To evaluate the incidence of death or neurodevelopmental impairment (NDI) at 18 to 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.
Evaluation of infants at 18 to 22 months corrected age included anthropomorphic measurements, a standard neurological examination, and the Bayley Scales of Infant Development-II, including the Mental Developmental Index (MDI) and the Psychomotor Developmental Index (PDI). NDI was defined as moderate or severe cerebral palsy, MDI or PDI less than 70, blindness, or hearing impairment.
Death or NDI at 18 to 22 months corrected age was similar in the dexamethasone and placebo groups (65 vs 66 percent, p= 0.99 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 percent, p=0.42 for weight less than 10th percentile). Forty nine percent of infants in the placebo group received treatment with corticosteroid compared to 32% in the dexamethasone group (p=0.02).
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 outcome; growth; bronchopulmonary dysplasia; cerebral palsy; neonatal follow-up
Candida remains an important cause of late-onset infection in preterm infants. Mortality and neurodevelopmental outcome of extremely low birthweight (ELBW) infants enrolled in the Candida study was evaluated based on infection status.
ELBW infants born at NICHD Neonatal Research Network (NRN) centers between March 2004 and July 2007 screened for suspected sepsis were eligible for inclusion in the Candida study. Primary outcome data for neurodevelopmental impairment (NDI) or death were available for 1317/1515 (90%) of the infants enrolled in the Candida study. The Bayley Scales of Infant Development (BSID)-II or the BSID-III was administered at 18 months adjusted age. A secondary comparison with 864 infants registered with NRN enrolled during the same cohort never screened for sepsis and therefore not eligible for the Candida study was performed.
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 (1.01,3.33, p=0.047).
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.
Candida; Neonatal sepsis; Neurodevelopmental and Prematurity
To determine whether small for gestational age (SGA) infants <27 weeks gestation is associated with mortality, morbidity, growth and neurodevelopmental impairment at 18–22 months’ corrected age (CA).
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’ gestation from January 2006 to July 2008 were included. SGA was defined as birth weight <10th percentile for gestational age by the Olsen growth curves. Infants with birth weight ≥10th percentile for gestational age were classified as non-SGA. Maternal and infant characteristics, neonatal outcomes and neurodevelopmental data were compared between the groups. Neurodevelopmental impairment was defined as any of the following: cognitive score <70 on BSID III, moderate or severe cerebral palsy, bilateral hearing loss (+/− amplification) or blindness (vision <20/200). Logistic regression analysis evaluated the association between SGA status and death or neurodevelopmental impairment.
There were 385 SGA and 2586 non-SGA infants. Compared with the non-SGA group, mothers of SGA infants were more likely to have higher level of education, prenatal care, cesarean delivery, pregnancy-induced hypertension and antenatal corticosteroid exposure. SGA infants were more likely to have postnatal growth failure, a higher mortality and to have received prolonged mechanical ventilation and postnatal steroids. SGA status was associated with higher odds of death or neurodevelopmental impairment [OR 3.91 (95% CI: 2.91–5.25), P<0.001].
SGA status among infants <27 weeks’ gestation was associated with an increased risk for postnatal steroid use, mortality, growth failure and neurodevelopmental impairment at 18–22 months’ CA.
extremely preterm infants; neurodevelopmental follow-up
To describe and compare 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 in susceptibility to LOS among VLBW twins by comparing same-sex with unlike-sex twin pairs.
We studied infants with birth weight 401–1500 grams cared for at clinical centers of the NICHD Neonatal Research Network 2002–2008. Only the first episode of LOS was examined. Stepwise logistic regression models were fitted separately for singleton and multiple pregnancies to examine the maternal and neonatal factors associated with LOS. LOS due to only gram-negative bacteria among singleton and multiple pregnancies was also examined in separate models. The heritability of LOS was estimated by examining concordance of LOS between twins from same-sex and unlike-sex pairs.
LOS occurred in 25.0% (3797/15,178) of singleton and 22.6% (1196/5294) of multiple 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. E. coli and Klebsiella species were the most commonly isolated gram-negative organisms, and Candida albicans was the most commonly isolated fungus. Concordance of LOS was not significantly different between same-sex and unlike-sex twin pairs.
LOS remains a common problem in VLBW infants. The incidence of LOS is similar for singleton and multiple infants. Similar concordance of LOS in same-sex and unlike-sex twin pairs provided no evidence that susceptibility to LOS among VLBW infants is genetically determined.
Heredity; preterm infants; twins
To examine whether preterm very low birth weight (VLBW) infants have an increased risk of late-onset sepsis (LOS) following early-onset sepsis (EOS).
