Combined femoral artery block and femoral nerve block reduces thigh tourniquet-induced hypertension

STUDY OBJECTIVE: Tourniquet hypertension (TH) is thought to be caused by sympathetically mediated C-fibers in the femoral epicardium following prolonged intraoperative inflation of the tourniquet, and we hypothesized that blocking the femoral artery at the same time as a conventional femoral nerve block would reduce the incidence of TH. DESIGN: A prospective, double-blind, randomized, controlled trial. SETTING: Operating room and hospital ward in the Third Hospital of Hebei Medical University. PATIENTS: A total of 72 patients receiving high tibial osteotomy under general anesthesia were recruited from June 2022 to September 2022. INTERVENTIONS: Patients were randomly assigned to receive either a classical femoral nerve block (CFNB) or a modified femoral nerve block (MFNB). Patients in the CFNB group received a 30 mL of 0.5% ropivacaine femoral nerve block and patients in the MFNB group received a 20 mL of 0.5% ropivacaine femoral nerve block combined with a 10 mL of 0.5% ropivacaine femoral artery block. MEASUREMENTS: The primary outcome assessed was the incidence of TH. Data on intraoperative esmolol dosage, analgesic effect, complications and hemodynamics during surgery were also recorded. MAIN RESULTS: Incidence of TH was significantly higher in the CFNB group compared with the MFNB group (71.88% vs 31.25%, P = 0.002). The systolic blood pressure in the CFNB group was significantly higher than that in the MFNB group at 45, 60, 75 and 90 min after tourniquet inflation (P = 0.029, P = 0.020, P = 0.009, P = 0.007). There was also a significant increase in intraoperative esmolol dosage in the CFNB group (65.63 ± 44.15 vs 22.19 ± 33.74, P < 0.001). Postoperative pain scores and patient satisfaction were not statistically significant between the two groups. CONCLUSIONS: The present study demonstrated that modified femoral nerve block reduced intraoperative esmolol dosage and the incidence of TH.