A CML membrane oxygenator (Cobe, Arvada, Colo) and a nonpulsatile pump (Saras, Ann Arbor, Mich) were used. As Stephens et als have shown that Ringers lactated solution priming does not modify blood glucose, the priming consisted of Ringers lactated solution (1,500 ml), sodium bicarbonate 1.4 percent (300 ml) and heparin (5,000 U). Saint Thomas’ Hospital crystalloid cardioplegic solution without glucose was injected at 4°C into the aortic root immediately after aortic cross-clamping and every 20 mn thereafter until unclamping. As is standard practice in our institution, mean arterial pressure was maintained between 50 and 80 mm Hg by adjusting perfusion index and use of nitroglycerin. Vasopressor agents were not used in these patients during CPB.
A heating mattress (38°C) was used continuously, except during cooling, in group 1. In this group rewarming did not begin before 30 min of CPB had passed, and the patients were rewarmed at 37°C (pulmonary artery temperature).
Reversal of heparin was accomplished with protamine sulfate, 4 mg/kg; aprotinine, 2,000,000 protease inhibitory units (Iniprol, Choay, Paris, France), was administered simultaneously.