Retrospective analysis of VLBW infants (401-1500 g) born September 1998 through December 2009 who survived >72 hours and were cared for within the NICHD Neonatal Research Network. Sepsis was defined by growth of bacteria or fungi in a blood culture obtained ≤72 hr of birth (EOS) or >72 hr (LOS) and antimicrobial therapy for ≥5 days or death <5 d while receiving therapy. Regression models were used to assess risk of death or LOS by 120d and LOS by 120d among survivors to discharge or 120d, adjusting for gestational age and other covariates.
Of 34,396 infants studied 504 (1.5%) had EOS. After adjustment, risk of death or LOS by 120d did not differ overall for infants with EOS compared with those without EOS [RR:0.99 (0.89-1.09)] but was reduced in infants born at <25wk gestation [RR:0.87 (0.76-0.99), p=0.048]. Among survivors, no difference in LOS risk was found overall for infants with versus without EOS [RR:0.88 (0.75-1.02)], but LOS risk was shorter in infants with BW 401-750 g who had EOS [RR:0.80 (0.64-0.99), p=0.047].
Risk of LOS after EOS was not increased in VLBW infants. Surprisingly, risk of LOS following EOS appeared to be reduced in the smallest, most premature infants, underscoring the need for age-specific analyses of immune function.
Very low birth weight; early-onset sepsis; late-onset sepsis
To compare 18- to 22-month cognitive scores and neurodevelopmental impairment (NDI) in 2 time periods using the National Institute of Child Health and Human Development’s Neonatal Research Network assessment of extremely low birth weight infants with the Bayley Scales of Infant Development, Second Edition (Bayley II) in 2006–2007 (period 1) and using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley III), with separate cognitive and language scores, in 2008–2011 (period 2).
Scores were compared with bivariate analysis, and regression analyses were run to identify differences in NDI rates.
Mean Bayley III cognitive scores were 11 points higher than mean Bayley II cognitive scores. The NDI rate was reduced by 70% (from 43% in period 1 to 13% in period 2; P < .0001). Multivariate analyses revealed that Bayley III contributed to a decreased risk of NDI by 5 definitions: cognitive score <70 and <85, cognitive or language score <70; cognitive or motor score <70, and cognitive, language, or motor score <70 (P < .001).
Whether the Bayley III is overestimating cognitive performance or whether it is a more valid assessment of emerging cognitive skills than the Bayley II is uncertain. Because the Bayley III identifies significantly fewer children with disability, it is recommended that all extremely low birth weight infants be offered early intervention services at the time of discharge from the neonatal intensive care unit, and that Bayley scores be interpreted with caution.
To examine pathogens and other characteristics associated with late-onset bloodstream infections (BSI) in infants with intestinal failure (IF) as a consequence of necrotizing enterocolitis (NEC).
Infants 401–1500 grams at birth who survived >72 hours and received care at NICHD Neonatal Research Network centers were studied. Frequency of culture positive BSI and pathogens were compared for infants with medical NEC, NEC managed surgically without IF, and surgical IF. Among infants with IF, duration of parenteral nutrition (PN) and other outcomes were evaluated.
932 infants were studied (IF, n=78; surgical NEC without IF, n=452; medical NEC, n=402). The proportion with BSI after NEC diagnosis was higher in infants with IF than with surgical NEC (p=0.007) or medical NEC (p<0.001). Gram positive pathogens were most frequent. Among infants with IF, increased number of infections was associated with longer hospitalization and duration on PN (0, 1, ≥2 infections; median stay (days): 172, 188, 260, p=0.06; median days on PN: 90, 112, 115, p=0.003), and the proportion who achieved full feeds during hospitalization decreased (87%, 67%, 50%, p=0.03).
Recurrent BSIs are common in VLBW infants with IF. Gram positive bacteria were most commonly identified in these infants.
Short bowel syndrome; Bloodstream infections; Late onset sepsis; Very low birth weight; Nutrition; Intestinal failure
To determine if selected pro-inflammatory and anti-inflammatory cytokines/mediators of inflammation reported to be related to development of cerebral palsy predict neurodevelopmental outcome in extremely low birth weight infants.
Infants with birth weights ≤ 1000 g (n=1067) had blood samples collected at birth and on days 3±1, 7±1, 14±3, and 21±3 to examine the association between cytokines and neurodevelopmental outcomes. The analyses were focused on five cytokines (IL-1β, IL-8, TNF-α, RANTES, and IL-2) reported to be most predictive of CP in term and late preterm infants.
