Preoperative Dexmedetomidine and intraoperative bradycardia in laparoscopic cholecystectomy: meta-analysis with trial sequential analysis

Background: Laparoscopic surgical procedures have various advantages over traditional open techniques, however, the artificial pneumoperitoneum is associated with severe bradycardia and also with cardiac arrest. Dexmedetomidine is an imidazole derivative that highly selectively binds to α2-receptors. It has sedative and analgesic properties, however it could cause hypotension and bradycardia. Our primary aim was to assess the association of dexmedetomidine use with intraoperative bradycardia during laparoscopic cholecystectomy. Methods: We performed a systematic review with meta-analysis and trial sequential analysis of the medical literature using the following PICOS: adult patients undergoing endotracheal intubation for laparoscopic cholecystectomy (P); intravenous dexmedetomidine before tracheal intubation (I); no intervention or any placebo administration (C); intraoperative bradycardia (primary outcome), intraoperative hypotension, SBP at intubation, MAP at intubation, HR at intubation, dose of anesthetic needed for induction of anesthesia, total anesthetics (both ipnotics and opioids) requirement throughout the operative procedure, percentage of patients requiring postoperative analgesics, PONV and postoperative shivering occurrence (O); randomized controlled trials (S). Results: Fifteen studies were included in the meta-analysis (980 patients). Patients receiving dexmedetomidine compared to patients not receiving it had a higher risk of developing intraoperative bradycardia (RR 2.81 (1.34 - 5.91)) and hypotension (RR 1.66 (0.92 - 2.98)), however they need lower dose of intraoperative anesthetics and had a lower incidence of PONV. In the TSA for bradycardia, the cumulative z-score crossed the monitoring boundary for harm at the tenth trial. Conclusions: Patients undergoing laparoscopic cholecystectomy receiving dexmedetomidine at tracheal intubation are more likely to develop intraoperative bradycardia and hypotension.