Retrograde Autologous Priming of the Cardiopulmonary Bypass Circuit: Safety and Impact on Postoperative Outcomes

Objectives: Retrograde autologous priming (RAP) is a blood conservation technique used to limit the severity of hemodilution during cardiopulmonary bypass and reduce perioperative transfusions. The aim of this investigation was to examine the safety of RAP and to determine the effect of RAP on adverse outcomes after cardiac surgery. Design: Retrospective cohort study. Setting: University hospital. Participants: Five hundred fifty-nine undergoing cardiopulmonary bypass. Interventions: Data were retrospectively collected on 2 cohorts of adult cardiac surgical patients operated on by a single surgeon. In the RAP group (n = 256), outcome data were analyzed on all subjects over a 2-year period during which RAP was used routinely. This group was compared with a similar cohort of patients undergoing cardiopulmonary bypass over a 2-year period immediately before the introduction of RAP into the clinical practice (no-RAP group, n = 287). Measurements and Main Results: In-hospital mortality was not significantly different between the RAP group (2.7%) and the no-RAP group (3.8%, p = 0.636). The incidence of postoperative cardiac arrest was significantly less in the RAP group (1 patient) compared to the no-RAP group (9 patients, p = 0.040). There were no differences between the 2 groups in the incidence of several other postoperative complications, including postoperative delirium (1.6% RAP v 3.1% no RAP), heart block (1.6% RAP v 4.2% no RAP), atrial fibrillation (19.1% RAP v 22.7% no RAP), and requiring postoperative ventilation >24 hours (2.7% RAP v 5.2% no RAP). Conclusions: The authors observed no evidence of any increase in adverse events in the RAP group of this retrospective cohort study, but they did observe a decrease in the incidence of postoperative cardiac arrest in the RAP group. These findings suggest that RAP is a safe technique and may have a beneficial effect on postoperative outcomes.