Home oxygen status and rehospitalisation and primary care requirements of infants with chronic lung disease

Non-invasive high-frequency ventilation in newborn infants with respiratory distress

BACKGROUND

Respiratory distress occurs in up to 7% of newborns, with respiratory support (RS) provided invasively via an endotracheal (ET) tube or non-invasively via a nasal interface. Invasive ventilation increases the risk of lung injury and chronic lung disease (CLD). Using non-invasive strategies, with or without minimally invasive surfactant, may reduce the need for mechanical ventilation and the risk of lung damage in newborn infants with respiratory distress.

OBJECTIVES

To evaluate the benefits and harms of nasal high-frequency ventilation (nHFV) compared to invasive ventilation via an ET tube or other non-invasive ventilation methods on morbidity and mortality in preterm and term infants with or at risk of respiratory distress.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL and three trial registries in April 2023.

SELECTION CRITERIA

Randomised controlled trials (RCTs), cluster- or quasi-RCTs of nHFV in newborn infants with respiratory distress compared to invasive or non-invasive ventilation.

DATA COLLECTION AND ANALYSIS

Two authors independently selected the trials for inclusion, extracted data, assessed the risk of bias, and undertook GRADE assessment.

MAIN RESULTS

We identified 33 studies, mostly in low- to middle-income settings, that investigated this therapy in 5068 preterm and 46 term infants. nHFV compared to invasive respiratory therapy for initial RS We are very uncertain whether nHFV reduces mortality before hospital discharge (RR 0.67, 95% CI 0.20 to 2.18; 1 study, 80 infants) or the incidence of CLD (RR 0.38, 95% CI 0.09 to 1.59; 2 studies, 180 infants), both very low-certainty. ET intubation, death or CLD, severe intraventricular haemorrhage (IVH) and neurodevelopmental disability (ND) were not reported. nHFV vs nasal continuous positive airway pressure (nCPAP) used for initial RS We are very uncertain whether nHFV reduces mortality before hospital discharge (RR 1.00, 95% CI 0.41 to 2.41; 4 studies, 531 infants; very low-certainty). nHFV may reduce ET intubation (RR 0.52, 95% CI 0.33 to 0.82; 5 studies, 571 infants), but there may be little or no difference in CLD (RR 1.35, 95% CI 0.80 to 2.27; 4 studies, 481 infants); death or CLD (RR 2.50, 95% CI 0.52 to 12.01; 1 study, 68 participants); or severe IVH (RR 1.17, 95% CI 0.36 to 3.78; 4 studies, 531 infants), all low-certainty evidence. ND was not reported. nHFV vs nasal intermittent positive-pressure ventilation (nIPPV) used for initial RS nHFV may result in little to no difference in mortality before hospital discharge (RR 1.86, 95% CI 0.90 to 3.83; 2 studies, 84 infants; low-certainty). nHFV may have little or no effect in reducing ET intubation (RR 1.33, 95% CI 0.76 to 2.34; 5 studies, 228 infants; low-certainty). There may be a reduction in CLD (RR 0.63, 95% CI 0.42 to 0.95; 5 studies, 307 infants; low-certainty). A single study (36 infants) reported no events for severe IVH. Death or CLD and ND were not reported. nHFV vs high-flow nasal cannula (HFNC) used for initial RS We are very uncertain whether nHFV reduces ET intubation (RR 2.94, 95% CI 0.65 to 13.27; 1 study, 37 infants) or reduces CLD (RR 1.18, 95% CI 0.46 to 2.98; 1 study, 37 participants), both very low-certainty. There were no mortality events before hospital discharge or severe IVH. Other deaths, CLD and ND, were not reported. nHFV vs nCPAP used for RS following planned extubation nHFV probably results in little or no difference in mortality before hospital discharge (RR 0.92, 95% CI 0.52 to 1.64; 6 studies, 1472 infants; moderate-certainty). nHFV may result in a reduction in ET reintubation (RR 0.42, 95% CI 0.35 to 0.51; 11 studies, 1897 infants) and CLD (RR 0.78, 95% CI 0.67 to 0.91; 10 studies, 1829 infants), both low-certainty. nHFV probably has little or no effect on death or CLD (RR 0.90, 95% CI 0.77 to 1.06; 2 studies, 966 infants) and severe IVH (RR 0.80, 95% CI 0.57 to 1.13; 3 studies, 1117 infants), both moderate-certainty. We are very uncertain whether nHFV reduces ND (RR 0.92, 95% CI 0.37 to 2.29; 1 study, 74 infants; very low-certainty). nHFV versus nIPPV used for RS following planned extubation nHFV may have little or no effect on mortality before hospital discharge (RR 1.83, 95% CI 0.70 to 4.79; 2 studies, 984 infants; low-certainty). There is probably a reduction in ET reintubation (RR 0.69, 95% CI 0.54 to 0.89; 6 studies, 1364 infants), but little or no effect on CLD (RR 0.88, 95% CI 0.75 to 1.04; 4 studies, 1236 infants); death or CLD (RR 0.92, 95% CI 0.79 to 1.08; 3 studies, 1070 infants); or severe IVH (RR 0.78, 95% CI 0.55 to 1.10; 4 studies, 1162 infants), all moderate-certainty. One study reported there might be no difference in ND (RR 0.88, 95% CI 0.35 to 2.16; 1 study, 72 infants; low-certainty). nHFV versus nIPPV following initial non-invasive RS failure nHFV may have little or no effect on mortality before hospital discharge (RR 1.44, 95% CI 0.10 to 21.33); or ET intubation (RR 1.23, 95% CI 0.51 to 2.98); or CLD (RR 1.01, 95% CI 0.70 to 1.47); or severe IVH (RR 0.47, 95% CI 0.02 to 10.87); 1 study, 39 participants, all low- or very low-certainty. Other deaths or CLD and ND were not reported.

AUTHORS' CONCLUSIONS

For initial RS, we are very uncertain if using nHFV compared to invasive respiratory therapy affects clinical outcomes. However, nHFV may reduce intubation when compared to nCPAP. For planned extubation, nHFV may reduce the risk of reintubation compared to nCPAP and nIPPV. nHFV may reduce the risk of CLD when compared to nCPAP. Following initial non-invasive respiratory support failure, nHFV when compared to nIPPV may result in little to no difference in intubation. Large trials, particularly in high-income settings, are needed to determine the role of nHFV in initial RS and following the failure of other non-invasive respiratory support. Also, the optimal settings of nHVF require further investigation.

Retrospective study of serial polysomnograms of bronchopulmonary dysplasia patients with oxygen dependence

INTRODUCTION

This retrospective study describes characteristics of serial polysomnograms (PSGs) of BPD patients on home oxygen therapy and describes PSG parameters associated with discontinuation of supplemental oxygen.

METHODS

A single-center study was performed at Children's Hospital Los Angeles, where serial PSGs for 44 patients with BPD infants discharged on home oxygen therapy were extracted for maximum of five PSGs or until oxygen discontinuation. Clinical and polysomnography data was collected. Characteristics of PSG1 were compared amongst the patients who were weaned from oxygen after PSG2 and PSG3.

RESULTS

Of 44 patients, 68.2% of patients were males with median birth gestational age of 26 weeks (IQR: 24.6-28.1), median birthweight of 777.5 g (IQR: 632.5-1054 g) and 77.3% of the cohort had severe BPD. A total of 138 PSGs were studied between all 44 patients serially. When comparing PSG1 and PSG2 parameters, statistically significant improvement was noted in multiple parameters. Median baseline SpO2, peak RR, and average PETCO2 were found to be potential predictors of prolonged oxygen use. Gestational age and birth weight were not associated with prolonged oxygen use after PSG3. The median age of oxygen discontinuation was calculated to be about 2 years of age.

CONCLUSIONS

The severity of hypoxia and tachypnea on initial infant PSG are associated with prolonged oxygen therapy past 2 years of age. Growth and development of lungs with maturation of control of breathing help improve these parameters over time regardless of BPD severity. The study may inform discussions between providers and parents for patients discharged home on oxygen therapy.

