DESIGN: Single blinded, international, multicenter randomized controlled trial with 1:1 allocation ratio.
SETTING: Tertiary and University hospitals.
INTERVENTIONS: Patients (n=10,600) undergoing coronary artery bypass graft will be randomized to receive either volatile anesthetic as part of the anesthetic plan, or total intravenous anesthesia.
MEASUREMENTS AND MAIN RESULTS: The primary end point of the study will be one-year mortality (any cause). Secondary endpoints will be 30-day mortality; 30-day death or non-fatal myocardial infarction (composite endpoint); cardiac mortality at 30day and at one year; incidence of hospital re-admission during the one year follow-up period and duration of intensive care unit, and hospital stay. The sample size is based on the hypothesis that volatile anesthetics will reduce 1-year unadjusted mortality from 3% to 2%, using a two-sided alpha error of 0.05, and a power of 0.9.
CONCLUSIONS: The trial will determine whether the simple intervention of adding a volatile anesthetic, an intervention that can be implemented by all anesthesiologists, can improve one-year survival in patients undergoing coronary artery bypass graft surgery.
METHODS: Sixty patients were randomised to receive IV dexmedetomidine 0.5 μg.kg-1 (Group DEX, n = 30) or IV saline (Group P, n = 30). General anaesthesia was maintained with Sevoflurane: oxygen: air, titrated to BIS 40-60. Pain intensity, sedation, rescue analgesics, nausea/vomiting and resumption of daily activities were recorded at 1 h, and postoperative day (POD) 1-5.
RESULTS: Group DEX patients had significant reduction in sevoflurane minimum alveolar concentration (MAC), mean (SD) DEX vs. Placebo 0.6 (0.2) vs. 0.9 (0.1), p = 0.037; reduced postoperative resting pain at 1 h (VAS 0-10) (mean (SD) 1.00 (1.84) vs. 2.63 (2.78), p = 0.004), POD 1 (mean (SD) 1.50 (1.48) vs. 2.87 (2.72), p = 0.002), POD 2 (0.53 (0.97) vs. 1.73 (1.96), p = 0.001) and POD 3 (0.30 (0.75) vs. 0.89 (1.49), p = 0.001). DEX patients also had less pain on movement POD 1 (3.00 (2.12) vs. 4.30 (3.10), p = 0.043) and POD 2 (2.10 (1.98) vs. 3.10 (2.46), p = 0.040), with higher resumption of daily activities by 48 h compared to placebo, 87% vs. 63%, p = 0.04.
CONCLUSIONS: We conclude that a single dose of dexmedetomidine was a useful adjuvant in reducing MAC and postoperative pain (at 1 h and POD 1-3), facilitating faster return to daily activities by 48 h.
TRIAL REGISTRATION: The Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617001120369 , 31st July 2017, retrospectively registered.