Effects of stored and fresh blood transfusions on postoperative pulmonary function. A clinical study on patients following extracorporeal circulation in association with aortic valve surgery.

The effects on postoperative pulmonary function of fresh versus stored blood when priming the heart-lung machine were studied in 49 patients subjected to aortic valvular replacement. The onset of extracorporeal circulation was considered to mimic the conditions of massive blood transfusion. The patients receiving heparinized fresh blood required more oxygen in the respirator than those receiving stored blood, but still had a significantly lower arterial oxygen tension during the first and second postoperative days. The fresh blood patients also showed a tendency to require a larger amount of diuretics to maintain adequate urine output. Pre- and postoperative bleeding and changes in postoperative hematological variables did not differ in the two groups. The results imply that stored blood should be preferable when substituting blood losses.