Outcomes of hypoxic-ischemic encephalopathy in neonates treated with hypothermia

This article examines the evidence regarding mortality and neurodevelopmental outcomes following hypothermia for neonatal hypoxic-ischemic encephalopathy. Data from randomized controlled trials regarding neurodevelopmental outcome at the end point of the major trials, and from 2 of the trials on childhood outcome following hypothermia for neonatal hypoxic-ischemic encephalopathy are presented. The predictors of outcome that can be evaluated in the neonatal period are also reviewed, as this information may assist in the counseling of families. Most trials of hypothermia have been performed in high-resource countries; published studies from the low- and middle-income countries are also reviewed.

Impact of interhospital transport on the physiologic status of very low-birth-weight infants

OBJECTIVES

To evaluate the change in physiologic stability of very low-birth-weight (VLBW) infants following transport using TRIPS (transport risk index of physiologic stability) score as a measure of physiologic stability and compare changes in TRIPS score in groups of VLBW infants who underwent shorter versus longer transport.

STUDY DESIGN

Retrospective chart review.

RESULTS

Our cohort of 106 infants, 44 (41%) of whom were females, had a mean birth weight of 777 g (standard deviation [SD] 159) and median gestational age of 26 weeks (range 23 to 32 weeks). Mean weight at transfer was 1,610 g (SD 924) and mean postnatal age at transfer was 56 days (SD 45). Median time on transport was 15 minutes (range 10 to 85 minutes). All 106 transports were ground transports. Of the 106 infants, 57 (54%) had deterioration, 20 (19%) had improvement, and 29 (27%) had no change in their physiologic status during transport. Comparison of the two transport duration groups based on median transport time as a cutoff point (i.e., ≤ 15 minutes and > 15 minutes) revealed a higher proportion of infants with deterioration in their physiologic status in the prolonged transport (>15 minutes) group (65% versus 45%; p = 0.03). Temperature change, either alone or in combination with other indices, was responsible for change in TRIPS score (deterioration or improvement) in 79% of these infants.

CONCLUSIONS

Interhospital transport of VLBW infants may cause deterioration in their physiologic status, the likelihood of which is increased with longer duration of transport. Better temperature regulation during interhospital transport may decrease the chances of deterioration in physiologic status of VLBW infants.

Neonatal encephalopathic cerebral injury in South India assessed by perinatal magnetic resonance biomarkers and early childhood neurodevelopmental outcome

Although brain injury after neonatal encephalopathy has been characterised well in high-income countries, little is known about such injury in low- and middle-income countries. Such injury accounts for an estimated 1 million neonatal deaths per year. We used magnetic resonance (MR) biomarkers to characterise perinatal brain injury, and examined early childhood outcomes in South India.

METHODS

We recruited consecutive term or near term infants with evidence of perinatal asphyxia and a Thompson encephalopathy score ≥6 within 6 h of birth, over 6 months. We performed conventional MR imaging, diffusion tensor MR imaging and thalamic proton MR spectroscopy within 3 weeks of birth. We computed group-wise differences in white matter fractional anisotropy (FA) using tract based spatial statistics. We allocated Sarnat encephalopathy stage aged 3 days, and evaluated neurodevelopmental outcomes aged 3½ years using Bayley III.

RESULTS

Of the 54 neonates recruited, Sarnat staging was mild in 30 (56%); moderate in 15 (28%) and severe in 6 (11%), with no encephalopathy in 3 (6%). Six infants died. Of the 48 survivors, 44 had images available for analysis. In these infants, imaging indicated perinatal rather than established antenatal origins to injury. Abnormalities were frequently observed in white matter (n = 40, 91%) and cortex (n = 31, 70%) while only 12 (27%) had abnormal basal ganglia/thalami. Reduced white matter FA was associated with Sarnat stage, deep grey nuclear injury, and MR spectroscopy N-acetylaspartate/choline, but not early Thompson scores. Outcome data were obtained in 44 infants (81%) with 38 (79%) survivors examined aged 3½ years; of these, 16 (42%) had adverse neurodevelopmental outcomes.

CONCLUSIONS

No infants had evidence for established brain lesions, suggesting potentially treatable perinatal origins. White matter injury was more common than deep brain nuclei injury. Our results support the need for rigorous evaluation of the efficacy of rescue hypothermic neuroprotection in low- and middle-income countries.

