Effect of bronchodilators on forced expiratory volume in 1 s in preterm-born participants aged 5 and over: a systematic review

Unravelling the respiratory health path across the lifespan for survivors of preterm birth

Many survivors of preterm birth will have abnormal lung development, reduced peak lung function and, potentially, an increased rate of physiological lung function decline, each of which places them at increased risk of chronic obstructive pulmonary disease across the lifespan. Current rates of preterm birth indicate that by the year 2040, around 50 years since the introduction of surfactant therapy, more than 700 million individuals will have been born prematurely-a number that will continue to increase by about 15 million annually. In this Personal View, we describe current understanding of the impact of preterm birth on lung function through the life course, with the aim of putting this emerging health crisis on the radar for the respiratory community. We detail the potential underlying mechanisms of prematurity-associated lung disease and review current approaches to prevention and management. Furthermore, we propose a novel way of considering lung disease after preterm birth, using a multidimensional model to determine individual phenotypes of lung disease-a first step towards optimising management approaches for prematurity-associated lung disease.

Oscillometry and spirometry are not interchangeable when assessing the bronchodilator response in children and young adults born preterm

INTRODUCTION

The European Respiratory Society Oscillometry Taskforce identified that clinical correlates of bronchodilator responses are needed to advance oscillometry in clinical practice. The understanding of bronchodilator-induced oscillometry changes in preterm lung disease is poor. Here we describe a comparison of bronchodilator assessments performed using oscillometry and spirometry in a population born very preterm and explore the relationship between bronchodilator-induced changes in respiratory function and clinical outcomes.

METHODS

Participants aged 6-23 born ≤32 (N = 288; 132 with bronchopulmonary dysplasia) and ≥37 weeks' gestation (N = 76, term-born controls) performed spirometry and oscillometry. A significant bronchodilator response (BDR) to 400 μg salbutamol was classified according to published criteria.

RESULTS

A BDR was identified in 30.9% (n = 85) of preterm-born individuals via spirometry and/or oscillometry, with poor agreement between spirometry and oscillometry definitions (k = 0.26; 95% confidence interval [CI] 0.18-0.40, p < .001). Those born preterm with a BDR by oscillometry but not spirometry had increased wheeze (33% vs. 11%, p = .010) and baseline resistance (Rrs5 z-score mean difference (MD) = 0.86, 95% CI 0.07-1.65, p = .025), but similar baseline spirometry to the group without a BDR (forced expiratory volume in 1 s [FEV1 ] z-score MD = -0.01, 95% CI -0.66 to 0.68, p > .999). Oscillometry was more feasible than spirometry (95% success rate vs. 85% (FEV1 ), 69% (forced vital capacity) success rate, p < .001), however being born preterm did not affect test feasibility.

CONCLUSION

In the preterm population, oscillometry is a feasible and clinically useful supportive test to assess the airway response to inhaled salbutamol. Changes measured by oscillometry reflect related but distinct physiological changes to those measured by spirometry, and thus these tests should not be used interchangeably.

Lung function deficits and bronchodilator responsiveness at 12 years of age in children born very preterm compared with controls born at term

INTRODUCTION

Very preterm birth is associated with lung function impairment later in life, but several aspects have not been studied. We aimed to comprehensively assess lung function at school age in very preterm infants and term controls, with special emphasis on bronchopulmonary dysplasia (BPD), sex, and bronchodilator response.

METHODS

At 12 years of age, 136 children born very preterm (85 with and 51 without BPD) and 56 children born at term performed spirometry, body plethysmography, impulse oscillometry, measurement of diffusion capacity, and multiple breath washout, before and after bronchodilator inhalation.

RESULTS

Airway symptoms and a diagnosis of asthma were more common in children born very preterm. These children had more airflow limitation, seen as lower forced expiratory volume in 1 s (FEV1 ) (p < .001), FEV1 /forced vital capacity (FVC) (p = .011), and mean forced expiratory flow between 25% and 75% of FVC (p < .001), and a higher total and peripheral airway resistance compared with term-born controls. There was no difference in total lung capacity but air trapping and lung clearance index were higher in children born very preterm. Diffusion capacity was lower in children born very preterm, especially in those with a diagnosis of BPD. In most other tests, the differences between preterm-born children with or without BPD were smaller than between children born preterm versus at term. Boys born preterm had more lung function deficits than preterm-born girls. In children born very preterm, airway obstruction was to a large extent reversible.

