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1.  Ten-Year Review of Major Birth Defects in VLBW Infants 
Pediatrics  2013;132(1):49-61.
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.
doi:10.1542/peds.2012-3111
PMCID: PMC3691532  PMID: 23733791
birth defects; prematurity; Neonatal Research Network; low birth weight
2.  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 to 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 2000–2005. The study infants were designated into 3 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.
Results
Infants with surgical necrotizing enterocolitis had the highest rate of death prior to hospital discharge (53.5%) and death or neurodevelopmental impairment (82.3%) compared to 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 OR 2.21, 95% 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).
Conclusions
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.
doi:10.1038/jp.2013.128
PMCID: PMC3877158  PMID: 24135709
spontaneous intestinal perforation; necrotizing enterocolitis; extremely low birth weight; neurodevelopmental impairment
3.  Outcomes of Small for Gestational Age Infants < 27 Weeks’ Gestation 
The Journal of pediatrics  2013;163(1):55-60.e1-3.
Objective
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).
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’ 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.
Results
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].
Conclusion
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.
doi:10.1016/j.jpeds.2012.12.097
PMCID: PMC3947828  PMID: 23415614
extremely preterm infants; neurodevelopmental follow-up
4.  Late-Onset Sepsis in Very Low Birth Weight Infants from Singleton and Multiple Gestation Births 
The Journal of pediatrics  2013;162(6):1120-1124.e1.
Objectives
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.
Study design
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.
Results
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.
Conclusions
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.
doi:10.1016/j.jpeds.2012.11.089
PMCID: PMC3633723  PMID: 23324523
Heredity; preterm infants; twins
5.  Neurodevelopmental Outcomes of Extremely Low Gestational Age Neonates with Low Grade Periventricular-Intraventricular Hemorrhage 
JAMA pediatrics  2013;167(5):451-459.
Objective
To compare neurodevelopmental outcomes at 18–22 months corrected age for extremely low gestational age infants with low grade (Grade 1 or 2) periventricular-intraventricular hemorrhage to infants with either no hemorrhage or severe (Grade 3 or 4) hemorrhage on cranial ultrasound.
Design
Longitudinal observational study
Setting
Sixteen centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network
Participants
1472 infants born at <27 weeks gestational age between 2006–2008 with ultrasound results within the first 28 days of life and surviving to 18–22 months with complete follow-up assessments were eligible.
Main Exposure
Low grade periventricular-intraventricular hemorrhage
Outcome Measures
Outcomes included cerebral palsy, gross motor functional limitation, Bayley III cognitive and language scores, and composite measures of neurodevelopmental impairment. Regression modeling evaluated the association of hemorrhage severity with adverse outcomes while controlling for potentially confounding variables and center differences.
Results
Low grade hemorrhage was not associated with significant differences in unadjusted or adjusted risk of any adverse neurodevelopmental outcome compared to infants without hemorrhage. Compared with low grade hemorrhage, severe hemorrhage was associated with decrease in adjusted continuous cognitive (−3.91, [95% Confidence Interval [CI]: −6.41, −1.42]) and language (−3.19 [−6.19, −0.19]) scores as well as increased odds of each adjusted categorical outcome except severe cognitive impairment (OR: 1.46 [0.74, 2.88]) and mild language impairment (OR: 1.35 [0.88, 2.06]).
Conclusion
At 18–22 months, the neurodevelopmental outcomes of extremely low gestational age infants with low grade periventricular-intraventricular hemorrhage are not significantly different from those without hemorrhage.
doi:10.1001/jamapediatrics.2013.866
PMCID: PMC3953349  PMID: 23460139
6.  Outcome of Extremely Low Birth Weight Infants with Congenital Heart Defects in the Eunice Kennedy Shriver NICHD Neonatal Research Network 
Pediatric cardiology  2012;33(8):1415-1426.
Little is known about the outcomes of extremely low birth weight (ELBW) preterm infants with congenital heart defects (CHDs). The aim of this study was to assess the mortality, morbidity, and early childhood outcomes of ELBW infants with isolated CHD compared with infants with no congenital defects. Participants were 401–1,000 g infants cared for at National Institute of Child Health and Human Development Neonatal Research Network centers between January 1, 1998 and December 31, 2005. Neonatal morbidities and 18–22 months’ corrected age outcomes were assessed. Neurodevelopmental impairment (NDI) was defined as moderate to severe cerebral palsy, Bayley II mental or psychomotor developmental index < 70, bilateral blindness, or hearing impairment requiring aids. Poisson regression models were used to estimate relative risks for outcomes while adjusting for gestational age, small for gestational-age status, and other variables. Of 14,457 ELBW infants, 110 (0.8 %) had isolated CHD, and 13,887 (96 %) had no major birth defect. The most common CHD were septal defects, tetralogy of Fallot, pulmonary valve stenosis, and coarctation of the aorta. Infants with CHD experienced increased mortality (48 % compared with 35 % for infants with no birth defect) and poorer growth. Surprisingly, the adjusted risks of other short-term neonatal morbidities associated with prematurity were not significantly different. Fifty-seven (52 %) infants with CHD survived to 18–22 months’ corrected age, and 49 (86 %) infants completed follow-up. A higher proportion of surviving infants with CHD were impaired compared with those without birth defects (57 vs. 38 %, p = 0.004). Risk of death or NDI was greater for ELBW infants with CHD, although 20% of infants survived without NDI.