IL-8 was higher on days 0–4 and subsequently in infants who developed CP compared with infants who did not develop CP in both unadjusted and adjusted analyses. Other cytokines (IL-12, IL-17, TNF-β, SIL-rα, MIP-1β) were found to be altered on days 0–4 in infants who developed CP.
CP in former preterm infants may, in part, have a late perinatal and/or early neonatal inflammatory origin.
To evaluate the association between early hypocarbia and 18-22 month outcome among neonates with hypoxic-ischemic encephalopathy (HIE).
Data from the NICHD NRN randomized controlled trial of whole body hypothermia for neonatal HIE were used for this secondary observational study. Infants (n=204) had multiple blood gases recorded from birth-12h of study intervention (hypothermia vs. intensive care alone). The relationship between hypocarbia and outcome (death/disability at 18-22 months) was evaluated by unadjusted and adjusted analyses examining minimum PCO2 and cumulative exposure to PCO2 <35 mmHg. The relationship between cumulative PCO2 <35 mmHg (calculated as the difference between 35mmHg and the sampled PCO2 multiplied by the duration of time spent <35 mmHg) and outcome was evaluated by level of exposure (none-high) using a multiple logistic regression analysis with adjustments for pH, level of encephalopathy, treatment group (± hypothermia), time to spontaneous respiration and ventilator days; results were expressed as OR and 95% confidence intervals. Alternative models of CO2 concentration were explored to account for fluctuations in CO2.
Both minimum PCO2 and cumulative PCO2 <35mmHg were associated with poor outcome (P<0.05). Moreover, death/disability increased with greater cumulative exposure to PCO2 <35mmHg.
Hypocarbia is associated with poor outcome following HIE.
hypocarbia; hypoxic ischemic encephalopathy; whole body hypothermia; outcome; neurodevelopmental impairment
To examine risk factors for neonatal clinical seizures and to determine the independent association with death or neurodevelopmental impairment (NDI) in extremely low birth weight (ELBW) infants.
A total of 6499 ELBW infants (401–1000 g) surviving to 36 weeks postmenstrual age (PMA) were included in this retrospective study. Unadjusted comparisons were performed between infants with (n=414) and without (n=6085) clinical seizures during the initial hospitalization. Multivariate logistic regression modeling examined the independent association of seizures with late death (after 36 weeks PMA) or NDI after controlling for multiple demographic, perinatal, and neonatal variables.
Infants with clinical seizures had a greater proportion of neonatal morbidities associated with poor outcome, including severe intraventricular hemorrhage, sepsis, meningitis, and cystic periventricular leukomalacia (all P < .01). Survivors were more likely to have NDI or moderate-severe cerebral palsy at 18 to 22 months corrected age (both P < .01). After adjusting for multiple confounders, clinical seizures remained significantly associated with late death or NDI (odds ratio 3.15 [95% confidence interval 2.37–4.19]).
ELBW infants with clinical seizures are at increased risk for adverse neurodevelopmental outcome, independent of multiple confounding factors.
preterm; neurodevelopmental impairment; electroencephalography
Determine the association between prenatal cocaine exposure and postnatal environmental adversity on salivary cortisol stress reactivity in school aged children.
Subjects included 743 11 year old children (n=320 cocaine exposed; 423 comparison) followed since birth in a longitudinal prospective multisite study. Saliva samples were collected to measure cortisol at baseline and after a standardized procedure to induce psychological stress. Children were divided into those who showed an increase in cortisol from baseline to post stress and those who showed a decrease or blunted cortisol response. Covariates measured included site, birthweight, maternal pre and postnatal use of alcohol, tobacco or marijuana, social class, changes in caretakers, maternal depression and psychological symptoms, domestic and community violence, child abuse and quality of the home.
With adjustment for confounding variables, cortisol reactivity to stress was more likely to be blunted in children with prenatal cocaine exposure. Cocaine exposed children exposed to domestic violence showed the strongest effects.
The combination of prenatal cocaine exposure and an adverse postnatal environment could down regulate the hypothalamic-pituitary-adrenal axis (HPA) resulting in the blunted cortisol response to stress possibly increasing risk for later psychopathology and adult disease.
prenatal cocaine exposure; cortisol reactivity; environmental adversity
To determine whether Neonatal Intensive Care Unit Network Neurobehavior Scales (NNNS) at 44 weeks predict motor outcome at 2 years in preterm infants from the Maternal Lifestyles Study (MLS).
Data were collected on all preterm infants (<36 weeks) in the MLS who had an NNNS at 44 weeks (n=395) and neurologic exam at 12–36 months or Bayley Psychomotor Development Index (PDI) at 24 months (n=270). Logistic regression analyzed NNNS summary scores associated with Cerebral Palsy (CP) or PDI <70, while controlling for birth weight 1250g.
