Abstract: Pulsatile cardiopulmonary flow closely approximating a natural heartbeat is generated in a heart-lung machine by using a proportioning valve to partly convey blood in the machine's cardiopulmonary circuit to the arterial supply line, and to partly recycle that blood into the cardiopulmonary circuit upstream of the arterial pump. The relative proportions of conveying and recycling are varied in accordance with a waveform approximating the waveform of a human heartbeat.

Abstract: A spiral-bound stand-up book has pages printed with one set of textual materials on one side, and a second independent set of textual materials on the other so as to allow two persons looking at the book from opposite sides to simultaneously read two independent sets of textual materials.

Abstract: The cardiotomy inlet connectors of a hardshell venous reservoir are mounted on a turret which is rotatable about the vertical axis of the cover and is in communication with the cardiotomy filter defoamer chamber. The venous inlet connector in turn is mounted on the turret for rotation about the axis of the turret. An axial extension of the venous inlet connector fits sealingly into a venous duct which extends along the axis of the cardiotomy chamber.

Abstract: Pulsatile blood flow in a heart-lung machine is accomplished by pumping blood into a bladder at a constant rate, and cyclically emptying the bladder into aortic line of the heart-lung machine either by means of the bladder's own elasticity or by a mechanical compression mechanism which can be programmed to simulate the human heartbeat.

Abstract: A reusable dust cap for tubing connectors on medical devices has an internal shoulder or ridge which engages a barb or groove on the connector to hold the cap during shipment. A grasping nub is provided on the cap to allow the cap to be forcibly disengaged from the barb or groove by the end user.

Abstract: A temporary holder for a physiologic mitral valve includes a structure which releasably clamps the annulus of the valve between the rim of a plate and a snap ring. The structure also includes a pair of papillary head holders which hold the papillary heads of the valve at a predetermined distance and angle from the annulus plate for optimum surgical positioning. The papillary heads are temporarily sutured to their holders and can be released by a simple scalpel stroke.

Abstract: A gasketless seal is formed between a flow tube in a venous reservoir and a rotatable connector telescoped into it, by forming on the connector one or more annular ribs of slightly larger diameter than the inner diameter. When the connector is inserted into the flow tube, the rib is partially crushed against the inner wall of the flow tube and forms a tight, rotatable seal with it.

Abstract: A wear surface for helicopter shoes is constructed by forming a railed enclosure on a curved base plate, placing a mosaic of smooth-surfaced tungsten carbide blocks on the base plate within the enclosure, brazing the blocks to the plate and rails, and grinding the rails to form a smooth, edgeless transition between the wear surface and the plate surface.

Abstract: An automatic speed control system continually adjusts the speed of an implanted cardiac assist blood pump to an optimum level for the varying physiological needs of the patient. It does this by periodically iteratively incrementing the speed setpoint of the pump. When the system detects the imminence of a ventricular collapse at diastole, it decrements the speed setpoint by a predetermined safety margin. An alarm condition is provided if the setpoint decrease results in an insufficient blood flow rate through the pump. The flow rate and imminence of ventricular collapse are computed in real time as functions of only the pump's motor current and speed setpoint.

Abstract: In a heart-lung machine, blood is defoamed without the use of defoaming chemicals by passing blood between parallel insulated electrodes whose electric field orients the blood protein molecules to break up the foam bubbles. The blood then passes into the venous reservoir through a bubble screen which traps any remaining bubbles.

Abstract: In a heart-lung machine, blood is defoamed without the use of defoaming chemicals by passing blood between parallel insulated electrodes whose electric field orients the blood protein molecules to break up the foam bubbles. The blood then passes into the venous reservoir through a bubble screen which traps any remaining bubbles.

Abstract: The blood volume contained in a soft-shell venous reservoir is measured by using strain gauges to detect variations in the expansion stress imposed upon the reservoir material or a film overlying the reservoir as the reservoir fills.

Abstract: In a cable-based external knee ligament system, tensioned cables are disposed in a zig-zag pattern on each side of the femoral, patellar and tibial areas, and the load on selected ligaments can be varied by laterally moving cable guides above and below the knee which form the zig-zag pattern.

Abstract: A one-piece, leakproof, top-mountable valve body for lavatories which has a uniform, screwthreaded outer diameter and parallel inlet and outlet ports in its bottom surface.

Abstract: A simple, self-supporting cardiotomy filter/defoamer is formed by a 20 .mu.m cylindrical spray spun hollow plastic filter cartridge impregnated with an anti-foaming agent.

Abstract: A diverter valve for Roman tubs also serves as a vacuum breaker. The valve disc which diverts the water flow to the shower head is spring-loaded to close the shower head line if the pressure at the water inlet drops below a predetermined minimum.

Abstract: The blood volume in a soft-shell venous reservoir is measured by immersing the reservoir in a fluid and measuring the displacement of that fluid, either by measuring a liquid level in an overflow tube or by measuring the temperature-compensated gas pressure if the displaced fluid is a gas in a sealed container. Equipment operable from outside the container to measure the reservoir or to expel air therefrom is also disclosed.

Abstract: Pulsatile cardiopulmonary flow closely approximating a natural heartbeat is generated in a heart-lung machine by using a proportioning valve to partly convey blood in the machine's cardiopulmonary circuit to the arterial supply line, and to partly recycle that blood into the cardiopulmonary circuit upstream of the arterial pump. The relative proportions of conveying and recycling are varied in accordance with a waveform approximating the waveform of a human heartbeat.

Abstract: Microair bubbles in a bloodstream are diverted from the bloodstream in a diversion chamber by ultrasonic energy, and are collected in a blood-filled stasis column where they can be accurately measured by a bubble detector and then vented to atmosphere. Bubbles of different sizes can be separated into different stasis columns for enhanced measurement.

Abstract: A modular moulding system uses slotted blocks which are first individually mounted on a support surface. A length of moulding runner is inserted deeply into the slot of one of the blocks, and then partially withdrawn while being inserted into the slot of the other block. In this manner, moulding can be assembled by one unskilled person working alone, and accuracy of the cut of moulding runners is not critical.