Abstract: Apparatus for retaining concentric parts within one another and enabling limited axial movement therebetween, includes an inner component having a shoulder disposed in an external perimeter thereof and an outer tubular component having a wall and an open end for receiving the inner component and an inner surface for abutting the shoulder and enabling a sliding interface therebetween. A retaining tab is provided and disposed in the wall proximate the open end for depression of a free end toward the wall and a slot formed in the wall beneath the tab enables the free end to be forced therepast for retaining the free end inside the wall for engagement with the shoulder, thus preventing separation of the inner component from the outer component.

Abstract: The need for a venous reservoir in a heart-lung machine is obviated by using a vacuum-purged negative-pressure air filter in the venous return line ahead of the main blood pump. The purging vacuum for the venous air filter can also be used to purge air from the cardiotomy reservoir if a backflow-preventing valve is used on the venous air filter.

Abstract: The efficiency of a hollow fiber wound oxygenator is improved by varying the packing density of the fiber bundle in a direction longitudinal and/or circumferential of the core.

Abstract: Blood mixing in fiber-wound oxygenators is improved by inserting at least one layer of a planar apertured mat between selected layers of wound gas-exchange fibers.

Abstract: The need for a venous reservoir in a heart-lung machine is obviated by using a vacuum-purged negative-pressure air filter in the venous return line ahead of the main blood pump. The purging vacuum for the venous air filter can also be used to purge air from the cardiotomy reservoir if a backflow-preventing valve is used on the venous air filter.

Abstract: A heat exchanger, or the heat exchanger component of a multi-function device, comprising a polymeric heat transfer material. The heat exchanger exhibits reduced voltage-induced breakdown of the polymeric material, which can lead to cross-contamination of the two fluids. Either or both of two approaches may be employed. The first approach modifies the polymeric material to increase its resistance to breakdown. The second approach employs at least one electrical bridge between the fluids in the two sides of the heat exchanger, thus placing the two fluids into electrical equilibrium.

Abstract: Heat exchanging contact of water and blood with a pleated metal bellow heat exchanging surface in a heat exchanger for an extracorporeal blood circuit is improved by so forming the pleats of the bellows that the fluid chamber inside each pleat continuously narrows from the mouth of the pleat toward the inner end of the chamber. Uniform water distribution along the bellows is accomplished by making the water manifold in the heat exchanger core much larger in cross section than the inlet fitting to the manifold.

Abstract: The need for a venous reservoir in a heart-lung machine is obviated by using a vacuum-purged negative-pressure air filter in the venous return line ahead of the main blood pump. The purging vacuum for the venous air filter can also be used to purge air from the cardiotomy reservoir if a backflow-preventing valve is used on the venous air filter.

Abstract: The present invention is direct to a method of connecting a piece of tubing to an outlet manifold of an oxygenator that prevents excessively high positive or negative pressure from forming in the oxygenator and helps to minimize the possibility of misidentifyig the outlet connector. The outlet connector is hollow and substantially cylindrically tubular in shape so that a hollow inner conduit is formed. The outlet connector is in fluid communication with the outlet manifold of an oxygenator through the inner conduit. In one embodiment, the outlet connector has an elongated hole extending through the tubular material of the outlet connector into the hollow inner conduit formed therein. The elongated hole is preferable large enough to be felt by the fingers of the person connecting tubing to the outlet connector. The elongated hole is preferably arrow shaped with the arrow pointing in the direction of fluid flow out of the outlet manifold.

Abstract: A blood inlet manifold is provided for connection to a first end of a blood heat exchanger including a plurality of hollow conduits arranged in a bundle. A plurality of first ends of the conduits terminate adjacent the first end of the blood heat exchanger and a plurality of second ends of the conduits terminate adjacent a second end of the blood heat exchanger. The blood inlet manifold includes a blood inlet nozzle having an upstream segment and a downstream segment. The upstream segment is connectable to a tube for conveying blood. The blood inlet manifold further includes a generally conical wall member connected to the downstream segment of the blood inlet nozzle and connectable to the first end of the blood heat exchanger. The connection of the blood inlet manifold to the blood heat exchanger defines a chamber between the conical wall member and the first set of ends of the conduits. An interior of the downstream segment of the blood inlet nozzle opens into this chamber.

Abstract: Blood heat exchanger apparatus with improved heat exchanged capability and improved bonding of micro-conduit heat exchange fibers. The micro-conduit comprises a plurality of elongated fibers, which may be made of a hydrophobic material such as polypropylene or polyethylene. The micro-conduit fibers may be provided as a heat exchanger micro-conduit wrapping material, wherein the micro-conduit fibers are attached to a thin flexible interconnect, such as woven netting, to maintain the fibers at predetermined and substantially parallel alignment with each other. The wrapping material is wrapped about an elongated spindle to provide a generally cylindrical heat exchange core. A shell is placed around the core to contain the heat transfer fluid which passes around the exterior of the fibers. Opposing first and second seals are created by applying potting compound between fibers proximate the spindle's first and second ends respectively.

