Low plasma retinol concentrations increase the risk of developing bronchopulmonary dysplasia and long-term respiratory disability in very-low-birth-weight infants

The role of nutritional interventions in the prevention and treatment of chronic lung disease of prematurity

Chronic lung disease of prematurity or bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Nutrition may affect incidence and severity of BPD. In this context, the Section on Nutrition, Gastroenterology and Metabolism, the Pulmonary Section of the European Society for Paediatric Research (ESPR) and SPR have joined forces to review the current knowledge on nutritional issues related to BPD. The aim of this narrative review is to discuss the clinical implications for nutritional practice. Nutrient deficiencies may influence pathogenesis of BPD. Adequate nutrition and growth can play a crucial role in the prevention of and recovery from BPD. Optimal nutrition strategy is an important principle, especially in the early postnatal period. As optimal energy intake in infants at risk of BPD or with evolving BPD is not yet defined, further research with well-designed studies on nutritional strategies for preterm infants with BPD is urgently needed. IMPACT: Based on current evidence it seems reasonable to recommend that BPD diagnosed infants should receive an energy supply ranging from 120 to 150 Kcal/kg/d. Exclusive MOM feed with adequate fortification should be encouraged as this is associated with a significant reduction in the risk of BPD. Suboptimal nutritional delivery is often seen in preterm infants with BPD compared to controls.

The Role of Vitamins in the Pathogenesis of Asthma

Vitamins play a crucial role in the proper functioning of organisms. Disturbances of their levels, seen as deficiency or excess, enhance the development of various diseases, including those of the cardiovascular, immune, or respiratory systems. The present paper aims to summarize the role of vitamins in one of the most common diseases of the respiratory system, asthma. This narrative review describes the influence of vitamins on asthma and its main symptoms such as bronchial hyperreactivity, airway inflammation, oxidative stress, and airway remodeling, as well as the correlation between vitamin intake and levels and the risk of asthma in both pre- and postnatal life.

Vitamin A Status in Preterm Infants Is Associated with Inflammation and Dexamethasone Exposure

Vitamin A has a key role in lung development and its deficiency is associated with an increased risk of bronchopulmonary dysplasia. This secondary cohort analysis of the ImNuT trial (Immature, Nutrition Therapy NCT03555019) aimed to (1) explore vitamin A status in preterm infants <29 weeks gestation and (2) assess the influence of inflammation and postnatal dexamethasone exposure on vitamin A concentrations in blood. We report detailed information on vitamin A biochemistry, vitamin A intake, markers of inflammation and dexamethasone exposure. After four weeks of age, infants exposed to dexamethasone (n = 39) showed higher vitamin A concentrations compared to unexposed infants (n = 41); median (IQR) retinol was 1.0 (0.74, 1.5) vs. 0.56 (0.41, 0.74) µmol/L, p < 0.001. Pretreatment retinol concentrations were lower in the dexamethasone group compared to non-exposed infants (p < 0.001); 88% vs. 60% of the infants were considered deficient in vitamin A (retinol < 0.7 µmol/L) at one week of age. Small size for gestational age, mechanical ventilation and elevated levels of interleukin-6 were factors negatively associated with first-week retinol concentrations. In conclusion, preterm infants <29 weeks gestation are at risk of vitamin A deficiency despite intakes that accommodate current recommendations. The presence of inflammation and dexamethasone exposure should be considered when interpreting vitamin A status.

BPD treatments: The never-ending smorgasbord

Despite important advances in neonatal care, rates of bronchopulmonary dysplasia (BPD) have remained persistently high. Numerous drugs and ventilator strategies are used for the prevention and treatment of BPD. Some, such as exogenous surfactant, volume targeted ventilation, caffeine, and non-invasive respiratory support, are associated with modest but important reductions in rates of BPD and long-term respiratory morbidities. Many other therapies, such as corticosteroids, diuretics, nitric oxide, bronchodilators and anti-reflux medications, are widely used despite conflicting, limited or no evidence of efficacy and safety. This paper examines the range of therapies used for the prevention or treatment of BPD. They are classified into those supported by evidence of effectiveness, and those which are widely used despite limited evidence or unclear risk to benefit ratios. Finally, the paper explores emerging therapies and approaches which aim to prevent or reduce BPD and long-term respiratory morbidity.

