ETAMINE is used commonly in cyanotic
infants for induction of anesthesia or sedation for diagnostic procedures such as cardiac catheterization. Advantages of the drug in cyanotic congenital heart disease (CHD) include maintenance of blood pressure and systemic vascular resistance (SVR). In addition, ketamine does not appear to increase pulmonary vascular resistance (PVR); therefore, pulmonary blood flow is maintained.H Ketamine has also been shown to maintain functional residual capacity (FRC) and minute ventilation in children, and apnea is rare. 3 ,4 These properties allow for accurate assessment of shunt fraction and pressure measurement in the various cardiac chambers during diagnostic catheterization due to the maintenance of spontaneous ventilation in a quiet resting state. Recently, prostaglandins have been used to improve pulmonary blood flow in cyanotic infants and to stabilize hemodynamics in acyanotic infants with obstructive lesions to left ventricular outflow (coarctation of aorta, interrupted aortic arch, and hypoplastic left heart syndrome)."? Apnea due to a central effect of the prostaglandins has been reported to occur in approximately 10% to 12% of infants, with the greatest occurrence shortly after the infusion is begun.' Two cases of neonates with ductusdependent congenital cardiac lesions are reported; they received prostaglandin E( (PGE 1 ) infusions and developed apnea shortly after receiving intramuscular (1M) ketamine for cardiac catheterization.
CASE REPORTS
Case 1
A 2-day-old, 3.2-kg boy (42 weeks postconceptual age) with transposition of the great vessels presented with cyanosis. After an echocardiogram confirmed the clinical