Effect of magnesium sulfate nebulization in reducing the incidence and severity of post operative sore throat in patients undergoing surgery in prone position

Introduction: Post operative Sore throat (POST), a common complaint after GA with tracheal intubation causes significant patient discomfort. Incidence is 21-65%. Many pharmacological and non-pharmacological methods have been studied for attenuation of POST. Changing patient’s position from supine to prone can cause tube displacement and changes endotracheal cuff pressure affecting incidence of POST. Therefore, we planned to study prophylactic effect of Magnesium Sulfate nebulization in patients undergoing surgery in prone position. Hypothesis of the study was magnesium sulfate nebulization reduces incidence of POST in prone position surgery. Methods: Hospital based prospective interventional randomized double blind study. After getting institutional ethical clearance, 140 consenting patients belonging to American society of anaesthesiologists status 1-2, 20-60 years, either sex undergoing lumbar spine surgery in prone position were randomly allocated in two groups (n = 70 each). Pre-operatively Group A and B were nebulized with 0.9% saline (5 ml) and magnesium sulfate (1 ml+ 4 ml saline) for 15 min respectively. GA was given and patients positioned prone 10 min after nebulization. Incidence and severity of POST was assessed at 1, 6 and 24 hr and graded on four point scale (0-3). Collected data was analysed using SPSS. Fisher’s Exact test and Mann Whitney U test was used to compare incidence and severity of POST among groups respectively. P<0.05 was considered statistically significant. Results: The overall incidence of POST was 53%, where 54 (77%) in Group A and 21 (30%) patients in Group B experienced POST (p<0.0001). POST was significantly attenuated at 1 hr and 6 hr in Group B (p<0.05). POST occurred in 31 patients of Group A versus 6 patients in Group B at 6 hr. Conclusion: Magnesium sulfate nebulization significantly attenuated incidence and severity of POST in patients undergoing surgery in Prone Position.