D-bifunctional protein deficiency caused by splicing variants in a neonate with severe peroxisomal dysfunction and persistent hypoglycemia.

D-bifunctional protein (DBP) deficiency is a rare, autosomal recessive peroxisomal enzyme deficiency resulting in a high burden of morbidity and early mortality. Patients with DBP deficiency resemble those with a severe Zellweger phenotype, with neonatal hypotonia, seizures, craniofacial dysmorphisms, psychomotor delay, deafness, blindness, and death typically within the first 2 years of life, although patients with residual enzyme function can survive longer. The clinical severity of the disease depends on the degree of enzyme deficiency. Loss-of-function variants typically result in no residual enzyme activity; however, splice variants may result in protein with residual function. We describe a full-term newborn presenting with hypotonia, seizures, and unexplained hypoglycemia, who was later found to have rickets at follow up. Rapid whole genome sequencing identified two HSD17B4 variants in trans; one likely pathogenic variant and one variant of uncertain significance (VUS) located in the polypyrimidine tract of intron 13. To determine the functional consequence of the VUS, we analyzed RNA from the patient's father with RNA-seq which showed skipping of Exon 14, resulting in a frameshift mutation three amino acids from the new reading frame. This RNA-seq analysis was correlated with virtually absent enzyme activity, elevated very-long-chain fatty acids in fibroblasts, and a clinically severe phenotype. Both variants are reclassified as pathogenic. Due to the clinical spectrum of DBP deficiency, this provides important prognostic information, including early mortality. Furthermore, we add persistent hypoglycemia to the clinical spectrum of the disease, and advocate for the early management of fat-soluble vitamin deficiencies to reduce complications.

An Initiative to Decrease Laboratory Testing in a NICU.

BACKGROUND AND OBJECTIVES: Laboratory testing is performed frequently in the NICU. Unnecessary tests can result in increased costs, blood loss, and pain, which can increase the risk of long-term growth and neurodevelopmental impairment. Our aim was to decrease routine screening laboratory testing in all infants admitted to our NICU by 20% over a 24-month period. METHODS: We designed and implemented a multifaceted quality improvement project using the Institute for Healthcare Improvement's Model for Improvement. Baseline data were reviewed and analyzed to prioritize order of interventions. The primary outcome measure was number of laboratory tests performed per 1000 patient days. Secondary outcome measures included number of blood glucose and serum bilirubin tests per 1000 patient days, blood volume removed per 1000 patient days, and cost. Extreme laboratory values were tracked and reviewed as balancing measures. Statistical process control charts were used to track measures over time. RESULTS: Over a 24-month period, we achieved a 26.8% decrease in laboratory tests performed per 1000 patient days (∽51 000 fewer tests). We observed significant decreases in all secondary measures, including a decrease of almost 8 L of blood drawn and a savings of $258 000. No extreme laboratory values were deemed attributable to the interventions. Improvement was sustained for an additional 7 months. CONCLUSIONS: Targeted interventions, including guideline development, dashboard creation and distribution, electronic medical record optimization, and expansion of noninvasive and point-of-care testing resulted in a significant and sustained reduction in laboratory testing without notable adverse effects.

Risk factors for tracheostomy requirement in extremely low birth weight infants.

AIM: To identify variables that affect the risk of tracheostomy in a population of extremely low birth weight (ELBW) infants. METHODS: A retrospective matched case-control study was conducted. ELBW infants with a tracheostomy were compared with controls without tracheostomy. Data collection included demographics, detailed information about each intubation and extubation attempt, the use of steroids and the presence of comorbidities. Statistical analyses include conditional logistic regression and Poisson regression for clustered observations. RESULTS: Twenty-eight ELBW infants with a tracheostomy were identified. Mean gestational age for both cases and controls was 25 weeks (22-29) and 67.9% were males. Tracheostomy was performed on average on day of life 118 (95%CI: 107-128) and weight at tracheostomy was 2877 g (95%CI: 2657-3098). In the final model, cumulative days with an endotracheal tube (ETT) and total number of intubation episodes were associated with a tracheostomy. For each additional day of intubation, odds of tracheostomy increased by 11% (OR = 1.11, 95%CI: 1.01, 1.23) and with each new intubation episode/failed extubation episode, odds of tracheostomy increased by 150% from the previous episode (OR = 2.5, 95%CI: 1.2, 5.2). CONCLUSIONS: Greater cumulative exposure to ETT ventilation and number of intubations is associated with having a tracheostomy.