Chorioamnionitis and early childhood outcomes among extremely low-gestational-age neonates

IMPORTANCE

Chorioamnionitis is strongly linked to preterm birth and neonatal infection. The association between histological and clinical chorioamnionitis and cognitive, behavioral, and neurodevelopmental outcomes among extremely preterm neonates is less clear. We evaluated the impact of chorioamnionitis on 18- to 22-month neurodevelopmental outcomes in a contemporary cohort of extremely preterm neonates.

OBJECTIVE

To compare the neonatal and neurodevelopmental outcomes of 3 groups of extremely low-gestational-age infants with increasing exposure to perinatal inflammation: no chorioamnionitis, histological chorioamnionitis alone, or histological plus clinical chorioamnionitis.

DESIGN, SETTING, AND PARTICIPANTS

Longitudinal observational study at 16 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Two thousand three hundred ninety extremely preterm infants born at less than 27 weeks' gestational age (GA) between January 1, 2006, and December 31, 2008, with placental histopathology and 18 to 22 months' corrected age follow-up data were eligible.

MAIN EXPOSURE

Chorioamnionitis.

MAIN OUTCOMES AND MEASURES

Outcomes included cerebral palsy, gross motor functional limitation, behavioral scores (according to the Brief Infant-Toddler Social and Emotional Assessment), cognitive and language scores (according to the Bayley Scales of Infant and Toddler Development, Third Edition), and composite measures of death/neurodevelopmental impairment. Multivariable logistic and linear regression models were developed to assess the association between chorioamnionitis and outcomes while controlling for important variables known at birth.

RESULTS

Neonates exposed to chorioamnionitis had a lower GA and higher rates of early-onset sepsis and severe periventricular-intraventricular hemorrhage as compared with unexposed neonates. In multivariable models evaluating death and neurodevelopmental outcomes, inclusion of GA in the model diminished the association between chorioamnionitis and adverse outcomes. Still, histological plus clinical chorioamnionitis was associated with increased risk of cognitive impairment as compared with no chorioamnionitis (adjusted odds ratio [OR], 2.38 [95% CI, 1.32 to 4.28] without GA; adjusted OR, 2.00 [95% CI, 1.10 to 3.64] with GA as a covariate). Histological chorioamnionitis alone was associated with lower odds of death/neurodevelopmental impairment as compared with histological plus clinical chorioamnionitis (adjusted OR, 0.68 [95% CI, 0.52 to 0.89] without GA; adjusted OR, 0.66 [95% CI, 0.49 to 0.89] with GA as a covariate). Risk of behavioral problems did not differ statistically between groups.

CONCLUSIONS AND RELEVANCE

Antenatal exposure to chorioamnionitis is associated with altered odds of cognitive impairment and death/neurodevelopmental impairment in extremely preterm infants.

Mortality and morbidity of VLBW infants with trisomy 13 or trisomy 18

OBJECTIVE

Little is known about how very low birth weight (VLBW) affects survival and morbidities among infants with trisomy 13 (T13) or trisomy 18 (T18). We examined the care plans for VLBW infants with T13 or T18 and compared their risks of mortality and neonatal morbidities with VLBW infants with trisomy 21 and VLBW infants without birth defects.

METHODS

Infants with birth weight 401 to 1500 g born or cared for at a participating center of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network during the period 1994-2009 were studied. Poisson regression models were used to examine risk of death and neonatal morbidities among infants with T13 or T18.

RESULTS

Of 52,262 VLBW infants, 38 (0.07%) had T13 and 128 (0.24%) had T18. Intensity of care in the delivery room varied depending on whether the trisomy was diagnosed before or after birth. The plan for subsequent care for the majority of the infants was to withdraw care or to provide comfort care. Eleven percent of infants with T13 and 9% of infants with T18 survived to hospital discharge. Survivors with T13 or T18 had significantly increased risk of patent ductus arteriosus and respiratory distress syndrome compared with infants without birth defects. No infant with T13 or T18 developed necrotizing enterocolitis.

CONCLUSIONS

In this cohort of liveborn VLBW infants with T13 or T18, the timing of trisomy diagnosis affected the plan for care, survival was poor, and death usually occurred early.

