Water Condensation and Gas Exchange Correlation in Different Models and Fibers of Blood Oxygenators: “How Can We Improve Performance?”

Abstract

Creation of water condensation in blood oxygenators is a phenomenon that is constantly present during cardiopulmonary bypass and in medium- to long-term extracorporeal life support. Clinical observation of condensation at the oxygenator exit is still a common event normally associated with sudden cooling of the gas flow proximal to the outlet cover (after exiting the fiber bundle), where the warming effect of blood is no longer present. Condensation could progressively obstruct a certain number of fibers, reducing the efficiency of gaseous exchange in the membrane of the oxygenator surface. The study included 48 patients divided into four oxygenator groups of 12 each: group 1 used an Inspire 6 F oxygenator from Livanova; group 2, an Affinity Fusion from Medtronic; group 3, an Alone from Eurosets, and group 4, an ECMO Alone from Eurosets; while the last group used an ECMO Alone oxygenator from Eurosets with polymethylpentene fiber. Each group of oxygenators comprising 12 patients were divided into two groups, namely, A and B, with six patients in each group. Group A used mild hypothermia during the procedure, and group B of six patients used normothermia; Groups A and B were further subdivided into four subgroups: A1, A2, B1, and B2, each consists of three patients; subgroups A1 and B1 used negative aspiration (−8 mmHg) measuring humidity (%) and temperature (°C) in the gas oxygenator output; consequently, a measurement system was necessary to be created; Subgroups A2 and B2 did not use negative aspiration in the oxygenator outlet. No statistically significant difference for PaO2 and humidity values was found in polypropylene and polymethylpentene oxygenators with mild hypothermia management with vacuum and without vacuum in the gas outlet in the first 60 minutes and 60 minutes later during cardiopulmonary bypass. In normothermia, a statistically significant difference in the PaO2–humidity relationship was observed with polypropylene and polymethylpentene fiber models. Results of this study show an inversely proportional correlation between gas exchange and condensation in statistically significant values during the use of normothermia and a reduction in oxygenation performance, in polypropylene and polymethylpentene fiber oxygenators.