Growth Outcomes of Preterm Infants Exposed to Different Oxygen Saturation Target Ranges from Birth.

OBJECTIVE: To test whether infants randomized to a lower oxygen saturation (peripheral capillary oxygen saturation [SpO2]) target range while on supplemental oxygen from birth will have better growth velocity from birth to 36 weeks postmenstrual age (PMA) and less growth failure at 36 weeks PMA and 18-22 months corrected age. STUDY DESIGN: We evaluated a subgroup of 810 preterm infants from the Surfactant, Positive Pressure, and Oxygenation Randomized Trial, randomized at birth to lower (85%-89%, n = 402, PMA 26 ± 1 weeks, birth weight 839 ± 186 g) or higher (91%-95%, n = 408, PMA 26 ± 1 weeks, birth weight 840 ± 191 g) SpO2 target ranges. Anthropometric measures were obtained at birth, postnatal days 7, 14, 21, and 28; then at 32 and 36 weeks PMA; and 18-22 months corrected age. Growth velocities were estimated with the exponential method and analyzed with linear mixed models. Poor growth outcome, defined as weight <10th percentile at 36 weeks PMA and 18-22 months corrected age, was compared across the 2 treatment groups by the use of robust Poisson regression. RESULTS: Growth outcomes including growth at 36 weeks PMA and 18-22 months corrected age, as well as growth velocity were similar in the lower and higher SpO2 target groups. CONCLUSION: Targeting different oxygen saturation ranges between 85% and 95% from birth did not impact growth velocity or reduce growth failure in preterm infants.

Pharmacokinetics and safety of a single intravenous dose of myo-inositol in preterm infants of 23-29 wk.

BACKGROUND: Myo-inositol given to preterm infants with respiratory distress has reduced death, increased survival without bronchopulmonary dysplasia, and reduced severe retinopathy of prematurity in two randomized trials. Pharmacokinetic (PK) studies in extremely preterm infants are needed before efficacy trials. METHODS: Infants born in 23-29 wk of gestation were randomized to a single intravenous (i.v.) dose of inositol at 60 or 120 mg/kg or placebo. Over 96 h, serum levels (sparse sampling population PK) and urine inositol excretion were determined. Population PK models were fit using a nonlinear mixed-effects approach. Safety outcomes were recorded. RESULTS: A single-compartment model that included factors for endogenous inositol production, allometric size based on weight, gestational age strata, and creatinine clearance fit the data best. The central volume of distribution was 0.5115 l/kg, the clearance was 0.0679 l/kg/h, endogenous production was 2.67 mg/kg/h, and the half-life was 5.22 h when modeled without the covariates. During the first 12 h, renal inositol excretion quadrupled in the 120 mg/kg group, returning to near-baseline value after 48 h. There was no diuretic side effect. No significant differences in adverse events occurred among the three groups (P > 0.05). CONCLUSION: A single-compartment model accounting for endogenous production satisfactorily described the PK of i.v. inositol.

Early nutrition mediates the influence of severity of illness on extremely LBW infants.

To evaluate whether differences in early nutritional support provided to extremely premature infants mediate the effect of critical illness on later outcomes, we examined whether nutritional support provided to "more critically ill" infants differs from that provided to "less critically ill" infants during the initial weeks of life, and if, after controlling for critical illness, that difference is associated with growth and rates of adverse outcomes. One thousand three hundred sixty-six participants in the NICHD Neonatal Research Network parenteral glutamine supplementation randomized controlled trial who were alive on day of life 7 were stratified by whether they received mechanical ventilation for the first 7 d of life. Compared with more critically ill infants, less critically ill infants received significantly more total nutritional support during each of the first 3 wk of life, had significantly faster growth velocities, less moderate/severe bronchopulmonary dysplasia, less late-onset sepsis, less death, shorter hospital stays, and better neurodevelopmental outcomes at 18-22 mo corrected age. Rates of necrotizing enterocolitis were similar. Adjusted analyses using general linear and logistic regression modeling and a formal mediation framework demonstrated that the influence of critical illness on the risk of adverse outcomes was mediated by total daily energy intake during the first week of life.

PaCO2 in surfactant, positive pressure, and oxygenation randomised trial (SUPPORT).