CONCLUSION

At 12 years of age, children born very preterm had lower lung function than children born at term in most aspects and there was only little difference between children with or without BPD. Airway obstruction improved markedly after bronchodilator inhalation.

Pharmacotherapy of BPD: Current status & future perspectives

Bronchopulmonary dysplasia (BPD) is a disease exclusive to prematurity and has changed in its definition since Northway first described it in 1967. There have been countless clinical trials evaluating the efficacy of drugs in the treatment and prevention of BPD in human subjects, and an even larger number of animal studies. Despite these, only a handful of drugs are used at the bedside today, primarily due to the lack of consistent efficacy seen in clinical trials or due to reports of adverse effects. This review summarizes the list of the most commonly used drugs and emerging new therapies which target BPD and BPD-related pulmonary hypertension (BPD-PH), including those which have shown promise in human trials but are not yet used routinely.

Characterising airway obstructive, dysanaptic and PRISm phenotypes of prematurity-associated lung disease

INTRODUCTION

Although obstructive airway disease has been shown to be associated with prematurity, other spirometry phenotypes are less well described.

OBJECTIVES

We characterised abnormal spirometry phenotypes in preterm-born children, including prematurity-associated obstructive lung disease (POLD, forced expiratory volume in 1 s (FEV1)

METHODS

768 children, aged 7-12 years, underwent FENO measurements and spirometry before and after salbutamol. Groups were compared using parametric tests; multinomial regression was used.

RESULTS

22.6% of 544 preterm-born (mean gestation: 31 weeks) and 9.2% of 195 term-born children, with satisfactory data available, were classified into one of four abnormal spirometry groups. Each phenotype was generally more prevalent in preterm-born children than in the term-born children. For the preterm group, POLD-reversible (4.4%) was associated with increased FENO, bronchopulmonary dysplasia (BPD) and intrauterine growth restriction. POLD-fixed group (3.3%) did not have increased FENO but was associated with BPD. 41% of the pDysanapsis group (5.9%) had bronchodilator response, 31% had increased FENO and was associated with postnatal weight gain. In the pPRISm group (9%), 13% responded to bronchodilators, FENO was not increased and was non-significantly associated with body mass index (p=0.064).

CONCLUSIONS

Further to airway obstruction, we describe airway dysanapsis and pPRISm spirometry phenotypes in survivors of prematurity, both of which have poor outlook in other disease groups. By identifying specific phenotypes, targeted therapy can be developed to improve long-term outcomes.

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Key Words

• paediatric lung disaese

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MESH Headings

• Humans
• Infant, Newborn
• Bronchodilator Agents/therapeutic use
• Bronchopulmonary Dysplasia/complications
• Forced Expiratory Volume/physiology
• Lung
• Lung Diseases, Obstructive
• Pulmonary Disease, Chronic Obstructive
• Spirometry
• Vital Capacity/physiology
• Premature Birth
• Infant, Premature

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Grants

• MR/M022552/1 Medical Research Council

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Affiliation(s)

Michael Cousins Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
Kylie Hart Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
Sarah J Kotecha Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
A John Henderson MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
W John Watkins Department of Child Health, Cardiff University School of Medicine, Cardiff, UK
Andrew Bush Centre for Paediatrics and Child Health, Imperial College of Medicine, London, UK
Sailesh Kotecha Department of Child Health, Cardiff University School of Medicine, Cardiff, UK

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Prematurity-associated wheeze: current knowledge and opportunities for further investigation

Prematurity-associated wheeze is a common complication of preterm birth, with significant impact on the health and healthcare utilization of former preterm infants. This wheezing phenotype remains poorly understood and difficult to predict. This review will discuss the current state of the literature on prematurity-associated wheeze. We will discuss etiology and pathophysiology, and offer two conceptual models for the pathogenesis of this complex condition. This review will also identify current methods of ascertainment, and discuss the strengths and limitations of each. We will explore research-backed approaches to prevention and management, and finally suggest both pre-clinical and clinical avenues for investigation. An in-depth understanding of prematurity-associated wheeze will aid clinicians in its diagnosis and management, and inspire scientists to pursue much-needed further study into causes and prevention of this common and impactful condition. IMPACT: There is no recent, concise review on the current state of research on prematurity-associated wheeze, which is a rapidly evolving area of study. This article highlights causal models of wheeze, methods of ascertainment, management strategies for the clinician, and opportunities for further research for the physician scientist.

