Is a fixed low-dose protamine better at reducing postoperative bleeding in off pump coronary artery bypass grafting?

Protamine is used ubiquitously in all cardiac surgeries for reversal of heparin. Risk of postoperative bleeding is increased with inadequate heparin reversal or due to anticoagulant side effects of protamine; hence, it is important to dose protamine properly. This study compares 80% protamine dose with full dose on postoperative bleeding and transfusion needs in OPCAB.

The aim of our study was to find whether lower dose of protamine could reduce postoperative bleeding and need for blood product transfusions in off pump coronary artery bypass grafting as compared to the regular dose of protamine.

This was a double-blinded randomised controlled trial where patients posted for off pump CABG meeting the inclusion criteria were included in the study.

Ninety patients were randomised to two groups, group F receiving full dose of protamine of 1 mg per mg heparin used, and group L received 0.8 mg per mg. Postoperative activated clotting time, bleeding at 1 h, 4 h, 24 h and total drainage till drains removal and blood product transfusion requirements were noted.Statistical analysis used: SPSS software.

Both groups were matched in demographics, preoperative cessation of heparin and aspirin and platelet counts. Both groups received equal heparin dose, activated clotting time before protamine, activated clotting time post protamine in OT and ICU were equal as were the conduits used. There was no significant difference between the groups in post-operative drainage over time or in the need for blood product transfusions.

Eighty per cent of the dose of protamine can adequately reverse the heparin used during off pump cardiac surgery without any increase in incidence of postoperative bleeding or need for blood product transfusions.