[Expert consensus on nutritional management of preterm infants with bronchopulmonary dysplasia]

Inadequate nutrition supply in the early stage after birth is a risk factor for the development of bronchopulmonary dysplasia (BPD) in preterm infants, and it is also closely associated with the progression and clinical outcome of BPD. Optimized nutritional support is of great importance to reduce the incidence and severity of BPD and promote lung development and neurological prognosis. Based on the relevant studies in China and overseas, the expert consensus on BPD nutrition management is developed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method. The consensus includes the following seven aspects: the importance of nutrition in BPD, fluid intake, energy intake, enteral nutrition, parenteral nutrition, post-discharge nutrition, and nutrition monitoring and evaluation.

Fat-soluble vitamins A and E and health disparities in a cohort of pregnant women at delivery

The objective of the present study was to evaluate intakes and serum levels of vitamin A, vitamin E, and related compounds in a cohort of maternal-infant pairs in the Midwestern USA in relation to measures of health disparities. Concentrations of carotenoids and tocopherols in maternal serum were measured using HPLC and measures of socio-economic status, including food security and food desert residence, were obtained in 180 mothers upon admission to a Midwestern Academic Medical Center labour and delivery unit. The Kruskal-Wallis and independent-samples t tests were used to compare measures between groups; logistic regression models were used to adjust for relevant confounders. P < 0·05 was considered statistically significant. The odds of vitamin A insufficiency/deficiency were 2·17 times higher for non-whites when compared with whites (95 % CI 1·16, 4·05; P = 0·01) after adjustment for relevant confounders. Similarly, the odds of being vitamin E deficient were 3·52 times higher for non-whites (95 % CI 1·51, 8·10; P = 0·003). Those with public health insurance had lower serum lutein concentrations compared with those with private health insurance (P = 0·05), and living in a food desert was associated with lower serum concentrations of β-carotene (P = 0·02), after adjustment for confounders. Subjects with low/marginal food security had higher serum levels of lutein and β-cryptoxanthin compared with those with high food security (P = 0·004 and 0·02 for lutein and β-cryptoxanthin). Diet quality may be a public health concern in economically disadvantaged populations of industrialised societies leading to nutritional disadvantages as well.

Vitamin A Supplementation by Endotracheal Application of a Nano-encapsulated Preparation Is Feasible in Ventilated Preterm Lambs

BACKGROUND

Vitamin A (VA) is crucial for lung growth and development. In premature infants, inadequate VA levels are associated with an increased risk of bronchopulmonary dysplasia (BPD). Intramuscular VA supplementation has been shown to decrease the incidence of BPD, but is not widely used in the clinical setting due to concerns about feasibility and pain. We studied VA kinetics, distribution, and the induction of early genetic expression of retinoid homeostatic genes in the lung after endotracheal and intravenous application in a preterm lamb model.

METHODS

Lambs were delivered prematurely after 85% of gestation, intubated, and ventilated for 3 hours. The animals were randomized to receive no VA ("control"), a bolus of VA intravenously ("i.v."), or VA endotracheally directly after administration of surfactant ("e.t.").

RESULTS

Animals treated with VA endotracheally directly after administration of surfactant showed significant increases of VA in serum and lung compared to controls. Animals treated with a bolus of VA intravenously showed significant increases of VA in serum, lung, and liver; however, peak serum concentrations and mRNA levels of homeostatic genes raised concerns about toxicity in this group.

CONCLUSIONS

Endotracheal VA supplementation in preterm lambs is feasible and might offer advantages in comparison to i.v. Further studies are warranted to explore biological effects in the context of BPD.

Vitamin A supplementation to prevent mortality and short- and long-term morbidity in very low birth weight infants

BACKGROUND

Vitamin A is necessary for normal lung growth and the integrity of respiratory tract epithelial cells. Preterm infants have low vitamin A status at birth and this has been associated with an increased risk of developing chronic lung disease.

OBJECTIVES

To evaluate supplementation with vitamin A on the incidence of death or neonatal chronic lung disease and long-term neurodevelopmental disability in very low birth weight (VLBW) infants compared with a control (placebo or no supplementation), and to consider the effect of the supplementation route, dose, and timing.