Hypothermia for hypoxic-ischemic encephalopathy

Moderate to severe hypoxic-ischemic injury in newborn infants, manifested as encephalopathy immediately or within hours after birth, is associated with a high risk of either death or a lifetime with disability. In recent multicenter clinical trials, hypothermia initiated within the first 6 postnatal hours has emerged as a therapy that reduces the risk of death or impairment among infants with hypoxic-ischemic encephalopathy. Prior to hypothermia, no therapies directly targeting neonatal encephalopathy secondary to hypoxic-ischemic injury had convincing evidence of efficacy. Hypothermia therapy is now becoming increasingly available at tertiary centers. Despite the deserved enthusiasm for hypothermia, obstetric and neonatology caregivers, as well as society at large, must be reminded that in the clinical trials more than 40% of cooled infants died or survived with impairment. Although hypothermia is an evidence-based therapy, additional discoveries are needed to further improve outcome after HIE. In this article, we briefly present the epidemiology of neonatal encephalopathy due to hypoxic-ischemic injury, describe the rationale for the use of hypothermia therapy for hypoxic-ischemic encephalopathy, and present results of the clinical trials that have demonstrated the efficacy of hypothermia. We also present findings noted during and after these trials that will guide care and direct research for this devastating problem.

Death or neurodevelopmental impairment at 18 to 22 months corrected age in a randomized trial of early dexamethasone to prevent death or chronic lung disease in extremely low birth weight infants

OBJECTIVE

To evaluate the incidence of death or neurodevelopmental impairment (NDI) at 18-22 months corrected age in subjects enrolled in a trial of early dexamethasone treatment to prevent death or chronic lung disease in extremely low birth weight infants.

STUDY DESIGN

Evaluation of infants at 18-22 months corrected age included anthropomorphic measurements, a standard neurological examination, and the Bayley Scales of Infant Development-II, including the Mental Developmental Index and the Psychomotor Developmental Index. NDI was defined as moderate or severe cerebral palsy, Mental Developmental Index or Psychomotor Developmental Index <70, blindness, or hearing impairment.

RESULTS

Death or NDI at 18-22 months corrected age was similar in the dexamethasone and placebo groups (65% vs 66%, P = .99 among those with known outcome). The proportion of survivors with NDI was also similar, as were mean values for weight, length, and head circumference and the proportion of infants with poor growth (50% vs 41%, P = .42 for weight less than 10th percentile); 49% of infants in the placebo group received treatment with corticosteroid compared with 32% in the dexamethasone group (P = .02).

CONCLUSION

The risk of death or NDI and rate of poor growth were high but similar in the dexamethasone and placebo groups. The lack of a discernible effect of early dexamethasone on neurodevelopmental outcome may be due to frequent clinical corticosteroid use in the placebo group.

Neurodevelopmental outcomes of extremely low birth weight infants with spontaneous intestinal perforation or surgical necrotizing enterocolitis

OBJECTIVE

To determine if extremely low birth weight infants with surgical necrotizing enterocolitis have a higher risk of death or neurodevelopmental impairment and neurodevelopmental impairment among survivors (secondary outcome) at 18-22 months corrected age compared with infants with spontaneous intestinal perforation and infants without necrotizing enterocolitis or spontaneous intestinal perforation.

STUDY DESIGN

Retrospective analysis of the Neonatal Research Network very low birth weight registry, evaluating extremely low birth weight infants born between 2000 and 2005. The study infants were designated into three groups: (1) spontaneous intestinal perforation without necrotizing enterocolitis; (2) surgical necrotizing enterocolitis (Bell's stage III); and (3) neither spontaneous intestinal perforation nor necrotizing enterocolitis. Multivariate logistic regression analysis was performed to evaluate the association between the clinical group and death or neurodevelopmental impairment, controlling for multiple confounding factors including center.

RESULT

Infants with surgical necrotizing enterocolitis had the highest rate of death before hospital discharge (53.5%) and death or neurodevelopmental impairment (82.3%) compared with infants in the spontaneous intestinal perforation group (39.1 and 79.3%) and no necrotizing enterocolitis/no spontaneous intestinal perforation group (22.1 and 53.3%; P<0.001). Similar results were observed for neurodevelopmental impairment among survivors. On logistic regression analysis, both spontaneous intestinal perforation and surgical necrotizing enterocolitis were associated with increased risk of death or neurodevelopmental impairment (adjusted odds ratio 2.21, 95% confidence interval (CI): 1.5, 3.2 and adjusted OR 2.11, 95% CI: 1.5, 2.9, respectively) and neurodevelopmental impairment among survivors (adjusted OR 2.17, 95% CI: 1.4, 3.2 and adjusted OR 1.70, 95% CI: 1.2, 2.4, respectively).

