Effects of epidural dexmedetomidine on perioperative hemodynamics in patients undergoing varicose vein surgery for the lower extremities: a prospective randomized, controlled, double-blind clinical trial

Abstract

Study objective: To investigate the effects of epidural dexmedetomidine infusion on perioperative hemodynamics in patients. Design: Randomized, interventional, blinded clinical trial. Setting: An operating room and postoperative period in university-affiliated teaching hospital. Patients: 90 patients aged 18~65 years, of ASA status I/II, posted for elective saphenous vein peeling or aspiration surgery. Interventions: Patients were randomly divided into 0.5 μg/kg dexmedetomidine combined with 0.67% ropivacaine epidural infusion group (ED group), 0.5 μg/kg dexmedetomidine intravenous infusion combined with 0.67% ropivacaine epidural infusion group (VD group), and 0.67% ropivacaine plus isovolumic saline epidural infusion group (NS group), with 30 cases in each group. Measurements: The primary outcome was the systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) at before dexmedetomidine infusion (T0), 5 min (T1), 15 min (T2), 30 min (T3), 1 h (T4), 2 h (T5), 4 h (T6), 6 h (T7), 8 h (T8) after the start of dexmedetomidine infusion. The secondary outcomes included plasma norepinephrine (NE) concentration, myocardial oxygen consumption (MVO2), the Ramsay sedation score, the Visual Analogue Scale (VAS) score, anesthetic efficiency between three groups, patient's satisfaction with postoperative anesthesia and the occurrence of adverse reactions. Main results: Compared with NS group, SBP at T3-7 and DBP at T4-5 and T7 were significantly decreased in ED group (P＜0.05 or 0.005), SBP and DBP at T1-8 were lower in VD group (P＜0.05 or 0.005). SBP and DBP at T1-2 in ED group were higher than that in VD group (P＜0.05 or 0.005). The heart rate at T3-4 and T6-7 was lower in ED group than in NS group (P＜0.05 or 0.005). Compared with VD group, the heart rate in ED group at T7 was significantly decreased (P＜0.001). The plasma NE concentration in ED and VD groups at T3-7 was dramatically decreased compared with NS group (P＜0.05 or 0.005). The plasma NE concentration in ED group was considerably increased at T3-4 and reduced at T6 compared with VD group (P＜0.005). MVO2 was lower in both ED and VD groups than in NS group (P＜0.05 or 0.005). The anesthesia efficiency was significantly enhanced in ED group compared with VD and NS groups (P＜0.05 or 0.005). Compared with NS group, the anesthesia satisfaction score was higher in ED and VD groups (P＜0.001). The incidence of dizziness in ED group and the incidence of hypotension and dizziness in VD group were higher than that in NS group (P＜0.05 or 0.005), and the occurrence of hypotension was less common in ED group than in VD group (P=0.003). Conclusion: 0.5 μg/kg dexmedetomidine epidural infusion can provide more stable perioperative hemodynamics for patients with varicose vein surgery under epidural anesthesia, with lower incidence of hypotension and significantly advanced efficiency of epidural anesthesia.