doi:10.1007/s00246-012-0375-8
PMCID: PMC3687358  PMID: 22644414
heart defects; congenital; follow-up studies
7.  Spontaneous Intestinal Perforation in Extremely Low Birth Weight Infants: Association with Indometacin Therapy and Effects on Neurodevelopmental Outcomes at 18-22 months Corrected Age 
Background
Spontaneous intestinal perforation (SIP) is associated with the use of postnatal glucocorticoids and indometacin in extremely low birth weight (ELBW) infants. We hypothesized: 1) an association of SIP with the use of antenatal steroids (ANS) and indometacin either as prophylaxis for IVH (P Indo) or for treatment of PDA (Indo/PDA) and 2) an increased risk of death or abnormal neurodevelopmental outcomes in infants with SIP at 18-22 months corrected age.
Design/Methods
We retrospectively identified ELBW infants with SIP in the Neonatal Research Network’s generic database. Unadjusted analysis identified the differences in maternal, neonatal and clinical variables between infants with and without SIP. Logistic regression analysis identified the adjusted odds ratio for SIP with reference to ANS, P Indo and Indo/PDA. Neurodevelopmental outcomes were assessed among survivors at 18 to 22 months corrected age.
Results
Indo/PDA was associated with an increased risk of SIP (adjusted OR 1.61; 95% CI 1.25,2.08), while P Indo and ANS were not. SIP was independently associated with an increased risk of death or NDI (adjusted OR−1.85; 95% CI 1.32,2.60) and NDI among survivors (adjusted OR−1.75, 95% CI 1.20,2.55).
Conclusion
Indometacin used for IVH prophylaxis and ANS were not associated with the occurrence of SIP in ELBW infants. Indometacin used for treatment of symptomatic PDA was however associated with an increased risk of SIP. ELBW infants with SIP have an increased risk of poor neurodevelopmental outcomes.
doi:10.1136/archdischild-2011-300659
PMCID: PMC3753803  PMID: 22684157
extremely low birth weight infant; intestinal perforation; indometacin; cerebral palsy
8.  Emperic Antifungal Therapy and Outcomes in Extremely-Low-Birth-Weight Infants with Invasive Candidiasis 
The Journal of Pediatrics  2012;161(2):264-269.e2.
Objective
To assess the impact of emperic antifungal therapy of invasive candidiasis on subsequent outcomes in premature infants.
Study design
This was a cohort study of infants ≤1000 g birth weight cared for at Neonatal Research Network sites. All infants had at least 1 positive culture for Candida. Emperic antifungal therapy was defined as receipt of a systemic antifungal on the day of or the day before the first positive culture for Candida was drawn. We created Cox proportional hazards and logistic regression models stratified on propensity score quartiles to determine the effect of emperic antifungal therapy on survival, time to clearance of infection, retinopathy of prematurity, bronchopulmonary dysplasia, end-organ damage, and neurodevelopmental impairment (NDI).
Results
136 infants developed invasive candidiasis. The incidence of death or NDI was lower for infants who received emperic antifungal therapy (19/38, 50%) compared with those who had not (55/86, 64%; odds ratio=0.27 [95% confidence interval 0.08–0.86]). There was no significant difference between the groups for any single outcome or other combined outcomes.
Conclusions
Emperic antifungal therapy was associated with increased survival without NDI. A prospective randomized trial of this strategy is warranted.
doi:10.1016/j.jpeds.2012.01.053
PMCID: PMC3380169  PMID: 22424952
Candida; neonate; mortality; neurodevelopmental impairment
9.  Brain injury following trial of hypothermia for neonatal hypoxic–ischaemic encephalopathy 
Objective
The objective of our study was to examine the relationship between brain injury and outcome following neonatal hypoxic–ischaemic encephalopathy treated with hypothermia.
Design and patients
Neonatal MRI scans were evaluated in the National Institute of Child Health and Human Development (NICHD) randomised controlled trial of whole-body hypothermia and each infant was categorised based upon the pattern of brain injury on the MRI findings. Brain injury patterns were assessed as a marker of death or disability at 18–22 months of age.
