Effect of extra protamine infusion in underweight patients undergoing cardiac surgery

Abstract Background The risk of post-operative bleeding was shown to be inversely correlated to Body Mass Index (BMI) in patients undergoing cardiac surgery. To identify whether an additional dose of protamine infusion given to underweight patients undergoing cardiac surgery will reduce postoperative blood loss, transfusion requirement and need for re-exploration for bleeding. Methods A prospective trial, where 100 underweight patients with BMI less than 20 kg/m 2 , underwent open cardiac surgery from May 2013 till June 2015. Patients were divided into two equal groups; Group (A), 50 patients, received additional protamine infusion at a dose of 25 mg/h for the first 6 h following complete neutralization of heparin at the end of surgery and Group (B), 50 patients, did not received any additional protamine. Results Blood loss was less in group A 576 ml ± 310 versus group B 800 ml ± 241 (P = 0.001). Transfusion requirement was also lower in group A 1.2 unit ± 0.7 versus group B 3.4 unit ± 1.5 (P = 0.001). The ACT (Activated Clotting Time) levels at 0 h (time of heparin neutralization) were not significantly different in both groups 108 s ± 9.1 versus 112 s ± 10.9 in groups A and B respectively (P = 0.4). However, after 6 h, the ACT was significantly lower in group A 110 s ± 9.7 versus 145 s ± 6.7 in group B (P = 0.01). Conclusion Additional protamine infusion for 6 h significantly reduced the amount of blood loss, transfusion requirement and the ACT at 6 h in underweight patients undergoing open cardiac surgery.