Effect of intravenous low-dose norepinephrine on blood loss in non-tourniquet total knee arthroplasty under general anesthesia: a randomized, double-blind, controlled, single-center trial

Abstract

Abstract Objective This prospective trial aimed to evaluate the effects of low-dose intravenous norepinephrine (NE) on intraoperative blood loss and bleeding from osteotomy sites during non-tourniquet total knee arthroplasty (TKA) under general anesthesia. Methods A total of 120 patients who underwent TKA between December 2020 and May 2022 were enrolled and randomly assigned to the intravenous low-dose NE Group (NE Group) or the control group (C Group). During surgery, NE Group received 0.05–0.1 μg/(kg min) of NE intravenously to raise and maintain the patient's mean arterial pressure (MAP). C Group received the same dose of saline as placebo. Intraoperative blood loss, bleeding score at osteotomy sites, Δlactate levels (Lac), postoperative complications, and transfusion rate during hospitalization were compared between groups. Results Intraoperative and osteotomy blood loss was significantly lower in the NE Group than in the C Group (P < 0.001). No significant difference was observed in ΔLac between groups (P > 0.05). There was no significant difference in complications between the groups 3 days after surgery (P > 0.05). In addition, there was no significant difference in blood transfusion rates between the two groups during hospitalization (P > 0.05). Conclusion In non-tourniquet TKA under general anesthesia, low-dose intravenous NE safely and effectively reduced intraoperative blood loss and provided a satisfactory osteotomy site while maintaining a higher MAP.