Objectives: The aim of this prospective, randomized, double blind trial was to investigate the effects of two different doses of remifentanil on bispectral index (BIS) values and intubation conditions in a simulated model of rapid sequence anesthesia induction (RSAI).
Material and methods: 54 ASA I-II adult patients undergoing elective surgery were randomly allocated to two groups. After preoxygenation for 3 minutes, induction and tracheal intubation was performed in a 300 head-up position. Group I (n=26) and Group II (n=28) received a 1 µg/kg or 0.5 µg/kg bolus of remifentanil, respectively, over 30 seconds. Propofol was the induction agent. 1 mg/kg of rocuronium was used in all patients. Patients were intubated 60 s after administration of the muscle relaxant. Hemodynamic data and BIS scores were obtained before induction (baseline), after induction, at intubation and at 1, 3, 5 and 10 minutes following intubation. Intubation conditions were scored with a standard scoring system.
Results: The hemodynamic variables at all the measurement intervals and the area under the hemodynamic variable-time curves were similar among the groups. There was no difference among the groups for BIS measurements. Moreover, the mean area under the BIS-time curve for Group I (300±45cm2) was comparable to Group II (315±49cm2) (p=0.432). The mean total intubation condition score (maximum 14 points) in Group I (12.6±1.67) was higher than Group II (10.3±4.79) (p=0.030).
Conclusions: 1 µg/kg of remifentanil compared to 0.5 µg/kg of remifentanil provides similar hemodynamic profiles and BIS scores, but 1 µg/kg of remifentanil was associated with superior endotracheal intubation conditions. According to this study design and medications used, a relation between BIS scores and intubation conditions couldn't be demonstrated.