SEARCH METHODS

For the original review and subsequent updates, we searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, Science Citation Index, and the Oxford Database of Perinatal Trials. The reference lists of relevant trials, paediatric and nutrition journals, and conference abstracts and proceedings were handsearched up to 2010.For the 2016 update, we used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 4), MEDLINE via PubMed (1 May 2016), EMBASE (1 May 2016), and CINAHL (1 May 2016). We also searched clinical trials' databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised controlled trials comparing vitamin A supplementation with a control (placebo or no supplementation) or other dosage regimens in VLBW infants (birth weight ≤ 1500 grams or less than 32 weeks' gestation).

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results, extracted data, and assessed the trials for risk of bias. Results were reported as risk ratios (RR), risk differences (RD), and number needed to treat to benefit (NNTB), all with 95% confidence intervals (CI). Trialists were contacted for additional data.

MAIN RESULTS

Eleven trials met the inclusion criteria. Ten trials (1460 infants) compared vitamin A supplementation with a control and one (120 infants) compared different regimens of vitamin A supplementation. Compared to the control group, vitamin A appeared to have a small benefit in reducing the risk of death or oxygen requirement at one month of age (typical RR 0.93, 95% CI 0.88 to 0.99; typical RD -0.05, 95% CI -0.10 to -0.01; NNTB 20, 95% CI 10 to 100; 6 studies, 1165 infants) and the risk of chronic lung disease (oxygen requirement) at 36 weeks' postmenstrual age (typical RR 0.87, 95% CI 0.77 to 0.99; typical RD -0.07, 95% CI -0.13 to -0.01; NNTB 11, 95% CI 6 to 100; 5 studies, 986 infants) (moderate-quality evidence). There was a marginal reduction of the combined outcome of death or chronic lung disease (typical RR 0.92, 95% CI 0.84 to 1.01; typical RD -0.05, 95% CI -0.11 to 0.01; 4 studies, 1089 infants). Neurodevelopmental assessment of 88% of the surviving infants in the largest trial showed no difference between the groups at 18 to 22 months of age, corrected for prematurity (low-quality evidence). There is no evidence to support different vitamin A dosing regimens. No adverse effects of vitamin A supplementation were reported, but it was noted that intramuscular injections of vitamin A were painful.

AUTHORS' CONCLUSIONS

Whether clinicians decide to utilise repeat intramuscular doses of vitamin A to prevent chronic lung disease may depend upon the local incidence of this outcome and the value attached to achieving a modest reduction in the outcome balanced against the lack of other proven benefits and the acceptability of the treatment. Information on long-term neurodevelopmental status suggests no evidence of either benefit or harm from the intervention.

Serum Retinol Concentrations, Race, and Socioeconomic Status in of Women of Childbearing Age in the United States

Background: Vitamin A is an essential nutrient during pregnancy and throughout the lifecycle due to its role in the development of critical organ systems. Because maternal tissue is progressively depleted of vitamin A to supply fetal demands, women who become pregnant while possessing marginal vitamin A reserves are at increased risk of vitamin A inadequacy as pregnancy progresses. Few studies have assessed the relationship between socioeconomic factors and retinol status in women of childbearing age. Methods: We used the National Health and Nutrition Examination Survey (NHANES) to assess the relationship between serum retinol concentrations and socioeconomic factors in women of childbearing age. Women 14–45 years of age (n = 3170) from NHANES cycles 2003–2004 and 2005–2006 were included. Serum retinol concentrations were divided into categories according to World Health Organization criteria. All statistical procedures accounted for the weighted data and complex design of the NHANES sample. A p-value of < 0.05 was considered statistically significant. Results: The poverty score and race were significantly associated with vitamin A status after adjustment for confounders. Odds of retinol concentrations of <1.05 µmol/L were 1.85 times higher for those of lower socioeconomic status when compared to those of higher status (95% CI: 1.12–3.03, p = 0.02), and 3.1 times higher for non-Hispanic blacks when compared to non-Hispanic whites (95% CI: 1.50–6.41, p = 0.002). Dietary intakes of retinol activity equivalents were significantly lower in groups with higher poverty scores (p = 0.004). Conclusion There appear to be disparities in serum vitamin A levels in women of childbearing age related to income and race in the United States.

Vitamin A Supplementation for Prevention of Bronchopulmonary Dysplasia: Cornerstone of Care or Futile Therapy?

OBJECTIVE

To review the evidence on vitamin A supplementation (VAS) and bronchopulmonary dysplasia (BPD) in extremely-low-birth-weight infants. We also discuss the impact of a vitamin A shortage on BPD rates.

