The Contribution of Intraoperative Mechanical Red Cell Salvage to Acidosis in the Immediate Postoperative Period After Cardiac Surgery

Metabolic acidosis is a common complication that patients experience in the early postoperative period following cardiac surgery. Increasingly, the composition and volume of intravenous fluids administered during surgery have been implicated in the development of postoperative acidosis. Intraoperative Cell Salvage (ICS), an autologous blood transfusion technique employed by Cardiac/Perfusion Units to minimize blood loss during surgery, involves the infusion of of one such fluid, 0.9% sodium chloride. The rapid infusion of large volumes of 0.9% sodium chloride has previously been linked with the development of hyperchloraemic acidosis. It was therefore hypothesized that the volume of mechanically salvaged of red blood cells re-infused into patients undergoing heart surgery contributes to the acidosis that occurs in the early postoperative period.

To test this, the investigators have designed an observational cohort study to check for correlation between the volume of cell salvaged blood infused during surgery and the severity of postoperative acidosis (which will be assessed using data from routine arterial blood gas samples).