CONCLUSION

Spontaneous intestinal perforation and surgical necrotizing enterocolitis are associated with a similar increase in the risk of death or neurodevelopmental impairment and neurodevelopmental impairment among extremely low birth weight survivors at 18-22 months corrected age.

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.

Serum tocopherol levels in very preterm infants after a single dose of vitamin E at birth

OBJECTIVE

Our aim was to examine the impact of a single enteral dose of vitamin E on serum tocopherol levels. The study was undertaken to see whether a single dose of vitamin E soon after birth can rapidly increase the low α-tocopherol levels seen in very preterm infants. If so, this intervention could be tested as a means of reducing the risk of intracranial hemorrhage.

METHODS

Ninety-three infants <27 weeks' gestation and <1000 g were randomly assigned to receive a single dose of vitamin E or placebo by gastric tube within 4 hours of birth. The vitamin E group received 50 IU/kg of vitamin E as dl-α-tocopheryl acetate (Aquasol E). The placebo group received sterile water. Blood samples were taken for measurement of serum tocopherol levels by high-performance liquid chromatography before dosing and 24 hours and 7 days after dosing.

RESULTS

Eighty-eight infants received the study drug and were included in the analyses. The α-tocopherol levels were similar between the groups at baseline but higher in the vitamin E group at 24 hours (median 0.63 mg/dL vs. 0.42 mg/dL, P = .003) and 7 days (2.21 mg/dL vs 1.86 mg/dL, P = .04). There were no differences between groups in γ-tocopherol levels. At 24 hours, 30% of vitamin E infants and 62% of placebo infants had α-tocopherol levels <0.5 mg/dL.

CONCLUSIONS

A 50-IU/kg dose of vitamin E raised serum α-tocopherol levels, but to consistently achieve α-tocopherol levels >0.5 mg/dL, a higher dose or several doses of vitamin E may be needed.

Apgar scores at 10 min and outcomes at 6-7 years following hypoxic-ischaemic encephalopathy

AIM

To determine the association between 10 min Apgar scores and 6-7-year outcomes in children with perinatal hypoxic-ischaemic encephalopathy (HIE) enrolled in the National Institute of Child Health and Human Development Neonatal Research Network (NICHD NRN) whole body cooling randomised controlled trial (RCT).

METHODS

Evaluations at 6-7 years included the Wechsler Preschool and Primary Scale of Intelligence III or Wechsler Intelligence Scale for Children IV and Gross Motor Functional Classification Scale. Primary outcome was death/moderate or severe disability. Logistic regression was used to examine the association between 10 min Apgar scores and outcomes after adjusting for birth weight, gestational age, gender, outborn status, hypothermia treatment and centre.

RESULTS

In the study cohort (n=174), 64/85 (75%) of those with 10 min Apgar score of 0-3 had death/disability compared with 40/89 (45%) of those with scores >3. Each point increase in 10 min Apgar scores was associated with a significantly lower adjusted risk of death/disability, death, death/IQ <70, death/cerebral palsy (CP) and disability, IQ<70 and CP among survivors (all p<0.05). Among the 24 children with a 10 min Apgar score of 0, five (20.8%) survived without disability. The risk-adjusted probabilities of death/disability were significantly lower in cooled infants with Apgar scores of 0-3; there was no significant interaction between cooling and Apgar scores (p=0.26).

CONCLUSIONS

Among children with perinatal HIE enrolled in the NICHD cooling RCT, 10 min Apgar scores were significantly associated with school-age outcomes. A fifth of infants with 10 min Apgar score of 0 survived without disability to school age, suggesting the need for caution in limiting resuscitation to a specified duration.

Characteristics of extremely low-birth-weight infant survivors with unimpaired outcomes at 30 months of age

OBJECTIVE

To evaluate characteristics of unimpaired outcome in extremely low-birth-weight (ELBW) survivors.

STUDY DESIGN

ELBW infants (n=714) with 30 months' assessments were analyzed. Logistic regression was used to develop a model for the binary outcome of unimpaired versus impaired outcome.

