Pulmonary and extrapulmonary features in bronchopulmonary dysplasia: a comparison with healthy children

Preterm birth and exercise capacity: what do we currently know?

Objectives

The long-term cardiopulmonary outcomes following preterm birth during the surfactant era remain unclear. Respiratory symptoms, particularly exertional symptoms, are common in preterm children. Therefore, cardiopulmonary exercise testing may provide insights into the pathophysiology driving exertional respiratory symptoms in those born preterm. This review aims to outline the current knowledge of cardiopulmonary exercise testing in the assessment of children born preterm in the surfactant era.

Design

This study is a narrative literature review.

Methods

Published manuscripts concerning the assessment of pulmonary outcomes using cardiopulmonary exercise testing in preterm children (aged <18 years) were reviewed. Search terms related to preterm birth, bronchopulmonary dysplasia, and exercise were entered into electronic databases, including Medline, PubMed, and Google Scholar. Reference lists from included studies were scanned for additional manuscripts.

Results

Preterm children have disrupted lung development with significant structural and functional lung disease and increased respiratory symptoms. The association between these (resting) assessments of respiratory health and exercise capacity is unclear; however, expiratory flow limitation and an altered ventilatory response (rapid, shallow breathing) are seen during exercise. Due to the heterogeneity of participants, treatments, and exercise protocols, the effect of the aforementioned limitations on exercise capacity in children born preterm is conflicting and poorly understood.

Conclusion

Risk factors for reduced exercise capacity in those born preterm remain poorly understood; however, utilizing cardiopulmonary exercise testing to its full potential, the pathophysiology of exercise limitation in survivors of preterm birth will enhance our understanding of the role exercise may play. The role of exercise interventions in mitigating the risk of chronic disease and premature death following preterm birth has yet to be fully realized and should be a focus of future robust randomized controlled trials.

Validity and reliability of the behavioral signs of respiratory instability (BSRI) © scale during activity for infants with bronchopulmonary dysplasia

OBJECTIVE

There is no reliable evidence on how best to evaluate the overall status of infants with severe forms of bronchopulmonary dysplasia (BPD). The Behavioral Signs of Respiratory Instability (BSRI) scale was developed as an objective measure of developmental capacity during occupational and physical therapy sessions. The purpose of this study was to determine the psychometric properties of the BSRI Scale.

STUDY DESIGN

The BSRI and Respiratory Severity Score (RSS) were compared for 25 infants with BPD and 15 infants without BPD. A cross-sectional design was used to test inter-rater reliability among 10 NICU occupational and physical therapists. A prospective cohort design was used to evaluate validity.

RESULTS

The BSRI demonstrated good to excellent inter-rater reliability (ρ = 0.47-0.91) and was strongly correlated with RSS (ρ = -0.77, p < 0.001; concurrent validity).

CONCLUSION

The BSRI Scale has preliminary psychometric support. Standardized measures like the BSRI may provide accurate, objective data that can improve care planning within interdisciplinary teams that supports brain growth and potentially improves neurodevelopment.

Increasing airway obstruction through life following bronchopulmonary dysplasia: a meta-analysis

Background

Few studies exist investigating lung function trajectories of those born preterm; however growing evidence suggests some individuals experience increasing airway obstruction throughout life. Here we use the studies identified in a recent systematic review to provide the first meta-analysis investigating the impact of preterm birth on airway obstruction measured by the forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) ratio.

Methods

Cohorts were included for analysis if they reported FEV1/FVC in survivors of preterm birth (<37 weeks' gestation) and control populations born at term. Meta-analysis was performed using a random effect model, expressed as standardised mean difference (SMD). Meta-regression was conducted using age and birth year as moderators.

Results

55 cohorts were eligible, 35 of which defined groups with bronchopulmonary dysplasia (BPD). Compared to control populations born at term, lower values of FEV1/FVC were seen in all individuals born preterm (SMD -0.56), with greater differences seen in those with BPD (SMD -0.87) than those without BPD (SMD -0.45). Meta-regression identified age as a significant predictor of FEV1/FVC in those with BPD with the FEV1/FVC ratio moving -0.04 sds away from the term control population for every year of increased age.

Conclusions

Survivors of preterm birth have significantly increased airway obstruction compared to those born at term with larger differences in those with BPD. Increased age is associated with a decline in FEV1/FVC values suggesting increased airway obstruction over the life course.