Eighteen of 395 infants (5%) had CP; 24 of 270 infants (9%) had PDI <70. CP was associated with low quality of movement (OR 1.95, 95% CI 1.24–3.06, p=0.004) and high lethargy (OR 1.67, 95% CI 1.01–2.76, p=0.045). The model contributed 19% of the variance in CP diagnosis at 12–36 months (R2=0.19, p<0.001). Low PDI was associated with low handling (OR 1.83; 95% CI 1.12–2.99, p=0.017), low quality of movement (OR 2.16; 95%CI 1.38–3.38, p=0.001), and hypotonia (OR 1.63; 95% CI 1.14–2.32, p=0.007). The model contributed 26% of the variance in PDI <70 at 24 months (R2=0.26, p<0.001).
The neurobehavioral profile of underarousal in 44 week preterm infants may predict poor motor outcome.
neurobehavior; outcomes; ELBW
To assess the association between urinary lactate to creatinine ratio (ULCR) and neurodevelopmental outcome in term infants with hypoxic ischemic encephalopathy and examine the effect of hypothermia on the change in ULCR.
Spot urine samples were collected in 58 term infants (28 hypothermia, 30 control subjects) with hypoxic ischemic encephalopathy. Urinary lactate and creatinine were measured by using 1H nuclear magnetic resonance spectroscopy and expressed as ULCR. Survivors were examined at 18 months of age.
The ULCR was significantly higher in infants who died or had moderate/severe neurodevelopmental disability. Logistic regression analysis controlling for hypothermia and severity of encephalopathy confirmed the association (adjusted odds ratio, 5.52; 95% CI, 1.36, 22.42; P < .02). Considerable overlap in ULCR was observed between infants with normal/mild disability and those who died or survived with moderate/severe disability. ULCR fell significantly between 6 and 24 hours and 48 and 72 hours of age for all infants. The magnitude of decline did not differ between hypothermia and control groups.
High ULCR is associated with death or moderate/severe neurodevelopmental disability. Significant overlap in values between the normal/mild and moderate/severe disability groups limits predictive value of this measure. Whole-body hypothermia did not affect the decline in ULCR.
To determine the relative contribution of clinical data versus head ultrasound (HUS) in predicting neurodevelopmental impairment (NDI) in extremely low birth weight (ELBW) infants.
2103 ELBW infants (<1000g) admitted to a National Institute of Child Health and Human Development Neonatal Research Network center who had a HUS within the first 28 days, a repeat one around 36 weeks’ post-menstrual age, and neurodevelopmental assessment at 18–22 months corrected age were selected. Multivariate logistic regression models were developed using clinical and/or HUS variables. The primary outcome was the predictive abilities of the HUS done before 28 days after birth and closer to 36 weeks post-menstrual age, either alone or in combination with “Early” and “Late” clinical variables.
Models using clinical variables alone predicted NDI better than models with only HUS variables at both 28 days and 36 weeks (both p < 0.001), and addition of the HUS data did not improve prediction. NDI was absent in 30% and 28% of the infants with grade IV intracranial hemorrhage or periventricular leukomalacia, respectively, but was present in 39% of the infants with a normal head ultrasound.
Clinical models were better than head ultrasound models in predicting neurodevelopment.
Logistic models; Predictive value of tests; ROC curve; Infant; premature; Intracerebral hemorrhage; Leukomalacia; periventricular
To assess interobserver reliability between two central readers of cranial ultrasound (CUS) and accuracy of local compared with central interpretations.
A retrospective analysis of CUS data from the NICHD trial of inhaled nitric oxide for premature infants. Interobserver reliability of two central readers was assessed by kappa or weighted kappa. Accuracy of local compared with central interpretations was assessed by sensitivity and specificity.
Cranial US from 326 infants had both central reader and local interpretations. Central reader agreement for grade 3/4 IVH, grade 3/4 IVH or PVL, grade of IVH, and degree of ventriculomegaly was very good (kappa=0.84, 0.81, 0.79, and 0.75, respectively). Agreement was poor for lower grade IVH and for PVL alone. Local interpretations were highly accurate for grade 3/4 IVH or PVL (sensitivity 87–90%, specificity 92–93%), but sensitivity was poor to fair for grade 1/2 IVH (48–68%) and PVL (20–44%).
Our findings demonstrate reliability and accuracy of highly unfavorable CUS findings, but suggest caution when interpreting mild to moderate IVH or white matter injury.
intraventricular; hemorrhage; leukomalacia; central reader; neurodevelopmental; brain