Hazards of ventilation during early separation from total cardiopulmonary bypass

ABSTRACT

The effect of pulmonary ventilation upon systemic arterial blood gases during cardiopulmonary bypass in presence of left ventricular ejection was evaluated in 20 adult male patients undergoing aortic vlave replacement. Following rewarming, establishment of a sinus rhythm, and production of pulse pressure of at least 20 mm Hg on the artirial pressure trace caused by left ventricular ejection, arterial blood gases were obtained from artirial and venous extracorporeal circuit and radial arterial cannula. Patients were divided into a non ventilated [n=10] or a ventilated [n=10] group. The ventilated group was given 10 breaths/min. with 100 oxygen at a tidal volume of 10 ml/kg. After 5 minutes the arterial blood gas data were again obtained. significant findings [p<0.05] include decrease in systemic carbon dioxide tension and increase in systemic pH in the ventilated group and decrease in systemic oxygen tension in the non-ventilated group. Although the changes in the arterial blood gases were significant. These changes occurred well within the limit of clinical acceptability. It is concluded that left ventricular ejection for short periods during full cardiopulmonary bypass does not necessitate pulmonary ventilation