Dose-dependent effectiveness of ketamine nebulisation in preventing post-operative sore throat due to tracheal intubation.

Background: Sore throat is a common and distressing post-operative complication following endotracheal intubation that contributes to patient discomfort. Several pharmacological and non-pharmacological methods may be used to attenuate post-operative sore throat. In literature, there is no study evaluating dose-dependent effectiveness of ketamine nebulisation, neither has there been a study to assess patient acceptability with ketamine nebulisation. The prime objective of this study was to assess graded doses of ketamine nebulization in attenuation of post-operative sore throat and patient acceptability and satisfaction.

Materials and Methods: 90 patients between age group of 18 and 60yrs of ASA physical status 1 and 2 of either sex undergoing surgeries in supine position under general anaesthesia lasting for > 1hr, were randomly allocated into three groups. Group A received 0.5mg/kg, group B received 1mg/kg and group C received 1.5mg/kg body weight of nebulized preservative free ketamine for 15mins, 5mins before intubation. The patients were then assessed for acceptability to ketamine nebulization. At the end of the surgery post-operative sore throat was assessed at 0, 2, 4, 6, 8, 12 and 24hrs.

Results: Nebulized ketamine at a dose of 0.5mg/kg was comparatively less effective than 1 mg/kg and 1.5 mg/kg and the difference was statistically significant. 1mg/kg and 1.5mg/kg of nebulized ketamine are better and equally effective in reducing the incidence and severity of post-operative sore throat. There was no statistical difference in the acceptability scores to the different doses of nebulised ketamine.

Conclusion: Nebulized ketamine is well accepted by all patients and effective in reducing the severity of post-operative sore throat without any untoward effects.  However larger population studies and estimation of serum ketamine levels is needed to find out a better dose of ketamine for nebulization to prevent the incidence and severity of post-operative sore throat.