The effect on coagulation parameters of the transfusion of cell saved blood after cardiac surgery

Introduction

Intraoperative cell salvage (IOCS) minimizes exposure to donor blood. However, the process removes plasma and platelets and may worsen the coagulopathy induced by heparinization and cardiopulmonary bypass (CPB). Accordingly, we undertook a prospective observational study to examine the changes in coagulation parameters following the retransfusion of IOCS blood.

Methods

Following Regional Ethical Committee approval and written informed patient consent, 50 patients undergoing elective cardiac surgery were recruited. Cardiac anaesthesia, surgery and perfusion were conducted according to institutional protocols. CPB incorporated a Dideco D903 oxygenator (Dideco S.p.A., Modena, Italy) with integral heat exchanger primed with 2 l Hartmann's solution. IOCS was performed with a Dideco Compact Advanced Cell Saver. All shed mediastinal blood prior to heparinization and following protamine reversal was salvaged in addition to the CPB residue after the termination of CPB. Blood samples were drawn prior to incision (T1), 5 min after protamine reversal of heparin (T2) and 15 min after retransfusion of IOCS blood (T3), and analysed for ionised calcium, albumin, international normalized ratio, activated partial thromboplastin time ratio, factors VII and IX, fibrinogen, antithrombin, activated protein C, platelet count, haemoglobin, packed cell volume (PCV) and thromboelastogram. IOCS blood was analysed in five patients. Statistical analysis used the appropriate parametric and nonparametric tests. Significance was taken at the 5% level.

Results

Nine patients were given intraoperative blood or blood products and were excluded from further analysis. Of the remaining 41 patients (mean age 64.6 years and mean weight 84 kg), 35 were male. Mean CPB was 74 min and mean cross clamp was 46 min. The median volume of IOCS was 613 ml (7.3 ml/kg). There were almost undetectable amounts of coagulation factors present in IOCS blood. Table 1 presents the coagulation data.

Table 1 Coagulation data

Conclusions

IOCS blood in routine cardiac surgical practice raises the PCV to a point at which red cell transfusion is not necessary. There are no deleterious effects on coagulation. We recommend its routine use. To minimize unnecessary exposure to blood products, where transfusion is protocol driven, coagulation studies should follow IOCS blood transfusion.