RESULT

Thirty-three percent of infants had an unimpaired outcome. Seventeen percent of ELBW survivors had a Bayley II Mental Developmental Index score of ≥ 101 and 2% had a score of ≥ 116. Female gender, use of antenatal steroids (ANS), maternal education ≥ high school and the absence of major neonatal morbidities were independent predictors of unimpaired outcome. The likelihood of an unimpaired outcome in the presence of major neonatal morbidities was higher in infants exposed to ANS.

CONCLUSION

The majority of unimpaired ELBW survivors had cognitive scores shifted toward the lower end of the normal distribution. Exposure to ANS was associated with higher likelihood of an unimpaired outcome in infants with major neonatal morbidities.

Neurodevelopmental outcome of extremely low birth weight infants with Candida infection

OBJECTIVE

Candida remains an important cause of late-onset infection in preterm infants. Mortality and neurodevelopmental outcome of extremely low birth weight (ELBW) infants enrolled in the Candida study were evaluated based on infection status.

STUDY DESIGN

ELBW infants born at Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NRN) centers between March 2004 and July 2007 who were screened for suspected sepsis were eligible for inclusion in the Candida study. Primary outcome data for neurodevelopmental impairment (NDI) or death were available for 1317 of the 1515 infants (87%) enrolled in the Candida study. The Bayley Scales of Infant Development-II or -III was administered at 18 months' adjusted age. A secondary comparison was performed with 864 infants enrolled in the NRN Generic Database during the same cohort who were never screened for sepsis and therefore not eligible for the Candida study.

RESULTS

Among ELBW infants enrolled in the Candida study, 31% with Candida and 31% with late-onset non-Candida sepsis had NDI at 18 months. Infants with Candida sepsis and/or meningitis had an increased risk of death and were more likely to have the composite outcome of death and/or NDI compared with uninfected infants in adjusted analysis. Compared with infants in the NRN registry never screened for sepsis, overall risk for death were similar but those with Candida infection were more likely to have NDI (OR 1.83, 95% CI 1.01-3.33, P = .047).

CONCLUSIONS

In this cohort of ELBW infants, those with infection and/or meningitis were at increased risk for death and/or NDI. This risk was highest among those with Candida sepsis and/or meningitis.

Cerebral palsy and growth failure at 6 to 7 years

OBJECTIVE

To evaluate the association between severity of cerebral palsy (CP) and growth to 6 to 7 years of age among children with moderate to severe (Mod/Sev) hypoxic ischemic encephalopathy (HIE). It was hypothesized that children with Mod/Sev CP would have poorer growth, lower cognitive scores, and increased rehospitalization rates compared with children with no CP (No CP).

METHODS

Among 115 of 122 surviving children followed in the hypothermia trial for neonatal HIE, growth parameters and neurodevelopmental status at 18 to 22 months and 6 to 7 years were available. Group comparisons (Mod/Sev CP and No CP) with unadjusted and adjusted analyses for growth <10th percentile and z scores by using Fisher's exact tests and regression modeling were conducted.

RESULTS

Children with Mod/Sev CP had high rates of slow growth and cognitive and motor impairment and rehospitalizations at 18 to 22 months and 6 to 7 years. At 6 to 7 years of age, children with Mod/Sev CP had increased rates of growth parameters <10th percentile compared with those with No CP (weight, 57% vs 3%; height, 70% vs 2%; and head circumference, 82% vs 13%; P < .0001). Increasing severity of slow growth was associated with increasing age (P < .04 for weight, P < .001 for length, and P < .0001 for head circumference). Gastrostomy feeds were associated with better growth.

CONCLUSIONS

Term children with HIE who develop Mod/Sev CP have high and increasing rates of growth <10th percentile by 6 to 7 years of age. These findings support the need for close medical and nutrition management of children with HIE who develop CP.

The role of prenatal substance exposure and early adversity on parasympathetic functioning from 3 to 6 years of age

We employed latent growth curve analysis to examine trajectories of respiratory sinus arrhythmia (RSA) from 3 to 6 years among children with varying levels of prenatal substance exposure and early adversity. Data were drawn from a prospective longitudinal study of prenatal substance exposure that included 1,121 participants. Baseline RSA and RSA reactivity to an attention-demanding task were assessed at 3, 4, 5, and 6 years. Overall, there were significant individual differences in the trajectories of RSA reactivity, but not baseline RSA, across development. Greater levels of prenatal substance exposure, and less exposure to early adversity, were associated with increased RSA reactivity at 3 years, but by 6 years, both were associated with greater RSA reactivity. Prenatal substance exposure had an indirect influence through early adversity on growth in RSA reactivity. Results are in support of and contribute to the framework of allostatic load.