Influence of bronchopulmonary dysplasia on lung function in adolescents who were born extremely prematurely

OBJECTIVES

To assess if a previous diagnosis of bronchopulmonary dysplasia (BPD) was associated with poorer lung function at 16 to 19 years of age, regardless of whether postnatal corticosteroids had been administered.

WORKING HYPOTHESIS

Infants with BPD will have poorer lung function at 16 to 19 years of age.

STUDY DESIGN

Prospective follow-up study.

PATIENT-SUBJECT SELECTION

One hundred and sixty-one participants aged between 16 and 19 years who were born at less than 29 weeks of gestation; 87 had had BPD.

METHODOLOGY

Lung function was assessed by spirometry (FEV₁ , FVC, FEV₁ /FVC, FEF₇₅ , FEF₅₀ , FEF₂₅ , FEF_{25 -75} , PEF), impulse oscillometry (R5Hz and R20Hz), plethysmography (FRC_pleth , TLC_pleth , RV_pleth ), diffusion capacity of the lungs for carbon monoxide (D_L CO, D_L CO/VA) and lung clearance index (LCI). Questionnaires were used to quantify respiratory symptoms and a shuttle sprint test to assess exercise capacity.

RESULTS

At 16 to 19 years, those who had had a diagnosis of BPD had poorer airway function (FEV₁ , FEF₇₅ , FEF₅₀ , FEF_{25 -75} ) compared to those without. FVC and D_L CO were also poorer in those who had BPD. Those differences remained significant after adjusting for sex, gestational age, and maternal smoking. When excluding those who had received postnatal corticosteroids, differences remained significant in FEV₁ , FVC, and FEF₇₅ . There were no significant differences in exercise capacity or respiratory symptoms between those with and without BPD.

CONCLUSIONS

In adolescents and young adults born prematurely, those who had BPD had poorer lung function compared to those without, regardless of whether they had received postnatal corticosteroids.

Geographical Differences and Temporal Improvements in Forced Expiratory Volume in 1 Second of Preterm-Born Children: A Systematic Review and Meta-analysis

Importance

Although preterm birth is associated with later deficits in lung function, there is a paucity of information on geographical differences and whether improvements occur over time, especially after surfactant was introduced.

Objective

To determine deficits in percentage predicted forced expiratory volume in 1 second (%FEV1) in preterm-born study participants, including those with bronchopulmonary dysplasia (BPD) in infancy, when compared with term-born control groups.

Data Sources

Eight databases searched up to December 2021.

Study Selection

Studies reporting spirometry for preterm-born participants with or without a term-born control group were identified.

Data Extraction and Synthesis

Data were extracted and quality assessed by 1 reviewer and checked by another. Data were pooled using random-effects models and analyzed using Review Manager and the R metafor package.

Main Outcomes and Measures

Deficits in %FEV1 between preterm-born and term groups. Associations between deficits in %FEV1 and year of birth, age, introduction of surfactant therapy, and geographical region of birth and residence were also assessed.

Results

From 16 856 titles, 685 full articles were screened: 86 with and without term-born control groups were included. Fifty studies with term controls were combined with the 36 studies from our previous systematic review, including 7094 preterm-born and 17 700 term-born participants. Of these studies, 45 included preterm-born children without BPD, 29 reported on BPD28 (supplemental oxygen dependency at 28 days), 26 reported on BPD36 (supplemental oxygen dependency at 36 weeks' postmenstrual age), and 86 included preterm-born participants. Compared with the term-born group, the group of all preterm-born participants (all preterm) had deficits of %FEV1 of -9.2%; those without BPD had deficits of -5.8%, and those with BPD had deficits of approximately -16% regardless of whether they had BPD28 or BPD36. As year of birth increased, there was a statistically significant narrowing of the difference in mean %FEV1 between the preterm- and term-born groups for the all preterm group and the 3 BPD groups but not for the preterm-born group without BPD. For the all BPD group, when compared with Scandinavia, North America and western Europe had deficits of -5.5% (95% CI, -10.7 to -0.3; P = .04) and -4.1% (95% CI, -8.8 to 0.5; P = .08), respectively.

Conclusions and Relevance

Values for the measure %FEV1 were reduced in preterm-born survivors. There were improvements in %FEV1 over recent years, but geographical region had an association with later %FEV1 for the BPD groups.

