The Effect of Ramosetron on Remifentanil in Preventing Emergence Cough from Sevoflurane Anesthesia in Female Patients

<P>Background: Remifentanil reduces cough during extubation. Ramosetron, a 5-HT3 receptor antagonist, is a potent antiemetic. Regarding the antitussive property of 5-HT receptor agonists, ramosetron can mediate the cough reflex by increasing the remifentanil requirement. This study evaluated the effect of ramosetron on the optimal effect-site concentration (Ce) of remifentanil for preventing emergence cough from sevoflurane anesthesia in female patients. <P> Methods: Forty-seven randomly selected female patients undergoing laparoscopic cholecystectomy received either ramosetron 0.3 mg (n = 23) or the same volume of normal saline (n = 24) intravenously at the end of surgery. The remifentanil Ce using target-controlled infusion in 50% of patients (EC50) and 95% of patients (EC95) were assessed using Dixon’s up-and-down or isotonic regression method with a bootstrapping approach. <P> Results: Using Dixon’s up-and-down method, the EC50 of remifentanil in the control group (1.33 ± 0.38 ng/mL) was comparable to that of ramosetron group (1.50 ± 0.69 ng/mL) (P = 0.615). Using isotonic regression analysis, the EC50 (83% confidence interval) did not differ between the two groups (1.17 [0.86-1.43] ng/mL and 1.13 [0.68-1.56] ng/mL in control and ramosetron groups). However, the EC95 (95% confidence interval) was significantly lower in the control group than in the ramosetron group (1.90 [1.45-1.96] ng/mL and 2.92 [2.35-2.97] ng/mL). <P> Conclusion: Remifentanil Ce for preventing emergence cough was higher in the ramosetron group than in the control group. It may indicate the lowering effect of ramosetron on the antitussive activity of remifentanil.</P>