This randomized controlled trial compared Bispectral Index (BIS) values in 40 patients after a modified rapid sequence induction using thiopentone 4 mg/kg or propofol 2 mg/kg with rocuronium 0.6 mg/kg as muscle relaxant. Endotracheal intubation was performed at 60 seconds from induction of anaesthesia and BIS values were recorded for three minutes after induction. At the 120, 150 and 180 second measurements there was a significantly greater proportion of subjects with BIS values < or = 60 ("anaesthetized") in the propofol group compared with the thiopentone group (P values < 0.02, < 0.01 and < 0.01 respectively). All intubations were completed within two minutes. No explicit recall of intubation was detected clinically with either induction agent. The BIS scores we have measured suggest that thiopentone 4 mg/kg is more likely to be associated with lighter planes of anaesthesia and consequent risk of awareness than propofol 2 mg/kg, if intubation is delayed or prolonged.
We have compared the effect of rocuronium and succinylcholine on intraocular pressure (IOP) during rapid sequence induction of anaesthesia using propofol and fentanyl, in a randomized double-blind study. We studied 30 adult patients, allocated to one of two groups. Anaesthesia was induced with fentanyl 2 micrograms kg-1 and propofol until loss of verbal response. This was followed by succinylcholine 1.5 mg kg-1 (group S; n = 15) or rocuronium 0.9 mg kg-1 (group R; n = 15). Laryngoscopy was performed 60 s later. IOP, mean arterial pressure (MAP) and heart rate (HR) were measured before induction, immediately before intubation and every minute after intubation for 5 min. A Keeler Pulsair air impulse tonometer was used to measure IOP and the mean of two readings obtained in the right eye at each measurement time was recorded. Intubating conditions were evaluated according to a simple scoring system. IOP in the succinylcholine group was significantly greater than that in the rocuronium group (mean 21.6 (SEM 1.4) mm Hg vs 13.3 (1.4) mm Hg; P < 0.001). Intubating conditions were equally good in both groups. We conclude that with rapid sequence induction of anaesthesia using propofol and fentanyl, rocuronium did not cause as great an increase in IOP as succinylcholine and may be an alternative in open eye injury cases.