Results
Scans were obtained on 136 of 208 trial participants (65%); 73 in the hypothermia and 63 in the control group. Normal scans were noted in 38 of 73 infants (52%) in the hypothermia group and 22 of 63 infants (35%) in the control group. Infants in the hypothermia group had fewer areas of infarction (12%) compared to infants in the control group (22%). Fifty-one of the 136 infants died or had moderate or severe disability at 18 months. The brain injury pattern correlated with outcome of death or disability and with disability among survivors. Each point increase in the severity of the pattern of brain injury was independently associated with a twofold increase in the odds of death or disability.
Conclusions
Fewer areas of infarction and a trend towards more normal scans were noted in brain MRI following whole-body hypothermia. Presence of the NICHD pattern of brain injury is a marker of death or moderate or severe disability at 18–22 months following hypothermia for neonatal encephalopathy.
doi:10.1136/archdischild-2011-301524
PMCID: PMC3722585  PMID: 23080477
10.  Feasibility Study of Early Blood Pressure Management in Extremely Preterm Infants 
The Journal of Pediatrics  2012;161(1):65-69.e1.
Objective
To assess the feasibility of a randomized placebo controlled trial (RCT) of blood pressure (BP) management for extremely preterm infants.
Study design
This was a prospective pilot RCT of infants 230/7 – 266/7 weeks gestation who had protocol-defined low BP in the first 24 postnatal hours. Enrolled infants were administered a study infusion (dopamine or placebo) and a study syringe medication (hydrocortisone or placebo).
Results
Of the 366 infants screened, 119 (33%) had low BP, 58 (16%) met all entry criteria, and 10 (3%) were enrolled. 161 (44%) infants were ineligible because they received early indomethacin. Only 17% of eligible infants were enrolled. Problems with consent included insufficient time, parent unavailability, and physician unwillingness to enroll critically ill infants. Two infants were withdrawn from the study due to the potential risk of intestinal perforation with simultaneous administration of hydrocortisone and indomethacin.
Conclusions
This pilot RCT was not feasible due to low eligibility and consent rates. An RCT of BP management for extremely preterm infants may require a waiver of consent for research in emergency care. The frequent use of early indomethacin and the associated risk of intestinal perforation when used with hydrocortisone may limit future investigations to only inotropic medications.
doi:10.1016/j.jpeds.2012.01.014
PMCID: PMC3357442  PMID: 22336574
Extremely preterm infant; hypotension; hydrocortisone; dopamine; informed consent
11.  Risk Factors for Post-NICU Discharge Mortality Among Extremely Low Birth Weight Infants 
The Journal of Pediatrics  2012;161(1):70-74.e2.
Objective
To evaluate maternal and neonatal risk factors associated with post-neonatal intensive care unit (NICU) discharge mortality among ELBW infants.
Study design
This is a retrospective analysis of extremely low birth weight (<1,000 g) and <27 weeks' gestational age infants born in the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network sites from January 2000 to June 2007. Infants were tracked until death or 18–22 months corrected age. Infants who died between NICU discharge and the 18–22 month follow-up visit were classified as post-NICU discharge mortality. Association of maternal and infant risk factors with post-NICU discharge mortality was determined using logistic regression analysis. A prediction model with six significant predictors was developed and validated.
Results
5,364 infants survived to NICU discharge. 557 (10%) infants were lost to follow-up, and 107 infants died following NICU discharge. Post-NICU discharge mortality rate was 22.3 per 1000 ELBW infants. In the prediction model, African-American race, unknown maternal health insurance, and hospital stay ≥120 days significantly increased risk, and maternal exposure to intra-partum antibiotics was associated with decreased risk of post-NICU discharge mortality.
Conclusion
We identified African-American race, unknown medical insurance and prolonged NICU stay as risk factors associated with post-NICU discharge mortality among ELBW infants.
doi:10.1016/j.jpeds.2011.12.038
PMCID: PMC3366175  PMID: 22325187
extremely preterm infants; discharge; mortality; predictive model
12.  Outcome Trajectories in Extremely Preterm Infants 
Pediatrics  2012;130(1):e115-e125.
OBJECTIVE:
Methods are required to predict prognosis with changes in clinical course. Death or neurodevelopmental impairment in extremely premature neonates can be predicted at birth/admission to the ICU by considering gender, antenatal steroids, multiple birth, birth weight, and gestational age. Predictions may be improved by using additional information available later during the clinical course. Our objective was to develop serial predictions of outcome by using prognostic factors available over the course of NICU hospitalization.
