[Sinus arrest during laryngoscopy for induction of general anesthesia with intravenous fentanyl and propofol].

A 43-year-old woman with Plummer's disease underwent left thyroid lobectomy without premedication using ambulatory electrocardiogram monitoring under general anesthesia. Anesthesia was induced with an intravenous bolus of fentanyl 100 microg, lidocaine 40 mg, propofol 80 mg and vecuronium 7 mg. As she moved 5 min after induction of anesthesia, fentanyl 100 microg and propofol 30 mg were administered additionally. After positive pressure ventilation by mask for 8 min, heart rate decreased from 71 beats x min(-1) to 48 beats x min(-1), and laryngoscopy was performed. When the tip of the laryngoscope was pressed on the base of the tongue and on lifting the epiglottis, the electrocardiogram showed RR interval prolongation and gradually going to sinus arrest. The laryngoscope was removed immediately and mask ventilation was performed. The heart beat resumed at 5.5 sec after sinus arrest. Atropine 0.5 mg was given intravenously and heart rate increased to 50 beats x min(-1). Additionally atropine 0.25 mg increased heart rate to 70 beats x min(-1). The second laryngoscopy was performed uneventfully. We consider this phenomenon as a result of vagovagal reflex. Fentanyl and propofol, by reducing sympathetic tone to a greater extent than parasympathetic tone, decrease blood pressure and heart rate, and predispose to a parasympathetic response for noxious stimulation. This case indicates that intravenous injection of atropine must be immediately used for bradycardia during laryngoscopy for induction of general anesthesia with fentanyl and propofol.