Role of topical magnesium in post-operative sore throat: A systematic review and meta-analysis of randomised controlled trials

Background and Aims: Post-operative sore throat (POST) is a common undesirable consequence of tracheal intubation. Magnesium, an N-methyl-D-aspartate receptor antagonist, has anti-nociceptive and anti-inflammatory properties, and has been found to be useful in POST prevention in various trials. We conducted this systematic review and meta-analysis to study the efficacy of topical magnesium in preventing POST in adult patients undergoing surgery under general anaesthesia with single lumen tracheal tube. Methods: Comprehensive literature search was performed in PubMed, Google Scholar, EMBASE, Scopus and the Cochrane central registers of controlled trial databases through July, 2018 and data were pooled using fixed effect modelling followed by random-effect methods (after assessing heterogeneity with fixed modelling). The primary outcome was the incidence of POST at 24 h after surgery/extubation. Comparative results were deliberated as pooled mean difference for continuous variables and Mantel-Haenszel (MH) odds ratio for dichotomous variables. Statistical analysis was done using Comprehensive Meta-Analysis-Version 3 (Biostat Inc., USA). Results: Seven trials involving 726 study participants were included in the final analysis. Incidence of POST at 24 hours was significantly lower in magnesium group (26/363) in comparison to active and non-active control group (89/363); P = 0.00- RR 0.22 (95%CI = 0.12-0.39, I² = 0%). No significant adverse events were reported with the use of topical magnesium. Conclusion: Prophylactic use of topical magnesium before the induction of general anaesthesia seems to be an effective measure to decrease the incidence of POST.