Lung water accumulation with and without left ventricular venting during cardiopulmonary bypass

The effect of venting on left atrial pressure and lung water accumulation was studied after prolonged aortic cross-clamping (90 min) and cardiopulmonary bypass in mongrel dogs. Two groups of animals, one with and one without venting, were studied. Left atrial pressure rose significantly (p less than 0.05) in the non-vented animals. This increase, however, did not allow for lung water accumulation or morphological evidence of pulmonary edema. These results appear to indicate that venting is only necessary if a normal left atrial pressure is sought during prolonged aortic cross-clamping. Since the increase in left atrial pressure did not have any detrimental effect on lung morphology or water accumulation, the role of venting under our experimental setting becomes more theoretical than necessary.