Changing survival and impairment rates at 18-24 months in outborn very low-birth-weight infants: 1984-1987 versus 1980-1983

Evidence-based feeding guidelines for very low-birth-weight infants

Clinical practice guidelines (CPG) for the nutritional management of premature infants are limited. This project focused on the development of a research-based enteral feeding CPG for infants of < 1,500 g. The CPG was based on an extensive literature review and developed through a process of consensus decision making by a team of clinical researchers. Infants that weigh < 1,000 g initiate minimal enteral nutrition (MEN) at 48 hours; nutritional feedings begin on day 5 to 6 of life. For infants between 1,000 and 1,500 g, nutritional feedings begin at 48 hours and are advanced at a rate of less than 30 mL/kg per day. The benefits and risks of continuous versus intermittent nasogastric tube feeding were inconclusive; therefore, the CPG does not stipulate a feeding method. Breast milk is used preferentially, and specific guidelines for the definition and management of feeding intolerance are provided. A follow-up study testing this CPG has been completed and is published in the original research section of this issue.

The Swedish national prospective study on extremely low birthweight (ELBW) infants. Incidence, mortality, morbidity and survival in relation to level of care

In a 2-year (1990-92) prospective national investigation, comprising all stillborn and live-born ELBW infants with a birthweight of < or = 1000 g born at 23 completed weeks of gestation or more, we examined the incidence, neonatal mortality, major morbidity and infant survival in relation to level of care and place of residence. A total of 633 ELBW infants were live-born, i.e. 0.26% of all live-born infants, and 298 were stillborn. The average neonatal mortality was 37% and 91% at 23 weeks, 70% at 24 weeks, and 40% at 25 weeks of gestation. Of neonatal survivors, 8% had intraventricular haemorrhage grade 3, 10% retinopathy of prematurity of stage > or = 3, 2% necrotizing enterocolitis, and 28% were oxygen-dependent at a time corresponding to 36 weeks of gestation. In all, 77% were treated with mechanical ventilation, whereas 19% survived without, almost all of them being CPAP treated. Infant mortality among infants born at level III (tertiary centres) was 30%, at level IIa (with full perinatal service) 46% and at level IIb (with basic neonatal service) 55%. Only 1% was born at hospital level I. Regarding the relation to place of residence, the mortality rates among infants residing in the areas served by levels III, IIa and IIb hospitals were 36%, 45% and 41%, respectively. The referral system thus functioned well, but can be improved, and increased perinatal referral, at borderline perinatal viability, might provide a better quality of care and a better chance of survival.

Secular changes in the outcomes to eighteen to twenty-four months of age of extremely low birth weight infants, with adjustment for changes in risk factors and severity of illness

OBJECTIVES

To analyze secular changes in the rates of death and of major impaired outcome in surviving outborn infants who weighted < or = 800 gm at birth and were admitted in 1980 to 1989, with adjustment for changes in risk factors and severity of illness around the time of birth; and to identify changes in these factors that might explain changes in outcomes.

DESIGN

Retrospective cohort study with follow-up to a minimum of 18 months of postterm age. After preliminary screening, multivariate models of association between risk/severity of illness factors and outcomes were constructed, validated, and used to adjust outcomes (death and major impairment to 18 to 24 months of age).

SETTING

Regional neonatal intensive care unit for referral of "outborn" infants.

PATIENTS

Two hundred eighty-seven consecutively admitted infants who weighted < or = 800 gm at birth (97% follow-up).

RESULTS

The death rate during the 1980s did not fall significantly (p adjusted for risk factors = 0.115). The major impairment rate fell (odds ratio, 0.24 (95% confidence interval, 0.10, 0.60); p = 0.002, adjusted for delivery route and respiratory failure measures), mainly because of a reduced rate of blindness, not attributable to cryotherapy. The risk factors that improved and were possibly related to the reduced impairment rate were blood pH and glucose concentration, and serum sodium concentration in the first 48 hours of life.

CONCLUSIONS

Despite an increasing selection for referral of less mature and more severely ill outborn babies near the "limit of viability," and despite more aggressive care, the rate of major impairment fell significantly during the 1980s. This trend was enhanced by adjustment for severity of illness. The fall was attributable to a reduced rate of blindness, and was associated with evidence of improved control of physiologic balance after birth.

Outcome of extremely low-birth-weight infants: 1980-1990

Neonatal and follow-up data of infants from the special care nursery whose birth weights were < 750 g, born between 1980 and 1990, were reviewed. There was a 20% relative improvement in the odds of surviving the neonatal period, a 16% improvement in the odds of being discharged and a 19% improvement in the odds of surviving until 2 years of age with each consecutive year. Home oxygen use increased significantly over the study period. The neurodevelopmental outcomes of infants were similar over the 11-year period, with 53% being classified as neurologically normal, with a mean developmental index of 83 at 1 to 2 years of age. We conclude that there has been an improved survival of infants with birth weights < 750 g in our institution, and that the overall incidence of serious neurodevelopmental deficits among survivors has remained stable.