Elevated leukotriene B4 and 8-isoprostane in exhaled breath condensate from preterm-born infants

BACKGROUND

Inflammation and oxidative stress play a key role in the development of bronchopulmonary dysplasia (BPD), possibly contributing to persistent respiratory morbidity after preterm birth. We aimed to assess if inflammatory markers were elevated in exhaled breath condensate (EBC) of infants born very prematurely (< 32 weeks gestation) at 12-16 corrected months of age, and if increased levels were associated with BPD diagnosis and respiratory morbidity.

METHODS

EBC samples and respiratory questionnaires were collected from 15 term-born infants and 33 preterm-born infants, 12 with a neonatal BPD diagnosis. EBC samples were analysed for leukotriene B4 (inflammation) and 8-isoprostane (oxidative stress) concentrations using enzyme-linked immune-assays. Differences between groups were analysed by Kruskal-Wallis Test with post-hoc comparisons, independent samples t-test or Mann-Whitney U test depending on normality of the data.

RESULTS

Leukotriene B4 and 8-isoprostane levels were elevated in exhaled breath condensate of preterm-born infants compared to those born at term (mean difference [95% CI]; 1.52 [0.45, 2.59], p = 0.02; 0.77 [0.52, 1.02], p < 0.001, respectively). Leukotriene B4 and 8-isoprostane levels were independent of BPD diagnosis and respiratory morbidity over the first year of life.

CONCLUSIONS

Infants born very prematurely exhibit elevated markers of airway neutrophilic inflammation and oxidative stress beyond the first year of life, regardless of a neonatal diagnosis of chronic lung disease or respiratory morbidity during infancy. These findings may have implications for future lung health.

TRIAL REGISTRATION

N/A.

Postnatal diuretics, weight gain and home oxygen requirement in extremely preterm infants

OBJECTIVES

Diuretics are often given to infants with evolving/established bronchopulmonary dysplasia (BPD) with the hope of improving their pulmonary outcomes. We aimed to determine if diuretic use in preterm infants was associated with improved pulmonary outcomes, but poorer weight gain.

METHODS

An observational study over a 5 year period was undertaken of all infants born at less than 29 weeks of gestation and alive at discharge in all neonatal units in England who received consecutive diuretic use for at least 7 days. Postnatal weight gain and home supplementary oxygen requirement were the outcomes. A literature review of randomised controlled trials (RCTs) and crossover studies was undertaken to determine if diuretic usage was associated with changes in lung mechanics and oxygenation, duration of supplementary oxygen and requirement for home supplementary oxygen.

RESULTS

In the observational study, 9,457 infants survived to discharge, 44.6% received diuretics for at least 7 days. Diuretic use was associated with an increased probability of supplementary home oxygen of 0.14 and an increase in weight gain of 2.5 g/week. In the review, seven of the 10 studies reported improvements only in short term lung mechanics. There was conflicting evidence regarding whether diuretics resulted in short term improvements in oxygenation.

CONCLUSIONS

Diuretic use was not associated with a reduction in requirement for supplemental oxygen on discharge. The literature review highlighted a lack of RCTs assessing meaningful long-term clinical outcomes. Randomised trials are needed to determine the long-term risk benefit ratio of chronic diuretic use.

Stabilisation of the preterm infant in the delivery room using nasal high flow: A 5-year retrospective analysis

AIM

This study reviews clinical outcomes after initiating a routine policy of preterm respiratory stabilisation using nasal high flow (HF) in the delivery room (DR).

METHOD

This was a retrospective observational cohort study in a single-centre neonatal intensive care unit and included all neonates born before 32 weeks of gestation between 1 April 2015 and 31 March 2020. Stabilisation measures and outcomes were recorded including oxygen requirements, admission temperature, surfactant administration, invasive ventilation within 72 h of birth, bronchopulmonary dysplasia (BPD) and death.

RESULTS

There were 491 eligible babies during the 5-year epoch. 292 were stabilised using HF in the DR. The median admission temperature in babies transferred on HF was 36.8°C, and the median FiO₂ at admission was 25%. 45% of these infants received surfactant. At 72 postnatal hours, 78% were either sustained on HF or were either self-ventilating in air (SVIA) or receiving low-flow nasal cannula (LFNC) respiratory support. 27% were intubated within 7 days. At 36 weeks postmenstrual age, 36% of survivors had BPD.

CONCLUSION

We have demonstrated that preterm babies <32 weeks can be effectively stabilised on HF in the DR.

Predicting the duration of supplemental home oxygen in prematurely-born infants at discharge from neonatal care

BACKGROUND

Discharge home of preterm infants on supplemental oxygen has significant healthcare, parental psychological and financial implications, but the potential ability of clinical parameters at discharge to predict the duration of home oxygen has not been previously examined.

AIMS

To use clinical and epidemiological parameters available at discharge to predict the duration of home oxygen therapy.

STUDY DESIGN

Retrospective observational cohort study with a primary and a validation cohort.

SUBJECTS

Seventy one infants born <32 completed weeks of gestational age, born between 1/1/2013-1/1/2020 at King's College Hospital NHS Foundation trust and discharged home on supplemental oxygen were studied.

OUTCOME MEASURE

Duration of home oxygen therapy.

RESULTS

In a primary cohort of 52 infants with a median (IQR) gestational age of 26.4 (25.0-28.1) weeks and birth weight of 0.81 (0.69-0.96) kg, the duration of home oxygen was four (3-7) months (range: 1-22 months). The postmenstrual age (adjusted p = 0.001) and oxygen flow at discharge (adjusted p = 0.046) were independently associated with the duration of home oxygen therapy. In a validation cohort of 19 infants, the correlation coefficient between the calculated and the observed duration of home oxygen was 0.62, p = 0.005 and the coefficient of determination was 0.38.

CONCLUSIONS

Infants discharged home on higher oxygen flows and at a greater postmenstrual age require a longer duration of home oxygen therapy and these parameters can be used to predict the duration of home oxygen therapy.

Early Changes and Indicators Characterizing Lung Aging in Neonatal Chronic Lung Disease

Infants suffering from neonatal chronic lung disease, i.e., bronchopulmonary dysplasia, are facing long-term consequences determined by individual genetic background, presence of infections, and postnatal treatment strategies such as mechanical ventilation and oxygen toxicity. The adverse effects provoked by these measures include inflammatory processes, oxidative stress, altered growth factor signaling, and remodeling of the extracellular matrix. Both, acute and long-term consequences are determined by the capacity of the immature lung to respond to the challenges outlined above. The subsequent impairment of lung growth translates into an altered trajectory of lung function later in life. Here, knowledge about second and third hit events provoked through environmental insults are of specific importance when advocating lifestyle recommendations to this patient population. A profound exchange between the different health care professionals involved is urgently needed and needs to consider disease origin while future monitoring and treatment strategies are developed.

Using a home oxygen weaning protocol and pCO2 to evaluate outcomes for infants with bronchopulmonary dysplasia discharged on home oxygen

BACKGROUND

Predischarge capillary blood gas partial pressure of carbon dioxide (pCO₂ ) has been associated with increased adverse events including readmission. This study aimed to determine if predischarge pCO₂ or 36-week pCO₂ was associated with increased respiratory readmissions or other pulmonary healthcare utilization in the year after neonatal intensive care unit (NICU) discharge for infants with bronchopulmonary dysplasia (BPD) discharged with home oxygen, using a standardized outpatient oxygen weaning protocol.

METHODS

This was a secondary cohort analysis of infants born <32 weeks gestational age with BPD, referred to our clinic for home oxygen therapy from either from our level IV NICU or local level III NICUs between 2015 and 2017. Infants with major nonrespiratory comorbidities were excluded. Subject information was obtained from electronic health records.

