Twenty-eight patients undergoing major aortic reconstructions were prospectively randomized into two groups to compare blood replacement with either whole blood (WB) or packed cells (PRBC). Cardiac index (CI), pulmonary capillary wedge pressure (PCWP), intrapulmonary shunt (Qs/Qt), serum colloid osmotic pressure (COP), platelets, prothrombin time (PT), partial thromboplastin time (PTT), and fibrinogen were measured before operation, during operation, and for three
days after operation. The postoperative CI increased significantly in both groups from preoperative value, but was not significantly different between the groups. In the PRBC group, there was a significant decrease in postoperative COP and COP-PCWP gradient from preoperative value. This did not occur in the WB group. There was no significant difference between groups in postoperative Qs/Qt, nor was there any evidence of clinical or radiographic pulmonary dysfunction. Both groups manifested a prolongation of the PT and PTT immediately after operation, but these returned to normal without intervention by the first day after operation. It is felt that blood replacement with reconstituted packed red cells can provide effective volume replacement without producing coagulopathy. The decreases observed in COP and COP-PCWP gradient do not result in physiologic or clinical evidence of significant pulmonary dysfunction.