The Comparison of the Effect of Three Anesthetic Induction Regimens on the Arterial Oxygen Saturation in Children with Tetralogy of Fallot Undergoing Cardiac Surgery

Background: Tetralogy of fallot (TOF) is the most common cyanotic congenital heart disease. Anesthesia induction is a challenging issue in these patients due to the risk of worsening hypoxemia following decrease in pulmonary blood flow. We evaluated the effect of three anesthetic induction regimens on the arterial oxygen saturation (SaO2%) in children with TOF. Methods: Seventy six children aged 50 days to 15 years old with TOF, scheduled in Nemazee and Faghihi hospitals to undergo elective cardiac surgery during 1385-1388 were randomly divided into 3 groups to receive three anesthetic induction agents including ketamine (2 mg/kg, IV), ketamine (5 mg/kg, IM) and halothane for gas induction. SaO2% and heart rate were recorded before induction and thereafter every 1 minute during induction of anesthesia till 10 min post-induction. Results: There were not significant differences between three groups regarding pattern of changes in SaO2% during 10 min post-induction. All three groups showed an increase in SaO2% committed over 6th minute but this pattern was not seen after that time. In addition, there were not significant differences among groups according to heart rate in the study period. Conclusion: It seems that anesthesia induction in TOF patients with ketamine IV and IM and halothane did not have significant adverse effects on SaO2%. Indeed, oxygenation during induction may offset other possible adverse effects of induction drugs on SaO2%