Induction of anesthesia
Anesthesia was inducted by sequential injections of 0.05 mg/kg midazolam, 0.5 μg/kg sufentanil, 0.3 mg/kg etomidate, and 0.8 mg/kg rocuronium in all three groups. We monitored neuromuscular function using a train of four (TOF) stimulation pattern. Intubation took place when a fully relaxed status was reached (TOF 0/4). All intubations were performed by two anesthesiologists, both of whom were attending physicians with more than 5 years but less than 10 years of clinical experience, each intubation device was used more than 200 times after training more than 100 times on manikins.