Routine administration of phenobarbital for the prevention of intraventricular hemorrhage in premature infants: five years' experience.

After it was reported in 1981 that phenobarbital reduced the incidence of intraventricular hemorrhage from 46.7% in control infants to 13.3% in treated premature infants, routine phenobarbital prophylaxis (loading dose, 20 mg/kg; maintenance, 5 mg/kg per day for 5 days) was introduced at the hospital of the original trial for all premature infants with birth weights of < or = 1800 gm. To assess continued efficacy, we reviewed all records of these infants from 1985 through 1989. The overall incidence of intraventricular hemorrhage was 27.5% (168/612); the proportion of severe intraventricular hemorrhage (grade 3 and 4) was 41.1% (69/168). The incidence of intraventricular hemorrhage was lower when loading occurred at < 4 hours: 25.9% (124/478) versus 32.8% (44/134). Outborn infants had a higher incidence of intraventricular hemorrhage than inborn infants (45.3% vs 23.0%). In addition to already known risk factors (gestational age, vaginal delivery, outborn status, pneumothorax, birth asphyxia, patent ductus arteriosus), intraventricular hemorrhage occurred more often in infants with hyperoxia (PO2 > 180 mmHg), hypocarbia (PcO2 > 28 mmHg), hypercarbia (PcO2 > 55 mmHg), and hypotension and hypertension (blood pressure > norm +/- 15 mmHg). These results support the hypothesis that phenobarbital has a role in the prophylaxis against intraventricular hemorrhage. Differences in the efficacy of phenobarbital prophylaxis between various studies may be caused by variations of age at loading and differences in the proportion of very low birth weight infants.(ABSTRACT TRUNCATED AT 250 WORDS)