Cardiopulmonary Bypass with Large Volume Nonblood Perfusate

Abstract

Experimental and clinical data have been presented which support the efficacy of using a large-volume nonblood perfusate for cardiopulmonary bypass. Dogs have consistently survived hemodilution of 100 to 120 ml/kg body wt when manifest hypoxic acidosis has been ameliorated with THAM (tris [hydroxymethyl] aminomethane) or sodium bicarbonate. Fifty-eight patients have undergone total bypass with the disc oxygenator totally primed with 2,500 to 3,000 ml of buffered Ringer's or Ringer's lactate solution. Normothermia and moderate hypothermia have been employed with a hemodilution of 33 to 60 ml/kg body wt and a mean perfusion hematocrit of 24%. Despite the decrease in oxygen-carrying capacity of the blood, acidosis has not been observed during prolonged perfusions at median flow rates. Following oxygenator reinfusion, the postoperative total blood volume has been normal. However, a decrease in red cell mass was observed which necessitated the administration of "packed red cells." With this technique, the clotting time was more readily restored to normal, and kidney function was markedly improved over a comparable series of patients perfused with donor blood.