METHODS:
Data on infants with birth weight ≤1.0 kg admitted to 18 large academic tertiary NICUs during 1998–2005 were used to develop multivariable regression models following stepwise variable selection. Models were developed by using all survivors at specific times during hospitalization (in delivery room [n = 8713], 7-day [n = 6996], 28-day [n = 6241], and 36-week postmenstrual age [n = 5118]) to predict death or death/neurodevelopmental impairment at 18 to 22 months.
RESULTS:
Prediction of death or neurodevelopmental impairment in extremely premature infants is improved by using information available later during the clinical course. The importance of birth weight declines, whereas the importance of respiratory illness severity increases with advancing postnatal age. The c-statistic in validation models ranged from 0.74 to 0.80 with misclassification rates ranging from 0.28 to 0.30.
CONCLUSIONS:
Dynamic models of the changing probability of individual outcome can improve outcome predictions in preterm infants. Various current and future scenarios can be modeled by input of different clinical possibilities to develop individual “outcome trajectories” and evaluate impact of possible morbidities on outcome.
doi:10.1542/peds.2011-3693
PMCID: PMC3382921  PMID: 22689874
logistic models; premature infant; predictive value of tests; prognosis
13.  Outcomes of Extremely Low Birth Weight Infants with Bronchopulmonary Dysplasia: Impact of the Physiologic Definition 
Early human development  2012;88(7):509-515.
Aims
We compared neurodevelopmental outcomes of extremely low birth weight (ELBW) infants with and without bronchopulmonary dysplasia (BPD), using the physiologic definition.
Study Design
ELBW (birth weights <1000 grams) infants admitted to the Neonatal Research Network centers and hospitalized at 36 weeks postmenstrual age (n=1,189) were classified using the physiologic definition of BPD. Infants underwent Bayley III assessment at 18-22 months corrected age. Multivariable logistic regression was used to determine the association between physiologic BPD and cognitive impairment (score < 70).
Results
BPD by the physiologic definition was diagnosed in 603 (52%) infants, 537 of whom were mechanically ventilated or on FiO2 > 30% and 66 who failed the room air challenge. Infants on room air (n=505) and those who passed the room air challenge (n=51) were classified as “no BPD” (n=556). At follow up, infants with BPD had significantly lower mean weight and head circumference. Moderate to severe cerebral palsy (7 vs. 2.1%) and spastic diplegia (7.8 vs. 4.1%) and quadriplegia (3.9 vs. 0.9%) phenotypes as well as cognitive (12.8 vs. 4.6%) and language scores < 70 (24.2 vs. 12.3%) were significantly more frequent in those with BPD compared to those without BPD. BPD was independently associated (adjusted OR 2.4; 95% CI 1.40-4.13) with cognitive impairment.
Conclusions
Rates of adverse neurodevelopmental outcomes in early childhood were significantly higher in those with BPD. BPD by the physiologic definition was independently associated with cognitive impairment using Bayley Scales III. These findings have implications for targeted post-discharge surveillance and early intervention.
doi:10.1016/j.earlhumdev.2011.12.013
PMCID: PMC3686277  PMID: 22236557
Outcome; preterm; bronchopulmonary dysplasia; physiologic definition
14.  Population Pharmacokinetics of Piperacillin Using Scavenged Samples from Preterm Infants 
Therapeutic Drug Monitoring  2012;34(3):312-319.
Objectives
Piperacillin is often used in preterm infants for intra-abdominal infections; however, dosing has been derived from small single-center studies excluding extremely preterm infants at highest risk for these infections. We evaluated the population pharmacokinetics (PK) of piperacillin using targeted sparse sampling and scavenged samples obtained from preterm infants ≤32 weeks gestational age at birth and <120 postnatal days.
Materials and Methods
A 5-center study was performed. A population PK model using nonlinear mixed effect modeling was developed. Covariate effects were evaluated based on estimated precision and clinical significance.
Results
Fifty-six preterm infants were evaluated and had a median (range) gestational age at birth of 25 (22–32) weeks, a postnatal age of 17 (1–77) days, a postmenstrual age of 29 (23–40) weeks, and a weight of 867 (400–2580) grams. The final PK data set contained 211 samples; 202/211 (96%) were scavenged from discarded clinical specimens. Piperacillin population PK was best described by a 1-compartment model. The population mean clearance (CL) was derived by the equation CL (liter/h)=0.479 x (weight)0.75 x 0.5/serum creatinine and using a volume of distribution (V) (liter) of 2.91 x (weight). The relative standard errors around parameter estimates ranged from 13.7–32.2%. A trend towards increased CL was observed with increasing gestational age at birth; infants with serum creatinine ≥1.2 mg/dL had a 60% reduction in piperacillin CL. The majority (>70%) of infants did not meet pre-defined pharmacodynamic efficacy targets.