Lung abnormalities do not influence aerobic capacity in school children born preterm

PURPOSE

Children born preterm have impaired lung function and altered lung structure. However, there are conflicting reports on how preterm birth impacts aerobic exercise capacity in childhood. We aimed to investigate how neonatal history and a diagnosis of bronchopulmonary dysplasia (BPD) impact the relationship between function and structure of the lung, and aerobic capacity in school-aged children born very preterm.

METHODS

Preterm children (≤ 32 w completed gestation) aged 9-12 years with (n = 38) and without (n = 35) BPD, and term-born controls (n = 31), underwent spirometry, lung volume measurements, gas transfer capacity, a high-resolution computer tomography (CT) scan of the chest, and an incremental treadmill exercise test.

RESULTS

Children born preterm with BPD had an elevated breathing frequency to tidal volume ratio compared to term controls (76% vs 63%, p = 0.002). The majority (88%) of preterm children had structural changes on CT scan. There were no differences in peak V̇O₂ (47.1 vs 47.7 mL/kg/min, p = 0.407) or oxygen uptake efficiency slope when corrected for body weight (67.6 vs 67.3, p = 0.5) between preterm children with BPD and term controls. There were no differences in any other exercise outcomes. The severity of structural lung disease was not associated with exercise outcomes in this preterm population.

CONCLUSION

Children born preterm have impaired lung function, and a high prevalence of structural lung abnormalities. However, abnormal lung function and structure do not appear to impact on the aerobic exercise capacity of preterm children at school age.

Exercise capacity in children with bronchopulmonary dysplasia at school age

OBJECTIVE

To assess the exercise capacity, exercise habits, and lung function of preterm born children with bronchopulmonary dysplasia (BPD) compared to term born controls at school age.

METHODS

Cardiopulmonary exercise test (CPET) by cycle ergometer and pulmonary function test were performed in children with BPD (n = 42) and compared with a term born control group (n = 42). Daily activity, participation in sports and respiratory symptoms were assessed by questionnaire.

RESULTS

Children with BPD versus controls had significantly lower values for oxygen consumption (V̇O₂ [mL/min] 1442 ± 417 vs. 1766 ± 541), minute ventilation (VE [L/min] 48 ± 14.92 vs. 60 ± 18.33), and workload (W [watt] 96.1 ± 16.7 vs. 110.6 ± 17.2) at peak exercise and a lower anaerobic threshold (VO₂ AT [mL/min] 1183 ± 345 vs. 1382 ± 398). When corrected for weight, only for the workload (2.7 ± 0.5 vs. 3.1 ± 0.5, p = 0.0013) did significant differences persist. The forced expiratory volume in 1 s and forced expiratory flow between 25 and 75% of expired forced vital capacity were significantly reduced in the BPD group (p < 0.0001). Children with BPD have a higher risk of reporting difficulties in physical activity (OR 2.5) and of suffering from wheezing or shortness of breath while exercising (OR 2.5).

CONCLUSION

Compared to term born controls, children with BPD at school age show airflow obstruction, a lower workload in CPET, and more respiratory symptoms related to physical activity. The comparable oxygen consumption based on weight suggests a functionally normal alveolar compartment.

One-minute sit-to-stand test as an alternative tool to assess the quadriceps muscle strength in children

BACKGROUND

Clinical tools for assessment of the skeletal muscle strength are scarce and have rarely been validated in children. The aims of this study were to verify the construct validity of the one-minute sit-to-stand test (1-MSTST) to evaluate the quadriceps strength in healthy children between 12 and 18 years old and to correlate these outcomes with the anthropometric parameters.

METHODS

Healthy children were recruited and consecutively performed 1-MSTST and maximal voluntary contraction of the quadriceps (QMVC).

RESULTS

Eighty-three children (15±2 years old) were analyzed. Contrarily to the QMVC, neither the number of 1-MSTST repetitions nor the sit-to-stand work (1-MSTST expressed as the product of body weight) differed between genders. The QMVC was not correlated with the number of repetitions (rho=-0.056; P=0.617) but correlated with 1-MSTST when expressed as a product of body weight (r=0.491; P<0.001). The QMVC was also correlated with age (r=0.314; P=0.004), height (r=0.672; P<0.001), weight (r=0.721; P<0.001) and BMI (r=0.451; P<0.001) whereas 1-MSTST did not correlate with any of these parameters. The leg length was related to the results of both tests.

