Pharmacological interventions for preventing postoperative nausea and vomiting in adult patients undergoing ambulatory surgery: Protocol for a systematic review and network meta-analysis

BACKGROUND: We aimed to conduct a systematic review and network meta-analysis (NMA) of published studies to comprehensively compare and rank the efficacy and safety of pharmacological interventions for preventing nausea and vomiting after ambulatory surgery. METHODS: A systematic and comprehensive search will be performed using the MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and Google Scholar databases, beginning from their inceptions to July and August 2019. Only randomized clinical trials on the efficacy and safety of pharmacologic interventions for preventing nausea and vomiting after ambulatory surgery will be included. The primary endpoints will be the incidences of postoperative nausea (PON), postoperative vomiting (POV), and postoperative nausea and vomiting (PONV) in the following recovery phases: before discharge (recovery phase I and II), after discharge but within 24 hours following surgery, and after discharge, after the initial 24-hour postoperative period. The incidences of delayed post-discharge nausea, post-discharge vomiting, and post-discharge nausea and vomiting, which occur after the initial 24-hour postoperative period, severities of PON, POV, and PONV, use of rescue antiemetics, and the incidence of complete response, as well as safety issues, including complications, such as headache, dizziness, and drowsiness, will be also assessed. We will conduct both pairwise meta-analysis and NMA. We will use surface under the cumulative ranking curve values and rankograms to present the hierarchy of the pharmacologic interventions. A comparison-adjusted funnel plot will be used to assess the presence of small-study effects. The quality of the studies included will be assessed using the risk of bias tool 2.0. All statistical analyses will be performed using Stata SE, version 15.0 (StataCorp, College Station, TX). RESULTS: The results of this systematic review and NMA will be published in a peer-reviewed journal. CONCLUSION: This systematic review and NMA will provide comprehensive and convincing evidence summarizing the efficacy and safety of pharmacological interventions for preventing nausea and vomiting after ambulatory surgery. TRIAL REGISTRATION NUMBER: CRD42018103068.