Toward the Development of a Neonatal Pulmonary Assist Membrane Oxygenator

摘要

A micro-channel membrane oxygenator is developed to assist the pulmonary function of infants with serious respiratory insufficiency. The unit is primarily designed for partial support along with one of the current respiratory assist techniques (such as CPAP, PEEP, and ventilation) when the latter alone cannot maintain adequate gas exchange in the lung. Biomechanical design criteria of this assist oxygenator and bypass system are based upon (1) keeping shear stress in the blood flow below the critical value that may lead to blood trauma; (2) low blood flow resistance for potential pumpless bypass; (3) low priming volume; and (4) optimal oxygen/carbon dioxide exchange. The present study is oriented toward the proper selection of these criteria and their effects on blood elements. The micro-channels were fabricated on metal sheets by a photochemical etching process with an approximate semi-circular shape (150 plus or minus 25 microns in radius). The gas exchange to the blood flow in the channels was accomplished through a membrane which was placed across the diametric plane of these channels. To search for potential reduction of blood trauma due to the interface between the blood and the bypass, the extracorporeal system was coated with TDMAC (tridodecylmethylammonium chloride). Other coating materials are presently being considered along with specific animal models for clinical applications.