Integrated heat exchanger/reservoir

摘要

A low prime membrane oxygenator and an integrated heat exchanger/reservoir for use alone or in combination in an extracorporeal blood circuit. The oxygenator has a simple, five-part construction including a housing defining an annular oxygenation chamber within which a plurality of hollow fibers are arranged in an annular bundle with flow spaces therebetween. A blood inlet port and manifold deliver blood through a plurality of evenly circumferentially spaced inlet apertures to the oxygenation chamber, and blood flows generally axially through the elongated annular chamber to a plurality of evenly circumferentially spaced outlet apertures. A gas inlet communicates with a header space to deliver gas having a high oxygen content to internal lumens of the fibers. Gas transfer between the blood and gas takes place through the semi-permeable hollow fiber membranes in the oxygenation chamber. Specific geometric ratios, a particular hollow fiber architecture, and the absence of a heat exchange function, all combine to reduce the prime volume required by the oxygenator. The reservoir includes a hard outer shell topped by a lid with a venous blood inlet. Blood from the inlet enters an elongated annular heat exchange chamber defined between two vertical cylindrical walls within the reservoir. A plurality of heat exchange coils in the annular chamber provides an efficient heat transfer function with low prime volume requirement. Cardiotomy fluid may be first debubbled and then combined with the venous blood stream entering the heat exchange chamber. After passing through the heat exchange chamber, the blood passes through a series of filters before being pumped to the oxygenator.