Effect of Preoperative Nebulised Dexamethasone and Nebulised Magnesium Sulphate on Postoperative Sore Throat in Prone Position Surgeries- A Randomised Double-Blind Study

Abstract

Introduction: Postoperative Sore Throat (POST) is a frequently encountered complication after general anaesthesia with tracheal intubation and positional changes. Magnesium Sulphate (MgSO4) is a N-Methyl D-Aspartate (NMDA) receptor antagonist and dexamethasone is a glucocorticoid, both drugs helps in reducing POST by various mechanisms. Aim: To compare the effects of preoperative dexamethasone nebulisation vs preoperative MgSO4 nebulisation on sore throat in prone position surgeries. Materials and Methods: Eighty patients undergoing lumbar spine surgeries from October 2017 to April 2019, under general anaesthesia in prone position, were randomly allocated into two groups- A and B. Thirty minutes before surgery patients in each group were nebulised with respective drugs, dexamethasone 8 mg in group A and 250 mg of MgSO4 in group B. Haemodynamic parameters during laryngoscopy were noted. A standardised protocol for providing general anaesthesia was followed for all patients. After extubation, at 0, 4, 6 and 24 hours all patients were asked to grade POST, hoarseness and cough. The severity of POST was graded with four-point scale. Continuous variables were expressed as mean±SD and analysed using student t-test. The p-value <0.05 was considered statistically significant. Results: The overall incidence of sore throat in dexamethasone group was 37.5% and 20% in MgSO4 group. The incidence (p=0.026) and severity (p=0.011) of POST was significantly decreased in MgSO4 group at 6 hours where none of the patient had sore throat compared to dexamethasone where 15 (37.5%) of them had sore throat (p=0.026). None of the patients had cough and hoarseness in both groups. Conclusion:Nebulisation with MgSO4preoperatively significantly decreases the incidence and severity of POST when compared to dexamethasone and there was no statistically significant haemodynamic variability between the two groups.