Bronchopulmonary dysplasia: an enduring challenge

Association of Fentanyl With Neurodevelopmental Outcomes in Very-Low-Birth-Weight Infants

Background: Opioids are commonly used in the neonatal intensive care unit (NICU). Negative neurodevelopmental effects in the short-term setting have been associated with opioids ; however, long-term studies have been limited. Objective: The primary objective was to determine if there is a dose relationship between fentanyl and neurodevelopmental outcomes, as measured by Bayley Scales of Infant and Toddler Development (Bayley-III) composite scores for language, cognition, and motor skills. Secondary objectives included comparison of Bayley-III scores and neurodevelopmental impairment classification based on fentanyl exposure. Methods: A retrospective evaluation of 147 very-low-birth-weight infants with Bayley-III scores obtained at a chronological age of 6 months to 2 years at clinic follow-up was conducted. Univariate and multivariable linear regression analyses were used to determine if there was a dose-related association between fentanyl and neurodevelopmental outcomes. To evaluate secondary outcomes, patients were divided based on cumulative fentanyl dose (“high-dose” versus “low/no-dose”). Results: The univariate analysis found a statistically significant decrease in cognition ( P = .034) and motor skills scores ( P = .006). No association was found in the multi-variable regression between fentanyl cumulative dose and Bayley-III scores. There was a significant decrease in the motor skills score between the high-dose versus low/no-dose group, 94 ± 20 versus 102 ± 15, respectively ( P = .026); however, no statistical differences were noted for language or cognition scores or neurological impairment classification. Conclusions: When controlling for other variables, the cumulative fentanyl dose did not correlate with neurodevelopmental outcomes. Further evaluation of benefits and risks of opioids in premature infants are needed.

Association of surfactant protein B gene polymorphisms (C/A-18, C/T1580, intron 4 and A/G9306) and haplotypes with bronchopulmonary dysplasia in chinese han population

This study aimed to investigate the association between surfactant protein B (SP-B) polymorphisms and bronchopulmonary dysplasia (BPD) in Chinese Han infants. We performed a casecontrol study including 86 infants with BPD and 156 matched controls. Genotyping was performed by sequence specific primer-polymerase chain reaction (PCR) and haplotypes were reconstructed by the fastPHASE software. The results showed that significant differences were detected in the genotype distribution of C/A-18 and intron 4 polymorphisms of SP-B gene between cases and controls. No significant differences were detected in the genotype distribution of C/T1580 or A/G9306 between the two groups. Haplotype analysis revealed that the frequency of A-del-C-A haplotype was higher in case group (0.12 to 0.05, P=0.003), whereas the frequency of C-inv-C-A haplotype was higher in control group (0.19 to 0.05, P=0.000). In addition, a significant difference was observed in the frequency of C-inv-T-A haplotype between the two groups. It was concluded that the polymorphisms of SP-B intron 4 and C/A-18 could be associated with BPD in Chinese Han infants, and the del allele of intron 4 and A allele of C/A-18 might be used as markers of susceptibility in the disease. Haplotype analysis indicated that the gene-gene interactions would play an important part in determining susceptibility to BPD.

Definition and outpatient management of the very low-birth-weight infant with bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease of prematurity, is the major cause of pulmonary disease in infants. The pathophysiology and management of BPD have evolved over the past four decades as improved neonatal intensive care unit (NICU) modalities have increased survival rates. The likelihood for developing BPD increases with the degree of prematurity and reaches 25-35% in very low-birth-weight and extremely low-birth-weight infants. BPD affects many organ systems, and infants with BPD are at increased risk for rehospitalization and numerous complications following NICU discharge. The management of BPD and medically related problems, particularly during the first 2 years of life, remains a continuing challenge for parents and healthcare providers. It is important that a multidisciplinary team consisting of the neonatologist/attending physician, primary care physician, and other specialized support staff work in concert and meet regularly to provide continuity of care and accurate patient assessments.

Newborn Individualized Developmental Care and Assessment Program (NIDCAP) - family-centered developmentally supportive care

The theoretical framework behind family-centered, developmentally supportive care (NIDCAP) is endorsed by research from several scientific fields, including neuroscience, developmental and family psychology, medicine and nursing. However, the introduction of NIDCAP involves a considerable investment at all levels of the organization. NIDCAP requires some physical changes in the NICU as well as substantial educational efforts and changes in the practice of care. The findings of the presented NIDCAP studies have been encouraging, and NIDCAP has been very well received by nursing staff, neonatologists and parents. It also is attractive from an ethical point of view. It appears reasonable to recommend that nurseries implement NIDCAP and investigate developmentally supportive care in different cultural contexts and with diversified, randomized multicenter trials.