DATA SOURCES

A PubMed search inclusive of dates 1946 to March 2016 was performed using the search terms bronchopulmonary dysplasia, chronic lung disease (CLD), and vitamin A STUDY SELECTION AND DATA EXTRACTION: All English-language studies were evaluated. Only those investigating VAS by intramuscular administration were included.

DATA SYNTHESIS

A total of 6 studies were evaluated. Additionally, a report on the incidence of BPD during a national shortage was reviewed. Investigators found mixed results with VAS and incidence of CLD or death in a varying number of neonates. In the largest evaluation, investigators found a statistically significant decrease in the rate of death or BPD: 55% in the VAS group versus 62% in the placebo group. The number needed to treat to prevent 1 case of BPD was 15 infants. Few studies found an increased incidence of adverse events following VAS. A report over a 2-year shortage period found that whereas the rate of VAS declined dramatically, BPD rates remained stable. This large observational evaluation calls into question the place of vitamin A in BPD prevention.

CONCLUSIONS

VAS has been identified as a strategy to decrease the incidence of BPD. Initial large-scale prospective evaluations have shown clear benefit of VAS in reducing the incidence of CLD or death. However, changing definitions of BPD and implementation of noninvasive ventilation strategies limit the application of early studies. During a drug shortage, VAS declined dramatically, but BPD rates remained stable. With concerns of sepsis and necrotizing enterocolitis in small-scale studies, and in light of the recent shortage evidence, further evaluations are necessary before VAS can be recommended as a cornerstone of BPD prevention.

Vitamin A deficiency induces structural and functional alterations in the molecular constituents of the rat hippocampus

To date, no structural study has been carried out on the effects of vitamin A deficiency (VAD) on hippocampal macromolecules. Therefore, in the present study, the effect of dietary VAD on the structure, content and function of rat hippocampal molecules was investigated using Fourier transform IF spectroscopy. Male Wistar rats were randomly divided into three groups: an experimental group maintained on a vitamin A-deficient liquid diet (VAD,n7); a control group maintained on a vitamin A-supplemented liquid diet (CON,n9); a pure control group maintained on standard solid laboratory chow (PC,n7). The PC group was included in the study to ensure that the usage of liquid diet did not influence the outcomes of VAD. Both the CON and PC groups were successfully discriminated from the VAD group by principal component analysis and hierarchical cluster analysis. The spectral analysis indicated a significant decrease in the contents of saturated and unsaturated lipids, cholesteryl esters, TAG and nucleic acids in the VAD group when compared with the CON group (P≤ 0·05). In addition, a significant decrease in membrane fluidity and a significant increase in lipid order (e.g. acyl chain flexibility) were observed in the VAD group (P≤ 0·001). The results of the artificial neural network analysis revealed a significant decrease in the α-helix structure content and a significant increase in the turn and random coil structure contents, indicating protein denaturation, in the VAD group when compared with the CON and PC groups (P≤ 0·05). Dietary exclusion of vitamin A for 3 months apparently had an adverse impact on compositional, structural and dynamical parameters. These changes can be due to increased oxidative stress, confirming the antioxidant protection provided by vitamin A when used as a dietary supplement at low-to-moderate doses.

Effectiveness of vitamin A in the prevention of complications of prematurity

BACKGROUND

To assess the effectiveness of vitamin A supplementation in very low birth weight (VLBW) infants to prevent complications of prematurity.

METHODS

This was a retrospective cohort study to determine the effectiveness of vitamin A in preventing complications of prematurity in VLBW infants. Vitamin A was delivered intramuscularly at a dose of 5000 IU, three times weekly during the first 28 days of life.

RESULTS

Of the 187 eligible VLBW infants, we excluded from the analysis (due to death or transfer to another hospital), 16 infants weighing <1000 g and 17 weighing 1000-1500 g. Sixty VLBW infants received the vitamin supplement. We observed no differences between the groups in the duration of oxygen therapy or in the risk of bronchopulmonary dysplasia. The risk of sepsis was up to three times higher among the infants who were given the vitamin A supplement.

CONCLUSION

Given the increased risk of sepsis in patients weighing >1000 g, the risk associated with repeated intramuscular injections of vitamin A and the modest clinical results described, we do not believe the universal administration of vitamin A to VLBW infants to be justified as prophylaxis for bronchopulmonary dysplasia.