Lung mechanics and respiratory morbidities in school-age children born moderate-to-late preterm

BACKGROUND

Late and moderate prematurity may have an impact on pulmonary function during childhood. The present study aimed to investigate lung mechanics in school-age children born moderate-to-late preterm (MLPT).

METHODS

Children aged 5-10 years were enrolled in this case-control study. Lung function and bronchodilator response were assessed by impulse oscillometry (IOS) at two hospital-based specialized clinics. A structured questionnaire was employed to assess respiratory morbidities.

RESULTS

A total of 123 children was divided into two groups: case (MLPT) n = 52 and control (children born at term) n = 71. The results showed no difference between groups in mean baseline IOS variables: R5 0.80 ± 0.20 vs 0.82 ± 0.22 kPa/L/s, p = 0.594, R20 0.54 ± 0.13 vs 0.55 ± 0.13 kPa/L/s, p = 0.732, R5-R20 0.26 ± 0.12 vs 0.27 ± 0.15 kPa/L/s, p = 0.615, X5 -0.29 ± 0.01 vs -0.29 ± 0.1 kPa/L/s, p = 0.990, Fres 21.1 ± 3.3 vs 21.7 ± 3.1 L/s, p = 0.380, and AX 2.7 ± 3.36 vs 2.5 ± 1.31 kPa/L/s, p = 0.626. Bronchodilator response and the occurrence of respiratory morbidities after birth were also similar between groups.

CONCLUSIONS

This study found lung mechanics parameters to be similar in school-age children born MLPT and those born at term, suggesting that pulmonary plasticity continues to occur in children up to school age.

IMPACT

Late and moderate prematurity is associated with an increased risk of reduced pulmonary function during childhood. Follow-up reports in adolescents and adults born MLPT are scarce but have indicated pulmonary plasticity with normalization of airway function. Our results show that the lung function in school-age children born MLPT is similar to that of children born at term.

Pharmacotherapy in Bronchopulmonary Dysplasia: What Is the Evidence?

Bronchopulmonary Dysplasia (BPD) is a multifactorial disease affecting over 35% of extremely preterm infants born each year. Despite the advances made in understanding the pathogenesis of this disease over the last five decades, BPD remains one of the major causes of morbidity and mortality in this population, and the incidence of the disease increases with decreasing gestational age. As inflammation is one of the key drivers in the pathogenesis, it has been targeted by majority of pharmacological and non-pharmacological methods to prevent BPD. Most extremely premature infants receive a myriad of medications during their stay in the neonatal intensive care unit in an effort to prevent or manage BPD, with corticosteroids, caffeine, and diuretics being the most commonly used medications. However, there is no consensus regarding their use and benefits in this population. This review summarizes the available literature regarding these medications and aims to provide neonatologists and neonatal providers with evidence-based recommendations.

Inhaled Corticosteroids Alone and in Combination With Long-Acting β2 Receptor Agonists to Treat Reduced Lung Function in Preterm-Born Children: A Randomized Clinical Trial

Importance

Decreases in future lung function are a hallmark of preterm birth, but studies for management of decreased lung function are limited.

Objective

To determine whether 12 weeks of treatment with inhaled corticosteroids (ICS) alone or in combination with long-acting β2 agonists (LABA) improves spirometry and exercise capacity in school-aged preterm-born children who had percent predicted forced expiratory volume in 1 second (%FEV1) less than or equal to 85% compared with inhaled placebo treatment.