CONCLUSION

We demonstrated that the one-minute sit-to-stand test can be considered as a valid and valuable alternative to evaluate the muscle strength when expressed as the product of body weight.

Lifelong pulmonary sequelae of bronchopulmonary dysplasia

PURPOSE OF REVIEW

To summarize the current literature evaluating long-term pulmonary morbidity among surviving very preterm infants with bronchopulmonary dysplasia (BPD).

RECENT FINDINGS

BPD predisposes very preterm infants to adverse respiratory signs and symptoms, greater respiratory medication use, and more frequent need for rehospitalization throughout early childhood. Reassuringly, studies also indicate that older children and adolescents with BPD experience, on average, similar functional status and quality of life when compared to former very preterm infants without BPD. However, measured deficits in pulmonary function may persist in those with BPD and indicate an increased susceptibility to early-onset chronic obstructive pulmonary disease during adulthood. Moreover, subtle differences in exercise tolerance and activity may put survivors with BPD at further risk of future morbidity in later life.

SUMMARY

Despite advances in neonatal respiratory care, a diagnosis of BPD continues to be associated with significant pulmonary morbidity over the first two decades of life. Long-term longitudinal studies are needed to determine if recent survivors of BPD will also be at increased risk of debilitating pulmonary disease in adulthood.

Association of sport participation in preterm and full term born children and body and fat mass indices from age 3 to 14 years

OBJECTIVES

To assess the association of gestational age groups (VP: <32 weeks, MP: 32-33 weeks, LP: 34-36 weeks and FT: ≥37 weeks of gestation) and club sport participation in childhood on body mass index (BMI), fat free mass index (FFMI) and fat mass index (FMI).

DESIGN

Longitudinal, cross sectional.

METHODS

BMI (age 3, 5, 7, 11 and 14 years; N=10581-14702) and FFMI/FMI (age 7, 11 and 14 years; N=10446-12996) and consistent club sport participation at age 5, 7 and 11 years (ranging from never participating to participating at all three ages) were assessed prospectively. These were compared by gestational age and their associations with BMI and FMI were investigated, while controlling for confounders (socio-economic, maternal obesity, child related, diet).

RESULTS

BMI and FFMI was lower in VP or MP until age 7, but no differences were found in BMI, FFMI or FMI after age 11 with regard to gestational age. Consistent club sport participation from age 5-11 was unrelated to BMI at ages 3-7. However, FT children with club sport participation had lower BMI and FMI at ages 11 and 14; but this association was not found in VP or MP.

CONCLUSIONS

During adolescence body composition of VP and MP become similar to FT born peers. Consistent sport participation reduces BMI and FMI in FT only. In VP or MP children modifying effects of sport on body composition might not be detected due to the catch-up growth in weight, height and fat mass at the same time.

An update on pulmonary and neurodevelopmental outcomes of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a common complication of extreme prematurity, and its rate is not improving, despite advances in perinatal intensive care. Children with BPD diagnosed in the neonatal period have higher risks for hospitalizations for respiratory problems over the first few years of life, and they have more asthma in later childhood. Neonates diagnosed with BPD have substantial airway obstruction on lung function testing in later childhood and early adulthood, and many are destined to develop adult chronic obstructive pulmonary disease. Survivors with neonatal BPD have more adverse motor function, worse cognitive development and poorer academic progress than those without BPD. Long-term outcomes for children born extremely preterm will improve if the rate of BPD can be substantially reduced.

Effect of foetal and infant growth and body composition on respiratory outcomes in preterm-born children

Body composition and growth outcomes of preterm-born subjects have been studied by many researchers. In general, preterm-born children have lower height and weight especially in infancy. Despite showing potential for catch-up growth, they continue to lag behind their term counterparts in adolescence and adulthood. The various methods of studying body composition and the differing gestations and ages at which it is assessed may go some way to explaining the inconsistent results observed in different studies. In addition, there is a paucity of data on the effects of foetal and infant growth and of body composition on later respiratory outcomes. In largely term-born subjects, foetal growth and growth trajectories appear to have differential effects on later respiratory outcomes. Early weight gain in infancy appears to be associated with increased respiratory symptoms in childhood but catch-up growth in infancy appears to be associated with possible improved lung function status.

