A randomized trial of the effect of low dose epinephrine infusion in addition to tranexamic acid on blood loss during total hip arthroplasty

Background: Total hip arthroplasty (THA) is associated with both intraoperative and postoperative blood loss resulting in anaemia and, in some patients, transfusion of red blood cells. Epinephrine enhances coagulation by several mechanisms. We evaluated the effect of intraoperative low dose infusion of epinephrine on intraoperative and early postoperative blood loss.

Methods: After consent, 106 subjects undergoing THA under spinal anaesthesia were randomly assigned to receive an i.v. infusion of either epinephrine 0.05 µg kg(-1) min(-1) or placebo (saline 0.9%) during the entire surgical procedure. Intraoperative tranexamic acid (TXA) was administered to all subjects. The primary outcome was intraoperative blood loss directly measured by drains and weighing swabs. Secondary outcome was total blood loss at 24 h postoperatively calculated using the Gross formula.

Results: Of 106 subjects randomized, 6 were excluded, leaving 100 subjects for analyses. Mean duration of surgery was 58 (21) min. Intraoperative blood loss was 343 (95% CI 300-386) ml in the epinephrine group compared with 385 (353-434) ml in the placebo group, P = 0.228. 24 h blood loss was 902 (800-1004) ml in the epinephrine group compared with 1080 (946-1220) ml in the placebo group, P = 0.038.

Conclusion: In subjects also receiving TXA, intraoperative low dose epinephrine infusion did not reduce intraoperative blood loss in THA but calculated 24 h blood loss was reduced by 180 ml compared with placebo. Further studies on low dose epinephrine in patients at high risk of significant bleeding are warranted.

Clinical trial registration: NCT 01708642.