Improved Oxygenators for Circulatory Assist Devices

摘要

Research was conducted to design, fabricate and evaluate an improved blood oxygenator of the capillary membrane type. The oxygenator utilizes a unique process to form capillaries in a microporous substrate, and to line them with a thin blood compatible membrane. The support of the substrate allows a thinner film to be used than would otherwise be practical. This together with favorable blood path geometry should result in high gas transfer rates for both oxygen and carbon dioxide. The oxygenator basically consists of one flat and one grooved membrane. Much of the research effort was devoted to the development of an ultrathin cellulose film for use as a gas permeable membrane. We were successful in depositing films which ranged in thickness from 2 to 4 microns on a micro-porous substrate. However, the cellulose membrane had to be abandoned because the films we produced had an unacceptably low oxygen permeability. The film depositing techniques acquired in working with cellulose were used to deposit films of silicone rubber on the substrate and early success was achieved in attaining good quality silicone rubber films, which had predictably high oxygen permeability. A full scale oxygenator was constructed. The machine contains 54 single elements, forming 53 blood passages, with a total of 30,000 capillaries rated for a flow of three liters per minute. Little difficulty was encountered in producing the machine. (Author)