of the thermal element. A temperature monitoring circuit in the thermal plug facilitates temperature measurement at the thermal element. The catheter also includes a thermistor and at least one injectate port for enabling the user to also conduct thermal dilution readings and obtain intermittent measurements of cardiac output. The combination of a thermal dilution catheter with a SV0.sub.

Abstract: A multi-lumen, multi-purpose cardiac catheter which incorporates optical filaments and an optical coupler for use with external apparatus for determining the oxygen concentration in the blood of a patient under critical care conditions, as well as incorporating therein a thermal element useable with a second external apparatus for measurement of continuous cardiac output. The thermal element is disposed at a necked down portion of the catheter at the distal end thereof, with at least one of the lumens of the catheter substantially compressed at the necked down portion thereof. The catheter also includes a thermistor and at least one injectate port for enabling the user to also conduct thermal dilution readings and obtain intermittent measurements of cardiac output. The combination of a thermal dilution catheter with a SVO.sub.

Abstract: A pumping system for positive displacement, volumetric liquid control includes a pump having a pumping chamber with a pumping chamber inlet and a pumping chamber outlet. The pumping system further includes a liquid supply inlet for receiving liquid from a liquid supply, and an detector for detecting air in liquid flowing through the liquid path. A liquid valve actuator regulates liquid flow through the liquid supply inlet and a second valve actuator regulates liquid flow through the pumping system outlet. A controller is responsive to an output from the detector to control the pump, the first valve actuator and the second valve actuator such that liquid is directed through the liquid supply inlet and the pumping system outlet during an initial priming sequence until the quantity of air in liquid at the pumping system outlet corresponds to a predetermined value.

Abstract: A cam assembly and method for providing a substantially constant load to a motor that drives the cam assembly. A torque compensated cam assembly (142,300) includes a plurality of tracks (140,150,152/310,312,314) that are profiled with a surface that varies radially as the cam rotates, thereby actuating cam followers, each of which rolls along a different track. A tangential force developed by the cam followers as they move over rapid radial changes in the surfaces of the tracks produces a total net torque that at times tends to aid the rotation of the cam and at times tends to impede its rotation. In the application of the torque compensated cam assembly disclosed, the cam is used in a volumetric pump (30) that accurately delivers a desired volume of fluid at a desire rate. To assist in maintaining the accuracy of these parameters, the torque compensated cam assembly presents a substantially constant load to a motor (146,304) that drives the cam.

Abstract: A dripless cannula system usable with a syringe or other fluid container in a fluid sampling procedure and operable to minimize retention of residual fluids at a sampling site following the sampling procedure. In the preferred embodiment, a vacuum chamber operatively connected to a blunt cannula of the dripless cannula system is operative upon withdrawal of the cannula from the sampling site to draw residual fluids at the site into the vacuum chamber for subsequent disposal. The dripless cannula system of the present invention is a simple, effective apparatus for minimizing the presence of residual fluids at a sampling site following a sampling procedure.

Abstract: A push button flow stop is mounted on a disposable infusion pumping cassette provided for use with a drug infusion pump. The flow stop is operative to enable or to block fluid flow through the cassette in a first mode and to monitor fluid pressure in the cassette in a second mode.

Abstract: A drug identification and security apparatus usable in conjunction with an electronic drug delivery system having at least one drug channel therein, the apparatus providing a first interlock mechanism between a locking member of the apparatus and the drug delivery system to lock the upper and lower doors of the drug channel and to disengage the drug delivery system and prevent removal of a drug container/cassette assembly when the locking member is in a locked position.

Abstract: A multi-lumen, multi-purpose cardiac catheter which incorporates optical filaments and an optical coupler for use with external apparatus for determining the oxygen concentration in the blood of a patient under critical care conditions, as well as incorporating therein a heater coil useable with a second external apparatus for measurement of continuous cardiac output. The catheter also includes a thermistor and at least one injectate port for enabling the user to also conduct thermal dilution readings and obtain intermittent measurements of cardiac output. The combination of a thermal dilution catheter with a SVO.sub.2 catheter and a continuous cardiac output catheter gives the multi-purpose catheter above described substantial versatility as well as providing the user with a versatile cardiac catheter device which enables him to conduct multiple evaluations of disparate blood-related parameters which require the use of separate apparatus.

