Electroencephalographic arousal response during tracheal intubation and laryngeal mask airway insertion after induction of anaesthesia with propofol

Laryngoscopy and tracheal intubation, or insertion of a laryngeal mask airw ay may lead to an arousal response on the electroencephalogram. We studied whether more intense stimulation (laryngoscopy and tracheal intubation) cau ses a greater arousal response than less intense stimulation (laryngeal mas k airway insertion). Thirty-four patients (ASA I-II) were anaesthetised wit h propofol 3 mg.kg(-1), followed by vecuronium 0.15 mg.kg(-1) and a propofo l infusion of 10 mg.kg(-1).h(-1). Three minutes after induction of anaesthe sia, either laryngoscopy and tracheal intubation (n = 18), or laryngeal mas k airway insertion (n = 16) was performed. Laryngoscopy and tracheal intuba tion caused a significantly greater increase in blood pressure (but not hea rt rate) than laryngeal mask airway insertion (p < 0.05). Electroencephalog ram responses were not different. More intense stimulation does not cause a greater arousal response during propofol anaesthesia.