Abstract: Both the number and the size of microair bubbles in a bloodstream are accurately determined optically, independently of oxygen saturation, by monitoring the intensity of light transmission in the 800-850 nm range through the bloodstream and indicating the count and amplitude range of peaks in the monitored intensity.

Abstract: A method and an apparatus for making tube bundles for various medical applications such as oxygenators, dialyzers, and heat exchangers is described. The tube bundle is suitable for use as a heat exchanger in, for example, a blood cardioplegia circuit. The winding apparatus axially winds a flexible tube around a winding core. The apparatus includes a tube shuttle, a shuttle driver and a core driver. The core driver rotates the winding core to distribute the tube on the winding core in layers.

Abstract: An apparatus and a method for making a transfer device comprising a tube bundle. The transfer device is suitable for use as a heat exchanger in a blood cardioplegia circuit, for example. The apparatus axially winds a flexible tube around a winding core. The apparatus includes a winding core, a core rotating means, a tube bobbin, and a tube shuttle to guide the tube around the core. A shuttle rotating means rotates the tube shuttle around the core. The method of making the transfer device includes providing a winding core, winding a tube from end to end around the winding core, fitting the wound bundle into a housing, sealing the first and second ends of the housing using a potting material, cutting the ends of the bundle to expose a lumen within the tubes, and attaching a first end cap and a second end cap.

Abstract: A softshell blood reservoir for heart-lung machines is symmetrical about a central vertical axis and is divided into two chambers: a small main chamber accessed by the blood inlet and outlet connectors, and a larger storage chamber accessed from the main chamber through a selectably closable passage. This arrangement greatly reduces the priming volume of the reservoir without substantially affecting its total capacity, and enhances the mixing of venous and cardiotomy blood.

Abstract: Coiled medical plastic tubing is set in the coil shape by exposing it to a radio-frequency field while it is subjected to slight radially inward pressure. The amount of pressure and the power of the RF field are so adjusted as to cause the rungs of the coil to lightly stick together without deforming or weakening the coil itself.

Abstract: Blood volume in a soft-shell venous reservoir is measured for real-time display by ultrasonically measuring the distance between the walls of the reservoir bag at representative points and determining the volume of the bag by an interpolation based on the known shape of the reservoir bag as it expands and contracts.

Abstract: A softshell reservoir has threaded fittings, one on each side of a central axis. Venous and cardiotomy blood are mixed in a mixer which screwthreadedly engages either of these fittings so the reservoir can be positioned on the right or the left of the perfusionist without crossed lines, and with a minimum of priming volume. A threaded outlet fitting may be provided on the central axis to cooperate with threaded outlet tubing to facilitate packaging and sterilizing, as well as setup and disposal.

Abstract: A softshell blood reservoir incorporates an integral flexible cardiotomy section in which a filter/defoamer unit is supported in a semirigid cage. The reservoir also incorporates a storage section and a mixing section. The three sections can selectively communicate with each other. Cardiotomy blood is supplied to the cardiotomy section, and venous blood is supplied to the mixing section. The storage section holds varying amounts of cardiotomy blood to maintain a constant mixed blood output from the mixing section. Only the filter/defoamer unit and the mixing section need be primed.

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: 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 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: 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: 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: 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 three-stage cardiotomy filter/defoamer dispenses with the conventional tricot sock covering by forming the secondary defoamer as a small-pore foam impregnated with a much heavier concentration of defoaming agent than the primary large-pore defoamer.

Abstract: An accurate real-time volume measurement of the blood content of a soft-shell venous reservoir is obtained by computing the volume from the weight of the blood in the reservoir modified by the hematocrit of the blood.

Abstract: In a connector for a hardshell venous reservoir, improved positioning and better line holding ability is provided by forming a line-retaining barb on only the upper half of the connector. A dual-size or combo connector using this principle is also disclosed.