RESULTS

Of 125 infants, 120 had complete 1-year follow-up. Twenty-three percent of infants experienced a respiratory readmission after NICU discharge. There was no significant association between predischarge or 36-week pCO₂ and respiratory readmissions, emergency room visits, new or increased bronchodilators, or diuretics. Higher 36-week pCO₂ was associated with a later corrected age when oxygen was discontinued (<6 months; median, 54 mmHg; interquartile range [IQR], 51-61; 6-11 months; median, 62 mmHg; IQR, 57-65; ≥12 months, median, 66 mmHg; IQR, 58-73; p = .006).

CONCLUSIONS

Neither predischarge pCO₂ nor 36-week pCO₂ was associated with 1-year respiratory readmissions. However higher pCO₂ at 36 weeks was associated with a longer duration of home oxygen. Neonatal illness measures like 36-week pCO₂ may be useful in communicating expectations for home oxygen therapy to families.

Transmitted Home Oximetry and Duration of Home Oxygen in Premature Infants

OBJECTIVES

To determine if a home oxygen therapy (HOT) management strategy that includes analysis of recorded home oximetry (RHO) data, compared with standard monthly clinic visit assessments, reduces duration of HOT without harm in premature infants.

METHODS

The RHO trial was an unmasked randomized clinical trial conducted in 9 US medical centers from November 2013 to December 2017, with follow-up to February 2019. Preterm infants with birth gestation ≤37 + 0/7 weeks, discharged on HOT, and attending their first pulmonary visit were enrolled. The intervention was an analysis of transmitted RHO between clinic visits (n = 97); the standard-care group received monthly clinic visits with in-clinic weaning attempts (n = 99). The primary outcomes were the duration of HOT and parent-reported quality of life. There were 2 prespecified secondary safety outcomes: change in weight and adverse events within 6 months of HOT discontinuation.

RESULTS

Among 196 randomly assigned infants (mean birth gestational age: 26.9 weeks; SD: 2.6 weeks; 37.8% female), 166 (84.7%) completed the trial. In the RHO group, the mean time to discontinue HOT was 78.1 days (SE: 6.4), compared with 100.1 days (SE: 8.0) in the standard-care group (P = .03). The quality-of-life scores improved from baseline to 3 months after discontinuation of HOT in both groups (P = .002), but the degree of improvement did not differ significantly between groups (P = .75).

CONCLUSIONS

RHO was effective in reducing the duration of HOT in premature infants. Parent quality of life improved after discontinuation. RHO allows physicians to determine which infants can be weaned and which need prolonged oxygen therapy between monthly visits.

Early childhood respiratory morbidity and antibiotic use in ex-preterm infants: a primary care population-based cohort study

Background

Globally, bronchopulmonary dysplasia (BPD) continues to increase in preterm infants. Recent studies exploring subsequent early childhood respiratory morbidity have been small or focused on hospital admissions.

Aims

To examine early childhood rates of primary care consultations for respiratory tract infections (RTI), lower respiratory tract infections (LRTI), wheeze and antibiotic prescriptions in ex-preterm and term children. A secondary aim was to examine differences between preterm infants discharged home with or without oxygen.

Methods

Retrospective cohort study using linked electronic primary care and hospital databases of children born between 1997 and 2014. We included 253 277 eligible children, with 1666 born preterm at <32 weeks' gestation, followed-up from primary care registration to age 5 years. Adjusted incidence rate ratios (aIRRs) were calculated.

Results

Ex-preterm infants had higher rates of morbidity across all respiratory outcomes. After adjusting for confounders, aIRRs for RTI (1.37, 95% CI 1.33–1.42), LRTI (2.79, 95% CI 2.59–3.01), wheeze (3.05, 95% CI 2.64–3.52) and antibiotic prescriptions (1.49, 95% CI 1.44–1.55) were higher for ex-preterm infants. Ex-preterm infants discharged home on oxygen had significantly greater morbidity across all respiratory diagnoses and antibiotic prescriptions compared to those without home oxygen. The highest rates of respiratory morbidity were observed in children from the most deprived socioeconomic groups.

Conclusion

Ex-preterm infants, particularly those with BPD requiring home oxygen, have significant respiratory morbidity and antibiotic prescriptions in early childhood. With the increasing prevalence of BPD, further research should focus on strategies to reduce the burden of respiratory morbidity in these high-risk infants after hospital discharge.

Home Oxygen Use and 1-Year Readmission among Infants Born Preterm with Bronchopulmonary Dysplasia Discharged from Children's Hospital Neonatal Intensive Care Units

OBJECTIVE

To determine associations between home oxygen use and 1-year readmissions for preterm infants with bronchopulmonary dysplasia (BPD) discharged from regional neonatal intensive care units.

STUDY DESIGN

We performed a secondary analysis of the Children's Hospitals Neonatal Database, with readmission data via the Pediatric Hospital Information System and demographics using ZIP-code-linked census data. We included infants born <32 weeks of gestation with BPD, excluding those with anomalies and tracheostomies. Our primary outcome was readmission by 1 year corrected age; secondary outcomes included readmission duration, mortality, and readmission diagnosis-related group codes. A staged multivariable logistic regression was adjusted for center, clinical, and social risk factors; at each stage we included variables associated at P < .1 in bivariable analysis with home oxygen use or readmission.

RESULTS

Home oxygen was used in 1906 of 3574 infants (53%) in 22 neonatal intensive care units. Readmission occurred in 34%. Earlier gestational age, male sex, gastrostomy tube, surgical necrotizing enterocolitis, lower median income, nonprivate insurance, and shorter hospital-to-home distance were associated with readmission. Home oxygen was not associated with odds of readmission (OR, 1.2; 95% CI, 0.98-1.56), readmission duration, or mortality. Readmissions for infants with home oxygen were more often coded as BPD (16% vs 4%); readmissions for infants on room air were more often gastrointestinal (29% vs 22%; P < .001). Clinical risk factors explained 72% of center variance in readmission.

CONCLUSIONS

Home oxygen use is not associated with readmission for infants with BPD in regional neonatal intensive care units. Center variation in home oxygen use does not impact readmission risk. Nonrespiratory problems are important contributors to readmission risk for infants with BPD.

Parent Preferences Regarding Home Oxygen Use for Infants with Bronchopulmonary Dysplasia

OBJECTIVES

To determine parent preferences for discharge with home oxygen in infants with bronchopulmonary dysplasia.

STUDY DESIGN

This was a prospective study of parents of infants born at <32 weeks' gestation with established bronchopulmonary dysplasia and approaching neonatal intensive care unit (NICU) discharge. Parents were presented a hypothetical scenario of an infant who failed weaning to room air and 2 options: discharge with home oxygen or try longer to wean oxygen. The initial scenario risks reflected a 1.5-week difference in NICU length of stay and no differences in other outcomes. Length of stay and readmission outcomes were increased or decreased until the parent switched preference. Three months after discharge, parents were asked to reconsider their preference. Differences were analyzed by χ² or Kruskal-Wallis tests.

RESULTS

Of 125 parents, 50% preferred home oxygen. For parents preferring home oxygen, the most important reason was comfort at home (79%). Forty percent switched preference when the length of stay difference decreased by 1 week; 35% switched when readmission increased by 5%. For parents preferring to stay in NICU, the most important reason was fear of taking care of the child at home (73%). Thirty-two percent switched preference when the length of stay difference increased by 1 week; 31% switched when readmission decreased by 5%. One hundred ten parents completed the 3-month follow-up; 80 were discharged with home oxygen. Seventy-eight percent would prefer home oxygen (97% who initially preferred home oxygen and 60% who initially preferred to stay in the NICU).

CONCLUSIONS

Parents weigh differences in NICU length of stay and readmission risk similarly. After discharge, most prefer earlier discharge with home oxygen. Earlier education to increase comfort with home technology may facilitate NICU discharge planning.

Impact of a protocol-driven unified service for neonates with bronchopulmonary dysplasia

Aim

A new specialised service for preterm infants with bronchopulmonary dysplasia requiring long-term oxygen therapy (LTOT) was established in 2007, led by the paediatric respiratory team, transitioning from neonatal-led follow-up. The new service included the utilisation of a clear protocol. Our objective was to review whether this service initiation led to a reduction of time in LTOT and hospital readmissions.

