Determination of the 95% effective dose of remifentanil for the prevention of coughing during extubation in children undergoing tonsillectomy (with or without adenoidectomy)

Abstract

BackgroundLimited data are available regarding the 95% effective dose (ED95) of remifentanil to prevent the cough response during emergence from general anesthesia in children. MethodsThis study included 40 patients aged 3-12years who underwent elective tonsillectomy with or without adenoidectomy. A predetermined remifentanil dose was infused continuously with desflurane during surgery and was continued until extubation. In the emergence period, the cough response during awake extubation was assessed to determine the remifentanil dose for the next patient. The first patient received remifentanil at the rate of 0.01gkg(-1)min(-1), and subsequent patients received a 0.01gkg(-1)min(-1) higher dose than the previous patient if there was more than moderate coughing detected, and the patient after those with less than mild coughing received either the same dose (95% probability) or a 0.01gkg(-1)min(-1) lower dose (5% probability) using the biased coin design. Times to extubation and adverse events were recorded. The ED95 was calculated using the maximum-likelihood estimation. ResultsThe ED95 of remifentanil for preventing coughing during extubation was 0.060gkg(-1)min(-1) (95% confidence interval, 0.037-0.068). There was moderate coughing in all groups receiving 0.01-0.06gkg(-1)min(-1) of remifentanil, but no cough response occurred in the group receiving remifentanil 0.07gkg(-1)min(-1). Time to extubation was weakly correlated with remifentanil infusion rate (r=0.331). One patient who received remifentanil 0.07gkg(-1)min(-1) showed desaturation over 5s immediately after extubation, but recovered after receiving 100% oxygen. ConclusionThe ED95 of the continuous remifentanil infusion rate was 0.060gkg(-1)min(-1) to prevent the cough response during extubation in children after tonsillectomy.