Randomized controlled trial on effect of different routes of dexmedetomidine on Haemodynamics in patients undergoing saphenectomy under epidural anaesthesia

Abstract

The effect of epidural infusion of dexmedetomidine on haemodynamics is unclear. This study aimed to explore the effects of epidural or intravenous infusion of dexmedetomidine on haemodynamics during lower extremity varicose veins surgery (saphenectomy) under epidural anaesthesia. Ninety patients were randomly allocated to three groups: ED group (epidural: 0.59% ropivacaine plus 0.5 µg/kg dexmedetomidine, intravenous: normal saline), VD group (epidural: 0.59% ropivacaine plus normal saline, intravenous: 0.5 µg/kg dexmedetomidine), or NS group (epidural: 0.59% ropivacaine plus normal saline, intravenous: normal saline). The primary outcome was the systolic blood pressure (SBP) at before anaesthesia (T₀) and at 5 (T₁), 15 (T₂), and 30 min (T₃) and 1 (T₄), 2 (T₅), 4 (T₆), 6 (T₇), and 8 h (T₈) after dexmedetomidine infusion. The secondary outcomes were diastolic blood pressure (DBP) and heart rate (HR) at T_{0 - 8}, plasma norepinephrine (NE), myocardial oxygen consumption (MVO₂) and anesthesia efficacy. Adverse reactions and other general data were also recorded. Compared with those in the NS group, the SBP at T_{3 - 7} and DBP at T_{4 - 5,7} were significantly lower in the ED group (P = 0.008, 0.001, 0.001, 0.001, 0.038 and P = 0.017, 0.006, 0.044, respectively), and the SBP and DBP at T_{1 - 8} were lower in the VD group (P < 0.001, 0.001, 0.001, 0.001, 0.004 and P < 0.001, 0.001, 0.001, 0.002, 0.001, 0.001, 0.001, 0.036, respectively). The SBP and DBP at T_{1 - 2} in the ED group were greater than those in the VD group (P = 0.021, 0.01 and P = 0.001, 0.011, respectively). The HR at T_{3 - 4,6-7} was lower in the ED group than in the NS group (P < 0.001, 0.021, 0.002, 0.004, respectively). Compared with that in the VD group, the HR in the ED group at T₇ was significantly lower (P < 0.001). Anaesthesia efficiency was improved in the ED group compared with VD and NS groups. The incidence of hypotension was lower in the ED group than in the VD group (P = 0.003). The combination of 0.5 µg/kg dexmedetomidine and 0.59% ropivacaine for epidural anaesthesia provides more stable haemodynamics with a lower incidence of hypotension and improved efficiency of epidural anaesthesia in patients undergoing saphenectomy.

Keywords: Administration routes; Anaesthetic effect; Dexmedetomidine; Epidural anaesthesia; Haemodynamics; Ropivacaine.

Fig. 1

CONSORT diagram. Flowchart epitomizing inclusion, allocation and analysis. ED group, epidural infusion of 0.5 µg/kg dexmedetomidine group. VD group, intravenous infusion of 0.5 µg/kg dexmedetomidine group. NS group, simple epidural infusion of the ropivacaine group.

Fig. 2

(A) Systolic blood pressure of ED group, VD group and NS group at baseline and at 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 6 h and 8 h after administration. (B) Diastolic blood pressure of ED group, VD group and NS group at baseline and at 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 6 h and 8 h after administration. (C) Heart rate of ED group, VD group and NS group at baseline and at 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 6 h and 8 h after administration. SBP systolic blood pressure, DBP diastolic blood pressure, HR heart rate. NS group, ropivacaine plus isovolumic saline epidural infusion group; VD group, dexmedetomidine intravenous infusion combined with ropivacaine epidural infusion group; ED group, dexmedetomidine combined with ropivacaine epidural infusion group. ^aP<0.05, vs. NS group; ^bP<0.05, vs. VD group; ^cP<0.05, vs. T₀, both comparisons were corrected by Bonferroni.

Fig. 3

(A) Norepinephrine of ED group, VD group and NS group at baseline and at 30 min, 1 h, 2 h, 4 h and 6 h after administration. (B) Myocardial oxygen consumption of ED group, VD group and NS group at baseline and at 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 6 h and 8 h after administration. NE norepinephrine, MVO₂ myocardial oxygen consumption. NS group, ropivacaine plus isovolumic saline epidural infusion group; VD group, dexmedetomidine intravenous infusion combined with ropivacaine epidural infusion group; ED group, dexmedetomidine combined with ropivacaine epidural infusion group. ^aP<0.05, vs. NS group; ^bP<0.05, vs. VD group; ^cP<0.05, vs. T₀, both comparisons were corrected by Bonferroni.

Fig. 4

(A) ED group, VD group, and NS group were scored with VAS scores at 2 h, 4 h, 6 h, and 8 h after administration. (B) ED group, VD group, and NS group were scored with Ramsay scores at baseline and at 5 min, 15 min, 30 min, 1 h and 2 h after administration. VAS visual analogue scale. NS group, ropivacaine plus isovolumic saline epidural infusion group; VD group, dexmedetomidine intravenous infusion combined with ropivacaine epidural infusion group; ED group, dexmedetomidine combined with ropivacaine epidural infusion group. ^aP<0.05, vs. NS group; ^bP<0.05, vs. VD group, boxes indicate the median with the 25th and 75th percentiles (interquartile range), whisker caps represent the minimum and maximum values, and + represents the average.