Methods

We performed a retrospective cohort study of infants born at <32 weeks’ gestation requiring LTOT in a single tertiary neonatal service. Cases were identified from hospital records, BadgerNet and a local database for two cohorts, 2004–2006 and 2008–2010. Data collected for infants requiring LTOT included demographic details, length of neonatal stay, time in oxygen and hospital attendance rates.

Results

The initiation of the service led to an increase in the number of discharges in LTOT: 13.1% of infants born alive before 32 weeks’ gestation in comparison to 3.5% (p<0.001). However, the length of time in LTOT reduced from 15 to 5 months (p=0.01). There was no difference in hospital readmission rates (p=0.365).

Conclusions

In our experience the increase in neonates requiring LTOT is likely to be due to enhanced provision of overnight oximetry studies prior to discharge. Structured monitoring and weaning led to a shorter duration of home oxygen therapy.

The implementation of a clear protocol for assessment and management of neonates with bronchopulmonary dysplasia may lead to more infants being discharged in home oxygen, but has potential to reduce overall healthcare costs and improve long-term outcomeshttp://ow.ly/fYcv30nIc2c

The optimization of home oxygen weaning in premature infants trial: Design, rationale, methods, and lessons learned

Improved survival among preterm infants has led to an increase in diagnosis of chronic lung disease and infants discharged home from the NICU on supplemental oxygen. Despite this increased prevalence, no clearly defined guidelines for the management of home oxygen therapy (HOT) exist. This lack of consensus leads to significant variability in the duration of home oxygen therapy and a general paucity of evidence-based practice. Our team has identified recorded home oxygen therapy (RHO) as a potential new resource to guide clinical decision making in the outpatient pulmonology clinic. By recording extended O2 saturation data during the weaning process, RHO has the potential to save cost and improve the processes of HOT management. Our team is currently supporting a prospective, multi-center, randomized, controlled trial of RHO guided HOT weaning with the aims of determining effect upon duration of HOT, perceived parent quality of life and effect upon growth and respiratory outcomes. We plan to randomize 196 infants into one of two study arms evaluating standard HOT management versus RHO guided oxygen weaning. Our primary outcomes are total HOT duration and parental quality of life. This trial represents an unprecedented opportunity to test a novel home monitoring intervention for weaning within a vulnerable yet quickly growing population. If effective, the use of RHO may provide clinicians a tool for safe weaning.

Predictors of hospitalization for acute lower respiratory infections during the first two years of life in a population of preterm infants with bronchopulmonary dysplasia

BACKGROUND

There have been few research studies aimed at obtaining a better understanding of the prediction of subsequent respiratory morbidity at follow-up in infants with a previous history of bronchopulmonary dysplasia (BPD) living in low- and middle-income countries (LMIC). The aim of the present study was to identify predictors of hospitalization for acute lower respiratory infections (ALRIs) in a population of infants with a history of BPD living in a LMIC.

METHODS

In a prospective cohort study, we determined independent predictors of the number of hospitalizations for ALRIs during the first two years of life in a population of infants with a history of BPD living in Bogota, Colombia. In multivariate analyses, we included both clinico-demographic variables and underlying disease characteristics as predictor variables of hospitalization for ALRIs.

RESULTS

Of a total of 138 patients included in the study, 83 (60.1%) had at least one hospitalization for ALRI during the follow-up period. Independent predictors of the number of hospitalizations for ALRIs included duration of neonatal ventilatory support (IRR 1.02; CI 95% 1.00-1.03; p = 0.010), duration of subsequent ambulatory oxygen therapy (IRR 2.06; CI 95% 1.16-3.64; p = 0.013), and breastfeeding in females (IRR 0.35; CI 95% 0.14-0.84; p = 0.019).

CONCLUSIONS

Duration of mechanical ventilation, duration of subsequent ambulatory oxygen therapy, and breastfeeding in females were independently associated with the number of hospitalizations for ALRIs in our population of infants with a history of BPD.

Persistent and progressive long-term lung disease in survivors of preterm birth

Preterm birth accounts for approximately 11% of births globally, with rates increasing across many countries. Concurrent advances in neonatal care have led to increased survival of infants of lower gestational age (GA). However, infants born <32 weeks of GA experience adverse respiratory outcomes, manifesting with increased respiratory symptoms, hospitalisation and health care utilisation into early childhood. The development of bronchopulmonary dysplasia (BPD) - the chronic lung disease of prematurity - further increases the risk of poor respiratory outcomes throughout childhood, into adolescence and adulthood. Indeed, survivors of preterm birth have shown increased respiratory symptoms, altered lung structure, persistent and even declining lung function throughout childhood. The mechanisms behind this persistent and sometimes progressive lung disease are unclear, and the implications place those born preterm at increased risk of respiratory morbidity into adulthood. This review aims to summarise what is known about the long-term pulmonary outcomes of contemporary preterm birth, examine the possible mechanisms of long-term respiratory morbidity in those born preterm and discuss addressing the unknowns and potentials for targeted treatments.

Health Care and Societal Costs of Bronchopulmonary Dysplasia

Despite significant technological advances and increasing survival of premature infants, bronchopulmonary dysplasia (BPD) continues to be the most prevalent major morbidity in surviving very low-birthweight infants. Infants with BPD are often sicker, require longer stays in the NICU, and accumulate greater hospital costs. However, care of the infant with BPD extends beyond the time spent in the NICU. This article reviews the costs of BPD in the health-care setting, during the initial hospitalization and beyond, and the long-term neurodevelopmental impact of BPD, as well as the impact on a family caring for a child with BPD.

Bronchopulmonary dysplasia: clinical aspects and preventive and therapeutic strategies

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the result of a complex process in which several prenatal and/or postnatal factors interfere with lower respiratory tract development, leading to a severe, lifelong disease. In this review, what is presently known regarding BPD pathogenesis, its impact on long-term pulmonary morbidity and mortality and the available preventive and therapeutic strategies are discussed.

MAIN BODY

Bronchopulmonary dysplasia is associated with persistent lung impairment later in life, significantly impacting health services because subjects with BPD have, in most cases, frequent respiratory diseases and reductions in quality of life and life expectancy. Prematurity per se is associated with an increased risk of long-term lung problems. However, in children with BPD, impairment of pulmonary structures and function is even greater, although the characterization of long-term outcomes of BPD is difficult because the adults presently available to study have received outdated treatment. Prenatal and postnatal preventive measures are extremely important to reduce the risk of BPD.

CONCLUSION

Bronchopulmonary dysplasia is a respiratory condition that presently occurs in preterm neonates and can lead to chronic respiratory problems. Although knowledge about BPD pathogenesis has significantly increased in recent years, not all of the mechanisms that lead to lung damage are completely understood, which explains why therapeutic approaches that are theoretically effective have been only partly satisfactory or useless and, in some cases, potentially negative. However, prevention of prematurity, systematic use of nonaggressive ventilator measures, avoiding supraphysiologic oxygen exposure and administration of surfactant, caffeine and vitamin A can significantly reduce the risk of BPD development. Cell therapy is the most fascinating new measure to address the lung damage due to BPD. It is desirable that ongoing studies yield positive results to definitively solve a major clinical, social and economic problem.

Respiratory morbidity was an important consequence of prematurity in the first two years after discharge in three cohorts from 1996 to 2009

AIM

This study aimed to evaluate the respiratory morbidity of preterm infants in the first two years after discharge in three cohorts from 1996 to 2009.

METHODS

We included infants with a gestational age from 25 + 0 to 29 + 6 weeks, who were born in 1996-1997, 2003-2004 and 2008-2009 at the Leiden University Medical Center in the Netherlands. The following parameters were recorded: bronchopulmonary dysplasia (BPD), defined as oxygen demand or positive pressure at 36 weeks, mortality, duration of supplemental oxygen, discharge with supplemental oxygen and a nasogastric feeding tube, rehospitalisation and the use of inhaled medication.

