Effects of autologous priming on blood conservation after cardiac surgery

Cardiopulmonary bypass can result in hemodilution due to the crystalloid prime, increasing the need for blood transfusion. Alternative perfusion techniques have the potential to decrease this hemodilution. The objective of this study was to determine whether a protocol of retrograde autologous prime (RAP) and venous antegrade prime (VAP) reduces the need for blood transfusion and increases the hematocrit following cardiac surgery.

We performed a retrospective review of 140 consecutive non-randomized patients who underwent cardiac surgery with cardiopulmonary bypass between November 2011 and September 2012. RAP and VAP techniques were used in 70 patients while the other 70 were managed with conventional perfusion strategies. The primary outcome measure was a composite outcome of any blood transfusion or a discharge hematocrit less than 27%.

Baseline demographics and patient characteristics were similar between the two groups, with the exception of the RAP/VAP group having a lower baseline creatinine. There was a trend toward decreased perioperative blood transfusions in the RAP/VAP group (13/70, 19%) compared with the non-RAP/VAP group (23/70, 33%, p=0.053). RAP/VAP patients had a significantly higher hematocrit at hospital discharge (30.0 ± 4.3% vs. 28.3 ± 4.1%, p=0.012). The number of patients receiving a transfusion or being discharged with an hematocrit less than 27% was significantly less in the RAP/VAP group (21 vs. 41, p=0.001). This effect persisted on multivariable analysis.

RAP and VAP perfusion techniques may reduce hemodilution, potentially resulting in less blood transfusions and higher postoperative hematocrits. These techniques should be considered in all patients undergoing cardiac surgery with cardiopulmonary bypass.