MASS SPECTROMETER MEASUREMENT OF OXYGEN UPTAKE AND CARBON DIOXIDE EXCHANGE DURING CARDIOPULMONARY BYPASS

Abstract

O2 uptake (.ovrhdot.VO2) and CO2 output (.ovrhdot.VCO2) were measured continuously in 4 children during cardiopulmonary bypass using the variation in concentration of a tracer gas, Ar, as a measure of flow and a mass spectrometer to monitor gas concentrations. Normal values for the ratio of .ovrhdot.VCO2:.ovrhdot.VO2 (0.8) indicated that gas exchange equilibrium was established following sudden changes in body temperature. During rapid cooling 10% CO2 is necessary to ensure CO2 homeostasis within the body.