Optimal dose of propofol for intubation after sevoflurane inhalation without neuromuscular blocking agent in children.

ABSTRACT

BACKGROUND: This study was designed to determine the optimal dose of propofol for excellent intubating conditions in children without neuromuscular blockade at various alveolar concentrations of sevoflurane. METHODS: Sixty-three children, aged 0.5-5 years, were randomized to three groups of end-tidal sevoflurane concentration (ETsevo) 3%, 3.5%, and 4%. Inhalation anesthesia was started with sevoflurane 7% in 100% oxygen. When the patients became unconscious, inspired concentration was adjusted to obtain the target ETsevo for each group. When ETsevo reached the target concentration, a predetermined dose of propofol was given and tracheal intubation was performed. The proper dose of propofol was determined using the 'up-and-down' method. RESULTS: The median dose (95% confidence intervals) of propofol for excellent tracheal intubating conditions in 50% of children were 1.25 mg/kg (0.84-1.75) at ETsevo of 3%, 0.76 mg/kg (0.35-1.21) at 3.5%, and 0.47 mg/kg (0.26-1.09) at 4%. The frequency of adverse effects was not different between groups during induction and recovery. CONCLUSION: Propofol 1.5-2 mg/kg provides excellent intubating conditions at 3-4% ETsevo in children without using any neuromuscular blocking agent.