OBJECTIVE: To determine the association of arterial partial pressure of carbon dioxide PaCO2 with severe intraventricular haemorrhage (sIVH), bronchopulmonary dysplasia (BPD), and neurodevelopmental impairment (NDI) at 18-22 months in premature infants. DESIGN: Secondary exploratory data analysis of Surfactant, Positive Pressure, and Oxygenation Randomised Trial (SUPPORT). SETTING: Multiple referral neonatal intensive care units. PATIENTS: 1316 infants 24 0/7 to 27 6/7 weeks gestation randomised to different oxygenation (SpO2 target 85-89% vs 91-95%) and ventilation strategies. MAIN OUTCOME MEASURES: Blood gases from postnatal day 0 to day14 were analysed. Five PaCO2 variables were defined: minimum (Min), maximum (Max), SD, average (time-weighted), and a four level categorical variable (hypercapnic (highest quartile of Max PaCO2), hypocapnic (lowest quartile of Min PaCO2), fluctuators (hypercapnia and hypocapnia), and normocapnic (middle two quartiles of Max and Min PaCO2)). PaCO2 variables were compared for infants with and without sIVH, BPD and NDI (±death). Multivariable logistic regression models were developed for adjusted results. RESULTS: sIVH, BPD and NDI (±death) were associated with hypercapnic infants and fluctuators. Association of Max PaCO2 and outcomes persisted after adjustment (per 10 mm Hg increase: sIVH/death: OR 1.27 (1.13 to 1.41); BPD/death: OR 1.27 (1.12 to 1.44); NDI/death: OR 1.23 (1.10 to 1.38), death: OR 1.27 (1.12 to 1.44), all p<0.001). No interaction was found between PaCO2 category and SpO2 treatment group for sIVH/death, NDI/death or death. Max PaCO2 was positively correlated with maximum FiO2 (rs0.55, p<0.0001) and ventilator days (rs0.61, p<0.0001). CONCLUSIONS: Higher PaCO2 was an independent predictor of sIVH/death, BPD/death and NDI/death. Further trials are needed to evaluate optimal PaCO2 targets for high-risk infants.

Neuroimaging and neurodevelopmental outcome in extremely preterm infants.

BACKGROUND: Extremely preterm infants are at risk for neurodevelopmental impairment (NDI). Early cranial ultrasound (CUS) is usual practice, but near-term brain MRI has been reported to better predict outcomes. We prospectively evaluated MRI white matter abnormality (WMA) and cerebellar lesions, and serial CUS adverse findings as predictors of outcomes at 18 to 22 months' corrected age. METHODS: Early and late CUS, and brain MRI were read by masked central readers, in a large cohort (n = 480) of infants <28 weeks' gestation surviving to near term in the Neonatal Research Network. Outcomes included NDI or death after neuroimaging, and significant gross motor impairment or death, with NDI defined as cognitive composite score <70, significant gross motor impairment, and severe hearing or visual impairment. Multivariable models evaluated the relative predictive value of neuroimaging while controlling for other factors. RESULTS: Of 480 infants, 15 died and 20 were lost. Increasing severity of WMA and significant cerebellar lesions on MRI were associated with adverse outcomes. Cerebellar lesions were rarely identified by CUS. In full multivariable models, both late CUS and MRI, but not early CUS, remained independently associated with NDI or death (MRI cerebellar lesions: odds ratio, 3.0 [95% confidence interval: 1.3-6.8]; late CUS: odds ratio, 9.8 [95% confidence interval: 2.8-35]), and significant gross motor impairment or death. In models that did not include late CUS, MRI moderate-severe WMA was independently associated with adverse outcomes. CONCLUSIONS: Both late CUS and near-term MRI abnormalities were associated with outcomes, independent of early CUS and other factors, underscoring the relative prognostic value of near-term neuroimaging.

Change in practice after the Surfactant, Positive Pressure and Oxygenation Randomised Trial.