RESULTS

In line with our protocols, 106, 120 and 156 infants were analysed in the three study periods and 29%, 22% and 18% were diagnosed with BPD. Respiratory morbidity did not change over time in infants with and without BPD, except for an increase in rehospitalisation for respiratory issues in infants with BPD. This decreased in infants without BPD. Respiratory morbidity occurred more frequently in infants with BPD than without BPD, but this was not statistically significant.

CONCLUSION

This study showed that when cohorts of preterm infants were compared over time, respiratory morbidity in the first two years of life remained an important consequence after discharge.

Predictors of prolonged length of hospital stay or readmissions for acute viral lower respiratory tract infections among infants with a history of bronchopulmonary dysplasia

Length of hospital stay and readmissions are outcome measures that have been largely overlooked in many studies that have evaluated the clinical evolution of pediatric patients with bronchopulmonary dysplasia (BPD). The aim of the present study was to identify predictors of prolonged hospitalizations or readmissions for acute lower respiratory infections (ALRIs) in infants with BPD. In a prospective cohort study, we determined independent predictors of prolonged hospitalizations or readmissions for ALRIs during the first 2 years of life in a population of infants with BPD living in Bogota, Colombia. Of a total of 138 patients included in the study, 83 (60.1%) had at least one hospitalization for ALRI during the follow-up period. After controlling for potential confounders, we found that independent predictors of prolonged hospitalizations or readmissions for ALRIs included male gender (OR = 3.09; CI 95% 1.27-7.52; P = 0.013), ambulatory oxygen therapy between 90 and 119 days (OR = 3.21; CI 95% 1.00-10.24; P = 0.049), ambulatory oxygen therapy equal to or greater than 120 days (OR = 5.73; CI 95% 2.01-16.32; P = 0.001), gestational age at birth (OR = 1.35; CI 95% 1.03-1.76; P = 0.026), birth weight (OR = 0.997; CI 95% 0.996-0.999; P = 0.010), and duration of breastfeeding equal to or greater than 6 months (OR = 0.39; CI 95% 0.16-0.96; P = 0.039). The factors identified can be taken into account when planning policies to reduce duration of hospital stay and readmissions in infants with BPD.

Two-Year Follow-Up Outcomes of Premature Infants Enrolled in the Phase I Trial of Mesenchymal Stem Cells Transplantation for Bronchopulmonary Dysplasia

OBJECTIVE

To determine the long-term safety and outcomes of mesenchymal stem cells (MSCs) for bronchopulmonary dysplasia in premature infants enrolled in a previous phase I clinical trial up to 2 years of corrected age (CA).

STUDY DESIGN

We assessed serious adverse events, somatic growth, and respiratory and neurodevelopmental outcomes at visit 1 (4-6 months of CA), visit 2 (8-12 months of CA), and visit 3 (18-24 months of CA) in a prospective longitudinal follow-up study up to 2 years' CA of infants who received MSCs (MSC group). We compared these data with those from a historical case-matched comparison group.

RESULTS

One of 9 infants in the MSC group died of Enterobacter cloacae sepsis at 6 months of CA, the remaining 8 infants survived without any transplantation-related adverse outcomes, including tumorigenicity. No infant in the MSC group was discharged with home supplemental oxygen compared with 22% in the comparison group. The average rehospitalization rate in the MSC group was 1.4/patient because of respiratory infections during 2 years of follow-up. The mean body weight of the MSC group at visit 3 was significantly higher compared with that of the comparison group. No infant in the MSC group was diagnosed with cerebral palsy, blindness, or developmental delay; in the comparison group, 1 infant was diagnosed with cerebral palsy and 1 with developmental delay.

CONCLUSIONS

Intratracheal transplantation of MSCs in preterm infants appears to be safe, with no adverse respiratory, growth, and neurodevelopmental effects at 2 years' CA.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01632475.

Hospital-assisted home care after early discharge from a Swedish neonatal intensive care unit was safe and readmissions were rare

AIM

It is common in Sweden to discharge infants early from a neonatal intensive care unit (NICU) and provide hospital-assisted neonatal home care (HANHC), as an alternative to hospital care, for infants with a persisting need for specialised care. This study assessed the safety of HANHC by reviewing hospital readmissions.

METHODS

We retrospectively reviewed the files of all 1410 infants enrolled in HANHC at the NICU at Sachs' Children's Hospital, Stockholm, from 2002 to 2011 up until hospital readmission or their discharge from HANHC. Each readmitted infant was matched to the next HANHC infant who was not readmitted. Predictors and reasons for readmission were investigated in a retrospective nested case-control study.

RESULTS

We readmitted 74 (5.2%) of the 1410 infants in HANHC. Extremely preterm infants, born at less than 28 weeks, were readmitted more frequently than other infants, with an odds ratio of 6.07 (range 2.06-17.8). The most common symptoms were respiratory symptoms (55%), and viral respiratory tract infections were the most common reason (28%) for readmission.

CONCLUSION

HANHC was safe for the vast majority of infants (94.8%). Extremely preterm birth was identified as a predictor for hospital readmission. Further studies investigating the safety of HANHC in other settings would be valuable.

[Respiratory outcome of bronchopulmonary dysplasia in school-age children]

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of infancy. The influence of its initial severity on long-term respiratory outcome remains uncertain.

OBJECTIVES

The purpose of this study was to examine the impact of "new BPD" on respiratory morbidity as well as respiratory function at rest and during exercise in school-age children.

METHODS

The 93 preterm newborns (<33 weeks gestation) presenting with BPD between 1997 and 2004 at the Rennes University Hospital had been proposed for a specific follow-up program. The children included in this cohort and presenting without severe handicap or motor deficit were eligible for this observational retrospective study. Their standardized clinical evaluation and the results of the pulmonary function tests and cardiopulmonary exercise tests performed between the ages of 7 and 14 years were studied. BPD was considered to be moderate when respiratory or oxygen support continued at 36 weeks gestation with an FiO2 less than 30% and severe when FiO2 was greater than 30%.

RESULTS

Among the 36 children assessed, the initial severity of the BPD was mild in 12 cases, moderate in 12 cases, and severe in 12 cases. The mean age at the time of the pulmonary function test (PFT) was 9.9 (±1.9) years, 19 children (53%) had respiratory symptoms during the year before the test, and six (17%) underwent long-term treatment. The PFT was abnormal for 32 children (89%): 23 showed airway obstruction, 16 hyperinflation, three increases in bronchial reactivity, and two restrictions. The residual volume/total lung capacity ratio was the only parameter related to the severity of BPD (P<0.05). The cardiopulmonary exercise test was given to 35 children: 15 of them had normal exercise ability but with a limited ventilatory reserve.

CONCLUSIONS

Half of the children included in this "new-BPD" follow-up cohort had clinical respiratory morbidity and most of the children followed presented with persistent alterations in pulmonary function tests at school age, which were not associated with significant alterations in the maximum aerobic performance.

Bronchopulmonary Dysplasia Within and Beyond the Neonatal Unit

BACKGROUND

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease of prematurity or chronic neonatal lung disease, is a major cause of respiratory illness in premature babies. Newborn babies survive at gestational ages of 23 to 26 weeks, earlier than when BPD was first described. New mechanisms of lung injury have therefore emerged and the clinical and pathological characteristics of pulmonary involvement have changed.

PURPOSE

Improved neonatal intensive care unit modalities have increased survival rates; the overall prevalence of the condition, however, has not changed. Management of evolving BPD aims at minimizing lung injury. Management of established, especially severe BPD, still poses significant clinical challenge as these babies need long-term oxygen therapy (LTOT) for variable length of time. We aim to give an overview of management of established BPD with particular focus on weaning home oxygen therapy at our local center in the United Kingdom.

SEARCH AND RESULTS

On the basis of most recent evidence, we concluded that an integrated pathway for managing babies on LTOT is very important after discharge from neonatal unit.