Parental perception of functional status following tracheostomy in infancy: a single center study

OBJECTIVE

To examine the functional outcomes of children who underwent a tracheostomy in the initial hospitalization after birth and to determine their correlates.

STUDY DESIGN

We administered the validated 43-item Functional Status-II (FS-II) questionnaire by Stein and Jessop over the telephone to caregivers of surviving children. The FS-II items generated a total score, age-specific: (1) total; (2) general health (GH); and (3) responsiveness, activity, or interpersonal functioning (IPF) scores in specific age group categories.

RESULTS

FS-II was administered to 51/62 (82.2%) survivors at a median (range) age of 5 (1-10) years; 27% children were on the ventilator and 43% required devices. About 40% of children had a median of 1 (1-4) hospitalization in the previous 6 months. Scores were >2 SD below means in 55%, 24%, and 55% cases for age-specific T, GH, and R/A/IPF scores respectively. The T and R/A/IPF scales were significantly higher in those with private, rather than public, maternal insurance, as were T and R/A/IPF scores for children ≥ 4 years, compared with younger children. On regression analysis, FS-II T, GH, and R/A/IPF scores were independently associated with maternal private insurance (P = .02). R/A/IPF scores were also significantly associated with corrected age at FS-II administration.

CONCLUSIONS

One-third of surviving children who underwent tracheostomy during their initial hospitalization remained technology-dependent. The parental FS-II questionnaires revealed low R/A/IPF scores, especially at younger ages and in those with maternal public insurance. Further research on family-level interventions to improve functional outcomes in this population is warranted.

Blood stream infection is associated with altered heptavalent pneumococcal conjugate vaccine immune responses in very low birth weight infants

OBJECTIVE

Sepsis in older children and adults modifies immune system function. We compared serotype-specific antibody responses to heptavalent pneumococcal conjugate vaccine (PCV7) in very low birth weight infants (<1500 g,VLBWs) with and without blood stream infection (BSI) during their birth hospitalization.

STUDY DESIGN

Retrospective analysis of prospectively collected data for the Neonatal Research Network study of PCV7 responses among VLBWs. Infants received PCV7 at 2, 4 and 6 months after birth with blood drawn 4 to 6 weeks after third dose. Serotype antibodies were compared between infants with or without a history of BSI. Regression models were constructed with BW groups and other confounding factors identified in the primary study.

RESULT

In all, 244 infants completed the vaccine series and had serum antibody available; 82 had BSI. After adjustment, BSI was not associated with reduced odds of serum antibody 0.35 μg ml(-1).

CONCLUSION

BSI was not associated with reduced odds of World Health Organization-defined protective PCV7 responses in VLBWs.

Ten-year review of major birth defects in VLBW infants

OBJECTIVE

Birth defects (BDs) are an important cause of infant mortality and disproportionately occur among low birth weight infants. We determined the prevalence of BDs in a cohort of very low birth weight (VLBW) infants cared for at the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NRN) centers over a 10-year period and examined the relationship between anomalies, neonatal outcomes, and surgical care.

METHODS

Infant and maternal data were collected prospectively for infants weighing 401 to 1500 g at NRN sites between January 1, 1998, and December 31, 2007. Poisson regression models were used to compare risk of outcomes for infants with versus without BDs while adjusting for gestational age and other characteristics.

RESULTS

A BD was present in 1776 (4.8%) of the 37 262 infants in our VLBW cohort. Yearly prevalence of BDs increased from 4.0% of infants born in 1998 to 5.6% in 2007, P < .001. Mean gestational age overall was 28 weeks, and mean birth weight was 1007 g. Infants with BDs were more mature but more likely to be small for gestational age compared with infants without BDs. Chromosomal and cardiovascular anomalies were most frequent with each occurring in 20% of affected infants. Mortality was higher among infants with BDs (49% vs 18%; adjusted relative risk: 3.66 [95% confidence interval: 3.41-3.92]; P < .001) and varied by diagnosis. Among those surviving >3 days, more infants with BDs underwent major surgery (48% vs 13%, P < .001).