Biochemical Screening for Pulmonary Hypertension in Preterm Infants with Bronchopulmonary Dysplasia.

BACKGROUND: Pulmonary hypertension (PH) in infants with bronchopulmonary dysplasia (BPD) is associated with increased morbidity and mortality. Elevated levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) and decreased levels of amino acid precursors of nitric oxide (NO) have been associated with PH, but have not been studied in infants with PH secondary to BPD. OBJECTIVE: The aim of this study was to identify a biochemical marker for PH in infants with BPD. METHODS: Twenty infants, born at <27 weeks' gestational age (GA) and/or with a birth weight (BW) ≤750 g, who met the criteria for BPD at 36 weeks' corrected GA (CGA) were enrolled in this cross-sectional pilot study. A screening echocardiogram was conducted at 36-38 weeks' CGA and plasma NT-proBNP and amino acid levels were obtained within 1 week of the screening echocardiogram. RESULTS: Five infants (25%) had echocardiographic evidence of PH. GA and BW were not significantly different between the 2 groups (a PH group and a No PH group). NT-proBNP was significantly elevated in the PH group (median 1,650 vs. 520 pg/ml; p = 0.001) but citrulline levels were significantly lower (median 21 vs. 36 µmol/l; p = 0.005). Arginine levels were not significantly different between the groups (median 78 vs. 79 µmol/l; p = 1). CONCLUSION: NT-proBNP and the NO precursor citrulline may be cost-effective biochemical markers for screening for the presence of PH in preterm infants who have BPD. If validated in a larger study, such biochemical markers may, in part, replace PH screening echocardiograms in these patients.

Low-Dose Intravenous Soybean Oil Emulsion for Prevention of Cholestasis in Preterm Neonates.

BACKGROUND: Premature infants depend on intravenous fat emulsions to supply essential fatty acids and calories. The dose of soybean-based intravenous fat emulsions (S-IFE) has been associated with parenteral nutrition (PN)-associated liver disease. This study's purpose was to determine if low-dose S-IFE is a safe and effective preventive strategy for cholestasis in preterm neonates. MATERIALS AND METHODS: This is a multicenter randomized controlled trial in infants with a gestational age (GA) ≤29 weeks. Patients <48 hours of life were randomized to receive a low (1 g/kg/d) or control dose (approximately 3 g/kg/d) of S-IFE. The primary outcome was cholestasis, defined as a direct bilirubin ≥15% of the total bilirubin at 28 days of life (DOL) or full enteral feeds, whichever was later, after 14 days of PN. Secondary outcomes included growth, length of hospital stay, death, and major neonatal morbidities. RESULTS: In total, 136 neonates (67 and 69 in the low and control groups, respectively) were enrolled. Baseline characteristics were similar for the 2 groups. When the low group was compared with the control group, there was no difference in the primary outcome (69% vs 63%; 95% confidence interval, -0.1 to 0.22; P = .45). While the low group received less S-IFE and total calories over time compared with the control group (P < .001 and P = .03, respectively), weight, length, and head circumference at 28 DOL, discharge, and over time were not different (P > .2 for all). CONCLUSION: Compared with the control dose, low-dose S-IFE was not associated with a reduction in cholestasis or growth.

Inhaled nitric oxide for the postoperative management of pulmonary hypertension in infants and children with congenital heart disease.