Azithromycin in the extremely low birth weight infant for the prevention of bronchopulmonary dysplasia: a pilot study

BACKGROUND

Azithromycin reduces the severity of illness in patients with inflammatory lung disease such as cystic fibrosis and diffuse panbronchiolitis. Bronchopulmonary dysplasia (BPD) is a pulmonary disorder which causes significant morbidity and mortality in premature infants. BPD is pathologically characterized by inflammation, fibrosis and impaired alveolar development. The purpose of this study was to obtain pilot data on the effectiveness and safety of prophylactic azithromycin in reducing the incidence and severity of BPD in an extremely low birth weight (< or = 1000 grams) population.

METHODS

Infants < or = 1000 g birth weight admitted to the University of Kentucky Neonatal Intensive Care Unit (level III, regional referral center) from 9/1/02-6/30/03 were eligible for this pilot study. The pilot study was double-blinded, randomized, and placebo-controlled. Infants were randomized to treatment or placebo within 12 hours of beginning mechanical ventilation (IMV) and within 72 hours of birth. The treatment group received azithromycin 10 mg/kg/day for 7 days followed by 5 mg/kg/day for the duration of the study. Azithromycin or placebo was continued until the infant no longer required IMV or supplemental oxygen, to a maximum of 6 weeks. Primary endpoints were incidence of BPD as defined by oxygen requirement at 36 weeks gestation, post-natal steroid use, days of IMV, and mortality. Data was analyzed by intention to treat using Chi-square and ANOVA.

RESULTS

A total of 43 extremely premature infants were enrolled in this pilot study. Mean gestational age and birth weight were similar between groups. Mortality, incidence of BPD, days of IMV, and other morbidities were not significantly different between groups. Post-natal steroid use was significantly less in the treatment group [31% (6/19)] vs. placebo group [62% (10/16)] (p = 0.05). Duration of mechanical ventilation was significantly less in treatment survivors, with a median of 13 days (1-47 days) vs. 35 days (1-112 days)(p = 0.02).

CONCLUSION

Our study suggests that azithromycin prophylaxis in extremely low birth weight infants may effectively reduce post-natal steroid use for infants. Further studies are needed to assess the effects of azithromycin on the incidence of BPD and possible less common side effects, before any recommendations regarding routine clinical use can be made.

Developmental patterns from 1 to 4 years of extremely preterm infants who required home oxygen therapy

BACKGROUND

Bronchopulmonary dysplasia (BPD) remains a common complication of prematurity, with those being discharged on home oxygen at particularly high risk of adverse developmental outcomes.

AIMS

To compare the developmental patterns, from 1 to 4 years, of extremely preterm infants with BPD discharged from hospital on home oxygen, extremely preterm infants with BPD discharged breathing room air, and extremely preterm infants without BPD.

SUBJECTS

Two hundred and seventy-six infants with a gestational age of <28 weeks or birthweight <1000 g, free from sensory and motor disabilities who were followed up longitudinally to 4 years corrected age.

OUTCOME MEASURES

Children were assessed on the Griffiths Mental Development Scales at 1 and 2 years corrected age, and the McCarthy Scales of Children's Abilities at 4 years corrected age.

RESULTS

The developmental trajectories of the three groups did not differ significantly, however at 1 year corrected age the non-BPD group had significantly higher developmental scores than both BPD groups. At 2 years corrected age the non-BPD group had significantly higher developmental scores than the BPD-home oxygen group, and at 4 years corrected age no differences between the groups were evident.

CONCLUSIONS

Extremely preterm children with BPD exhibited an initial developmental lag compared to preterm peers. Children with BPD discharged breathing room air had developmental scores at 2 years corrected age that were comparable to the non-BPD group, but those discharged on home oxygen still had lower developmental scores. At 4 years, no differences between the groups were evident.

Developmentally supportive care and NIDCAP

With increasing advances in field of perinatal medicine and new breakthroughs in technology, the perinatal mortality has shown a steady decline worldwide. This has given rise to a new dimension, that of developmentally oriented care of these sick neonates while they are still in intensive care. NIDCAP &developmentally supportive care is aimed at decreasing the stress levels in these babies by individualized care which also involves the family. Growth and development has been shown to get enhanced by this approach. There are only few well designed studies on this issue of extreme importance. This article presents a brief review of current literature as well as outlines relevant policies followed in the author's unit.