Design, Setting, and Participants

A double-blind, randomized, placebo-controlled trial was conducted to evaluate ICS and ICS/LABA against placebo. Preterm-born children (age, 7-12 years; gestation ≤34 weeks at birth) who did not have clinically significant congenital, cardiopulmonary, or neurodevelopmental abnormalities underwent spirometry, exercise testing, and measurement of fractional exhaled nitric oxide before and after treatment. A total of 144 preterm-born children at the Children's Hospital for Wales in Cardiff, UK, were identified and enrolled between July 1, 2017, and August 31, 2019.

Interventions

Each child was randomized to 1 of 3 cohorts: fluticasone propionate, 50 μg, with placebo; fluticasone propionate, 50 μg, with salmeterol, 25 μg; or placebo inhalers, all given as 2 puffs twice daily for 12 weeks. Children receiving preexisting ICS treatment underwent washout prior to randomization to ICS or ICS/LABA.

Main Outcomes and Measures

The primary outcome was between-group differences assessed by adjusted pretreatment and posttreatment differences of %FEV1 using analysis of covariance. Intention-to-treat analysis was conducted.

Results

Of 144 preterm-born children who were identified with %FEV1 less than or equal to 85%, 53 were randomized. Treatment allocation was 20 children receiving ICS (including 5 with prerandomization ICS), 19 children receiving ICS/LABA (including 4 with prerandomization ICS), and 14 children receiving placebo. The mean (SD) age of children was 10.8 (1.2) years, and 29 of the randomized children (55%) were female. The posttreatment %FEV1 was adjusted for sex, gestation, bronchopulmonary dysplasia, intrauterine growth restriction, pretreatment corticosteroid status, treatment group, and pretreatment values. Posttreatment adjusted means for %FEV1, using analysis of covariance, were 7.7% (95% CI, -0.27% to 15.72%; P = .16) higher in the ICS group and 14.1% (95% CI, 7.3% to 21.0%; P = .002) higher in the ICS/LABA group compared with the placebo group. Active treatment decreased the fractional exhaled nitric oxide and improved postexercise bronchodilator response but did not improve exercise capacity. One child developed cough when starting inhaler treatment; no other adverse events reported during the trial could be attributed to the inhaler treatment.

Conclusions and Relevance

The results of this randomized clinical trial suggest that combined ICS/LABA treatment is beneficial for prematurity-associated lung disease in children.

Trial Registration

EudraCT number: 2015-003712-20.

Outpatient Respiratory Management of Infants, Children, and Adolescents with Post-Prematurity Respiratory Disease: An Official American Thoracic Society Clinical Practice Guideline

Background: Premature birth affects millions of neonates each year, placing them at risk for respiratory disease due to prematurity. Bronchopulmonary dysplasia is the most common chronic lung disease of infancy, but recent data suggest that even premature infants who do not meet the strict definition of bronchopulmonary dysplasia can develop adverse pulmonary outcomes later in life. This post-prematurity respiratory disease (PPRD) manifests as chronic respiratory symptoms, including cough, recurrent wheezing, exercise limitation, and reduced pulmonary function. This document provides an evidence-based clinical practice guideline on the outpatient management of infants, children, and adolescents with PPRD. Methods: A multidisciplinary panel of experts posed questions regarding the outpatient management of PPRD. We conducted a systematic review of the relevant literature. The Grading of Recommendations, Assessment, Development, and Evaluation approach was used to rate the quality of evidence and the strength of the clinical recommendations. Results: The panel members considered the strength of each recommendation and evaluated the benefits and risks of applying the intervention. In formulating the recommendations, the panel considered patient and caregiver values, the cost of care, and feasibility. Recommendations were developed for or against three common medical therapies and four diagnostic evaluations in the context of the outpatient management of PPRD. Conclusions: The panel developed recommendations for the outpatient management of patients with PPRD on the basis of limited evidence and expert opinion. Important areas for future research were identified.

Wheezing in preterm infants and children

Wheezing is a common outcome of preterm birth. This article will review the mechanisms, epidemiology, and treatment of wheezing in preterm children with and without a history of bronchopulmonary dysplasia.

Multimodal longitudinal respiratory function assessment in very low birth weight 7-year-old children

PURPOSE

Preterm birth is associated with adverse pulmonary outcomes. We aimed to evaluate respiratory morbidities and lung function of very low birth weight (VLBW) Polish children followed up at the age of 7 years old, and to compare with electrical impedance segmentography (EIS) results recorded at 4 years of age.

