Effects of Ultrathin Silicone Coating of Porous Membrane on Gas Transfer and Hemolytic Performance

Abstract: To assess the effect of an ultrathin (0.2 μm) silicone-coated microporous membrane oxygenator on gas transfer and hemolytic performance, a silicone-coated capillary membrane oxygenator (Mera HP Excelung-prime, HPO-20H-C, Senko Medical Instrument Mfg. Co., Ltd. Tokyo, Japan) was compared with a noncoated polypropylene microporous membrane oxygenator of the same model and manufacturer using an in vitro test circuit. The 2 oxygenators showed little difference in the oxygen (O₂) transfer rate over a wide range of blood flow rates (1 L/min to 8 L/min). The carbon dioxide (CO₂) transfer rate was almost the same in both devices at low blood flow rates. but the silicone-coated oxygenator showed a decrease of more than 20% in the CO₂ transfer rate at higher blood flow rates. This loss in performance could be partly attenuated by increasing the gas/blood flow ratio from 0.5 or 1.0 to 2.0. In the hemolysis study, the silicone-coated membrane oxygenator showed a smaller increase in plasma free hemoglobin than the noncoated oxygenator. The pressure drop across both oxygenators was the same. These results suggest that the ultrathin silicone-coated porous membrane oxygenator may be a useful tool for long-term extracorporeal lung support while maintaining a sufficient gas transfer rate and causing less blood component damage.