Minimal enteral feeding within 3 d of birth in prematurely born infants with birth weight < or = 1200 g improves bone mass by term age

BACKGROUND

Evidence-based practice guidelines for aggressive nutritional intervention by using parenteral amino acids (AAs) and minimal enteral feeding (MEF) as early as the first day of life have not been tested for benefits to bone mass.

OBJECTIVE

We investigated whether early introduction of parenteral AAs and MEF improves growth and bone mass achieved by term age in infants born prematurely.

DESIGN

Twenty-seven infants who were < or = 1200 g and < or = 32 wk gestation at birth were randomly assigned by using a 2 x 2 design to treatment of either 1 g AAs/kg within the first 24 h or 12 mL MEF x kg(-1) x d(-1) within the first 72 h of life. Nutrition and growth were documented during hospitalization, and bone mineral content (BMC) of lumbar spine 1-4, femur, and whole body was measured at term age. Biomarkers of bone metabolism were measured at weeks 1, 3, and 5 and at discharge. Statistical analysis was conducted by using 2 x 2 analysis of variance for intent to treat and for infants receiving protocol nutrition.

RESULTS

Over the first 14 d of life, a main effect of early AAs elevated total intake of protein, and a main effect of early MEF was a higher frequency of MEF volumes exceeding > 12 mL x kg(-1) x d(-1). Main effects on growth were not evident. An interaction effect was observed for osteocalcin whereby early AAs or MEF alone elevated osteocalcin. A main effect of early MEF yielded higher BMC of spine and femur.

CONCLUSION

Early aggressive nutrition support with MEF enhances BMC in premature infants, but early MEF or AAs do not improve growth.

Special relationships between fetal inflammatory response syndrome and bronchopulmonary dysplasia in neonates

OBJECTIVE

To confirm previous known relationships between Fetal Inflammatory Response Syndrome (FIRS) and neonatal bronchopulmonary dysplasia (BPD) and to present information on previously unknown special relationships between inflammatory variables and BPD.

STUDY DESIGN

At delivery, we obtained biological specimens including umbilical cord venous blood for plasma interleukin-6 levels, as well as placental histology and bacteriology. Among other neonatal outcomes, we collected prospective information on BPD.

RESULTS

Of 141 newborns in the study, 16 had BPD; 79% of these had antecedent FIRS, 27% of those without FIRS had BPD. By multivariable regression, only very low birth weight (adjusted [adj] odds ratio [OR] 32.0, 95% Confidence Interval [CI] 5.0 to positive infinity) and FIRS (adj OR 5.7, 95% CI 1.1 to 42.3) remained significant risk factors. Escherichia coli, perhaps due to its pyogenic nature (strongly elicits inflammatory responses), may have had a special relationship with BPD.

CONCLUSIONS

In our data, FIRS and neonatal BPD are highly associated. It is possible that certain pyogenic bacteria in the chorioamnion space may be implicated more often than others.

CONDENSATION

Neonates having Fetal Inflammatory Response Syndrome at delivery may later develop BPD. Pyogenic bacteria, such as Escherichia coli, may be implicated more frequently.

Effects of erythropoietin on hyperoxic lung injury in neonatal rats

Pulmonary oxygen toxicity is believed to play a prominent role in the lung injury that leads to the development of bronchopulmonary dysplasia (BPD). To determine whether human recombinant erythropoietin (rhEPO) treatment reduces the risk of developing BPD, we investigated the effect of rhEPO treatment on the histopathologic changes seen in hyperoxia-induced lung injury of BPD. Twenty-five rat pups were divided into four groups: air-exposed control group (n = 5), hyperoxia-exposed placebo group (n = 7), hyperoxia-exposed rhEPO-treated group (n = 6), and air-exposed rhEPO-treated group (n = 7). Measurement of alveolar surface area, quantification of secondary crest formation, microvessel count, evaluation of alveolar septal fibrosis, and smooth muscle actin immunostaining were performed to assess hyperoxia-induced changes in lung morphology. Treatment of hyperoxia-exposed animals with rhEPO resulted in a significant increase in the mean alveolar area, number of secondary crests formed, and the microvessel count in comparison with hyperoxia-exposed placebo-treated animals. There was significantly less fibrosis in rhEPO-treated animals. However, treatment of hyperoxia-exposed animals with rhEPO did not result in a significant change in smooth muscle content compared with hyperoxia-exposed placebo treated animals. Our results suggest treatment with rhEPO during hyperoxia exposure is associated with improved alveolar structure, enhanced vascularity, and decreased fibrosis. Therefore, we conclude that treatment of preterm infants with EPO might reduce the risk of developing BPD.