IMPLICATIONS FOR PRACTICE

A structured weaning pathway for premature babies on home oxygen improves outcome.

IMPLICATIONS FOR RESEARCH

The management of severe BPD and related complications, particularly during the first 2 years of life, remains a continuing challenge for parents and healthcare providers. The most beneficial respiratory support strategy to minimize lung injury and/or promote lung healing remains unclear and requires further investigation.

Permissive hypercapnia in extremely low birthweight infants (PHELBI): a randomised controlled multicentre trial

BACKGROUND

Tolerating higher partial pressure of carbon dioxide (pCO2) in mechanically ventilated, extremely low birthweight infants might reduce ventilator-induced lung injury and bronchopulmonary dysplasia. We aimed to test the hypothesis that higher target ranges for pCO2 decrease the rate of bronchopulmonary dysplasia or death.

METHODS

In this randomised multicentre trial, we recruited infants from 16 tertiary care perinatal centres in Germany with birthweight between 400 g and 1000 g and gestational age 23-28 weeks plus 6 days, who needed endotracheal intubation and mechanical ventilation within 24 h of birth. Infants were randomly assigned to either a high target or control group. The high target group aimed at pCO2 values of 55-65 mm Hg on postnatal days 1-3, 60-70 mm Hg on days 4-6, and 65-75 mm Hg on days 7-14, and the control target at pCO2 40-50 mmHg on days 1-3, 45-55 mm Hg on days 4-6, and 50-60 mm Hg on days 7-14. The primary outcome was death or moderate to severe bronchopulmonary dysplasia, defined as need for mechanical pressure support or supplemental oxygen at 36 weeks postmenstrual age. Cranial ultrasonograms were assessed centrally by a masked paediatric radiologist. This trial is registered with the ISRCTN registry, number ISRCTN56143743.

RESULTS

Between March 1, 2008, and July 31, 2012, we recruited 362 patients of whom three dropped out, leaving 179 patients in the high target and 180 in the control group. The trial was stopped after an interim analysis (n=359). The rate of bronchopulmonary dysplasia or death in the high target group (65/179 [36%]) did not differ significantly from the control group (54/180 [30%]; p=0·18). Mortality was 25 (14%) in the high target group and 19 (11%; p=0·32) in the control group, grade 3-4 intraventricular haemorrhage was 26 (15%) and 21 (12%; p=0·30), and the rate of severe retinopathy recorded was 20 (11%) and 26 (14%; p=0·36).

INTERPRETATION

Targeting a higher pCO2 did not decrease the rate of bronchopulmonary dysplasia or death in ventilated preterm infants. The rates of mortality, intraventricular haemorrhage, and retinopathy did not differ between groups. These results suggest that higher pCO2 targets than in the slightly hypercapnic control group do not confer increased benefits such as lung protection.

FUNDING

Deutsche Forschungsgemeinschaft.

Bronchopulmonary dysplasia early changes leading to long-term consequences

Neonatal chronic lung disease, i.e., bronchopulmonary dysplasia, is characterized by impaired pulmonary development resulting from the impact of different risk factors including infections, hyperoxia, and mechanical ventilation on the immature lung. Remodeling of the extracellular matrix, apoptosis as well as altered growth factor signaling characterize the disease. The immediate consequences of these early insults have been studied in different animal models supported by results from in vitro approaches leading to the successful application of some findings to the clinical setting in the past. Nonetheless, existing information about long-term consequences of the identified early and most likely sustained changes to the developing lung is limited. Interesting results point towards a tremendous impact of these early injuries on the pulmonary repair capacity as well as aging related processes in the adult lung.

Pharmacokinetics, microbial response, and pulmonary outcomes of multidose intravenous azithromycin in preterm infants at risk for Ureaplasma respiratory colonization

The study objectives were to refine the population pharmacokinetics (PK) model, determine microbial clearance, and assess short-term pulmonary outcomes of multiple-dose azithromycin treatment in preterm infants at risk for Ureaplasma respiratory colonization. Fifteen subjects (7 of whom were Ureaplasma positive) received intravenous azithromycin at 20 mg/kg of body weight every 24 h for 3 doses. Azithromycin concentrations were determined in plasma samples obtained up to 168 h post-first dose by using a validated liquid chromatography-tandem mass spectrometry method. Respiratory samples were obtained predose and at three time points post-last dose for Ureaplasma culture, PCR, antibiotic susceptibility testing, and cytokine concentration determinations. Pharmacokinetic data from these 15 subjects as well as 25 additional subjects (who received either a single 10-mg/kg dose [n = 12] or a single 20-mg/kg dose [n = 13]) were analyzed by using a nonlinear mixed-effect population modeling (NONMEM) approach. Pulmonary outcomes were assessed at 36 weeks post-menstrual age and 6 months adjusted age. A 2-compartment model with all PK parameters allometrically scaled on body weight best described the azithromycin pharmacokinetics in preterm neonates. The population pharmacokinetics parameter estimates for clearance, central volume of distribution, intercompartmental clearance, and peripheral volume of distribution were 0.15 liters/h · kg(0.75), 1.88 liters · kg, 1.79 liters/h · kg(0.75), and 13 liters · kg, respectively. The estimated area under the concentration-time curve over 24 h (AUC24)/MIC90 value was ∼ 4 h. All posttreatment cultures were negative, and there were no drug-related adverse events. One Ureaplasma-positive infant died at 4 months of age, but no survivors were hospitalized for respiratory etiologies during the first 6 months (adjusted age). Thus, a 3-day course of 20 mg/kg/day intravenous azithromycin shows preliminary efficacy in eradicating Ureaplasma spp. from the preterm respiratory tract.

Chronic lung disease in the preterm infant. Lessons learned from animal models

Neonatal chronic lung disease, also known as bronchopulmonary dysplasia (BPD), is the most common complication of premature birth, affecting up to 30% of very low birth weight infants. Improved medical care has allowed for the survival of the most premature infants and has significantly changed the pathology of BPD from a disease marked by severe lung injury to the "new" form characterized by alveolar hypoplasia and impaired vascular development. However, increased patient survival has led to a paucity of pathologic specimens available from infants with BPD. This, combined with the lack of a system to model alveolarization in vitro, has resulted in a great need for animal models that mimic key features of the disease. To this end, a number of animal models have been created by exposing the immature lung to injuries induced by hyperoxia, mechanical stretch, and inflammation and most recently by the genetic modification of mice. These animal studies have 1) allowed insight into the mechanisms that determine alveolar growth, 2) delineated factors central to the pathogenesis of neonatal chronic lung disease, and 3) informed the development of new therapies. In this review, we summarize the key findings and limitations of the most common animal models of BPD and discuss how knowledge obtained from these studies has informed clinical care. Future studies should aim to provide a more complete understanding of the pathways that preserve and repair alveolar growth during injury, which might be translated into novel strategies to treat lung diseases in infants and adults.

Epidemiology of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is among the most common and serious sequelae of preterm birth. BPD affects at least one-quarter of infants born with birth weights less than 1500 g. The incidence of BPD increases with decreasing gestational age and birth weight. Additional important risk factors include intrauterine growth restriction, sepsis, and prolonged exposure to mechanical ventilation and supplemental oxygen. The diagnosis of BPD predicts multiple adverse outcomes including chronic respiratory impairment and neurodevelopmental delay. This review summarizes the diagnostic criteria, incidence, risk factors, and long-term outcomes of BPD.

Long-term respiratory consequences of premature birth at less than 32 weeks of gestation

Chronic respiratory morbidity is a common adverse outcome of very premature birth, particularly in infants who had developed bronchopulmonary dysplasia (BPD). Prematurely born infants who had BPD may require supplementary oxygen at home for many months and affected infants have increased healthcare utilisation until school age. Chest radiograph abnormalities are common; computed tomography of the chest gives predictive information in children with ongoing respiratory problems. Readmission to hospital is common, particularly for those who have BPD and suffer respiratory syncytial virus lower respiratory infections (RSV LRTIs). Recurrent respiratory symptoms requiring treatment are common and are associated with evidence of airways obstruction and gas trapping. Pulmonary function improves with increasing age, but children with BPD may have ongoing airflow limitation. Lung function abnormalities may be more severe in those who had RSV LRTIs, although this may partly be explained by worse premorbid lung function. Worryingly, lung function may deteriorate during the first year. Longitudinal studies are required to determine if there is catch up growth.