Conclusions
Scavenged PK sampling is a minimal-risk approach that can provide meaningful information related to development of PK models but not dosing recommendations for piperacillin. The utility of scavenged sampling in providing definitive dosing recommendations may be drug-dependent and needs to be further explored.
doi:10.1097/FTD.0b013e3182587665
PMCID: PMC3354042  PMID: 22569355
neonate; drug; pharmacokinetics; piperacillin
15.  Approach to Infants Born at 22 to 24 Weeks’ Gestation: Relationship to Outcomes of More-Mature Infants 
Pediatrics  2012;129(6):e1508-e1516.
OBJECTIVE:
We sought to determine if a center’s approach to care of premature infants at the youngest gestational ages (22–24 weeks’ gestation) is associated with clinical outcomes among infants of older gestational ages (25–27 weeks’ gestation).
METHODS:
Inborn infants of 401 to 1000 g birth weight and 22 0/7 to 27 6/7 weeks’ gestation at birth from 2002 to 2008 were enrolled into a prospectively collected database at 20 centers participating in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Markers of an aggressive approach to care for 22- to 24-week infants included use of antenatal corticosteroids, cesarean delivery, and resuscitation. The primary outcome was death before postnatal day 120 for infants of 25 to 27 weeks’ gestation. Secondary outcomes were the combined outcomes of death or a number of morbidities associated with prematurity.
RESULTS:
Our study included 3631 infants 22 to 24 weeks’ gestation and 5227 infants 25 to 27 weeks’ gestation. Among the 22- to 24-week infants, use of antenatal corticosteroids ranged from 28% to 100%, cesarean delivery from 13% to 65%, and resuscitation from 30% to 100% by center. Centers with higher rates of antenatal corticosteroid use in 22- to 24-week infants had reduced rates of death, death or retinopathy of prematurity, death or late-onset sepsis, death or necrotizing enterocolitis, and death or neurodevelopmental impairment in 25- to 27-week infants.
CONCLUSIONS:
This study suggests that physicians’ willingness to provide care to extremely low gestation infants as measured by frequency of use of antenatal corticosteroids is associated with improved outcomes for more-mature infants.
doi:10.1542/peds.2011-2216
PMCID: PMC3362905  PMID: 22641761
low-birth weight infant; NICUs; treatment; patient outcome assessment
16.  Evolution of Encephalopathy during Whole Body Hypothermia for Neonatal Hypoxic-Ischemic Encephalopathy 
The Journal of Pediatrics  2011;160(4):567-572.e3.
Objective
To examine the predictive ability of stage of hypoxic-ischemic encephalopathy (HIE) for death or moderate/severe disability at 18 months among neonates undergoing hypothermia.
Study design
Stage of encephalopathy was evaluated at <6 hr of age, during study intervention and at discharge among 204 participants in the NICHD Neonatal Research Network Trial of whole body hypothermia for HIE. HIE was examined as a predictor of outcome by regression models.
Results
Moderate and severe HIE occurred at <6 hrs of age among 68% and 32% of 101 hypothermia group infants and 60% and 40% of 103 control group infants, respectively. At 24 and 48 hrs of study intervention, infants in the hypothermia group had less severe HIE than infants in the control group. Persistence of severe HIE at 72 hrs increased the risk of death or disability after controlling for treatment group. The discharge exam improved the predictive value of stage of HIE at < 6hrs for death/disability.
Conclusions
On serial neurological examinations, improvement in stage of HIE was associated with cooling. Persistence of severe HIE at 72 hours and an abnormal neurological exam at discharge was associated with a greater risk of death or disability.
doi:10.1016/j.jpeds.2011.09.018
PMCID: PMC3299861  PMID: 22050871
Neurological examinations; neonates; clinical biomarker; death; disability
17.  Methicillin-Resistant and Susceptible Staphylococcus aureus Bacteremia and Meningitis in Preterm Infants 
Pediatrics  2012;129(4):e914-e922.
BACKGROUND:
Data are limited on the impact of methicillin-resistant Staphylococcus aureus (MRSA) on morbidity and mortality among very low birth weight (VLBW) infants with S aureus (SA) bacteremia and/or meningitis (B/M).
METHODS:
Neonatal data for VLBW infants (birth weight 401–1500 g) born January 1, 2006, to December 31, 2008, who received care at centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network were collected prospectively. Early-onset (≤72 hours after birth) and late-onset (>72 hours) infections were defined by blood or cerebrospinal fluid cultures and antibiotic treatment of ≥5 days (or death <5 days with intent to treat). Outcomes were compared for infants with MRSA versus methicillin-susceptible S aureus (MSSA) B/M.