OBJECTIVE: To test the hypothesis that the proportion of endotracheal intubation (ETI) in the delivery room (DR) decreased in Neonatal Research Network (NRN) centres after the National Institute of Child Health and Human Development NRN Surfactant, Positive Pressure, and Oxygenation Randomised Trial (SUPPORT). DESIGN: Retrospective cohort study using the prospective NRN generic database. SETTING: Eleven centres that participated in the SUPPORT trial and remained part of the NRN. Preterm neonates 24(0/7)-27(6/7) weeks' gestational age enrolled in the SUPPORT trial were randomised to: (1) DR continuous positive airway pressure or DR ETI with early surfactant administration; and (2) oxygen saturation targets of 85-89% or 91-95%. The prior NRN feasibility trial had assessed the feasibility of randomisation to continuous positive airway pressure versus ETI. PATIENTS: Infants 24(0/7)-27(6/7) weeks' gestational age, excluding infants with syndromes or major malformations and those on comfort care only. MAIN OUTCOME MEASURE: Proportion of DR ETI. RESULTS: The proportion of DR ETI decreased significantly in the group of infants from centres that had not participated in the feasibility trial (91% before vs 75% after SUPPORT, adjusted relative risk 0.86, 95% CI 0.83-0.89, p<0.0001) but not in the group of infants from the other centres, where the proportion of ETI was already lower prior to initiation of the SUPPORT trial (61% before vs 58% after SUPPORT, adjusted relative risk 0.96, 95% CI 0.89 to 1.05, p=0.40). CONCLUSION: This study shows that DR ETI changed after SUPPORT only in NRN centres that had not participated in a similar trial. TRIAL REGISTRATION NUMBER: NCT00063063 (GDB) and NCT00233324 (SUPPORT).

Individual and aggregate years-of-life-lost associated with overweight and obesity.

This study presents nationally representative estimates of individual and aggregate years-of-life-lost (YLLs) associated with overweight and three categories of obesity separately by age, race, smoking status, and gender strata. Using proportional hazards analysis and data from the National Health Interview Survey (NHIS) Linked Mortality Files, we estimated life expectancies for each BMI strata and quantified YLLs by comparing differences between each strata and the normal BMI reference group. Our results provide further evidence that overweight and mild obesity are not associated with a reduction in life expectancy. However, higher BMI categories are associated with lower expected survival. In aggregate, excess BMI is responsible for approximately 95 million YLLs. White females account for more than two-thirds of the aggregate YLLs. Unless something is done to reduce the rising prevalence of those with BMIs >35, or to mitigate the impact of obesity or its correlates on YLLs, expected life expectancy for US adults may decrease in the future.

Unimpaired outcomes for extremely low birth weight infants at 18 to 22 months.

OBJECTIVE: The goal was to identify, among extremely low birth weight (or=85, normal neurologic examination findings, and normal vision, hearing, swallowing, and walking. Outcomes were determined for 5250 (86%) of 6090 extremely low birth weight inborn infants. RESULTS: Of the 5250 infants whose outcomes were known at 18 months, 850 (16%) were unimpaired, 1153 (22%) had mild impairments, 1147 (22%) had moderate/severe neurodevelopmental impairments, and 2100 (40%) had died. Unimpaired survival rates varied according to birth weight, from <1% for infants

Growth in the neonatal intensive care unit influences neurodevelopmental and growth outcomes of extremely low birth weight infants.

OBJECTIVES: The objectives of this study were to assess whether (1) in-hospital growth velocity is predictive of neurodevelopmental and growth outcomes at 18 to 22 months' corrected age among extremely low birth weight (ELBW) infants and (2) in-hospital growth velocity contributes to these outcomes after controlling for confounding demographic and clinical variables. METHODS: Infants 501 to 1000 g birth weight from a multicenter cohort study were divided into quartiles of in-hospital growth velocity rates. Variables considered for the logistic-regression models included gender, race, gestational age, small for gestational age, mother's education, severe intraventricular hemorrhage, periventricular leukomalacia, age at regaining birth weight, necrotizing enterocolitis, late-onset infection, bronchopulmonary dysplasia, postnatal steroid therapy for pulmonary disease, and center. RESULTS: Of the 600 discharged infants, 495 (83%) were evaluated at 18 to 22 months' corrected age. As the rate of weight gain increased between quartile 1 and quartile 4, from 12.0 to 21.2 g/kg per day, the incidence of cerebral palsy, Bayley II Mental Developmental Index (MDI) <70 and Psychomotor Developmental Index (PDI) <70, abnormal neurologic examination, neurodevelopmental impairment, and need for rehospitalization fell significantly. Similar findings were observed as the rate of head circumference growth increased. The in-hospital rate of growth was associated with the likelihood of anthropometric measurements at 18 months' corrected age below the 10th percentile values of the Centers for Disease Control and Prevention 2000 growth curve. Logistic-regression analyses, controlling for potential demographic or clinical cofounders, and adjusted for center, identified a significant relationship between growth velocity and the likelihood of cerebral palsy, MDI and PDI scores of <70, and neurodevelopmental impairment. CONCLUSIONS: These analyses suggest that growth velocity during an ELBW infant's NICU hospitalization exerts a significant, and possibly independent, effect on neurodevelopmental and growth outcomes at 18 to 22 months' corrected age.

