ABSTRACT
Haemodilution resulting from crystalloid priming of the cardiopulmonary bypass (CPB) circuit is one of the important reasons for blood transfusion in cardiac surgery, especially in patients with low body surface area (BSA). A prospective study was performed to investigate the technique of intraoperative blood donation (IAD) and retrograde autogous priming (RAP) to limit haemodilution and transfusion requirements. Forty patients with low BSA (<1.7m2) undergoing primary valvular cardiac surgery were assigned to either RAP group or a control group (C). The RAP group (n=20) was subjected to IAD by collecting a calculated volume of blood (272+/-44.3 mL) after induction of anaesthesia. Prior to initiation of CPB the prime volume was reduced by discarding some of it and the CPB reservoir was filled retrogradely through the aortic cannula draining 482+/-78.4 mL of blood. In group C (n=20) only IAD was carried out collecting 295.0+/-62.6 mL of blood. Anaesthetic technique was similar in both groups. Strict transfusion thresholds were observed. There were no significant difference between the groups with respect to baseline characteristics, BSA, type of procedure, perfusion technique and haematologic profile. The haematocrit on CPB was significantly higher in the RAP group as compared with group C (24.2+/-1.3% and 22.1+/-2.5% respectively, p=0.009). Transfusion of allogenic blood during and after surgery was significantly lower in the RAP group (143.6+/-117mL) versus 405.2+/-358.1mL in group C (p=0.02). Postoperative chest tube drainage was 218+/-67.4 mL in the RAP group and 300+/-191 mL in group C which was not significantly different (p=0.18). The technique of intraoperative autologous donation and retrograde priming is simple, safe and cost effective procedure for blood conservation in patients with small BSA undergoing primary valvular surgery.