Optimal dose of succinylcholine for laryngeal mask airway insertion: systematic review, meta-analysis and metaregression of randomised control trials

OBJECTIVES To evaluate the optimal dose of succinylcholine for laryngeal mask airway (LMA) insertion and all related morbidities. DESIGN Systematic review, meta-analysis and metaregression of randomised controlled trials (RCTs). DATA SOURCE AND STUDY ELIGIBILITY CRITERIA A comprehensive search of RCTs in the PubMed, Embase, the Cochrane Library and the ClinicalTrials.gov registry up to July 2016 and articles that evaluated the use of succinylcholine chloride for LMA insertion were included in the analyses. The relative risk (RR) and the corresponding 95% CIs were determined. INTERVENTION Succinylcholine as the coinduction agent and the doses were divided into mini (≤0.3 mg/kg) and low (0.3-1.0 mg/kg) doses for dose-dependent effect analyses. PRIMARY AND SECONDARY OUTCOMES The primary outcome was the first-attempt LMA insertion failure rate. Secondary outcomes included all related adverse events. RESULTS Data from 10 RCTs comprising 625 participants showed that succinylcholine reduced the first-attempt LMA insertion failure rate (RR, 0.22; 95% CI 0.12 to 0.43), coughing and gagging (RR, 0.26; 95% CI 0.15 to 0.45) and laryngospasm (RR, 0.14; 95% CI 0.05 to 0.39). The use of succinylcholine did not result in a significant increase of postoperative myalgia (RR, 2.58; 95% CI 0.79 to 8.44) and did not reduce the risk of postoperative sore throat (RR, 0.76; 95% CI 0.55 to 1.03). Subgroup analysis further showed that low-dose succinylcholine reduced the LMA insertion failure rate and its related coughing and gagging when compared with mini dose. CONCLUSION The use of succinylcholine compared with none can facilitate LMA insertion and reduce insertion-related reflexes without significant postoperative myalgia. However, additional prospective studies with a larger sample size are required to fully evaluate the dose-dependent effect and complications of succinylcholine for LMA insertion.