CONCLUSIONS

Prevalence of BDs increased during the 10 years studied. BDs remain an important cause of neonatal morbidity and mortality among VLBW infants.

Individual and center-level factors affecting mortality among extremely low birth weight infants

OBJECTIVE

To examine factors affecting center differences in mortality for extremely low birth weight (ELBW) infants.

METHODS

We analyzed data for 5418 ELBW infants born at 16 Neonatal Research Network centers during 2006-2009. The primary outcomes of early mortality (≤12 hours after birth) and in-hospital mortality were assessed by using multilevel hierarchical models. Models were developed to investigate associations of center rates of selected interventions with mortality while adjusting for patient-level risk factors. These analyses were performed for all gestational ages (GAs) and separately for GAs <25 weeks and ≥25 weeks.

RESULTS

Early and in-hospital mortality rates among centers were 5% to 36% and 11% to 53% for all GAs, 13% to 73% and 28% to 90% for GAs <25 weeks, and 1% to 11% and 7% to 26% for GAs ≥25 weeks, respectively. Center intervention rates significantly predicted both early and in-hospital mortality for infants <25 weeks. For infants ≥25 weeks, intervention rates did not predict mortality. The variance in mortality among centers was significant for all GAs and outcomes. Center use of interventions and patient risk factors explained some but not all of the center variation in mortality rates.

CONCLUSIONS

Center intervention rates explain a portion of the center variation in mortality, especially for infants born at <25 weeks' GA. This finding suggests that deaths may be prevented by standardizing care for very early GA infants. However, differences in patient characteristics and center intervention rates do not account for all of the observed variability in mortality; and for infants with GA ≥25 weeks these differences account for only a small part of the variation in mortality.

Outcomes of small for gestational age infants born at <27 weeks' gestation

OBJECTIVE

To determine whether small for gestational age (SGA) infants born at <27 weeks gestational age (GA) are at increased risk for mortality, morbidity, and growth and neurodevelopmental impairment at 18-22 months corrected age.

STUDY DESIGN

This was a retrospective cohort study from National Institute of Child Health and Human Development Neonatal Research Network's Generic Database and Follow-Up Studies. Infants born at <27 weeks GA between January 2006 and July 2008 were included. SGA was defined as birth weight <10th percentile for GA based on Olsen growth curves. Infants with birth weight ≥ 10th percentile for GA were classified as non-SGA. Maternal and infant characteristics, neonatal outcomes, and neurodevelopmental data were compared in SGA and non-SGA infants. Neurodevelopmental impairment was defined as any of the following: cognitive score <70 on the Bayley Scales of Infant Development III, moderate or severe cerebral palsy, bilateral hearing loss (with and without amplification), or blindness (bilateral vision <20/200). Logistic regression analysis was applied to evaluate the associations between SGA status and death or neurodevelopmental impairment.

RESULTS

The SGA group comprised 385 infants; the non-SGA group, 2586 infants. Compared with mothers of non-SGA infants, mothers of SGA infants were more likely to have a high school education, prenatal care, cesarean delivery, pregnancy-induced hypertension, and antenatal corticosteroid exposure. Compared with non-SGA infants, SGA infants had higher mortality and were more likely to have postnatal growth failure, prolonged mechanical ventilation, and postnatal steroid use. SGA status was associated with increased risk of death or neurodevelopmental impairment (OR, 3.91; 95% CI, 2.91-5.25; P < .001).

CONCLUSION

SGA status in infants born at <27 weeks GA is associated with an increased likelihood of postnatal steroid use, mortality, growth failure, and neurodevelopmental impairment at 18-22 months corrected age.

Late-onset sepsis in very low birth weight infants from singleton and multiple-gestation births

OBJECTIVES

To describe and compare the incidence of late-onset sepsis (LOS) and demographic and clinical characteristics associated with LOS in very low birth weight (VLBW) infants from singleton and multiple births, and to examine the heritability of susceptibility to LOS among VLBW twins by comparing same-sex and unlike-sex twin pairs.

STUDY DESIGN

The study group comprised infants with birth weight 401-1500 g seen at clinical centers of the Eunice Kennedy Shriver National Institute of Child and Human Development Neonatal Research Network between 2002 and 2008. Only the first episode of LOS was included in our analysis. Stepwise logistic regression models were fitted separately for singleton and multiple pregnancies to examine the maternal and neonatal factors associated with LOS. LOS due solely to gram-negative bacteria in singleton and multiple pregnancies was also examined in separate models. The heritability of LOS was estimated by examining the concordance of LOS in twins from same-sex and unlike-sex pairs.