MATERIALS AND METHODS

VLBW children were compared with term controls using impulse oscillometry and spirometry. Perinatal data and current respiratory morbidities were analyzed and pulmonary function test results were compared with previous EIS results.

RESULTS

We included 40 VLBW children and 30 controls in the analysis. Elevated total airway resistance and forced expiratory volume in the first second below the lower limit of normal were more prevalent in VLBW children compared with term controls (15 vs 0%; 18 vs 0%). A positive bronchodilator response was more common in VLBW children (R_{5 Hz}: 46 vs 13.3%; R_5-20 ​Hz: 65 vs 36.7%). Children with bronchopulmonary dysplasia (BPD) had higher total airway resistance (R_{5 Hz}/R_{5 Hz pred}: 1.35 vs 0.95; p ​< ​0.001), large airway resistance (R_{20 Hz}/R_{20 Hz pred}: 0.89 vs 0.66; p ​= ​0.001), small airway resistance (R_5-20 ​Hz: 0.57 vs 0.34 ​kPa ​L^-1 ​s^-1; p ​= ​0.009), than controls. Strong correlation between BDR in EIS and R_{5 Hz}/R_{5 Hz pred} was observed in children with BPD (r ​= ​0.7).

CONCLUSION

VLBW school-aged children with BPD presented with substantial respiratory morbidity and persistent reduction of lung function, affecting small and large airways and lung parenchyma. EIS may be an alternative tool for lung function assessment in children with BPD.

Tracheomalacia in bronchopulmonary dysplasia: Trachealis hyper-relaxant responses to S-nitrosoglutathione in a hyperoxic murine model

BACKGROUND

Bronchopulmonary dysplasia (BPD) with airway hyperreactivity is a long-term pulmonary complication of prematurity. The endogenous nonadrenergic, noncholinergic signaling molecule, S-nitrosoglutathione (GSNO) and its catabolism by GSNO reductase (GSNOR) modulate airway reactivity. Tracheomalacia is a major, underinvestigated complication of BPD. We studied trachealis, left main bronchus (LB), and intrapulmonary bronchiolar (IPB) relaxant responses to GSNO in a murine hyperoxic BPD model.

METHODS

Wild-type (WT) or GSNOR knockout (KO) newborn mice were raised in 60% (BPD) or 21% (control) oxygen during the first 3 weeks of life. After room air recovery, adult trachealis, LB, and IPB smooth muscle relaxant responses to GSNO (after methacholine preconstriction) were studied using wire myographs. Studies were repeated after GSNOR inhibitor (GSNORi) pretreatment and in KO mice.

RESULTS

GSNO relaxed all airway preparations. GSNO relaxed WT BPD trachealis substantially more than WT controls (P < .05). Pharmacologic or genetic ablation of GSNOR abolished the exaggerated BPD tracheal relaxation to GSNO and also augmented BPD IPB relaxation to GSNO. LB ring contractility was not significantly different between groups or conditions. Additionally, GSNORi treatment induced relaxation of WT IPBs but not trachealis or LB.

CONCLUSION

GSNO dramatically relaxed the trachealis in our BPD model, an effect paradoxically reversed by loss of GSNOR. Conversely, GSNOR inhibition augmented IBP relaxation. These data suggest that GSNOR inhibition could benefit both the BPD trachealis and distal airways, restoring relaxant responses to those of room air controls. Because therapeutic options are limited in this high-risk population, future studies of GSNOR inhibition are needed.

Fractional exhaled nitric oxide in preterm-born subjects: A systematic review and meta-analysis

BACKGROUND

Decreased lung function is common in preterm-born survivors. Increased fractional exhaled nitric oxide (FeNO) appears to be a reliable test for eosinophillic airway inflammation especially in asthma. We, systematically, reviewed the literature to compare FeNO levels in preterm-born children and adults who did or did not have chronic lung disease of prematurity (CLD) in infancy with term-born controls.

METHODS

We searched eight databases up to February 2018. Studies comparing FeNO levels in preterm-born subjects (<37 weeks' gestation) in childhood and adulthood with and without (CLD) with term-born subjects were identified and extracted by two reviewers. Data were analysed using Review Manager v5.3.