RESULTS:
Of 8444 infants who survived >3 days, 316 (3.7%) had SA B/M. Eighty-eight had MRSA (1% of all infants, 28% of infants with SA); 228 had MSSA (2.7% of all infants, 72% of infants with SA). No infant had both MRSA and MSSA B/M. Ninety-nine percent of MRSA infections were late-onset. The percent of infants with MRSA varied by center (P < .001) with 9 of 20 centers reporting no cases. Need for mechanical ventilation, diagnosis of respiratory distress syndrome, necrotizing enterocolitis, and other morbidities did not differ between infants with MRSA and MSSA. Mortality was high with both MRSA (23 of 88, 26%) and MSSA (55 of 228, 24%).
CONCLUSIONS:
Few VLBW infants had SA B/M. The 1% with MRSA had morbidity and mortality rates similar to infants with MSSA. Practices should provide equal focus on prevention and management of both MRSA and MSSA infections among VLBW infants.
doi:10.1542/peds.2011-0966
PMCID: PMC3313632  PMID: 22412036
Staphylococcus aureus; methicillin resistant; infant; newborn
18.  Association of antenatal corticosteroids with mortality and neurodevelopmental outcomes among infants born at 22–25 weeks gestation 
Context
Current guidelines, initially published in 1995, recommend antenatal corticosteroids for mothers with preterm labor from 24–34 weeks gestational age, but not before 24 weeks because of lack of data. However, many infants born before 24 weeks are provided intensive care now.
Objective
To determine if antenatal corticosteroids are associated with improvement in major outcomes in infants born at 22 and 23 weeks.
Design, Setting, Participants
Data for this cohort study were collected prospectively on 401–1000 gram inborn infants (N=10,541) of 22–25 weeks gestation born between 1993–2009 at 23 academic perinatal centers in the United States. Certified examiners unaware of exposure to antenatal corticosteroids performed follow-up examinations on 4,924 (86.5%) of the infants born in 1993–2008 who survived to 18–22 months. Logistic regression models generated adjusted odds ratios, controlling for maternal and neonatal variables.
Main Outcome Measures
Mortality and neurodevelopmental impairment at 18–22 months corrected age
RESULTS
Death or neurodevelopmental impairment at 18–22 months was lower for infants whose mothers received antenatal corticosteroids born at 23 weeks (antenatal corticosteroids, 83.4% vs no antenatal corticosteroids, 90.5%; adjusted odds ratio 0.58; 95% CI, 0.42–0.80), at 24 weeks (antenatal corticosteroids, 68.4% vs no antenatal corticosteroids, 80.3%; adjusted odds ratio 0.62; 95% CI, 0.49–0.78), and at 25 weeks (antenatal corticosteroids, 52.7% vs no antenatal corticosteroids, 67.9%; adjusted odds ratio 0.61; 95% CI, 0.50–0.74) but not at 22 weeks (antenatal corticosteroids, 90.2% vs no antenatal corticosteroids, 93.1%; adjusted odds ratio 0.80; 95% CI, 0.29–12.21). Death by 18–22 months, hospital death, death/intraventricular hemorrhage/periventricular leukomalacia, and death/necrotizing enterocolitis were significantly lower for infants born at 23, 24, and 25 weeks gestational age if the mothers had received antenatal corticosteroids but the only outcome significantly lower at 22 weeks was death/necrotizing enterocolitis (antenatal corticosteroids, 73.5% vs no antenatal corticosteroids, 84.5%; adjusted odds ratio 0.54; 95% CI, 0.30–0.97).
CONCLUSIONS
Among infants born at 23–25 weeks gestation, use of antenatal corticosteroids compared to non-use was associated with a lower rate of death or neurodevelopmental impairment at 18–22 months.
doi:10.1001/jama.2011.1752
PMCID: PMC3565238  PMID: 22147379
prematurity; infant mortality; neonatal intensive care; neurodevelopmental impairment; lung maturation; limits of viability
19.  Outcomes Following Candiduria in Extremely Low Birth Weight Infants 
Extremely low birth weight (ELBW) infants with candiduria are at substantial risk for death or neurodevelopmental impairment. Therefore, identification of candiduria should prompt a systemic evaluation for disseminated Candida infection and initiation of treatment in all ELBW infants.
Background. Candidiasis carries a significant risk of death or neurodevelopmental impairment (NDI) in extremely low birth weight infants (ELBW; <1000 g). We sought to determine the impact of candiduria in ELBW preterm infants.
Methods. Our study was a secondary analysis of the Neonatal Research Network study Early Diagnosis of Nosocomial Candidiasis. Follow-up assessments included Bayley Scales of Infant Development examinations at 18–22 months of corrected age. Risk factors were compared between groups using exact tests and general linear modeling. Death, NDI, and death or NDI were compared using generalized linear mixed modeling.