BACKGROUND: Nitric oxide (NO) is a prevalent molecule in humans that is responsible for many physiologic activities including pulmonary vasodilation. An exogenous, inhaled form (iNO) exists that mimics this action without affecting systemic blood pressure. This therapy has been implemented in the treatment of pulmonary hypertension. This review examines the efficacy of iNO in the postoperative management of infants and children with congenital heart disease (CHD). The original review was published in 2005, updated in 2008 and again in 2014. OBJECTIVES: To compare the effects of postoperative administration of iNO versus placebo or conventional management, or both, on infants and children with CHD and pulmonary hypertension. The primary outcome was mortality. Secondary outcomes included length of hospital stay; neurodevelopmental disability; number of pulmonary hypertensive crises (PHTC); changes in mean pulmonary arterial pressure (MPAP), mean arterial pressure (MAP), and heart rate (HR); changes in oxygenation measured as the ratio of arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2); and measurement of maximum methaemoglobin level as a marker of toxicity. SEARCH METHODS: In this updated version we extended the CENTRAL search to 2013, Issue 12 of The Cochrane Library, and MEDLINE and EMBASE through to 1 December 2013. The original search was performed in July 2004 and again in November 2007. We included abstracts and all languages. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials comparing iNO with placebo or conventional management, or both. Trials included only children with CHD requiring surgery complicated by pulmonary hypertension. DATA COLLECTION AND ANALYSIS: Two authors extracted data. Data were collected on mortality; number of PHTC; changes in MPAP, MAP, HR, and PaO2:FiO2; and maximum methaemoglobin level. Data on long-term mortality, neurodevelopmental disability, and length of hospital stay were unavailable. We performed subgroup analysis by method of control (placebo or conventional management). MAIN RESULTS: We reran the searches to December 2013 and identified three new studies. These three studies did not fulfil our inclusion criteria. Therefore, no new studies were included in this updated review. In total four randomized trials involving 210 participants were included in this review. We observed no differences in mortality (OR 1.67, 95% CI 0.38 to 7.30; P = 0.50); PHTC (OR 0.80, 95% CI 0.15 to 4.18; P = 0.79); changes in MPAP (treatment effect -2.94 mm Hg, 95% CI -9.28 to 3.40; P = 0.36), MAP (treatment effect -3.55 mm Hg, 95% CI -11.86 to 4.76; P = 0.40), HR (treatment effect 0.02 bpm, 95% CI -8.13 to 8.18; P = 1.00), or PaO2:FiO2 (mean difference 17.18, 95% CI -28.21 to 62.57; P = 0.46). There was a significant increase in the methaemoglobin level (mean difference 0.30%, 95% CI 0.24 to 0.36; P < 0.00001) in patients treated with iNO, although levels did not reach toxicity levels. Data from long-term mortality, neurodevelopmental disability, and length of stay were not available. Two trials had a low risk of bias. Very low quality of the evidence was observed considering grading of the outcomes. AUTHORS' CONCLUSIONS: We observed no differences with the use of iNO in the outcomes reviewed. No data were available for several clinical outcomes including long-term mortality and neurodevelopmental outcome. We found it difficult to draw valid conclusions given concerns regarding methodologic quality, sample size, and heterogeneity.

Ear drainage and the role of sepsis evaluations in the neonatal intensive care unit.

AIM: To design and implement an intervention to reduce ear drainage and subsequent sepsis evaluation and treatment in the neonatal intensive care unit. METHODS: From 2008 to 2011, we observed an increase in the rates of ear drainage warranting investigation. Data collection was performed from 1991 to 2013 on 50 cases. Preliminary analysis revealed an association between timing of endotracheal tube tape changes and onset of drainage. We speculated that pooling of anti-adhesive solution into the external auditory canal was precipitating an inflammatory process. Unit-wide education was conducted to protect the ears during tape removal. Post-initiative rates of drainage were collected and compared with pre-initiative rates. RESULTS: Median gestational age and birthweight were 26 weeks and 754 g, respectively. In 64% of cases, an anti-adhesive solution was used on the face within 48 h of the onset of drainage. Sepsis evaluation was performed in 68% of cases. Rates of ear drainage peaked from 2008 to 2011 at 9.18 per 1000 admissions when a new anti-adhesive product was used, declining to 0.66 post-initiative (rate difference: -8.52; 95% CI: -12.00, -5.03). CONCLUSION: Protecting the ear from anti-adhesive solutions during tape removal may reduce rates of noninfectious ear drainage and limit unnecessary interventions.

Concurrent bloodstream infections in infants with necrotizing enterocolitis.

OBJECTIVE: To determine the incidence, microbiology, risk factors, and outcomes related to bloodstream infections (BSIs) concurrent with the onset of necrotizing enterocolitis (NEC). STUDY DESIGN: We performed a retrospective review of all cases of NEC in a single center over 20 years. BSI was categorized as "NEC-associated" if it occurred within 72 hours of the diagnosis of NEC and "post-NEC" if it occurred >72 hours afterwards. Demographics, hospital course data, microbiologic data, and outcomes were compared via univariate and multivariate analyses. RESULTS: NEC occurred in 410 infants with mean gestational age and birth weight of 29 weeks and 1290 g, respectively; 158 infants were diagnosed with at least one BSI; 69 (43.7%) with NEC-associated BSI, and 89 (56.3%) with post-NEC BSI. Two-thirds of NEC-associated BSI were due to gram-negative bacilli compared with 31.9% of post-NEC BSI (OR: 4.27; 95% CI: 2.02, 9.03) and 28.5% of all BSI in infants without NEC (OR: 5.02; 95% CI: 2.82, 8.96). Infants with NEC-associated BSI had higher odds of requiring surgical intervention (aOR: 3.51; 95% CI: 1.98, 6.24) and death (aOR: 2.88; 95% CI: 1.39, 5.97) compared with those without BSI. CONCLUSIONS: BSI is a common, underappreciated complication of NEC occurring concurrent with the onset of disease and afterwards. The microbiologic etiology of NEC-associated BSI is different from post-NEC and late-onset BSI in infants without NEC with a predominance of gram-negative bacilli. Infants with NEC-associated BSI are significantly more likely to die than those with post-NEC BSI and NEC without BSI.

