Functional capacity during exercise in very-low-birth-weight premature children

The HYdrocortisone for Bronchopulmonary Dysplasia Respiratory and Developmental (HYBRiD) outcomes study: protocol for a longitudinal cohort study

BACKGROUND

Bronchopulmonary dysplasia (BPD) affects up to half of extremely preterm infants, and is associated with adverse long-term respiratory, neurodevelopmental, and educational sequelae and costly health service and family economic outcomes. The NICHD Neonatal Research Network Hydrocortisone for Bronchopulmonary Dysplasia (BPD) Trial evaluated the efficacy and safety of hydrocortisone treatment to prevent BPD in high-risk infants. The trial enrolled 800 very preterm infants with respiratory failure and followed the participants until 2 years corrected age to assess safety of the trial intervention. Longer-term impacts of hydrocortisone exposure and severity of BPD on functional outcomes of high-risk infants remain unknown. The HYdrocortisone for BPD Respiratory and Developmental (HYBRiD) Outcomes Study extends follow-up of all surviving children enrolled in the Hydrocortisone for BPD Trial until early school age. It aims to characterize the childhood functional motor, cognitive, academic, and pulmonary outcomes of this large, well-phenotyped trial cohort.

METHODS

Parents of surviving trial participants complete telephone questionnaires when their children are 3 and 4 years corrected age. A single in-person study visit takes place at early school age (5 years, 0 months to 7 years, 11 months corrected age). Children undergo a multidimensional assessment of functional outcomes and parents complete a battery of questionnaires. In 5 of 19 participating centers, respiratory mechanics are evaluated with impulse oscillometry.

DISCUSSION

The HYBRiD Outcomes Study will be the largest and most comprehensive evaluation to date of the functional early school age outcomes of children with a history of severe neonatal lung disease and of children exposed to HC during infancy. This will substantially improve understanding of the longer-term implications of severe neonatal lung disease; provide data to facilitate the development of future randomized intervention trials in this population; and inform public policy by enhancing knowledge about school age resource requirements in children with a history of prematurity and lung disease.

TRIAL REGISTRATION

clinicaltrials.gov ID NCT01353313. Primary trial registration 5/11/11 modified to include followup through school age 12/13/17. This manuscript reflects version 3 of the trial manuscript, dated 10/12/2020.

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.

Functional capacity and quality of life in children and adolescents with sickle cell anemia

OBJECTIVE

To evaluate the functional and exercise capacity, lung function, quality of life of children and adolescents with sickle cell anemia (SCA HbSS) and to test the reproducibility of functional capacity tests in this population.

METHOD

Cross-sectional study with volunteers with SCA Hb-SS (SCAG), aged 6-18 years matched in age and gender to the control group (CG) with healthy individuals. Spirometry, 5-repetition sit-to-stand test (5STS-test), modified shuttle test (MST), and Pediatric Quality of Life Questionnaire (PedsQL) were performed. The reproducibility of 5STS-test and MST was evaluated: RESULTS: Forty eight volunteers of SCAG and 48 of CG were evaluated. Lung function of SCAG (FVC: 92 ± 15% pred.; FEV₁ /FVC: 84 ± 8% pred.) was worse than the CG (104 ± 15% pred.; FEV₁ /FVC: 90 ± 6% pred.) p < 0.05. SCAG had worse functional capacity registered by distance walked: 576 m (515-672 m) and 5STS-test: 8 s (7.4-8.9 s) compared with the CG who showed distance walked: 1010 m (887-1219 m) and 5STS-test: 7 s (7.0-8.1 s), p < 0.001. SCAG had worse quality of life compared to CG, p < 0.05. The reproducibility of MST (ICC 0.99 (0.98-0.99 IC-95%)) and 5STS-test (ICC 0.80 (0.69-0.88) was considered good, p < 0.001.