RESULTS

From 6042 article titles, 183 full articles were screened for inclusion. Nineteen studies met the inclusion criteria. Seventeen studies compared FeNO levels in preterm- and term-born children and adults; 11 studies (preterm n = 640 and term n = 4005) were included in a meta-analysis. The mean FeNO concentration difference between the preterm-born and term-born group was -0.74 (95% CI -1.88 to 0.41) ppb. For the six studies reporting data on CLD (preterm n = 204 and term n = 211) the mean difference for FeNO levels was -2.82 (95% CI -5.87 to 0.22) ppb between the preterm-born CLD and term-born groups.

CONCLUSIONS

Our data suggest that preterm born children with and without CLD have similar FeNO levels to term-born children suggesting an alternative mechanism to eosinophilic inflammation for symptoms of wheezing and airway obstruction observed in preterm-born subjects.

Comparison of the Associations of Early-Life Factors on Wheezing Phenotypes in Preterm-Born Children and Term-Born Children

Although respiratory symptoms, including wheezing, are common in preterm-born subjects, the natural history of the wheezing phenotypes and the influence of early-life factors and characteristics on phenotypes are unclear. Participants from the Millennium Cohort Study who were born between 2000 and 2002 were studied at 9 months and at 3, 5, 7, and 11 years. We used data-driven methods to define wheezing phenotypes in preterm-born children and investigated whether the association of early-life factors and characteristics with wheezing phenotypes was similar between preterm- and term-born children. A total of 1,049/1,502 (70%) preterm-born children and 12,307/17,063 (72%) term-born children had recent wheeze data for 3 or 4 time points. Recent wheeze was more common at all time points in the preterm-born group than in term-born group. Four wheezing phenotypes were defined for both groups: no/infrequent, early, persistent, and late. Early-life factors and characteristics, especially antenatal maternal smoking, atopy, and male sex, were associated with increased rates for all phenotypes in both groups, and breastfeeding was protective in both groups, except late wheeze in the preterm group. Preterm-born children had similar phenotypes to term-born children. Although early-life factors and characteristics were similarly associated with the wheezing phenotypes in both groups, the preterm-born group had higher rates of early and persistent wheeze. However, a large proportion of preterm-born children had early wheeze that resolved with time.

Bronchial hyper-responsiveness in preterm-born subjects: A systematic review and meta-analysis

BACKGROUND

Preterm-born survivors have increased respiratory symptoms and decreased lung function, but the nature of bronchial hyper-responsiveness (BHR) is unclear. We conducted a systematic review and meta-analysis for BHR in preterm-born survivors including those with and without chronic lung disease in infancy (CLD) comparing results to term-born subjects.

METHODS

We searched eight databases up to December 2016. Included articles compared BHR in preterm-born and term-born subjects. Studies reporting BHR as decreases in forced expiratory volume in 1 second (FEV₁ ) after provocation stimuli were included. The analysis used Review Manager V5.3.

RESULTS

From 10 638 titles, 265 full articles were screened, and 28 included in a descriptive analysis. Eighteen articles were included in a meta-analysis as they reported the proportion of subjects who had BHR. Pooled odds ratio (OR) estimates (95% confidence interval) for BHR comparing the preterm and term-born groups was 1.88 (1.32, 2.66). The majority of the studies reported BHR after a methacholine challenge or an exercise test. Odds ratio was 1.89 (1.12, 3.19) after methacholine challenge and 2.59 (1.50, 4.50) after an exercise test. Nine of fifteen articles reporting BHR in CLD subjects were included in a meta-analysis. Differences for BHR including for methacholine (OR 4.35; 2.36, 8.03) and exercise (OR 5.13; 1.82, 14.47) were greater in the CLD group compared to the term group.

CONCLUSIONS

Preterm-born subjects especially those who had CLD had increased rates of BHR to direct (methacholine) and indirect (exercise) stimuli compared to term-born subjects suggesting subgroups might benefit from anti-inflammatory or bronchodilator therapies.

