The optimal dose of dexmedetomidine as a 0.59% ropivacaine adjuvant for epidural anesthesia in great saphenous varicose vein surgery, based on hemodynamics and anesthesia efficacy: a randomized, controlled, double-blind clinical trial

Objective This study aimed to explore the optimal dose of dexmedetomidine as a 0.59% ropivacaine adjuvant for epidural anesthesia on perioperative hemodynamics and anesthesia efficacy in patients undergoing great saphenous varicose vein surgery. Methods A total of 90 patients were randomly divided into three groups: 0.25 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED 1 group), 0.5 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED 2 group), and 0.75 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED 3 group). Hemodynamics, anesthesia efficiency, and adverse reactions were recorded. Main results Compared with the ED 1 group, the ED 2 group had lower systolic blood pressure at T 1-3 (T 1 , 95%CIs, 6.52–21.93, p < 0.001; T 2 , 95%CIs, 2.88–18.21, p = 0.004; T 3 , 95%CIs, 0.49–18.17, p = 0.035), and the diastolic blood pressure at T 1-2 was decreased (T 1 , 95%CIs, 4.55–14.36, p < 0.001; T 2 , 95%CIs, 0.37–12.17, p = 0.033). Compared with the ED 2 group, the ED 3 group had higher systolic blood pressure at T 1-2 (T 1 , 95%CIs, 5.90–21.46, p < 0.001; T 2 , 95%CIs, 2.07–17.55, p = 0.008) and higher diastolic blood pressure at T 1-3 (T 1 , 95%CIs, 2.91–12.81, p = 0.001; T 2 , 95%CIs, 1.32–13.23, p = 0.011; T 3 , 95%CIs, 0.14–11.52, p = 0.043). Compared with the ED 2 group, the heart rate was significantly decreased at T 1-4 in the ED 3 group (T 1 , 95%CIs, 2.25–15.72, p = 0.005; T 2 , 95%CIs, 2.35–13.82, p = 0.003; T 3 , 95%CIs, 0.50–9.79, p = 0.025; T 4 , 95%CIs, 1.46–10.36, p = 0.005). The myocardial oxygen consumption in all three groups was significantly decreased at each time point compared to T 0 ( p < 0.05 or < 0.001), and no significant between-group differences were detected ( P >0.05). Compared with the ED 1 group, the anesthesia efficiency of ED 2 and ED 3 groups was markedly enhanced, but the risk of bradycardia in ED 2 and ED 3 groups was dramatically increased (6 of 28 [21.4%] vs. 14 of 30 [46.7%] and 14 of 27 [51.9%], p = 0.023), one patient in the ED 3 group experienced difficulty urinating, and remaining adverse reactions were mild in all three groups. Conclusion A measure of 0.5 μg/kg dexmedetomidine is the optimal dose as a 0.59% ropivacaine adjuvant for epidural anesthesia in patients undergoing great saphenous varicose vein surgery. Clinical trial registration http://www.chictr.org.cn/ , registration number: ChiCTR2200060619.