Effect of Preoperative Ketamine Nebulisation on Attenuation of Incidence and Severity of Postoperative Sore Throat, Hoarseness of Voice and Cough: A Randomised Double-Blind Study

Introduction: Postoperative Sore Throat (POST) occurs in a majority i.e., upto 62% of patients who undergo endotracheal intubation under general anaesthesia. Ketamine nebulisation has been reported to reduce the incidence and severity of POST.

Aim: To evaluate the effect of ketamine nebulisation on incidence and severity of POST, hoarseness of voice and cough.

Materials and Methods: This prospective, randomised, double-blind study was conducted between September 2020 to February 2021 at J.L.N. Medical College, Ajmer, Rajasthan, India. Total of 100 American Society of Anesthesiologists (ASA) physical status I and II patients were enrolled, and randomly allocated into two groups of 50 each. The patients in Group K (n=50) were nebulised with ketamine (50 mg) with 4 mL normal saline (NS) and in Group S (n=50) were nebulised with 5 mL NS 15 minutes prior to endotracheal intubation. The incidence and severity of POST, hoarseness of voice and cough were assessed just after extubation (0 hour) and thereafter at 2, 4, 6, 12 and 24 hours postoperatively. Haemodynamic parameters {Heart Rate, (HR) Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP), and Oxygen Saturation (SpO2)} were noted before and after nebulisation, and just after intubation. Side-effect profile was also noted. The data from patients was analysed using Statistical Package for Social Sciences (SPSS Inc., Chicago, IL, USA, version 21.0 for windows).

Results: Mean age of Group S was 36.22±9.386 years and Group K was 37.40±9.604 years (p-value=0.534). The incidence and severity of POST was significantly lower in patients in Group K at 0 hours (p-value=0.003), at 2 hours (p-value=0.001), at 4 hours (p-value=0.003), at 6 hours (p-value=0.004) and at 12 hours (p-value=0.003), when compared to patients in Group S. The incidence and severity of cough was also significantly lower in patients in Group K at 0 hours, 2 hours, 4 hours and 6 hours (p-value <0.001). Incidence and severity of postoperative hoarseness of voice in Group K was significantly less as compared to Group S at 0 hours, 2 hours, 4 hours and 6 hours (p-value <0.001) and at 12 hours (p-value=0.001). No significant haemodynamic changes (p-value >0.05) and side-effects (p-value=0.727) were noted in both the groups.

Conclusion: Preoperative ketamine nebulisation was found to be effective in reducing the incidence and severity of postoperative sore throat, hoarseness of voice and postoperative cough after general anaesthesia with endotracheal intubation along with no or minimal haemodynamic changes and side-effects.