Cardiac arrhythmias in children during outpatient general anaesthesia for dentistry: a prospective randomised trial

Background Deaths in children associated with outpatient general dental anaesthesia may be attributable to sudden cardiovascular collapse precipitated by ventricular arrhythmias. A causal link between halothane anaesthesia, ventricular arrhythmias, and deaths has been suggested. We did a prospective, randomised trial to investigate the frequency and character of arrhythmias during anaesthesia with halothane and the alternative anaesthetic agent, sevoflurane. Methods 150 children, aged 3-15 years, who needed dental extraction under general anaesthesia were randomly assigned sevoflurane or halothane supplementation of 66% nitrous oxide in oxygen with spontaneous ventilation. The halothane group (n=50) received halothane introduced in 0•75% increments, every two to three breaths, to a maximum of 3•0%, with maintenance at 1•5%. The incremental sevoflurane group (n=50) received sevoflurane introduced in 2% increments increased to a maximum of 8%, with maintenance at 4%. The 8%, sevoflurane group (n=50) received sevoflurane introduced at 8%, with maintenance at 4%. Findings 24 (48%) children receiving halothane had arrhythmias compared with four (8%) receiving incremental sevoflurane (difference 40% [95% Ci for differences 24-56] p<0•0001), and eight (16%) receiving 8% sevoflurane (difference 32% [15-50] p=0•0013). Halothane-associated arrhythmias occurred during dental extraction or emergence and were mainly ventricular. Six (12%) children in the halothane group had ventricular tachycardia. The methods of sevoflurane administration did not differ significantly for the frequency of arrhythmias (p=0•357). Sevoflurane-associated arrhythmias were mainly single supraventricular ectopic beats. Interpretation There was a strong association between halothane and ventricular arrhythmias, especially ventricular tachycardia. The use of sevoflurane in preference to halothane could contribute to a decline in morbidity and mortality associated with dental anaesthesia.