Low-Dose Fentanyl Can Improve the Quality of Sevoflurane Induction in Adult Patients with Midazolam Premedication

Abstract

Background: Although sevoflurane is almost ideal for the ihalation inducdtion of anesthesia, considerable hemodynamic and respiratory effects have been reported during inhalation induction. The goal of this study was to evaluate the effects of low-dose fentanyl on high concentration of sevoflurane induction in adult patients with midazolam premedication. Methods: 104 healthy patients (16-55 yr) premedicated with midazolam were randomized to receive I.V. fentanyl 0.5/kg (F) or placebo (P) before induction. Three vital capacity breathing with 8 vol% sevoflurane/70% was applied to patients after priming of circuit with the anesthetic mixture. A blinded observer recorded the sequence of breaths (1st, 2nd, 3rd) to loss of eyelash reflex, response to verbal command (RVC), side effects, and the intubation time. MAP, HR, respiratory rate (RR), sevoflurane ET%, BIS values, , and were recorded at 1 minute intervals. Hypotension, tachycardia, and tachypnea were defined as a 30% decrease in MAP, a HR over 100 bpm, and a RR of over 25/min, respectively. Data were analyzed using the Chi-Square Test, ANOVA, and Post Hoc test. Results were considered significant at a P 18.6 to 59.2 20.4) than in F (from 36.0 9.0 to 39.9 10.3). Time to Intubation showed no difference between groups. Conclusions: We conclude that low-dose fentanyl can reduce the incidence 6 marked changes in HR and RR, and even in BIS changes at intubation during inhalation induction with sevoflurane. Fentanyl may affect the quality of sevoflurane induction rather than induction speed.