Novel FOXF1 deep intronic deletion causes lethal lung developmental disorder, alveolar capillary dysplasia with misalignment of pulmonary veins.

Haploinsufficiency of FOXF1 causes an autosomal dominant neonatally lethal lung disorder, alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV). We identified novel 0.8-kb deletion within the 1.4-kb intron of FOXF1 in a deceased newborn diagnosed with ACDMPV. The deletion arose de novo on the maternal copy of the chromosome 16, and did not affect FOXF1 minigene splicing tested in lung fibroblasts. However, FOXF1 transcript level in the ACDMPV peripheral lung tissue was reduced by almost 40%. We found that, in an in vitro reporter assay, the FOXF1 intron exhibited moderate transcriptional enhancer activity, correlating with the presence of binding sites for expression regulators CTCF and CEBPB, whereas its truncated copy, which lost major CTCF and CEBPB-binding sites, inhibited the FOXF1 promoter. Our data further emphasize the importance of testing the non-protein coding regions of the genome currently not covered by diagnostic chromosomal microarray analyses or whole-exome sequencing.

Genetic contribution to patent ductus arteriosus in the premature newborn.

BACKGROUND: The most common congenital heart disease in the newborn population, patent ductus arteriosus, accounts for significant morbidity in preterm newborns. In addition to prematurity and environmental factors, we hypothesized that genetic factors play a significant role in this condition. OBJECTIVE: The objective of this study was to quantify the contribution of genetic factors to the variance in liability for patent ductus arteriosus in premature newborns. PATIENTS AND METHODS: A retrospective study (1991-2006) from 2 centers was performed by using zygosity data from premature twins born at < or =36 weeks' gestational age and surviving beyond 36 weeks' postmenstrual age. Patent ductus arteriosus was diagnosed by echocardiography at each center. Mixed-effects logistic regression was used to assess the effect of specific covariates. Latent variable probit modeling was then performed to estimate the heritability of patent ductus arteriosus, and mixed-effects probit modeling was used to quantify the genetic component. RESULTS: We obtained data from 333 dizygotic twin pairs and 99 monozygotic twin pairs from 2 centers (Yale University and University of Connecticut). Data on chorioamnionitis, antenatal steroids, gestational age, body weight, gender, respiratory distress syndrome, patent ductus arteriosus, necrotizing enterocolitis, oxygen supplementation, and bronchopulmonary dysplasia were comparable between monozygotic and dizygotic twins. We found that gestational age, respiratory distress syndrome, and institution were significant covariates for patent ductus arteriosus. After controlling for specific covariates, genetic factors or the shared environment accounted for 76.1% of the variance in liability for patent ductus arteriosus. CONCLUSIONS: Preterm patent ductus arteriosus is highly familial (contributed to by genetic and environmental factors), with the effect being mainly environmental, after controlling for known confounders.

Circulating stem cells in extremely preterm neonates.

AIM: To measure circulating CD34+ cell levels in premature neonates and to correlate the initial CD34+ counts with measures of pulmonary function and neonatal morbidity. METHODS: CD34+ cell counts were measured in the peripheral blood of preterm neonates (gestational ages 24-32 weeks) ventilated for respiratory disease at <48 h of life, and at the start of the 2nd, 3rd and 4th weeks of life. Data pertaining to neonatal demographics and short-term outcomes were collected. Pulmonary function tests were performed to coincide with CD34+ sampling. RESULTS: Thirty preterm neonates with median gestational age of 24 weeks and birth weight of 641 g were analysed. A mean of 99.4 CD34+ cells per microliter was observed in the 1st week of life with a decline to 54.4 cells per microliter by the 4th week. An inverse correlation between initial CD34+ count and gestational age (p=0.01) was observed. No significant correlations were observed with measures of pulmonary function or neonatal morbidities. CONCLUSIONS: Extremely premature neonates have remarkably high levels of CD34+ cells in their peripheral blood at birth. Umbilical cord blood from this population may potentially provide an abundant source of hematopoietic stem and progenitor cells for therapeutic purposes.

