Background: Hemodilution occurring with cardiopulmonary bypass imposes a risk for blood transfusion. Autologous priming of the cardiopulmonary bypass circuit at the initiation of bypass partially replaces the priming solution with autologous blood. We examined the efficacy of autologous priming of the circuit in reducing blood transfusion.
Methods: One hundred and four patients were entered into a prospective, randomized, controlled study. Initiation of cardiopulmonary bypass was with or without autologous priming.
Results: With autologous priming, a mean volume of 808.8 +/- 159.3 mL of priming solution was replaced with autologous blood. This allowed a higher hematocrit value on admission to the intensive care unit and at discharge from hospital. In all, 49% of the control group required a blood transfusion compared with 17% from the autologous priming group (p = 0.0007). The mean volume of blood transfused was 277.6 +/- 363.8 mL in the control group compared with 70.1 +/- 173.5 mL in the autologous priming group (p = 0.0005).
Conclusions: Retrograde autologous priming of the bypass circuit reduces homologous blood transfusion owing to the reduction in bypass circuit priming volume.