Management of cardiac surgery in the neonate.

The incidence of major congenital defects is approximately 2.5% of total births. Congenital heart disease and neural tube defects each account for about onethird of all defects. From several studies in Europe and the United States it is estimated that the incidence of congenital heart disease is about seven cases per 1000 births (Lancet, 1975). As more than one cardiac lesion is sometimes present, classification is usually based on the major lesion or combination of lesions, for example Fallot's tetralogy. On this basis, ventricular septal defect is by far the commonest defect with an incidence of 2.1/1000 births, followed by patent ductus arteriosus 0.7, pulmonary stenosis 0.5 and atrial septal defect 0.5/1000 births. Transposition of the great arteries, aortic stenosis, coarctation of the aorta and Fallot's tetralogy each have an incidence of about 0.3/1000 births. Total anomalous pulmonary venous drainage, although it has an incidence of only 0.1/1000 births, is of considerable importance in neonatal cardiac surgery, for reasons given later. Some of these lesions produce no symptoms in the neonatal period or in infancy. However, about 50% of children born with congenital heart disease die in the first year of life unless effectively treated. Onethird of these deaths occur in the first month of life (Mehrizi, Hirsch and Taussig, 1964). Lesions which often pose an early threat to life and present as neonatal emergencies are: total anomalous pulmonary venous drainage, transposition of the great arteries, coarctation of the aorta, patent ductus arteriosus, pulmonary atresia, aortic stenosis, ventriculo-septal defect and Fallot's tetralogy. Neonates who become seriously ill as a result of congenital heart disease are almost always suffering from severe hypoxia or congestive heart failure, or both. Congestive heart failure may be precipitated or accentuated by respiratory infection to which infants with congenital heart disease are particularly prone. Serious hypoxia occurs in those infants who have a severe obstructive lesion in the pulmonary circula-