Results. Of 1515 infants enrolled, 34 (2.2%) had candiduria only. Candida was isolated from blood only (69 of 1515 [4.6%]), cerebrospinal fluid (CSF) only (2 of 1515 [0.1%]), other sterile site only (not urine, blood, or CSF; 4 of 1515 [0.3%]), or multiple sources (28 of 1515 [2%]). Eleven infants had the same Candida species isolated in blood and urine within 3 days; 3 (27%) had a positive urine culture result first. Most urine isolates were Candida albicans (21 of 34 [62%]) or Candida parapsilosis (7 of 34 [29%]). Rate of death or NDI was greater among those with candiduria (50%) than among those with suspected but not proven infection (32%; odds ratio, 2.5 [95% confidence interval, 1.2–5.3]) after adjustment. No difference in death and death or NDI was noted between infants with candiduria and those with candidemia.
Conclusions. These findings provide compelling evidence that ELBW infants with candiduria are at substantial risk of death or NDI. Candiduria in ELBW preterm infants should prompt a systemic evaluation (blood, CSF, and abdominal ultrasound) for disseminated Candida infection and warrants treatment.
doi:10.1093/cid/cir800
PMCID: PMC3258271  PMID: 22144537
20.  Temperature Profile and Outcomes of Neonates Undergoing Whole Body Hypothermia for Neonatal Hypoxic-Ischemic Encephalopathy 
BACKGROUND
Decreases below target temperature were noted among neonates undergoing cooling in the NICHD Neonatal Research Network Trial of whole body hypothermia for neonatal hypoxic-ischemic encephalopathy.
OBJECTIVE
To examine the temperature profile and impact on outcome among ≥ 36 week gestation neonates randomized at ≤ 6 hours of age targeting esophageal temperature of 33.5°C for 72 hours.
DESIGN/SETTING/PATIENTS
Infants with intermittent temperatures recorded < 32.0°C during induction and maintenance of cooling were compared to all other cooled infants and relationship with outcome at 18 months was evaluated.
RESULTS
There were no differences in stage of encephalopathy, acidosis, or 10 minute Apgar scores between infants with temperatures < 32.0°C during induction (n=33) or maintenance (n=10) and all other infants who were cooled (n=58); however birth weight was lower and need for blood pressure support higher among infants with temperatures < 32.0 °C compared to all other cooled infants. No increase in acute adverse events were noted among infants with temperatures < 32.0 °C and hours spent < 32°C were not associated with the primary outcome of death or moderate/severe disability or the Bayley II Mental Developmental Index at 18 months.
CONCLUSION
Term infants with a lower birth weight are at risk for decreasing temperatures < 32.0°C while undergoing body cooling using a servo controlled system. This information suggests extra caution during the application of hypothermia as these lower birth weight infants are at risk for overcooling. Our findings may assist in planning additional trials of lower target temperature for neonatal hypoxic-ischemic encephalopathy.
doi:10.1097/PCC.0b013e31821926bc
PMCID: PMC3161166  PMID: 21499182
temperature; hypothermia; newborn; hypoxia-ischemia; encephalopathy; whole-body cooling
21.  Bloodstream infections in very low birth weight infants with intestinal failure 
The Journal of pediatrics  2011;160(1):54-9.e2.
Objective
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).
Study design
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.
Results
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).
Conclusion
Recurrent BSIs are common in VLBW infants with IF. Gram positive bacteria were most commonly identified in these infants.
doi:10.1016/j.jpeds.2011.06.034
PMCID: PMC3419271  PMID: 21840538
Short bowel syndrome; Bloodstream infections; Late onset sepsis; Very low birth weight; Nutrition; Intestinal failure
22.  Phenobarbital and temperature profile during hypothermia for hypoxic-ischemic encephalopathy 
Journal of child neurology  2011;27(4):451-457.
Data from the whole body hypothermia trial was analyzed to examine the effects of phenobarbital administration prior to cooling (+PB) on the esophageal temperature (Te) profile, during the induction phase of hypothermia. A total of 98 infants were analyzed. At enrollment, +PB infants had a higher rate of severe HIE and clinical seizures and lower Te and cord pH than infants that have not received PB (−PB). There was a significant effect of PB itself and an interaction between PB and time in the Te profile. Mean Te in the +PB group was lower than in the −PB group and the differences decreased over time. In +PB infants the time to surpass target Te of 33.5°C and to reach the minimum Te during overshoot were shorter. In conclusion, the administration of PB prior to cooling was associated with changes that may reflect a reduced thermogenic response associated with barbiturates.