Validation of the National Institutes of Health consensus definition of bronchopulmonary dysplasia.

OBJECTIVE: A number of definitions of bronchopulmonary dysplasia (BPD), or chronic lung disease, have been used. A June 2000 National Institute of Child Health and Human Development/National Heart, Lung, and Blood Institute Workshop proposed a severity-based definition of BPD for infants <32 weeks' gestational age (GA). Mild BPD was defined as a need for supplemental oxygen (O2) for > or =28 days but not at 36 weeks' postmenstrual age (PMA) or discharge, moderate BPD as O2 for > or =28 days plus treatment with <30% O2 at 36 weeks' PMA, and severe BPD as O2 for > or =28 days plus > or =30% O2 and/or positive pressure at 36 weeks' PMA. The objective of this study was to determine the predictive validity of the severity-based, consensus definition of BPD. METHODS: Data from 4866 infants (birth weight < or =1000 g, GA <32 weeks, alive at 36 weeks' PMA) who were entered into the National Institute of Child Health and Human Development Neonatal Research Network Very Low Birth weight (VLBW) Infant Registry between January 1, 1995 and December 31, 1999, were linked to data from the Network Extremely Low Birth Weight (ELBW) Follow-up Program, in which surviving ELBW infants have a neurodevelopmental and health assessment at 18 to 22 months' corrected age. Linked VLBW Registry and Follow-up data were available for 3848 (79%) infants. Selected follow-up outcomes (use of pulmonary medications, rehospitalization for pulmonary causes, receipt of respiratory syncytial virus prophylaxis, and neurodevelopmental abnormalities) were compared among infants who were identified with BPD defined as O2 for 28 days (28 days definition), as O2 at 36 weeks' PMA (36 weeks' definition), and with the consensus definition of BPD. RESULTS: A total of 77% of the neonates met the 28-days definition, and 44% met the 36-weeks definition. Using the consensus BPD definition, 77% of the infants had BPD, similar to the cohort identified by the 28-days definition. A total of 46% of the infants met the moderate (30%) or severe (16%) consensus definition criteria, identifying a similar cohort of infants as the 36-weeks definition. Of infants who met the 28-days definition and 36-weeks definition and were seen at follow-up at 18 to 22 months' corrected age, 40% had been treated with pulmonary medications and 35% had been rehospitalized for pulmonary causes. In contrast, as the severity of BPD identified by the consensus definition worsened, the incidence of those outcomes and of selected adverse neurodevelopmental outcomes increased in the infants who were seen at follow-up. CONCLUSION: The consensus BPD definition identifies a spectrum of risk for adverse pulmonary and neurodevelopmental outcomes in early infancy more accurately than other definitions.

Extremely low birthweight neonates with protracted ventilation: mortality and 18-month neurodevelopmental outcomes.

OBJECTIVE: To compare duration of ventilation to mortality and adverse neurodevelopmental outcomes among extremely low birth weight (ELBW; 501-1000 g) infants. STUDY DESIGN: Retrospective analysis of prospectively collected data from 5364 infants with a birthweight of 501 to 1000 g born at National Institute of Child Health and Human Development (NICHD) Neonatal Research Network centers from 1995 to 1998. The main outcome measures were: survival, duration of mechanical ventilation, and neurodevelopmental outcome. RESULTS: Overall survival was 71%. The median duration of ventilation for survivors was 23 days; 75% were free of mechanical ventilation by 39 days, and 7% were ventilated for > or = 60 days. Of those ventilated for > or = 60 days, 24% survived without impairment. Of those ventilated for > or = 90 days, only 7% survived without impairment. Of those ventilated > or = 120 days, all survivors were impaired. CONCLUSIONS: The prognosis for ELBW with protracted ventilation remains grim. The cohort who remain intubated have diminished survival and high rates of impairment. Parents of these infants should be informed of changes in prognosis as the time of ventilation increases.