Patient selection: primary (first time), isolated (no valve replacement)
Predictors identified on multivariate analysis:
(1) body weight <= 70 kilograms
(2) preoperative hematocrit <= 40% (preoperative hemoglobin <= 13 g/dL)
(3) serum creatinine > 100 µmol/L
(4) use of cardiopulmonary bypass (CPB)
Additional factors may include:
(1) female gender
(2) age > 65 years
(3) body mass index (BMI) <= 25 kg per square meter
(4) body surface area (BSA) < 1.75 square meter
(5) postoperative chest tube drainage > 1,000 mL
(6) higher EuroScore
(7) use of the radial artery
(8) greater number of distal anastomoses (which may correlate with longer surgery)
In their series of 71 patients two thirds of patients were transfused with half of these (one third of total) requiring more than 2 units of RBCs. One in six patients will require more than 4 units.