Prenatal retinoid deficiency leads to airway hyperresponsiveness in adult mice

There is increasing evidence that vitamin A deficiency in utero correlates with abnormal airway smooth muscle (SM) function in postnatal life. The bioactive vitamin A metabolite retinoic acid (RA) is essential for formation of the lung primordium; however, little is known about the impact of early fetal RA deficiency on postnatal lung structure and function. Here, we provide evidence that during murine lung development, endogenous RA has a key role in restricting the airway SM differentiation program during airway formation. Using murine models of pharmacological, genetic, and dietary vitamin A/RA deficiency, we found that disruption of RA signaling during embryonic development consistently resulted in an altered airway SM phenotype with markedly increased expression of SM markers. The aberrant phenotype persisted postnatally regardless of the adult vitamin A status and manifested as structural changes in the bronchial SM and hyperresponsiveness of the airway without evidence of inflammation. Our data reveal a role for endogenous RA signaling in restricting SM differentiation and preventing precocious and excessive SM differentiation when airways are forming.

Prematurity and programming: contribution of neonatal Intensive Care Unit interventions

Contemporary clinical practice for the care of the prematurely born babies has markedly improved their rates of survival so that most of these babies are expected to grow up to live a healthy functional life. Since the clinical follow-up is of short duration (years), only limited data are available to relate non-communicable diseases in adult life to events and interventions in the neonatal period. The major events that could have a programming effect include: (1) intrauterine growth restriction; (2) interruption of pregnancy with change in redox and reactive oxygen species (ROS) injury; (3) nutritional and pharmacological protocols for clinical care; and (4) nutritional care in the first 2 years resulting in accelerated weight gain. The available data are discussed in the context of perturbations in one carbon (methyl transfer) metabolism and its possible programming effects. Although direct evidence for genomic methylation is not available, clinical and experimental data on impact of redox and ROS, of low protein intake, excess methionine load and vitamin A, on methyl transfers are reviewed. The consequences of antenatal and postnatal administration of glucocorticoids are presented. Analysis of the correlates of insulin sensitivity at older age, suggests that premature birth is the major contributor, and is compounded by gain in weight during infancy. We speculate that premature interruption of pregnancy and neonatal interventions by affecting one carbon metabolism may cause programming effects on the immature baby. These can be additive to the effects of intrauterine environment (growth restriction) and are compounded by accelerated growth in early infancy.

Vitamin A supplementation to prevent mortality and short- and long-term morbidity in very low birthweight infants

BACKGROUND

Vitamin A is necessary for normal lung growth and the integrity of respiratory tract epithelial cells. Preterm infants have low vitamin A status at birth, and this has been associated with increased risk of developing chronic lung disease.

OBJECTIVES

To evaluate vitamin A supplementation on the incidence of death and/or neonatal chronic lung disease and long-term neurodevelopmental disability in very low birthweight infants (VLBW); and to consider the effect of the supplementation route, dose, and timing.

SEARCH STRATEGY

In August 2011, the Cochrane Central Regsiter of Controlled Trials (Central, The Cochrane Library), MEDLINE, Science Citation Index and the Oxford Database of Perinatal Trials were searched. The reference lists of relevant trials, paediatric and nutrition journals, and conference abstracts and proceedings were handsearched up to 2007.

SELECTION CRITERIA

Randomised controlled trials comparing vitamin A supplementation with a control (placebo or no supplementation) or other dosage regimens in VLBW infants (birthweight ≤ 1500 g or < 32 weeks' gestation).

DATA COLLECTION AND ANALYSIS

Both review authors screened the search results, extracted data, and assessed the trials' risk of bias. Results were reported as risk ratios (RR), risk differences (RD), and number needed to treat to benefit (NNTB), all with 95% confidence intervals (CI). Trialists were contacted for additional data.

MAIN RESULTS

Nine trials met the inclusion criteria, eight compared vitamin A supplementation with a control (1291 infants), and one compared different regimens (120 infants). Compared to the control group, vitamin A appears to be beneficial in reducing death or oxygen requirement at one month of age (RR 0.93, 95% CI 0.88 to 0.99; RD -0.05, 95% CI -0.10 to -0.01; NNTB 20, 95% CI 10 to 100; 1165 infants) and oxygen requirement at 36 weeks' postmenstrual age (RR 0.87, 95% CI 0.77 to 0.98; RD -0.08, 95% CI -0.14 to -0.01; NNTB 13, 95% CI 7 to 100; 824 infants). A trend towards a reduction in death or oxygen requirement at 36 weeks' postmenstrual age was also noted (RR 0.91, 95% CI 0.82 to 1.00; 1001 infants). Neurodevelopmental assessment of 88% of surviving infants in the largest trial showed no differences between the groups at 18 to 22 months of age, corrected for prematurity. The different dosage vitamin A regimens showed similar results.

