High altitude combined with low barometric pressure can present unique challenges during cardiopulmonary bypass (CPB), not only for the perfusionist, but also for the oxygenator. Manufacturers of cardiopulmonary devices have responded to the requests from the perfusion community with a variety of oxygenators which balance low priming volumes and low pressure drops against high gas transfer. This paper will feature the first author’s clinical studies using the Sorin Monolyth Oxygenator in a selected group of patients at an altitude of approximately 5200 feet and an average barometric pressure of 634 mmHg (sea level is 760 mmHg). A review of the 47 charts on patients requiring CPB and who met the selection criteria was performed retrospectively. To qualify for this study, the patient needed to weigh more than 91 kg. The data reviewed included type of surgery, age, weight, bypass time, crossclamp time, pump flows (l/min/m2), hematocrits pre- and post-CPB, and pressure drop across the membrane. The PaO2, PaCO2, FiO2 and sweep gas flow at hypothermia and normothermia were recorded. Data concerning oxygen transfer were obtained from the manufacturer’s report to the Food and Drug Administration. All patients had adequate blood gases while on CPB. We feel that the design of the Sorin Monolyth Oxygenator met our criteria for an oxygenator: low priming volume, low pressure drop, and sufficient gas transfer to provide safe oxygenation of all patients at high altitude.
Low pressure gas transfer in fibrous media with progressive infiltration: correlation between different transfer modes