The Impact of Bronchopulmonary Dysplasia on Childhood Outcomes

The rate of bronchopulmonary dysplasia (BPD) in preterm infants is increasing; this trend reflects, in part, improved survival among extremely premature infants. BPD is associated with adverse developmental and medical outcomes in early childhood and at least through school age. Therefore, BPD imposes a significant burden on infants and children, their families, and society. Many interventions to decrease BPD and the sequelae of BPD have been studied; few to date have been proved to decrease both BPD and later disability.

Pulmonary sequelae and functional limitations in children and adults with bronchopulmonary dysplasia

Preterm infants with bronchopulmonary dysplasia (BPD) often suffer from life-long pulmonary impairments in pulmonary physical function. This review summarizes our current understanding of the chronic pulmonary impairments and physical functional limitations associated with BPD from preterm birth to adulthood. It also identifies opportunities for intervention in children and adults living with chronic lung disease (CLD) after preterm birth.

Development of severe bronchopulmonary dysplasia is associated with alterations in fecal volatile organic compounds

BackgroundThe aim of this study was to evaluate the potential of fecal volatile organic compounds (VOCs), obtained by means of an electronic nose device (Cyranose 320), as early non-invasive biomarker for BPD.MethodsIn this nested case-control study performed at three Neonatal Intensive Care Units, fecal samples obtained at postnatal age of 7, 14, 21, and 28 days from preterm infants with severe bronchopulmonary dysplasia (BPD) were compared with fecal VOC profiles from matched controls. Microbiota analysis was performed by means of IS-pro technique on fecal samples collected at 28 days postnatally.ResultsVOC profiles of infants developing severe BPD (n=15) could be discriminated from matched controls (n=15) at postnatal age of 14 days (area under the curve (±95% confidence interval), P-value, sensitivity, specificity; 0.72 (0.54-0.90), 0.040, 60.0%, 73.3%), 21 days (0.71 (0.52-0.90), 0.049, 66.7%, 73.3%) and 28 days (0.77 (0.59-0.96), 0.017, 69.2%, 69.2%) but not at 7 days. Intestinal microbiota did not differ between BPD subjects and controls.ConclusionFecal VOC profiles of infants developing BPD could be differentiated from controls at postnatal day 14, 21, and 28. VOC differences could not be directed to intestinal microbiota alterations but presumably reflect local and systemic metabolic and inflammatory pathways associated with BPD.

Recent advances in our understanding of the mechanisms of late lung development and bronchopulmonary dysplasia

The objective of lung development is to generate an organ of gas exchange that provides both a thin gas diffusion barrier and a large gas diffusion surface area, which concomitantly generates a steep gas diffusion concentration gradient. As such, the lung is perfectly structured to undertake the function of gas exchange: a large number of small alveoli provide extensive surface area within the limited volume of the lung, and a delicate alveolo-capillary barrier brings circulating blood into close proximity to the inspired air. Efficient movement of inspired air and circulating blood through the conducting airways and conducting vessels, respectively, generates steep oxygen and carbon dioxide concentration gradients across the alveolo-capillary barrier, providing ideal conditions for effective diffusion of both gases during breathing. The development of the gas exchange apparatus of the lung occurs during the second phase of lung development-namely, late lung development-which includes the canalicular, saccular, and alveolar stages of lung development. It is during these stages of lung development that preterm-born infants are delivered, when the lung is not yet competent for effective gas exchange. These infants may develop bronchopulmonary dysplasia (BPD), a syndrome complicated by disturbances to the development of the alveoli and the pulmonary vasculature. It is the objective of this review to update the reader about recent developments that further our understanding of the mechanisms of lung alveolarization and vascularization and the pathogenesis of BPD and other neonatal lung diseases that feature lung hypoplasia.

Physical activity outcomes following preterm birth

Physical activity (PA) is an important mediator of health and disease. Many correlates may play an important role in explaining differences in PA between populations; however, the role of birth outcomes such as prematurity on levels of PA is relatively poorly represented in the literature. Children born preterm may be at risk for reduced levels of PA as they have increased respiratory symptoms as well as decrements in lung function and exercise capacity. Emerging evidence suggests that the effects are prevalent across the whole range of gestational age. This review summarises the current literature in regards to levels of PA in preterm-born children and also explores PA in cohorts of young adults in order to contextualise the possible impact on long term risks to respiratory health.