Israel Medical Association Journal

Abstract

Parenteral nutrition (PN) must be initiated as soon as possible after delivery in very low birth weight (VLBW) preterm infants in order to prevent postnatal growth failure and improve neurodevelopmental outcome. When administered early, high levels of parenteral amino acids (AA) are well tolerated and prevent negative nitrogen balance. Although proteins are the driving force for growth, protein synthesis is energy demanding. Intravenous lipid emulsions (ILE) constitute a good energy source because of their high energy density and provide essential fatty acids (FA) along with their long-chain polyunsaturated fatty acid (LC-PUFA) derivatives necessary for central nervous system and retinal development. Early supply of ILE is not associated with increased morbidity. No significant differences were found between ILE based on soybean oil only and mixed ILE containing soybean oil in combination with other fat sources, except for a reduction in the incidence of sepsis with non-pure soybean ILE, and possibly less PN-associated liver disease with mixed ILE containing some fish oil. In preterm infants glucose homeostasis is still immature in the first days of life and abnormalities of glucose homeostasis are common. VLBW infants may not tolerate high levels of glucose infusion without hyperglycemia. Administering lower levels of glucose infusion as part of full early PN seems more successful than insulin at this stage. Postpartum there is a transition period when the water and electrolyte balance may be severely disturbed and should be closely monitored. Avoiding fluid overload is critical for preventing respiratory and other morbidities

Background: High frequency oscillatory ventilation based on optimal lung volume strategy is one of the accepted modes of ventilatory support for respiratory distress syndrome in very low birth weight infants. In 1999 it was introduced in our unit as the primary ventilation modality for RDS[1].

Objectives: To evaluate if the shift to HFOV[2] influenced the outcome of ventilated VLBW[3] infants in the neonatal intensive care unit of Carmel Medical Center.

Methods: Data were obtained from the medical charts of VLBW infants born at Carmel Medical Center, and late mortality data were taken from the Israel Ministry of Internal Affairs records. A retrospective analysis and a comparison with a historical control group ventilated by the conventional method were performed.

Results: A total of 232 VLBW infants with RDS were mechanically ventilated, from 1995 to 2003: 120 were ventilated using HFOV during the period 1999–2003 and 102 infants using CV[4] during 1995–1999. The mean gestational age of survivors was 27.4 ± 2 weeks in the HFOV group and 28.4 ± 2 in the conventional ventilation group (P = 0.03). The sub-sample of infants with birth weights <1000 g ventilated with HFOV showed higher survival rates than the infants in the conventional ventilation group, 53 vs. 25 (64.6% vs. 44.6%) respectively (P < 0.05). A trend for lower incidence of pulmonary interstitial emphysema was observed in the HFOV group.

Conclusions: The introduction of HFOV based on optimal lung volume strategy proved to be an efficient and safe method of ventilation support for VLBW infants in our unit.

Background: The incidence of congenital heart defects, reported to be 5–8/1000 in term infants, is not well established in very low birth weight infants.

Objectives: To establish the incidence of congenital heart defects in VLBW[1] infants in the neonatal intensive care unit of our institution.

Methods: A retrospective analysis of the population in the NICU[2] at our institution was performed. VLBW (BW ≤ 1500 g) infants born between 2001 and 2006 who survived more than 48 hours were included in the study. Infants with clinical signs of heart disease underwent echocardiography.

Results: During the study period 437 VLBW live-born infants met the inclusion criteria. Of these, 281 (64.3 %) underwent echocardiography. CHD[3] was detected in 19 infants (4.4%, 95% confidence interval 2.4–5.4%), significantly higher than the incidence of 5–8/1000 in the general population (P < 0.0001). In the subgroup of 154 infants with BW < 1000 g there were 10 (6.5%) with CHD. In the subgroup of 283 infants with BW 100–-1500 g there were 9 (3.2 %, P = 0.19 vs. VLBW) with CHD.

Conclusions:  Our observations show an increased incidence of CHD in VLBW neonates, as compared to the general population. Since not all infants underwent echocardiography, and minor cardiac defects may have been missed in our VLBW infants, the true incidence may be higher than reported here.

Background: Necrotizing enterocolitis is a common progressive gastrointestinal disease affecting more than 5% of very low birth weight infants and associated with a high mortality rate.

Objectives: To determine whether excessive weight gain in preterm infants is an early sign of NEC[1].

Methods: Seventeen preterm infants with perforated NEC were identified and matched with 17 control subjects for birth weight and gestational age. The postnatal age (days) at diagnosis of NEC was identified, and weight changes as well as clinical and laboratory data were recorded and compared for 7 days prior through 7 days post-diagnosis.

Results: A significant difference in weight gain was noticed between D-1 and D 0. The NEC and control groups gained 5.1% and 1.2%, respectively (P = 0.002). None of the sick infants lost weight on days -1 to D 0.

Conclusions: Excessive weight gain was observed in premature infants who subsequently developed NEC. Daily evaluation of weight changes should be considered part of a strategy for early identification of infants at risk for developing NEC. Future studies are needed to confirm this finding in a prospective manner and to investigate its pathogenesis.

Objectives: To compare the neonatal outcome (survival, intraventricular hemorrhage and bronchopulmonary dysplasia) of inborn and outborn very low birth weight infants, accounting for sociodemographic, obstetric and perinatal variables, with reference to earlier published data.

Methods: We compared 129 premature infants with birth weights of 750–1250 g delivered between 1996 and 2000 in a hospital providing neonatal intensive care to 99 premature babies delivered in a referring hospital. In the statistical analysis, variables with a statistical significant association with the outcome variables and dissimilar distribution in the two hospitals were identified and entered together with the hospital of birth as explanatory variables in a logistic regression.

Results: Accounting for the covariates, the odds ratios (outborns relative to inborns) were 0.31 (95% confidence interval = 0.11–0.86, P = 0.03) for mortality, 1.37 (95%CI[1] = 0.64–2.96, P = 0.42) for severe intraventricular hemorrhage, and 0.86 (95%CI = 0.38–1.97, P = 0.78) for bronchopulmonary dysplasia. The odds ratio for survival without severe intraventricular hemorrhage was 1.10 (95%CI = 0.55–2.20, P = 0.78). Comparing the current results with earlier (1990–94) published data from the same institution showed that mortality decreased in both the outborn and inborn infants (OR[2] = 0.23, 95%CI = 0.09–0.58, P = 0.002 and 0.46; 95%CI = 0.20–1.04, P = 0.06, respectively), but no significant change in the incidence of severe intraventricular hemorrhage or brochopulmonary dysplasia was observed. Increased survival was observed also in these infants receiving surfactant, more so among the outborn. The latter finding could be attributed to the early, pre-transport surfactant administration, implemented only during the current study.

Conclusions: Our data suggest that very low birth weight outborn infants may share an outcome comparable with that of inborn babies, if adequate perinatal care including surfactant administration is provided prior to transportation to a tertiary center.