The Fate of the Baby under 1501 g at Birth

Assessment of different hospitals' performance in neonatal intensive care has tended to rely on risk of mortality adjusted only for birthweight. We have developed a neonatal scoring system, CRIB (clinical risk index for babies), to take account of other factors. Scores are given for birthweight, gestational age, maximum and minimum fraction of inspired oxygen and maximum base excess during the first 12 h, and presence of congenital malformations. CRIB was developed retrospectively in a cohort of 812 infants of birthweight 1500 g or less or gestational age less than 31 weeks treated in four UK tertiary hospitals between 1988 and 1990. The scoring system was then validated by comparing its value as a predictor of hospital death with that of birthweight in a separate cohort of 488 similar infants. The area under the receiver operating characteristic (ROC) curve for predicting death in this validation cohort (a measure of the predictor's accuracy) was significantly greater for CRIB than for birthweight alone (0·90 [SE 0·05] vs 0·78 [0·03], p=0·03). Both indices of initial risk were used to assess the performance of nine tertiary and four non-tertiary hospitals in the UK. We looked at hospital mortality among the 1300 infants in the development and validation cohorts plus 248 other infants of birthweight 1500 g or less or gestational age less than 31 weeks. Without adjustment for initial risk, there was no clear difference in group mortality between the tertiary and non-tertiary hospitals. However, calculation of risk- adjusted mortality by means of CRIB showed that babies were twice as likely to die in the non-tertiary hospitals as in the tertiary hospitals (odds ratio 2·12 [95% Cl 1·39-3·24]). Adjustment for birthweight alone also showed higher odds of death in non-tertiary hospitals (1·45 [1·01-2·11]). CRIB is a robust index of initial neonatal risk that is more accurate than birthweight and simple enough for routine use. International comparisons of staffing policy and organisation of neonatal intensive care units are needed to investigate the reasons for variations in performance.

In a nationwide prospective survey on very preterm and very-low-birthweight infants in the Netherlands, a neurodevelopmental assessment was made at the corrected age of two years in a virtually complete population. The study achieved a 97·4% follow-up rate. A major handicap was found in 59 children and a minor handicap in 111 children (4·4% and 8·3% of liveborn infants, respectively). Unlike mortality, handicap was apparently unrelated to gestational age or birthweight.

Physicians who deliver babies in Alabama were surveyed to determine their level of knowledge about the survival of low-birth weight/early gestational age infants. These estimates of neonatal survival were compared to the actual neonatal survival rates at local hospitals and at the regional perinatal centers in Alabama. In addition, the physicians' knowledge of survival rates was correlated with their management decisions in hypothetical cases of premature labor Our findings indicate that physicians who perform deliveries tended to underestimate the potential for neonatal survival in premature infants. Equally as important, the range of responses varied markedly. In the hypothetical cases, management decisions often appeared to be based on incorrect information about neonatal survival. These decisions, including not electronically monitoring fetuses, not performing a cesarean section for fetal distress, and not transferring women in premature labor to a perinatal center, if made in actual cases, would result in potentially viable fetuses receiving less than optimal management.

Two large perinatal centres in Melbourne, Australia collaborated in standardised assessment of surviving very-low-birthweight (500-1500 g) infants born in 1977 and 1978. 291 (97·3%) of the 299 long-term survivors were assessed at or shortly after the age of 2 years; some data were available for a further 6 (2·0%) children, and only 2 (0·7%) of the cohort were not traced. Rates of handicap for inborn and outborn infants in each of the hospitals were calculated separately. 35 (11·8%) of the children assessed had cerebral palsy, 4 (1·3%) had severe sensorineural deafness, and 5 (1·7%) were blind. Results of the Bayley scales of infant development were similar for the two hospital populations; however, the mean scores were lower, and there were more children with both higher and lower scores, than would be expected. 54 children (18·0% of the study population) had one or more major handicaps.

The neonatal units in two large maternity hospitals collaborated in a study of 440 liveborn infants weighing 500-1500 g born in 1977 and 1978: 377 (85·7%) were born in hospital. The overall survival rate was 70·5%, with a range of 67·5% to 71·5% for the inborn and outborn categories of infants in each hospital. In hospital A the survival rate of infants weighing ≥1100 g was higher than that in hospital B, whereas the survival rate of infants weighing <800 g was higher in hospital B. Obstetric risk factors and obstetric management differed little between the hospitals, but there were several important differences in paediatric management; in particular, hospital B (with a better survival rate of infants weighing under 800 g) used ventilatory support and parenteral feeding much more frequently.