Management of infants with chronic lung disease of prematurity in Australasia

Chronic lung disease is common in extremely preterm infants born in Australasia. In 2002, 53% of surviving infants born before 28 weeks' gestation remained either oxygen-dependent or on other respiratory support at 36 weeks' postmenstrual age. In the first weeks of life oxygenation should be kept generally "lower", although what is the most appropriate level remains uncertain. During the mid-phase of the neonatal course, functional oxygen saturation levels around 90-95% probably confer the best benefit/risk balance. The most appropriate target saturation range for infants on home oxygen also remains uncertain. Definitive data to guide clinical practice is lacking regarding the use of postnatal corticosteroids, bronchodilators, and diuretics for either the treatment or prevention of chronic lung disease. Home oxygen programmes are effective in avoiding prolonged hospitalisation for infants with chronic lung disease, but require the coordination of a large, multidisciplinary team.

Susceptibility to neoplastic and non-neoplastic pulmonary diseases in mice: genetic similarities

Chronic inflammation predisposes toward many types of cancer. Chronic bronchitis and asthma, for example, heighten the risk of lung cancer. Exactly which inflammatory mediators (e.g., oxidant species and growth factors) and lung wound repair processes (e.g., proangiogenic factors) enhance pulmonary neoplastic development is not clear. One approach to uncover the most relevant biochemical and physiological pathways is to identify genes underlying susceptibilities to inflammation and to cancer development at the same anatomic site. Mice develop lung adenocarcinomas similar in histology, molecular characteristics, and histogenesis to this most common human lung cancer subtype. Over two dozen loci, called Pas or pulmonary adenoma susceptibility, Par or pulmonary adenoma resistance, and Sluc or susceptibility to lung cancer genes, regulate differential lung tumor susceptibility among inbred mouse strains as assigned by QTL (quantitative trait locus) mapping. Chromosomal sites that determine responsiveness to proinflammatory pneumotoxicants such as ozone (O3), particulates, and hyperoxia have also been mapped in mice. For example, susceptibility QTLs have been identified on chromosomes 17 and 11 for O3-induced inflammation (Inf1, Inf2), O3-induced acute lung injury (Aliq3, Aliq1), and sulfate-associated particulates. Sites within the human and mouse genomes for asthma and COPD phenotypes have also been delineated. It is of great interest that several susceptibility loci for mouse lung neoplasia also contain susceptibility genes for toxicant-induced lung injury and inflammation and are homologous to several human asthma loci. These QTLs are described herein, candidate genes are suggested within these sites, and experimental evidence that inflammation enhances lung tumor development is provided.

Early developmental care for preterm neonates: a call for more research

Developmental care is the use of a range of medical and nursing interventions to decrease the stress of preterm neonates in neonatal intensive care units. This article reviews the theory underlying such interventions and research based data in different scientific fields, including neuroscience, developmental and family psychology, medicine, and nursing. The conclusion is that more research is needed.

Perioperative implications of common respiratory problems

Pediatric surgical patients can present with a number of challenging common respiratory problems. This article reviews potential perioperative implications and anesthetic management of asthma, upper respiratory tract infections, bronchopulmonary dysplasia, and the effects of passive environmental smoke on children presenting for surgery.

DNA microarray analysis of neonatal mouse lung connects regulation of KDR with dexamethasone-induced inhibition of alveolar formation

Treatment of newborn mice with dexamethasone (Dex) inhibits the subdivision of lung saccules to form alveoli; treatment with all- trans retinoic acid (RA) prevents this inhibition of septation. To better understand the early molecular signals responsible for the effects of Dex and RA, Affymetrix gene profiling was done on RNA isolated from 4-day-old mice after treatment with 1) diluent, 2) RA (1 mg/kg), 3) Dex (0.7 μg/pup), or 4) RA + Dex. Each sample was assayed in duplicate on U74Av2 GeneChips. Data were analyzed with Affymetrix suite 5.0, corrected for saturation, and evaluated with GeneSpring 5.1 software. Stringent filtering of data by the global error model and condition-to-condition comparisons was used to identify 46 genes demonstrating significantly different expression between the lungs of Dex- and RA + Dex-treated mice. A query of the gene ontology database revealed that the major biological processes affected by treatment with Dex and RA were cell growth/maintenance and cellular communication. On the basis of microarray data analysis, we hypothesize that Dex-induced inhibition of septation is associated with a block in angiogenesis due to downregulation of the kinase domain receptor (KDR), also known as VEGF receptor-2 and fetal liver kinase, and that the downregulation of KDR is prevented by treatment with RA.