Perioperative analgesic profile of dexmedetomidine infusions in morbidly obese undergoing bariatric surgery: a meta-analysis and trial sequential analysis

Background: Opioid-sparing analgesia for bariatric surgery in morbidly obese can potentially prevent catastrophic airway complications. Our meta-analysis attempts to consolidate the evidence on dexmedetomidine evaluating its analgesic and safety profile. Methods: Trails comparing perioperative dexmedetomidine infusion to conventional analgesic regimens for bariatric surgery were searched. Comparisons were made for 24-hour and post anesthesia care unit (PACU) morphine consumed, PACU pain scores, postoperative nausea and vomiting pain scores, and heartrate. Meta-regression was performed for length of stay to evaluate various analgesic control subgroups. Results: Six trials were included in the final analysis. Dexmedetomidine infusion (reported in 5 intraoperative subgroups and 2 postoperative subgroups) decreased 24-hour morphine by 18.13 +/- 6.11 mg (random effects: P<.001, I-2 = 95.48%). Despite the small number of included studies, the sample size for avoiding a false positive result was adequate as the trial sequential analysis found the present sample size (362) to be well past the required sample size (n = 312) for 85% power. Meta-regression for infusion dose on morphine consumption difference found a predictability of 49% (coefficient = 39.93, random-effects, Tau(2) = 396.08), and predictability of the model improved to 68% on inclusion of time of initiation of infusion. The dexmedetomidine group had lower PACU morphine consumption (by 6.91 +/- 1.19, I-2 = 34.37%), lower pain scores (scale of 0-10 +/- 2.27, I-2 = 88.14%), lower postoperative nausea and vomiting incidence (odds ratio = +/- 0.26, I-2 = 0%), and lower heart rate (73.25 versus. 83.50) (mean difference = +/- 10.15 I-2 = 94.04%). No adverse events were reported across trials. Conclusion: Perioperative dexmedetomidine infusion in obese patients undergoing bariatric surgery is a promising and safe alternative. Both intraoperative or postoperative infusions lead to significant opioid sparing in early and extend postoperative recovery phase. Morbidly obese patients receiving perioperative dexmedetomidine infusions have overall better pain control and lower incidence of postoperative nausea-vomiting. All the aforementioned merits come with a stable hemodynamic profile and without any reported major adverse events. (C) 2017 American Society for Metabolic and Bariatric Surgery. All rights reserved.