AUTHORS' CONCLUSIONS

Whether clinicians decide to utilise repeat intramuscular doses of vitamin A to prevent chronic lung disease may depend upon the local incidence of this outcome and the value attached to achieving a modest reduction in this outcome, balanced against the lack of other proven benefits and the acceptability of treatment. Information on long-term neurodevelopmental status suggests no evidence of either benefit or harm from the intervention.

Marginal vitamin A deficiency affects lung maturation in rats from prenatal to adult stage

Mild or marginal vitamin A deficiency (MVAD) is still a serious and widespread public health problem in pregnant women and children in developing countries. This study investigated rat lung maturation from prenatal to adult stage during pregnancy and postnatal MVAD and the recovery after postnatal vitamin A supplementation (VAS). Adult female rats and their offspring were randomized into three groups. 1.

CONTROL

the mothers and offspring received a normal diet.2. MVAD: The mothers and offspring received a MVAD diet.3. VAS: the mothers received MVAD diet till parturition, and then received the normal diet. The offspring of the VAS group were given low-dose vitamin A from postnatal day 1 to day 7 and received the normal diet after weaning. The lung development, structure, and collagen and elastic fiber of offspring were monitored by morphometric analysis at age 1 d, 2 and 8 wk, respectively. Lower body weight, lung weight, reduced numbers of alveoli and total alveolar surface area as well as increased alveoli septa thickness was observed in MVAD compared to that in the control animals. Increased collagen deposits and decreasing elastic fiber were found in MVAD rats. However, all of these were significantly improved in VAS-treated animals. These data suggest that the rat lung is sensitive to MVAD during the developing stage. Early postnatal vitamin A supplementation can partially restore the normal lung structure.

Decreased incidence of bronchopulmonary dysplasia after early management changes, including surfactant and nasal continuous positive airway pressure treatment at delivery, lowered oxygen saturation goals, and early amino acid administration: a historical cohort study

OBJECTIVE

The goal was to investigate the clinical impact of 3 early management practice changes for infants of < or = 1000 g.

METHODS

We performed an historical cohort study of appropriately sized, preterm infants without congenital anomalies who were born between January 2001 and June 2002 (pre-early management practice change group; n = 87) and between July 2004 and December 2005 (post-early management practice change group; n = 76).

RESULTS

Only 1 (1%) of 87 infants in the pre-early management practice change group received continuous positive airway pressure treatment in the first 24 hours of life, compared with 61 (80%) of 76 infants in the post-early management practice change group. The proportions of infants who required any synchronized intermittent mandatory ventilation during their hospital stays were 98.8% and 59.5%, respectively. The mean durations of synchronized intermittent mandatory ventilation were 35 days and 15 days, respectively. The combined incidence rates of moderate and severe bronchopulmonary dysplasia at corrected gestational age of 36 weeks were 43% and 24%, respectively. The use of vasopressor support for hypotension in the first 24 hours of life decreased from 39.1% (before early management practice changes) to 19.7% (after practice changes), the cumulative days of oxygen therapy decreased from 77 +/- 52 days to 56 +/- 47 days, and the proportions of infants discharged with home oxygen therapy decreased from 25.7% to 10.1%; the incidence of patent ductus arteriosus requiring surgical ligation increased from 1% to 10%. There were no differences in rates of death, intraventricular hemorrhage, periventricular leukomalacia, pneumothorax, necrotizing enterocolitis, or retinopathy of prematurity.

CONCLUSIONS

Successful early management of extremely preterm infants with surfactant treatment followed by continuous positive airway pressure treatment at delivery, lowered oxygen saturation goals, and early amino acid supplementation is possible and is associated with reductions in the incidence and severity of bronchopulmonary dysplasia.

Vitamin A supplementation to prevent mortality and short and long-term morbidity in very low birthweight infants

BACKGROUND

Vitamin A is necessary for normal lung growth and the ongoing integrity of respiratory tract epithelial cells. Preterm infants have low vitamin A status at birth and this has been associated with increased risk of developing chronic lung disease. Several studies have been undertaken to assess whether vitamin A supplementation beyond that routinely given in multivitamin preparations can reduce the incidence of this outcome.

