Cardiovascular changes during halothane induction in children

The incidence of bradycardia and myocardial depression following halothane induction in children is well documented. Bradycardia leads to reduced cardiac output, which can result in compromised organ perfusion. Halothane may sometimes induce arrhythmia. There is at present no study in this sub-region on the cardiovascular changes of halothane induction in children. This study was designed to investigate the cardiovascular changes and incidence of arrhythmias following halothane induction.

Ninety ASA I - II children aged 6 months to 12 years were studied. Premedication with oral promethazine 1mg/kg was given to all patients above the age of one year. Anaesthesia was achieved with incremental halothane up to 3% in 33% oxygen and nitrous oxide. Halothane induction led to a significant drop in SBP, DBP and MAP in all patients at the end of induction. (p < 0.005). Heart rate values were significantly less postinduction in children older than one year (p < 0.05). Arrhythmias occurred in 3.3% of all patients. No patient experienced bradycardia. Other complications included hypotension (8.8% ) and mild laryngeal spasm (2.2% ).

Halothane induction in children results in significant reduction in heart rate and blood pressure. Bradyarrhthmias are uncommon with promethazine premedication.