CONCLUSION

Children and adolescents with sickle cell anemia presented worse capacity to walk or run, and to perform sit-to-stand test when compared with their control peers. Additionally, they have poorer quality of life. The MST and 5STS-test showed good reproducibility to be applied in pediatric individuals with SCA.

Is the modified shuttle test a maximal effort test in children and adolescents with asthma?

PURPOSE

Whether the modified shuttle test (MST) achieves maximal effort in children and adolescents with asthma is unclear. The aim was to compare the physiological responses of MST to the cardiopulmonary exercise test (CPET) in pediatric patients with asthma, to observe its convergent validity.

PATIENTS AND METHODS

A cross-sectional study with volunteers with asthma (6-17 years of age) under regular treatment. The MST is an external-paced test, and the participants were allowed to walk/run. CPET was performed on a cycle ergometer to compare with MST. Gas exchange (VO₂ , VCO₂ , and VE) and heart rate (HR) were the outcomes and were continuously assessed in both tests.

RESULTS

Forty-seven volunteers were included, normal lung function expiratory forced volume at 1st second/forced vital capacity (FEV₁ /FVC) 88.6 (7.7). VO_2peak was higher at MST (2.0 ± 0.6 L/min) compared to CPET (1.6 ± 0.5 L/min), p < 0.001. Similar results was observed to VE at MST (50 ± 16 L/min) versus VE at CPET (40 ± 13 L/min), and to VCO₂ at MST (2.1 ± 0.8 L/min) versus VCO₂ at CPET (1.7 ± 0.6 L/min), p < 0.001. HR was also higher at MST (94 ± 6%pred) versus CPET (87 ± 8%pred), p = 0.002. VO_2peak in MST correlated to the CPET (r = 0.78, p < 0.001). The ICC of VO_2peak between tests was 0.73 (0.06-0.89), p < 0.001, and VO_2peak Bland-Altman analysis showed a bias of 0.46 L/min.

CONCLUSION

The MST showed a maximal physiologic response in children and adolescents with asthma. It is a valid test and can be used as an alternative to evaluating exercise capacity.

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.

Evolution of Muscular Oxygenation during a Walking Test in Preterm Children

OBJECTIVE

To explore measures of peripheral muscular oxygenation, coupled to gait characteristics, between preterm and full-term children during a 6-minute walking test (6MWT).

STUDY DESIGN

Prepubescent children performed a 6MWT. During the test, changes in muscular oxyhemoglobin, deoxyhemoglobin, and total hemoglobin were measured with Near-infrared spectroscopy technology, positioned on subjects' calves. Gait variables were monitored with the OptoGait system.

RESULTS

Forty-five children (33 full-term children and 12 preterm children, mean age, 4.9 ± 0.7 and 4.6 ± 0.9 years, respectively) participated in this study. Statistical analysis highlighted a decreased walking performance for preterm children, with significantly lower walking distance (P < .05) than children born full-term (405.1 ± 91.8 m vs 461.0 ± 73.3 m respectively; -9%). A concomitant increase of oxygen extraction (over the time course of Variation of desoxyhemoglobin) was observed from the third minute of the test (P < .05). No statistically significant difference was found for other near-infrared spectroscopy measures. Finally, the analysis of gait variables highlighted a group effect for walking speed (P < .05) and stride length (P < .01).

CONCLUSIONS

Premature children showed decreased walking performance and greater change in peripheral muscular oxygen extraction, associated with slower walking speed and stride length. This may point to a muscular maladjustment and reduced functional capacities for children born preterm. These phenomena could be responsible for greater muscular fatigue.

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 between thoracic musculoskeletal abnormalities and lung function in preterm infants

INTRODUCTION

In view of the difficulties and risks of performing lung function tests in infants and the hypothesis that children with abnormal pulmonary test may exhibit thoracic musculoskeletal alterations.

OBJECTIVES

This study aimed to determine the frequency of abnormal lung function and their relationship.

