Alpha-stat and pH-stat management techniques in artificial blood oxygenators

This clinical observation relates blood pCO 2 , solubility, total CO 2 content, oxygenator FiCO 2 and ventilation rate, CO 2 transfer, and respiratory quotient during hypothermic cardiopulmonary bypass. Techniques employed to obtain the above parameters include blood gas analysis, temperature correction, gas and blood flow settings, mass spectrometry, Kelman's algorithm of the SingerHasting nomogram, and O 2 and CO 2 transfer calculations. Membrane lung O 2 and CO 2 transfer curves demonstrate the following respiratory quotient (RQ) and CO 2 blood content requirements for two common hypothermic pCO 2 management techniques: TECHNIQUE COOLING WARMING pH-Stat CO 2 content increase, RQ lower than normal CO 2 content decrease, RQ much greater than normal Alpha-Stat CO 2 content constant, RQ normal CO 2 content constant, RQ normal Oxygen, carbon dioxide transfer versus patient temperature plots from hypothermic CPB demonstrate the perfusionist's complete control of blood CO 2 content and blood pCO 2 .