Assessing the Effectiveness of Retrograde Autologous Priming of the Cardiopulmonary Bypass Machine in Isolated Coronary Artery Bypass Grafts

Introduction: Currently, around 35-80% of patients undergoing cardiac surgery in the UK receive a blood transfusion. Retrograde autologous priming (RAP) of the cardiopulmonary bypass circuit has been suggested as a possible strategy to reduce blood transfusion during cardiac surgery.

Methods: Data from 101 consecutive patients undergoing isolated coronary artery bypass grafts (where RAP was used) were collected prospectively and compared with 92 historic patients prior to RAP use in our centre.

Results: Baseline characteristics (ie age, preoperative haemoglobin [Hb] etc) were not significantly different between the RAP and non-RAP groups. The mean pump priming volume of 1,013ml in the RAP group was significantly lower (p<0.001) than that of 2,450ml in the non-RAP group. The mean Hb level at initiation of bypass of 9.1g/dl in patients having RAP was significantly higher (p<0.001) than that of 7.7g/dl in those who did not have RAP. There was no significant difference between the RAP and non-RAP groups in transfusion of red cells, platelets and fresh frozen plasma, 30-day mortality, re-exploration rate and predischarge Hb level. The median durations of cardiac intensive care unit stay and in-hospital stay of 1 day (inter-quartile range [IQR]: 1-2 days) and 5 days (IQR: 4-6 days) in the RAP group were significantly shorter than those of the non-RAP group (2 days [IQR: 1-3 days] and 6 days [IQR: 5-9 days]).

Conclusions: In the population group studied, RAP did not influence blood transfusion rates but was associated with a reduction in duration of hospital stay.