Response of pulmonary venous admixture. A means of comparing therapies?

Patients who require cardiopulmonary bypass have a reproducible increase in interstitial pulmonary water and pulmonary venous admixture, a decrease in functional residual capacity, and a mild arterial hypoxemia. Therefore, such patients are good subjects for evaluating therapy with positive end-expiratory pressure and steroids, both of which are controversial. We sought to determine if the response of the pulmonary venous admixture to varying concentrations of inspired oxygen could affect the apparent efficacy of these types of therapy. Results of our study are presented.