Abstract: A connector is provided for mounting on an anesthetic vaporizer to connect the inlet of the vaporizer with a discharge port of a container of liquid anesthetic. The connector includes a first coupling attachable to the vaporizer and defining a first passage communicating at one end with the vaporizer inlet. A second coupling is attachable to the container and defines a second passage communicating at one end with the container discharge port. A third passage defined by one of the couplings and communicates with one of the first and second passages. A combination valve and mounting structure is cooperatively defined by the couplings to accommodate pivoting of the second coupling to a closed position occluding the first and second passages, to a raised fill position establishing communication between the first and second passages, and to a lowered drain position in which the first and second passages communicate through the third passage.

Abstract: A character display in which failures are evident. Selected segments of a seven-segment LCD are activated by control signals supplied through selected fore plane and back plane traces. By coupling specific ones of the fore plane and back plane control signals to selected segments, any failure in the control signal or circuitry providing the signal to the segments of the display character becomes immediately evident to an operator when the character represented by the display is not one of a predefined set of characters.

Abstract: A bi-directional cracking valve that can be selectively opened. Bi-directional cracking valve (10, 70) is formed using an elastomeric membrane (34). Centered within the elastomeric membrane is a slit (36) that remains closed, blocking fluid flow through the device until a differential pressure across the elastomeric membrane exceeds a predefined cracking pressure, sufficient to force fluid through the slit. The elastomeric membrane is an integral part of an elastomeric cylinder (28), which is mounted in a valve carrier (12). The valve carrier includes ports disposed at opposite ends and the ports are adapted to couple to tubing. An operator can selectively enable fluid flow through the device by squeezing side tabs (40, 42) disposed on opposite sides of the elastomeric membrane together, forcing the slit open. A latch (46) is provided to keep the bi-directional cracking valve in an open state.

Abstract: The present invention relates to a control system for use with an automated intravenous drug and fluid infusion system having plural pumping channels that operate independently for intravenously infusing drugs and fluid. The pumping channels are controlled by a microprocessor-based host controller that monitors each of the channels concurrently. In an exemplary embodiment, the system functions include identifying the particular drug that is to be pumped through a channel, preventing priming of a channel unless verification is provided that the channel is not connected to a patient and initiating the priming of each of the pumping channels independently.

Abstract: An apparatus wherein the primary dye container is connected to a secondary dye container with sufficient safeguards, including at least one-way check valve and at least one stopcock between the primary dye container and the secondary dye container, to assure a sterile barrier between the primary and secondary dye sources so that less than the total amount of sterile contrast media can be transferred from the primary dye container in an amount sufficient to perform a cardiac catheterization procedure.

Abstract: A latching piercing pin useable to retain the pin and an associated fluid vial in latching relation. Latching members provided on the pin engage a peripheral lip provided on the end cap of the vial to maintain the latching relation between the pin and the vial. The pin is useable with vials and end caps of varying sizes, although larger end caps may require the mounting of a locking ring on the end cap of the vial to receive and engage the latching piercing pin.

Abstract: An improved rotor for use with a segmented peristaltic cartridge comprising a housing and a cover for assembly, said assembled housing and cover defining a pumping chamber which holds the improved rotor, a rotor sleeve and a section of flexible tubing wrapped around the rotor and connected to respective inlet and outlet ports of the cartridge. The flexible rotor includes an eccentric structure wherein flexible beam members provided on an outer surface of the rotor form a compliant member which improves the flexibility of the rotor assembly to avoid excessive compression loads or high torque and/or dynamic leak back or low torque for the tubing in the cartridge.

Abstract: A blood sampling system incorporates a fluid storage mechanism which can be disposed along the longitudinal axis of a fluid line extending from an injection site to a fluid supply. Both the main body portion of the fluid storage mechanism and a fluid draw element of the fluid storage mechanism are axially aligned with the longitudinal axis of the fluid line. The fluid storage mechanism also incorporates a vortex inducer element at the distal end of the fluid draw element to induce a swirl of fluid to cleanse the fluid storage mechanism once a sample drawn into the fluid storage mechanism has been returned to the patient. An alternative embodiment of the fluid storage mechanism includes a volume control device.

Abstract: An optical distribution system incorporating an improved luminescent based optical fiber sensor incorporating a signal generating component for generating a first optical signal, a signal separating component for delivering said first optical signal to the sensor, delivering said second returned optical signal to an associated signal detector, and including signal interference means to separate said first and second signals and minimize cross-talk therebetween. A sensor optical fiber connects a sensor tip to the signal separating component. The signal detector receives a returned signal from the signal separating component and transmits it to a signal-measuring component of the distribution system.