PULMONARY parenchymal hemorrhage in cases undergoing open heart surgery using cardiopulmonary bypass may well be caused by hypoxia in the lungs. Three important factors seem to be involved in the hypoxic production of pulmonary parenchymal hemorrhage: pulmonary artery flow, bronchial arterial oxygen saturation, and bronchial arterial flow.
A considerable amount of clinical and experimental work has been done to determine the cause of pulmonary parenchymal changes occurring during cardiopulmonary bypass.
Gibbon,1 in his early work with cardiopulmonary bypass, unexpectedly found that postoperative pulmonary dysfunction was contributing more than other complications to the morbidity after open heart operations. He published a paper reporting his findings in 1959.
One year before Gibbon's paper was actually published, Dodrill2 reported that pulmonary problems accounted for at least 15% to 25% of deaths following heart surgery. Kirklin3 et al found pulmonary complications in early open heart patients and con sidered inadequate perfusion