OBJECTIVES

To assess the benefit and risk of supplementation with vitamin A in very low birthweight infants.

SEARCH STRATEGY

Searches were made of the Oxford Database of Perinatal Trials, MEDLINE up to November 2006, Cochrane Central Register of Controlled Trials Register (CENTRAL, The Cochrane Library, Issue 4, 2006), and Science Citation Index. The reference lists of relevant trials, recent issues of paediatric and nutrition journals, abstracts and proceedings from relevant conferences in the English language were hand searched.

SELECTION CRITERIA

Randomised controlled trials which compared the effects of supplemental vitamin A with standard vitamin A regimes in infants with birthweight </= 1500 g and reported clinical outcomes (death, chronic lung disease or bronchopulmonary dysplasia, long-term neurodevelopmental status) and/or vitamin A concentrations were considered for the review, as were trials which compared vitamin A dosing regimes and reported biochemical outcomes (retinol concentrations at 28 days).

DATA COLLECTION AND ANALYSIS

Data on mortality, requirement for supplemental oxygen at one month of age and at 36 weeks postmenstrual age, retinopathy of prematurity, nosocomial sepsis and follow-up at 18 to 22 months, as well as retinol concentrations at 28 days in trials comparing dosage regimes, were excerpted by both reviewers independently. Data analysis was conducted according to the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

Eight eligible trials comparing vitamin A supplementation with standard regimes were identified, one having a much larger sample size than the others combined. The meta-analysis suggests supplementation with vitamin A is beneficial in reducing death or oxygen requirement at one month of age [typical RR 0.93 (95% CI 0.88, 0.99), RD -0.05 ( 95% CI -0.10, -0.01), NNT 20 (10, 100) and oxygen requirement at 36 weeks postmenstrual age [typical RR 0.87 (95% CI 0.77, 0.98), RD -0.08 ( 95% CI -0.14, -0.01), NNT 13 (7, 100)], and trends towards reduction in oxygen requirement in survivors at one month of age [typical RR 0.93 (95% CI 0.86, 1.01) and death or oxygen requirement at 36 weeks postmenstrual age [typical RR 0.91 (95% CI 0.82, 1.00)]. Meta-analysis of the three studies from which data on retinopathy of prematurity are available suggests a trend towards reduced incidence in vitamin A supplemented infants. Neurodevelopmental assessment of 85% of surviving infants participating in the largest trial showed no differences in outcome between supplementation and placebo groups at 18 to 22 months corrected age.

AUTHORS' CONCLUSIONS

Supplementing very low birthweight infants with vitamin A is associated with a reduction in death or oxygen requirement at one month of age and oxygen requirement among survivors at 36 weeks postmenstrual age, with this latter outcome being confined to infants with birthweight less than 1000 g. Whether clinicians decide to utilise repeat intramuscular doses of vitamin A to prevent chronic lung disease may depend upon the local incidence of this outcome and the value attached to achieving a modest reduction in this outcome, balanced against the lack of other proven benefits and the acceptability of treatment. Information on long-term neurodevelopmental status suggests no evidence of either benefit or harm from the intervention. The benefits, in terms of vitamin A status, safety and acceptability of delivering vitamin A in an intravenous emulsion compared with repeat intramuscular injections, should be assessed in a further trial.

The role of nutrition in the prevention and management of bronchopulmonary dysplasia

Nutrition plays a critical role in the prevention and management of bronchopulmonary dysplasia (BPD). Growth failure in infants with BPD is predominantly due to malnutrition. Malnutrition can worsen BPD by compromising lung growth. Feeding difficulties in these infants can further affect nutrition. Dexamethasone, used to facilitate extubation and treat severe BPD, is known to have adverse effects on growth. Nutritional management of very low birth weight (VLBW) infants should be addressed from the first day of life to enhance growth and minimize respiratory morbidity. Fluid restriction, parenteral nutrition with protein and lipids, and early enteral feeding may help decrease the incidence of BPD. High calorie concentrated formula can be used in infants to achieve adequate growth if total daily fluid intake is restricted. Vitamin A supplementation may help to prevent further damage to lungs. The role of such therapies as inositol, vitamin E, and selenium in management of these infants remains speculative. Close post discharge follow up of infants with BPD is necessary to monitor growth and to ensure intake of sufficient protein and calories.