Abstract: A blood outlet manifold is provided for a membrane-type blood oxygenator made of a plurality of micro-porous fibers. The fibers have first and second ends wound into a generally cylindrical bundle. The blood outlet manifold comprises a generally cylindrical vessel having a first annular wall dimensioned to snugly overly an exterior surface of the oxygenator fiber bundle. The vessel further has a flared portion including a second annular wall radially spaced from an end portion of the exterior surface of the oxygenator fiber bundle adjacent to the second ends of the fibers. An annular blood collection chamber is defined between the exterior surface of the oxygenator fiber bundle and the second annular wall for receiving blood flowing radially outwardly from around the fibers of the oxygenator fiber bundle. A seal is provided between the end portion of the oxygenator fiber bundle and the second annular wall.

Abstract: Micro-conduit with enhanced wetting characteristics for use in providing a blood heat exchanger apparatus with improved heat exchange capability. The micro-conduit comprises a plurality of elongated fibers, which may be made of a hydrophobic material such as polypropylene or polyethylene. Each fiber is open at two opposing ends, and has an inner surface between the open ends. The inner surface is coated with a wetting agent, such as phosphatidyl choline or another ampiphilic material with a hydrophilic end and a hydrophobic end. The fibers may have a shape and size that without presence of the wetting agent, would otherwise substantially impair free passage of water. The micro-conduit may be provided as a heat exchanger micro-conduit wrapping material, wherein micro-conduit fibers are attached to a thin flexible interconnect, such as woven netting, to maintain the fibers at predetermined spacings in substantially parallel alignment with each other.

Abstract: A transition manifold is provided for use in association with the upper end of a generally cylindrical heat exchanger fiber bundle having a plurality of vertically extending conduits with open upper ends terminating in substantially co-planar fashion. The transition manifold is specially configured for redirecting blood flowing out of the upper end of the heat exchanger fiber bundle radially outwardly around the fibers of a concentric, surrounding oxygenator fiber bundle. The transition manifold includes a generally conical wall member defining a surface which extends at a relatively flat angle with respect to a plane perpendicular to a vertical central axis of the heat exchanger fiber bundle. The surface of the conical wall member diverges away from the upper end of the heat exchanger fiber bundle in a direction moving radially outwardly from the central axis.

Abstract: The present invention is an outlet connector configuration for an oxygenator that prevents excessively high positive or negative pressure from forming in the oxygenator and helps to minimize the possibility of misidentifying the outlet connector. The outlet connector is hollow and substantially cylindrically tubular in shape so that a hollow inner conduit is formed. The outlet connector is in fluid communication with the outlet manifold of an oxygenator through the inner conduit. In one embodiment, the outlet connector has an elongated hole extending through the tubular material of the outlet connector into the hollow inner conduit formed therein. The elongated hole is preferable large enough to be felt by the fingers of the person connecting tubing to the outlet connector. The elongated hole is preferably arrow shaped with the arrow pointing in the direction of fluid flow out of the outlet manifold.

Abstract: The obstruction of a curved blood manifold window in a blood oxygenator by oxygenation fibers which lie along a chord of a curved window when wound upon the oxygenator core is avoided by recessing the manifold wall portions most closely adjacent the window sufficiently so that the fibers lying on that chord remain sufficiently spaced from those closest wall portions to allow blood flow between those wall portions and the closest fibers.

Abstract: A filter device for a cardiotomy reservoir comprises multiple layers of concentric, tubular elements with a central passage for supply of blood, purified by passage through the device. A first, inner element for defoaming the blood comprises a porous sponge material within a second element comprising a depth filter medium for filtering the blood. The depth filter is surrounded by a third element of porous sponge material spacing apart the depth filter and the outer, fourth element, a fine-filter screen for removing substantially all remaining, undesirable particulate matter in the blood.

Abstract: A blood defoamer for use in surgical procedures is disclosed comprising a porous defoaming element, a non-porous end piece in contact with a surface of the defoaming element, and a layer of fabric affixed to the end piece adjacent to said surface. Bypass of blood flow around the layer of fabric, which is situated downstream of the defoaming element, and accumulation of bubbles in the defoamed blood reservoir are prevented by bonding a suitably configured retaining ring to the end piece with a portion of the layer of fabric held in a fluid-tight seal between the end piece and the retaining ring.