Dose-dependent attenuation by fentanyl on cough during emergence from general anesthesia

Background: Although fentanyl suppresses tracheal tube-induced cough during anesthetic recovery, it has not been proven if its antitussive effect is dose dependent and complication free. The purpose of this study is to evaluate the relationship between fentanyl doses and cough suppression during emergence from sevoflurane anesthesia. Methods: Sixty patients undergoing thyroidectomy were randomly allocated to one of four groups (F0, F1, F1.5, and F2) according to the fentanyl dose (0 mcg/kg, 1 mcg/kg, 1.5 mcg/kg, or 2 mcg/kg). Fentanyl was administered immediately after sevoflurane discontinuation. Coughing was assessed throughout the periextubation period. The relationship between fentanyl dose and incidence of cough was analyzed using Cochran-Armitage trend test. Incidence of more than 30% elevation of mean arterial pressure (MAP) and heart rate (HR), awakening time, extubation time, and respiratory rate after extubation were recorded and compared using Mantel-Haenszel chi-square test and one-way analysis of variance. Results: Fentanyl suppressed emergence cough in a dose-related manner (P = 0.002), and the ED50 and ED90 were 1.1 mcg/kg and 2.1 mcg/kg, respectively. The higher dose of fentanyl further reduced the number of patient with MAP and HR elevation (P = 0.003 and 0.005, respectively). Awakening time (8.4 +/- 1.9 min) in F2 was comparable with that in F1 and F1.5. Respiratory rate (9 +/- 2 bpm) and extubation time (11.9 +/- 1.8 min) in F2 were only different from those in F0 (13 +/- 3 bpm and 10.4 +/- 1.1 min, respectively). Conclusions: Fentanyl suppressed cough in a dose-related manner during recovery from general sevoflurane anesthesia, and 2 mcg/kg may be considered as a proper dose.