RESULTS

LOS occurred in 25.0% (3797 of 15,178) of singleton and 22.6% (1196 of 5294) of multiple-birth VLBW infants. Coagulase-negative staphylococci were the most common infecting organisms, accounting for 53.2% of all LOS episodes in singletons and 49.2% in multiples. Escherichia coli and Klebsiella species were the most commonly isolated gram-negative organisms, and Candida albicans was the most commonly isolated fungus. Concordance of LOS did not differ significantly between same-sex and unlike-sex twin pairs.

CONCLUSION

LOS remains a common problem in VLBW infants. The incidence of LOS is similar for singleton and multiple-birth infants. The similar concordance of LOS in same-sex and unlike-sex twin pairs provides no evidence that susceptibility to LOS among VLBW infants is genetically determined.

Use of antihypotensive therapies in extremely preterm infants

OBJECTIVE

To investigate the relationships among blood pressure (BP) values, antihypotensive therapies, and in-hospital outcomes to identify a BP threshold below which antihypotensive therapies may be beneficial.

METHODS

Prospective observational study of infants 23(0/7) to 26(6/7) weeks' gestational age. Hourly BP values and antihypotensive therapy use in the first 24 hours were recorded. Low BP was investigated by using 15 definitions. Outcomes were examined by using regression analysis controlling for gestational age, the number of low BP values, and illness severity.

RESULTS

Of 367 infants enrolled, 203 (55%) received at least 1 antihypotensive therapy. Treated infants were more likely to have low BP by any definition (P < .001), but for the 15 definitions of low BP investigated, therapy was not prescribed to 3% to 49% of infants with low BP and, paradoxically, was administered to 28% to 41% of infants without low BP. Treated infants were more likely than untreated infants to develop severe retinopathy of prematurity (15% vs 8%, P = .03) or severe intraventricular hemorrhage (22% vs 11%, P < .01) and less likely to survive (67% vs 78%, P = .02). However, with regression analysis, there were no significant differences between groups in survival or in-hospital morbidity rates.

CONCLUSIONS

Factors other than BP contributed to the decision to use antihypotensive therapies. Infant outcomes were not improved with antihypotensive therapy for any of the 15 definitions of low BP investigated.

Elevated temperature and 6- to 7-year outcome of neonatal encephalopathy

OBJECTIVE

A study was undertaken to determine whether higher temperature after hypoxia-ischemia is associated with death or intelligence quotient (IQ)<70 at 6 to 7 years among infants treated with intensive care without hypothermia.

METHODS

Control infants (noncooled, n=106) of the National Institute of Child Health and Human Development Neonatal Research Network hypothermia trial had serial esophageal and skin temperatures over 72 hours. Each infant's temperature was ranked to derive an average of the upper and lower quartile, and median of each site. Temperatures were used in logistic regressions to determine adjusted associations with death or IQ<70 at 6 to 7 years. Secondary outcomes were death, IQ<70, and moderate/severe cerebral palsy (CP). IQ and motor function were assessed with Wechsler Scales for Children and Gross Motor Function Classification System. Results are odds ratio (OR; per degree Celsius increment within the quartile or median) and 95% confidence interval (CI).

RESULTS

Primary outcome was available for 89 infants. At 6 to 7 years, death or IQ<70 occurred in 54 infants (37 deaths, 17 survivors with IQ<70) and moderate/severe CP in 15 infants. Death or IQ<70 was associated with the upper quartile average of esophageal (OR=7.3, 95% CI=2.0-26.3) and skin temperature (OR=3.5, 95% CI=1.2-10.4). CP was associated with the upper quartile average of esophageal (OR=12.5, 95% CI=1.02-155) and skin temperature (OR=10.3, 95% CI=1.3-80.2).

INTERPRETATION

Among noncooled infants of a randomized trial, elevated temperatures during the first postnatal days are associated with increased odds of a worse outcome at 6 to 7 years.

Therapeutic hypothermia for neonatal encephalopathy in low- and middle-income countries: a systematic review and meta-analysis

Although selective or whole body cooling combined with optimal intensive care improves outcomes following neonatal encephalopathy in high-income countries, the safety and efficacy of cooling in low-and middle-income countries is not known.