Perfusion Characteristics During Cardiopulmonary Bypass and Subsequent Changes in Alveolar-Arterial Oxygen Tension Gradients

Abstract

In 11 elective coronary artery bypass graft (CABG) recipients, changes in alveolar-arterial O2 tension difference (ΔaDO2) from 5 minutes before to 30 minutes after cardiopulmonary bypass (CPB) ranged from −54.9 to + 63.1 torr and exhibited significant linear correlation (r = 0.77, p < 0.01) with the mean arterial perfusion pressure (MAPP) during CPB multiplied by the duration (T) of CPB divided by the body surface area (BSA) of the patient. The regression equation (ΔaDO2 = 0.015 MAPP/BSA × T - 50) enables estimation of the ΔaDO2 to result from a given episode of CPB. Mural edema of airways and pulmonary vasculature, developing during CPB, may be a mechanism underlying this correlation.