Comparison of speed of inhalational induction in children with and without congenital heart disease

BACKGROUND: Conduct of stable inhalational anesthetic induction in children with congenital heart disease (CHD) presents special challenges. It requires in-depth understanding of the effect of congenital shunt lesions on the uptake, delivery, and equilibration of anesthetic drugs. Intracardiac shunts can alter the induction time and if delivery of anesthetic agent is not carefully titrated, can lead to overdosing and undesirable myocardial depression. AIMS: To study the effect of congenital shunt lesions on the speed of inhalational induction and also the impact of inhalational induction on hemodynamics in the presence of congenital shunt lesions. SETTING: Tertiary care hospital. DESIGN: A prospective, single-center clinical study. MATERIALS AND METHODS: Ninety-three pediatric patients undergoing elective surgery were segregated into three equal groups, namely, Group 1: no CHD, Group 2: acyanotic CHD, and Group 3: cyanotic CHD. General anesthesia was induced with 8% sevoflurane in 6 L/min air-oxygen. The time to induction was noted at loss of eyelash reflex and decrease in bispectral index (BIS) value below 60. End-tidal sevoflurane concentration, minimum alveolar concentration, and BIS were recorded at 15 s intervals for the 1(st) min followed by 30 s interval for another 1 min during induction. Hemodynamic data were recorded before and after induction. RESULTS: Patients in Group 3 had significantly prolonged induction time (99 ± 12.3 s; P < 0.001), almost twice that of the patients in other two groups (51 ± 11.3 s in Group 1 and 53 ± 12.0 s in Group 2). Hypotension occurred after induction in Group 1. No other adverse hemodynamic perturbations were observed. CONCLUSION: The time to inhalational induction of anesthesia is significantly prolonged in patients with right-to-left shunt, compared to patients without CHD or those with left-to-right shunt, in whom it is similar. Sevoflurane is safe and maintains stable hemodynamics in the presence of CHD.