doi:10.1177/0883073811419317
PMCID: PMC3530920  PMID: 21960671
phenobarbital; hypoxic-ischemic encephalopathy; hypothermia; temperature control
23.  Population Pharmacokinetics of Metronidazole Evaluated Using Scavenged Samples from Preterm Infants 
Pharmacokinetic (PK) studies in preterm infants are rarely conducted due to the research challenges posed by this population. To overcome these challenges, minimal-risk methods such as scavenged sampling can be used to evaluate the PK of commonly used drugs in this population. We evaluated the population PK of metronidazole using targeted sparse sampling and scavenged samples from infants that were ≤32 weeks of gestational age at birth and <120 postnatal days. A 5-center study was performed. A population PK model using nonlinear mixed-effect modeling (NONMEM) was developed. Covariate effects were evaluated based on estimated precision and clinical significance. Using the individual Bayesian PK estimates from the final population PK model and the dosing regimen used for each subject, the proportion of subjects achieving the therapeutic target of trough concentrations >8 mg/liter was calculated. Monte Carlo simulations were performed to evaluate the adequacy of different dosing recommendations per gestational age group. Thirty-two preterm infants were enrolled: the median (range) gestational age at birth was 27 (22 to 32) weeks, postnatal age was 41 (0 to 97) days, postmenstrual age (PMA) was 32 (24 to 43) weeks, and weight was 1,495 (678 to 3,850) g. The final PK data set contained 116 samples; 104/116 (90%) were scavenged from discarded clinical specimens. Metronidazole population PK was best described by a 1-compartment model. The population mean clearance (CL; liter/h) was determined as 0.0397 × (weight/1.5) × (PMA/32)2.49 using a volume of distribution (V) (liter) of 1.07 × (weight/1.5). The relative standard errors around parameter estimates ranged between 11% and 30%. On average, metronidazole concentrations in scavenged samples were 30% lower than those measured in scheduled blood draws. The majority of infants (>70%) met predefined pharmacodynamic efficacy targets. A new, simplified, postmenstrual-age-based dosing regimen is recommended for this population. Minimal-risk methods such as scavenged PK sampling provided meaningful information related to development of metronidazole PK models and dosing recommendations.
doi:10.1128/AAC.06071-11
PMCID: PMC3318328  PMID: 22252819
24.  Hypocarbia and Adverse Outcome in Neonatal Hypoxic-Ischemic Encephalopathy 
The Journal of pediatrics  2010;158(5):752-758.e1.
Objective
To evaluate the association between early hypocarbia and 18-22 month outcome among neonates with hypoxic-ischemic encephalopathy (HIE).
Study design
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.
Results
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.
Conclusion
Hypocarbia is associated with poor outcome following HIE.
doi:10.1016/j.jpeds.2010.10.019
PMCID: PMC3229432  PMID: 21146184
hypocarbia; hypoxic ischemic encephalopathy; whole body hypothermia; outcome; neurodevelopmental impairment
25.  Neurodevelopmental Outcomes of Triplets or Higher-Order Extremely Low Birth Weight Infants 
Pediatrics  2011;127(3):e654-e660.
BACKGROUND:
Extremely low birth weight twins have a higher rate of death or neurodevelopmental impairment than singletons. Higher-order extremely low birth weight multiple births may have an even higher rate of death or neurodevelopmental impairment.
METHODS:
Extremely low birth weight (birth weight 401–1000 g) multiple births born in participating centers of the Neonatal Research Network between 1996 and 2005 were assessed for death or neurodevelopmental impairment at 18 to 22 months' corrected age. Neurodevelopmental impairment was defined by the presence of 1 or more of the following: moderate to severe cerebral palsy; mental developmental index score or psychomotor developmental index score less than 70; severe bilateral deafness; or blindness. Infants who died within 12 hours of birth were excluded. Maternal and infant demographic and clinical variables were compared among singleton, twin, and triplet or higher-order infants. Logistic regression analysis was performed to establish the association between singletons, twins, and triplet or higher-order multiples and death or neurodevelopmental impairment, controlling for confounding variables that may affect death or neurodevelopmental impairment.
RESULTS:
Our cohort consisted of 8296 singleton, 2164 twin, and 521 triplet or higher-order infants. The risk of death or neurodevelopmental impairment was increased in triplets or higher-order multiples when compared with singletons (adjusted odds ratio: 1.7 [95% confidence interval: 1.29–2.24]), and there was a trend toward an increased risk when compared with twins (adjusted odds ratio: 1.27 [95% confidence: 0.95–1.71]).
CONCLUSIONS:
Triplet or higher-order births are associated with an increased risk of death or neurodevelopmental impairment at 18 to 22 months' corrected age when compared with extremely low birth weight singleton infants, and there was a trend toward an increased risk when compared with twins.
doi:10.1542/peds.2010-2646
PMCID: PMC3304548  PMID: 21357334
extremely low birth weight; triplets; neurodevelopmental outcomes

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