Adults born preterm: a review of general health and system-specific outcomes

In this review of 126 publications, we report that an overwhelming majority of adults born at preterm gestations remain healthy and well. However, a small, but a significant fraction of them remain at higher risk for neurological, personality and behavioural abnormalities, cardio-pulmonary functional limitations, systemic hypertension and metabolic syndrome compared to their term-born counterparts. The magnitude of increased risk differed across organ systems and varied across reports. The risks were proportional to the degree of prematurity at birth and seemed to occur more frequently among preterm infants born in the final two decades of the 20th century and later. These findings have considerable public health and clinical practice relevance.

CONCLUSION

Preterm birth needs to be considered a chronic condition, with a slight increase in the risk for long-term morbidities among adults born preterm. Therefore, obtaining a history of gestational age and weight at birth should be a routine part of care for patients of all age groups.

Management of Prematurity-Associated Wheeze and Its Association with Atopy

Introduction

Although preterm birth is associated with respiratory morbidity in childhood, the role of family history of atopy and whether appropriate treatment has been instituted is unclear. Thus we assessed (i) the prevalence of respiratory symptoms, particularly wheezing, in childhood; (ii) evaluated the role of family history of atopy and mode of delivery, and (iii) documented the drug usage, all in preterm-born children compared to term-born control children.

Methods

We conducted a cross-sectional population-based questionnaire study of 1–10 year-old preterm-born children (n = 13,361) and matched term-born controls (13,361). Data (n = 7,149) was analysed by gestational groups (24–32 weeks, 33–34 weeks, 35–36 weeks and 37–43 weeks) and by age, <5 years old or ≥ 5 years.

Main Results

Preterm born children aged <5 years (n = 2,111, term n = 1,402) had higher rates of wheeze-ever [odds ratio: 2.7 (95% confidence intervals 2.2, 3.3); 1.8 (1.5, 2.2); 1.5 (1.3, 1.8) respectively for the 24–32 weeks, 33–34 weeks, 35–36 weeks groups compared to term]. Similarly for the ≥5 year age group (n = 2,083, term n = 1,456) wheezing increased with increasing prematurity [odds ratios 3.3 (2.7, 4.1), 1.8 (1.5, 2.3) and 1.6 (1.3, 1.9) for the three preterm groups compared to term]. At both age groups, inhaler usage was greater in the lowest preterm group but prematurity-associated wheeze was independent of a family history of atopy.

Conclusions

Increasing prematurity was associated with increased respiratory symptoms, which were independent of a family history of atopy. Use of bronchodilators was also increased in the preterm groups but its efficacy needs careful evaluation.

Response to bronchodilators in very preterm infants with evolving bronchopulmonary dysplasia

BACKGROUND

There are few effective and safe medications to treat very low birth weight (VLBW) infants with evolving BPD. Bronchodilators are often given to patients who have clinical signs of reactive airway disease, but there is not enough information regarding their effectiveness within this population.

OBJECTIVE

To quantify the pulmonary function response to bronchodilator therapy in a population of VLBW infants with evolving BPD.

DESIGN/METHODS

This is a retrospective analysis of an ongoing large database of pulmonary function tests (PFTs) in premature infants. We reviewed pre and post bronchodilator PFTs ordered by a physician due to concern for reactive airway disease. Inclusion criteria: BW< 1500 grams; > 14 days of age; admission diagnosis of respiratory distress syndrome; requiring ongoing oxygen, CPAP or ventilator support at the time of PFT. PFTs were done prior to albuterol therapy and repeated 30 minutes after the therapy was given. PFTs included the measurement of passive respiratory mechanics with the single breath occlusion technique, including passive respiratory compliance (Crs), resistance (Rrs) and tidal volume (Vt).

RESULTS

40 VLBW infants (mean gestation of 27.4 weeks; mean birth weight (BW) of 848 grams) were identified as having PFTs. 29 of these patients had a BW of ≤ 1000 grams. Patients were studied at a mean corrected gestational age of 34.9 weeks. 29 of 40 were extubated at the time of the PFT. Of these patients, 21 (52.5%) had a decrease in Rrs of ≥10%. From the other 19 patients, 5 (12.5%) had a decrease of 0 to < 10% in Rrs, 14 (35%) showed no response to therapy. There was no significant difference in Crs between groups.