Cell therapy: a novel treatment approach for bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a major cause of substantial lifelong morbidity in preterm infants. Despite a better understanding of the pathophysiology of BPD and significant research effort into its management, there remains today no effective treatment. Cell-based therapy is a novel approach that offers much promise in the prevention and treatment of BPD. Recent research supports a therapeutic role for cell transplantation in the management of a variety of acute and chronic adult and childhood lung diseases, with potential of such therapy to reduce inflammation and prevent acute lung injury. However, considerable uncertainties remain regarding cell therapies before they can be established as safe and effective clinical treatments for BPD. This review summarizes the current literature investigating cell therapies in lung disease, with particular focus on the various types of cells available and their specific properties in the context of a future therapy for BPD.

Hospital readmissions for newly discharged pediatric home mechanical ventilation patients

BACKGROUND

Ventilator-dependent children have complex chronic conditions that put them at risk for acute illness and repeated hospitalizations.

OBJECTIVES

To determine the 12-month incidence of and risk factors for non-elective readmission in children with chronic respiratory failure (CRF) after initiation on home mechanical ventilation (HMV) via tracheostomy.

METHODS

A retrospective cohort study of 109 HMV patients initiated and followed at an university-affiliated children's hospital between 2003 and 2009. Patient characteristics are presented using descriptive statistics; generalized estimated equations are used to estimate adjusted odds ratios of select predictor variables for readmission.

RESULTS

The 12-month incidence of non-elective readmission was 40%. Close to half of these readmissions occurred within the first 3 months post-index discharge. Pneumonia and tracheitis were the most common reasons for readmission; 64% were pulmonary- or tracheostomy-related. Most demographic and clinical patient characteristics were not statistically associated with non-elective readmissions. Although, a change in the child's management within 7 days before discharge was associated readmissions shortly after index discharge.

CONCLUSION

Non-elective readmissions of newly initiated pediatric HMV patients were common and likely multifactorial. Many of these readmissions were airway-related, and some may have been potentially preventable.

Long term respiratory outcomes of very premature birth (<32 weeks)

Many very prematurely born infants develop bronchopulmonary dysplasia (BPD), remaining oxygen dependent for many months and requiring frequent rehospitalisations. Troublesome, recurrent respiratory symptoms requiring treatment and lung function abnormalities at follow-up are common. The most severely affected may remain symptomatic with evidence of airways obstruction even as adults. Data from adolescents and adults on the respiratory outcome of extreme prematurity, however, are usually from patients who have had 'classical' BPD with severe respiratory failure in the neonatal period. Nowadays, infants have 'new' BPD developing chronic oxygen dependence despite initially minimal or even no respiratory distress. Affected patients do suffer chronic respiratory morbidity and their lung function may deteriorate during the first year after birth. Infants who suffer respiratory syncytial virus lower respiratory tract infections are most likely to require rehospitalisation and suffer chronic respiratory morbidity, but this may reflect greater abnormal premorbid lung function.

Long-term respiratory outcome of babies born prematurely

Chronic respiratory morbidity is a common adverse outcome of premature birth, particularly in infants who develop bronchopulmonary dysplasia (BPD). Prematurely born infants who had BPD may require supplementary oxygen at home for many months, but few remain oxygen dependent beyond 2 years of age. Readmission to hospital is common, particularly for those who had BPD, but only in the first 2 years after birth. The readmissions are usually for respiratory problems, particularly respiratory syncytial virus lower respiratory infections. Recurrent respiratory symptoms requiring treatment are common, particularly in those who had BPD, even at school age and in adolescence. Affected children have evidence of airways obstruction. Pulmonary function does improve with age, but children with BPD may have ongoing airflow limitation. Computed tomography of the chest gives helpful information at follow up of patients with ongoing respiratory problems who had BPD.

Clinical predictors and institutional variation in home oxygen use in preterm infants

OBJECTIVE

To assess home oxygen use in preterm infants, identify risk factors predicting home oxygen use, and quantify the extent of institutional variation in home oxygen use across neonatal intensive care units.

STUDY DESIGN

We conducted a retrospective cohort analysis of surviving infants of 23- to 31-week gestational age discharged home in 2009, with de-identified electronic medical record information from the Pediatrix Clinical Data Warehouse. Mixed-effects logistic regression quantified clinical risk factors and institutional variation affecting home oxygen use.

RESULTS

A total of 8167 infants were identified. Home oxygen use varied by gestational age, from 59% of infants 23 to 24 weeks gestational age to 7% of infants 29 to 31 weeks gestational age. Other risk factors included small for gestational age, congenital anomalies, mechanical ventilation in the first 72 hours, fraction of inhaled oxygen >0.4 in the first 72 hours, and patent ductus arteriosus. After adjusting for clinical risk factors, there was still a 4- to 5-fold difference in institutions' odds of home oxygen use.

CONCLUSIONS

Home oxygen use was common in infants of earlier gestational ages and infants with more severe respiratory illness. Institutional variation accounted for 4- to 5-fold variation in home oxygen use. Families should be counseled about the likelihood of home oxygen use, and prospective research must identify optimal treatment strategies for high-risk infants.

Respiratory morbidity, healthcare utilisation and cost of care at school age related to home oxygen status

The aim of the study was to determine whether respiratory morbidity, lung function, healthcare utilisation and cost of care at school age in prematurely born children who had bronchopulmonary dysplasia (BPD) were influenced by use of supplementary oxygen at home after neonatal intensive care unit discharge. Healthcare utilisation and cost of care in years 5 to 7 and respiratory morbidity (parent-completed respiratory questionnaire) and lung function measurements at least at age 8 years were assessed in 160 children. Their median gestational age was 27 (range 22-31) weeks and 65 of them had received supplementary oxygen when discharged home (home oxygen group). The home oxygen group had more outpatient attendances (p = 0.0168) and respiratory-related outpatient attendances (p = 0.0032) with greater related cost of care (p = 0.0186 and p = 0.0030, respectively), their cost of care for prescriptions (p = 0.0409) and total respiratory related cost of care (p = 0.0354) were significantly greater. There were, however, no significant differences in cough, wheeze or lung function results between the two groups.

CONCLUSION

Prematurely born children who had BPD and supplementary oxygen at home after discharge had increased healthcare utilisation at school age. Whether such children require greater follow, in the absence of excess respiratory morbidity, merits investigation.

Preterm birth and respiratory disease in later life

Chronic respiratory diseases are a common complication of preterm birth, particularly among very immature infants or those suffering from bronchopulmonary dysplasia. Major progress in the treatment of preterm newborns has changed the pattern of late respiratory complications. The major respiratory problem in infancy and early childhood is respiratory exacerbations caused by infections (particularly viral ones), which need hospitalization. The symptoms become mild in school-age children; however, a group of children still present with chronic airway obstruction defined by recurrent episodes of wheezing and decreased lung function tests (decreased forced expiratory volume). For some preterm infants, particularly those with bronchopulmonary dysplasia, obstructive lung disease persists into adulthood. They are very likely to develop chronic obstructive pulmonary disease or similar disease later in life. In these patients, a program of lung function monitoring and pulmonary prophylaxis by means of elimination of specific risk factors in adulthood is advisable.

Domiciliary oxygen for children

Domiciliary oxygen is used increasingly in pediatric practice, and the largest patient group to receive it is ex-premature babies with chronic neonatal lung disease. Because of a scarcity of good evidence to inform clinicians, there is a lack of consensus over many issues, even those as fundamental as the optimum target oxygen saturation. Nevertheless, many children benefit from receiving supplemental oxygen at home, particularly because it helps to keep them out of the hospital.

