Marked increases in heart rate associated with sevoflurane but not with halothane following suxamethonium administration in children.

The changes in heart rate and arterial blood pressure following the administration of suxamethonium in healthy children (mean age 3.8 +/- 0.3 years) during inhalational induction with either sevoflurane (n = 22) or halothane (n = 19) were studied. Heart rate 60s following suxamethonium administration increased significantly in the sevoflurane but not in the halothane group. In the halothane group, four children required intravenous (i.v.) atropine as as result of bradycardia. None of the children in the sevoflurane group developed bradycardia following suxamethonium (P < 0.05). Values of oxygenation, ventilation and age corrected minimal alveolar concentration were comparable at all measurement times. The haemodynamic response to the administration of suxamethonium in children anaesthetized with sevoflurane seems to reflect the stimulation of the autonomic ganglia by suxamethonium whereas this positive chronotropic effect is attenuated or reversed by halothane.