Tehran University of Medical Sciences Archives of Anesthesiology and Critical Care 2423-5849 9 1 2022 10 15 46 51 Fatemeh Hajimohamadi Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Abolghasem Yoosefi Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Mehrdad Behzadi Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Nader Ali Nazemian Yazdi Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Hamed Abdollahi Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Afshar Etemadi-Aleagha Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran. Samira Parvizi Omran Department of Anesthesiology, Amir A’lam Hospital, Tehran University of Medical Sciences, Tehran, Iran. 2022 03 23 2022 05 11 Background: Sevoflurane is preferred for induction of general anesthesia in pediatrics. We examined the minimum duration of sevoflurane administration resulting in most optimal intubation conditions. Methods: We included 75 children, aged 2-12 years, undergoing tonsillectomy under general anesthesia at Amir-Alam Hospital. They were given midazolam 0.05 mg/kg and fentanyl 2 mic/kg IV, five minutes before induction with sevoflurane 8% in 60% N2O and 40% O2 with total gas flow of 10 lit/min via face mask for 90 seconds (group I), 120 sec (group II) or 150 sec (group III), randomly. After tracheal intubation, intubation condition was assessed using Steyn's modification of Helbo Hansen scoring system. The total scores were divided into clinically acceptable (≤10) or unacceptable (>10). Results: There was no statistically significant difference among the three groups in demographic characteristics. Mean ± SD of intubation scores were 10.04±2.9, 8.12±3.2, and 5.64±1.15 in groups 1-3, respectively (P<0.001) with statistically significant differences between all three groups: between groups I and II (P=0.044), I and III (P<0.001), as well as II and III (P=0.004). Intubation conditions were acceptable in 11, 16, and 25 patients in each group, respectively (P<0.001). Conclusion: Inhalation induction by sevoflurane 8% in 150s provides acceptable clinical situation for intubation in pediatrics. https://aacc.tums.ac.ir/index.php/aacc/article/view/509