Restoration of volume by crystalloid versus colloid after coronary artery bypass

Abstract

We compared Ringer's acetate-gluconate solution with 6% dextran-70 infused during rewarming after coronary bypass surgery. In a randomized study, 18 patients received 56 +/- 15 ml/kg of crystalloid (group 1), and 14 patients received 16 +/- 6 ml/kg of dextran (group 2). Data were taken at the following intervals: 4 to 5 h after terminating the cardiopulmonary bypass, after rewarming, the next morning on controlled ventilation and continuous positive airway pressure (CPAP) breathing, and after extubation. The patients were followed for 14 days. Prophylactic nitroglycerin infusion may have increased the need for plasma expansion. After volume loading, the stroke index increased in both groups, but the left ventricular stroke work index increased in group 2 only. After transition to the CPAP mode, hydrostatic pressures increased, more in group 2, doubling the pulmonary shunt flow. Pulmonary extravascular thermal volume did not change in either group. We conclude that hemodynamic stability occurred faster with dextran, and ventilatory weaning was somewhat easier with crystalloid.