Relationships among haemoglobin level, packed red cell transfusion and clinical outcomes in patients after cardiac surgery.

Abstract

To identify associations among haemoglobin (Hb) concentrations, blood transfusions, and clinical outcomes in patients after cardiac surgery, especially in those who undergo valve replacement or bypass surgery. Prospective observational trial. Surgical intensive care unit in a tertiary-level university hospital. 1216 Consecutive patients. Haemoglobin at admission and 6, 12, 24, and 48 h later, and then, every 24 h while patients remained in the intensive care unit (ICU); number of transfusions and clinical events. Patients were divided into quartiles according to minimal haemoglobin, the first and second of which (Hb <8.10 and <8.91 g/dL, respectively) differed significantly (P < 0.001) from the other two quartiles in terms of more organ failure, longer ICU stay, and higher mortality. We found associations between being transfused >or=4 packed red cells (PRCs) and a worse clinical outcome and higher mortality. The associated mortality rate was higher for patients who underwent bypass surgery when they had Hb <or=8.9 g/dL and for those who underwent valve replacement when they had Hb >8.9 g/dL and were transfused >or=4 PRCs. Low haemoglobin concentrations and transfusions in patients undergoing cardiac surgery are associated with increased morbidity and mortality. Also, anemia and transfusions are associated with poor outcome. Therefore, intra- and postoperative bleeding seem to be a risk factor in patients undergoing cardiac surgery.