Emerging drugs for the prevention of bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a common adverse outcome of very premature birth and is associated with chronic respiratory morbidity.

OBJECTIVE

To determine if there were preventative therapies proven safe and efficacious in appropriately powered randomised trials.

METHODS

A literature review was undertaken.

RESULTS

Systemically administered corticosteroids, if given in the first 2 weeks, do significantly reduce BPD but have serious side effects. Vitamin A also reduces BPD, but has side effects, and further investigation is needed to identify the safest dosage regimen. There are, however, promising therapies that include antioxidants, low-dose nitric oxide and methylxanthines.

CONCLUSION

Further work is necessary to identify safe and effective preventative drugs for BPD.

RESPIRATORY DISTRESS SYNDROME

Respiratory Distress Syndrome (RDS) is due to immaturity of the lungs, primarily the surfactant synthesising system; hence, the risk of RDS is inversely proportional to gestational age. The incidence of RDS has been reduced by the routine use of both antenatal corticosteroids and postnatal surfactant, but still approximately one per cent of babies develop RDS. Hyaline membranes, formed from plasma proteins which have leaked onto the lung surface through damaged capillaries and endothelial cells, line the terminal airways. Hence, RDS has also been called hyaline membrane disease, but RDS is the preferred name as the presence of hyaline membranes can only be confirmed histologically. The aim of this review is to emphasize the pathophysiology of RDS and the clinical presentation and relevance of diagnostic techniques in the current population of very prematurely born infants, highlighting the differential diagnosis. In addition, the evidence base for prophylactic and management strategies including whether new therapies and techniques of respiratory support have positively impacted on outcomes are discussed. The mortality and long term morbidity associated with very premature birth are described. Our increasing understanding that the so-called new bronchopulmonary dysplasia (BPD) and associated chronic adverse respiratory outcomes in such infants can reflect antenatal events resulting in abnormal lung growth is highlighted.

Surfactant-replacement therapy for respiratory distress in the preterm and term neonate

Respiratory failure secondary to surfactant deficiency is a major cause of morbidity and mortality in preterm infants. Surfactant therapy substantially reduces mortality and respiratory morbidity for this population. Secondary surfactant deficiency also contributes to acute respiratory morbidity in late-preterm and term neonates with meconium aspiration syndrome, pneumonia/sepsis, and perhaps pulmonary hemorrhage; surfactant replacement may be beneficial for these infants. This statement summarizes indications, administration, formulations, and outcomes for surfactant-replacement therapy. The impact of antenatal steroids and continuous positive airway pressure on outcomes and surfactant use in preterm infants is reviewed. Because respiratory insufficiency may be a component of multiorgan dysfunction, preterm and term infants receiving surfactant-replacement therapy should be managed in facilities with technical and clinical expertise to administer surfactant and provide multisystem support.

Late respiratory outcomes after preterm birth

Chronic respiratory morbidity is common following premature birth, particularly if complicated by bronchopulmonary dysplasia (BPD) development. Affected patients can remain oxygen dependent for many months, but unusually beyond two years. Those requiring supplementary oxygen at home have increased healthcare utilisation, even during the preschool years when no longer oxygen dependent. More than 50% of "BPD" patients require readmission in the first two years, particularly for respiratory infections. Prematurely born children, especially those who had BPD, are more likely to suffer frequent troublesome symptoms at school age and in adolescence than term born controls. This is associated with evidence of airways obstruction. Although lung function improves as the clinical condition improves, abnormalities can be detected even in young adults who had severe BPD. Nowadays, severe BPD is uncommon, but those with "new" BPD may have abnormal antenatal lung growth, whether they achieve appropriate catch up lung growth needs careful investigation.

Sleeping position, oxygen saturation and lung volume in convalescent, prematurely born infants

OBJECTIVE

To determine whether the effects of sleeping position on lung volume and oxygenation are influenced by postmenstrual age (PMA) and oxygen dependency in convalescent prematurely born infants.

DESIGN

Prospective study.

SETTING

Tertiary neonatal unit.

PATIENTS

41 infants (21 oxygen dependent), median gestational age 28 weeks (range 24-31 weeks) and birth weight 1120 g (range 556-1780 g).

INTERVENTION

Infants were studied both supine and prone at two-weekly intervals from 32 weeks' PMA until discharge. Each posture was maintained for 1 h.

MAIN OUTCOME MEASURES

Pulse oximeter oxygen saturation (Spo(2)) was monitored continuously, and at the end of each hourly period functional residual capacity (FRC) was measured.

RESULTS

Overall, lung volumes were higher in the prone position throughout the study period; there was no significant effect of PMA on lung volumes. Overall, Spo(2) was higher in the prone position (p = 0.02), and the effect was significant in the oxygen-dependent infants (p = 0.03) (mean difference in Spo(2) between prone and supine was 1.02%, 95% CI 0.11% to 1.92%), but not in the non-oxygen-dependent infants. There was no significant influence of PMA on Spo(2).

CONCLUSION

In the present study, prone sleeping did not improve oxygenation in prematurely born infants, 32 weeks' PMA or older and with no ongoing respiratory problems. However, the infants were monitored in each position for an hour, thus it is recommended that oxygen saturation should continue to be monitored after 32 weeks' PMA to be certain that longer periods of supine sleeping are not associated with loss of lung volume and hypoxaemia.

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.

End-tidal carbon monoxide levels in prematurely born infants developing bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is associated with an early inflammatory response that persists after the first week of life. Inflammatory mediators can induce hemoxygenase-1 with a consequent increase in carbon monoxide (CO) production. End-tidal CO (ETCO) levels would be elevated in infants developing BPD. Serial measurements of ETCO levels were attempted on d 3, 5, 7, 14, 21, and 28 in 50 prematurely born infants (median gestational age 29 wk). Fourteen infants developed BPD [oxygen dependent beyond 36 wk post-menstrual age (PMA)] and had higher ETCO levels compared with the rest of the cohort on d 7, 14, 21, and 28. On d 14, the mean (SD) ETCO levels of the BPD group were 3.19 (1.11) ppm and 1.43 (0.61) ppm in the non-BPD group (p<0.001). An ETCO level on d 14>2.15 ppm had a sensitivity of 80% and specificity of 92% in predicting oxygen dependency at 36 wk PMA. Measurement of ETCO levels in prematurely born infants may be useful in the prediction of BPD.

A scoring system to predict chronic oxygen dependency

INTRODUCTION

Chronic oxygen dependency (COD) is a common adverse outcome of very premature birth. It is, therefore, important to develop an accurate and simple predictive test to facilitate targeting of interventions to prevent COD. Our aim was to determine if a simple score based on respiratory support requirements predicted COD development.

METHODS

A retrospective study of 136 infants, median gestation age (GA) 28 weeks (range: 23-33 weeks) and a prospective study of 75 infants, median GA 30 weeks (range: 23-32 weeks), were performed. The score was calculated by multiplying the inspired oxygen concentration by the level of respiratory support (mechanical ventilation: 2.5; continuous positive airway pressure: 1.5; nasal cannula or head box oxygen or air: 1.0). Scores were calculated on data from days 2 and 7, and their predictive ability compared to that of the maximum inspired oxygen concentration at those ages and (retrospective study) the results of lung volume measurement.

RESULTS

Infants that were oxygen dependent at 28 days and 36 weeks post-menstrual age (PMA) had higher scores on days 2 (p<0.0001, p<0.0001, respectively) and 7 (p<0.0001, p<0.0001, respectively) than the non-oxygen dependent infants in both the retrospective and prospective cohorts. Construction of receiver operator characteristic curves demonstrated the score performed better than the inspired oxygen level and lung volume measurement results. A score on day 7 >0.323 had 95% specificity and 78% sensitivity in predicting COD at 28 days, and 80% specificity and 73% sensitivity in predicting COD at 36 weeks PMA.

CONCLUSION

Chronic oxygen dependency can be predicted using a simple scoring system.