INCIDENCE OF ARRHYTHMIAS IN DENTAL ANAESTHESIA: A CROSS-OVER COMPARISON OF HALOTHANE AND ISOFLURANE

Fifty patients received halothane anaesthesia during the surgical removal of 3rd molars from one side of the mouth and isoflurane during extractions on the other. Degree of surgical difficulty was matched, and end-tidal PcO 2 did not differ significantly between sides. A significantly higher incidence of arrhythmias occurred during halothane, compared with isoflurane, anaesthesia. This difference occurred primarily when halothane was given for the first operated side. A clinically important feature of the stability of cardiac rhythm during isollurane anaesthesia was demonstrated—when frequent ectopic beats occur during halothane anaesthesia, a significant decrease in the rate of premature contractions occurs within 3 min of discontinuing halothane and introducing isoflurane.