Effect of dexmedetomidine on hemodynamic responses to tracheal intubation: A meta-analysis with meta-regression and trial sequential analysis.

Study objective: An uncontrolled adrenergic response during tracheal intubation may lead to life-threatening complications. Dexmedetomidine binds to alpha 2-receptors and may attenuate this response. The primary aim of our meta-analysis is to investigate dexmedetomidine efficacy in attenuating sympathetic response to tracheal intubation, compared with placebo or no dexmedetomidine, in terms of heart rate and blood pressure at intubation. Design: Meta-analysis with meta-regression and trial sequential analysis. Setting: Systematic search from inception until December 1, 2020 in the following databases: Pubmed, Scopus, the Cochrane Central Register of Controlled Trials, EMBASE and Google Scholar. Interventions: All randomized controlled trials investigating intravenous dexmedetomidine as premedication in adult patients undergoing tracheal intubation were included in our study. Studies were included without any language or publication date restriction. A trial sequential analysis and a post-hoc meta-regression were performed on the main outcomes. Measurements: Hemodynamic parameters and heart rate at tracheal intubation, dose of anesthetic needed for induction of anesthesia, total anesthetic requirement throughout the operative procedure, postoperative pain and percentage of patients requiring analgesics at 24 postoperative hours, postoperative nausea and vomiting, intraoperative and postoperative bradycardia, hypotension, dizziness, shivering and/or respiratory depression. Main results: Ninety-nine included studies randomized 6833 patients. During laryngoscopy, all hemodynamic parameters were significantly greater in the no dexmedetomidine group. In particular, in the dexmedetomidine group, systolic blood pressure differed by -21.8 mm Hg (95% CI -26.6 to -17.1, p-value < 0.001, I2 97%), mean arterial pressure by -12.8 mm Hg (95% CI -15.6 to -10.0, p-value < 0.001, I2 98%), and heart rate by -16.9 bpm (95% CI -19.8 to -13.9, p-value < 0.001, I2 98%). Conclusions: Patients receiving premedication with dexmedetomidine for tracheal intubation, compared with no dexmedetomidine, have a lower blood pressure and heart rate, however, the risk of bradycardia and hypotension is relevant and its use during daily practice should be cautiously evaluated for each patient.