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

Abstract

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.