Management and outcome of low birth weight neonates with congenital heart disease.

In 100 consecutive neonates with birth weights < or = 2500 gm (range, 540 to 2500 gm; median, 2200 gm), major congenital heart disease (excluding patent ductus arteriosus, isolated atrial septal defect, and ventricular septal defect) was diagnosed between January 1987 and January 1991; 46 had ductus-dependent lesions. Of the 100 neonates, 30 had genetic aberrations or significant associated congenital anomalies. The four most common cardiac diagnoses were tetralogy of Fallot with or without pulmonary atresia (n = 16); coarctation of the aorta (n = 12); transposition of the great arteries (n = 11); and common atrioventricular canal (n = 11). The hospital survival rate for the entire group of 100 neonates was 70%. The patients were separated into three groups on the basis of the time of intervention. Group 1 (early intervention) included 62 infants. These neonates (including 31 with ductus-dependent lesions) had surgical or catheter intervention during the initial hospitalization (median age, 9 days), all at weights < or = 2500 gm. The hospital survival rate was 81% (50/62); survival rates for palliation (78%, 18/23) and for correction (82%, 32/39) were similar. There were 26 neonates in group 2 (late intervention). These neonates did not have surgical intervention during the initial hospitalization. All were managed medically; survivors were discharged and had surgical procedures later (at a median age of 4.3 months). Six neonates (23%) died during medical management; all 20 survivors returned and had surgical procedures, with 90% survival. Overall survival rate for this group was 69% (18/26). The remaining 12 patients (group 3) had complicating features that precluded intervention; none survived. On the basis of these results, we conclude that early intervention, even with corrective surgery, can be performed in low birth weight neonates with an acceptable mortality rate. Prolonged medical therapy to achieve further weight gain did not appear to improve the survival rate.

Diuresis and pulmonary function in premature infants with respiratory distress syndrome.

A prospective study of 99 premature infants with severe respiratory distress syndrome who were randomly assigned to receive diuretic treatment with either furosemide or chlorothiazide was analyzed to examine the relationship of diuretic administration and diuresis to survival and to the duration and degree of mechanical ventilatory support. Subjects were given a diuretic, usually beginning on the second or third day of life, if they had not initiated the expected spontaneous diuresis and did not show pulmonary improvement. Infants given furosemide experienced a postnatal weight loss nearly identical to that in infants who were deemed not to need a diuretic; infants given chlorothiazide lost weight more slowly and had significantly greater body weight on postnatal days 4 and 5. Four factors were independently correlated with improved survival: furosemide usage, high birth weight, low initial mean airway pressure, and the absence of intraventricular hemorrhage. Ventilator mean airway pressure on the seventh day of life and duration of mechanical ventilation were both related to diuresis. These data provide additional evidence for the importance of water homeostasis in determining the course of respiratory distress syndrome in premature infants and indicate that furosemide administration is beneficial when spontaneous diuresis does not occur. Furosemide may be particularly effective if combined with early closure of the ductus arteriosus.

Direct and indirect pulmonary vascular effects of tolazoline in the newborn lamb.

The pulmonary vascular effects of tolazoline were studied in unsedated newborn lambs during normal oxygenation and hypoxia. Direct and indirect pulmonary vascular responses were analyzed separately. During normal oxygenation, tolazoline (1 mg/kg) given into a branch pulmonary artery increased cardiac output while decreasing systemic and pulmonary resistances. Pulmonary flow distribution did not change, suggesting that the fall in pulmonary resistance was due to an indirect rather than a direct action of the drug. Tolazoline had similar effects on systemic and pulmonary resistances in the hypoxic lamb; however, there was a shift in blood flow toward the injected lung, indicating local pulmonary vasodilation induced by the drug. In either case, tolazoline did not alter the resistance ratio between the injected lung and the systemic circulation. We conclude that tolazoline is a direct pulmonary vasodilator in the hypoxic lamb, but does not appear to lower the pulmonary to systemic resistance ratio.