Case-control analysis of endemic Serratia marcescens bacteremia in a neonatal intensive care unit.

BACKGROUND: Serratia marcescens is an opportunistic gram-negative rod which typically infects compromised hosts. OBJECTIVES: To identify risk factors, signs, and outcomes associated with non-epidemic S marcescens bacteremia in a neonatal intensive care unit (NICU). METHODS: The records of infants with S marcescens bacteremia while in the Yale-New Haven Hospital NICU from 1980-2004 were reviewed. A matched case-control study was performed by comparing each case of S marcescens to 2 uninfected controls and 2 cases of Escherichia coli bacteremia. RESULTS: Twenty-five sporadic cases of S marcescens bacteremia were identified. Eleven available isolates were determined to be different strains by pulse field gel electrophoresis. Infants with S marcescens bacteremia had median gestational age and birth weight of 28 weeks and 1235 grams, respectively. Compared to matched, uninfected controls, infants with S marcescens bacteremia were more likely to have had a central vascular catheter (OR = 4.33; 95% CI (1.41 to 13.36)) and surgery (OR = 5.67; 95% CI (1.81 to 17.37)), and had a higher overall mortality (44% vs 2%; OR = 38.50; 95% CI (4.57 to 324.47)). Compared to E coli matched controls, infants with S marcescens bacteremia had later onset of infection (median of 33 days of life vs 10; p<0.001), prolonged intubation (OR = 5.76; 95% CI (1.80 to 18.42)), and a higher rate of CVC (OR = 7.77; 95% CI (2.48 to 24.31)) use at the time of infection. A higher rate of meningitis (24% vs 7%; OR = 3.98; 95% CI (1.09 to 14.50)) was observed with S marcescens bacteremia compared to E coli. CONCLUSIONS: S marcescens bacteremia occurs sporadically in the NICU, primarily in premature infants requiring support apparatus late in their hospital course. Associated meningitis is common and mortality high.

Genetic susceptibility to retinopathy of prematurity.

OBJECTIVES: The goals were to isolate and to estimate the genetic susceptibility to retinopathy of prematurity. METHODS: A retrospective study (1994-2004) from 3 centers was performed with zygosity data for premature twins who were born at a gestational age of < or = 32 weeks and survived beyond a postmenstrual age of 36 weeks. Retinopathy of prematurity was diagnosed and staged by pediatric ophthalmologists at each center. Data analyses were performed with mixed-effects logistic regression analysis and latent variable probit modeling. RESULTS: A total of 63 monozygotic and 137 dizygotic twin pairs were identified and analyzed. Data on gestational age, birth weight, gender, respiratory distress syndrome, retinopathy of prematurity, bronchopulmonary dysplasia, duration of ventilation and supplemental oxygen use, and length of stay were comparable between monozygotic and dizygotic twins. In the mixed-effects logistic regression analysis for retinopathy of prematurity, gestational age and duration of supplemental oxygen use were significant covariates. After controlling for known and unknown nongenetic factors, genetic factors accounted for 70.1% of the variance in liability for retinopathy of prematurity. CONCLUSION: In addition to prematurity and environmental factors, there is a strong genetic predisposition to retinopathy of prematurity.

Familial and genetic susceptibility to major neonatal morbidities in preterm twins.

BACKGROUND: Intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia remain significant causes of morbidity and mortality in preterm newborns. OBJECTIVES: Our goal was to assess the familial and genetic susceptibility to intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia. METHODS: Mixed-effects logistic-regression and latent variable probit model analysis were used to assess the contribution of several covariates in a multicenter retrospective study of 450 twin pairs born at < or =32 weeks of gestation. To determine the genetic contribution, concordance rates in a subset of 252 monozygotic and dizygotic twin pairs were compared. RESULTS: The study population had a mean gestational age of 29 weeks and birth weight of 1286 g. After controlling for effects of covariates, the twin data showed that 41.3%, 51.9%, and 65.2%, respectively, of the variances in liability for intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia could be accounted for by genetic and shared environmental factors. Among the 63 monozygotic twin pairs, the observed concordance for bronchopulmonary dysplasia was significantly higher than the expected concordance; 12 of 18 monozygotic twin pairs with > or =1 affected member had both members affected versus 3.69 expected. After controlling for covariates, genetic factors accounted for 53% of the variance in liability for bronchopulmonary dysplasia. CONCLUSIONS: Twin analyses show that intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia are familial in origin. These data demonstrate, for the first time, the significant genetic susceptibility for bronchopulmonary dysplasia in preterm infants.