MATERIALS AND METHODS

This was a cross-sectional study with children from 6 to 12 months of corrected age, born at a gestational age of <37 weeks and with a birthweight ≤1500 g, who were subjected to a lung function test and photogrammetry--an objective and non-invasive procedure. To verify the association between the thoracic musculoskeletal abnormalities and measure changes in lung function, univariate linear regression was used. The level of statistical significance was setted at P < 0.05.

RESULTS

Of the 38 infants, 12 (31.6%) exhibited abnormal lung function, including 9 (23.7%) with obstructive function and 3 (7.9%) with restrictive function. A significant association was noted between forced expiratory volume at 0.5 second <-2 z score and the acromion/xiphoid process/acromion angle (β = 4.935); forced vital capacity <-2 z score and the angle of the manubrium/left acromion/trapezium (β = 0.033) and forced expiratory volume at 0.5 second and forced vital capacity ratio <-2 z score and the inframammillary point/xiphoid process/inframammillary point angle (β = 0.043).

CONCLUSION

Preterm infants with very low birthweight presented a high frequency of abnormal lung function, particularly obstructive type and thoracic musculoskeletal abnormalities were associated with changes in lung function.

Aerobic Capacity of Preterm Children with Very Low Birth Weight at School Age and its Associated Factors

INTRODUCTION

Respiratory morbidities of preterm infants can cause significant ventilatory impairment thus compromising the aerobic capacity in childhood and adolescence. Therefore, the present study was conducted to evaluate the aerobic capacity in school age preterm children with VLBW and its associated factors.

METHODS

A cross-sectional study was conducted among preterm born with VLBW and term children, both aged 6-9 years. An individualized symptom-limited treadmill testing protocol performed aerobic capacity. Measured variables: oxygen pulse (PuO₂), percentage of maximum heart rate for age (%HR max), tidal volume/inspiratory capacity ratio (TV/IC), oxygen consumption (VO₂) peak, and the ratio of the anaerobic threshold of gas exchange to the predicted percentage of maximum VO₂ (VO₂@LA/%VO₂ max.pred.) were compared between groups. Univariate and multiple linear regression analyses were used to determine the factors associated with aerobic capacity.

RESULTS

Thirty-four preterm and 32 term children were included. Similar VO₂ peak and the other variables were observed. The development of bronchopulmonary dysplasia (BPD) and being obese/overweight was positively associated with %HR max. The Z-score for height/age and birth weight <1000g was positively associated with PuO₂ and peak VO₂, and negatively associated with overweight/obesity and female sex.

CONCLUSIONS

Aerobic capacity was similar in both groups. Sex, development of BPD, birth weight <1000g and factors related to body growth, such as Z-score for height/age and overweight/obesity, were associated with aerobic capacity in preterm children with VLBW.

In silico profiling the interaction mechanism of 2,5-diketopiperazine derivatives as oxytocin antagonists

Oxytocin plays a vital role in the occurrence of preterm birth by interacting with oxytocin receptor (OTR), and thus OTR antagonists provide effective approaches for the treatment of early birth. Presently, for purpose of exploring the structural traits affecting the antagonism potency, the up-to-date largest set of 121 2,5-diketopiperazine derivatives as OTR antagonists was subjected to ligand-based three-dimensional quantitative structure-activity (3D-QSAR) analysis applying comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods. The resultant optimal CoMSIA model displays proper validity and predictability with cross-validated correlation coefficient Q² = 0.614, non-cross-validated correlation coefficient R²_ncv = 0.969 and predicted correlation coefficient R²_pre = 0.912 for the test set of compounds, respectively. In addition, docking study was carried out for further elucidating the binding modes of OTR antagonists. The final docking cavity was located among the TM2-TM7 helices of the target protein and proved to be the same as described by other scholars' researches of other type of OTR antagonists. The major amino acids forming the cavity are Q92, Q96, K116, Q119, V120, M123, G196, I201, Q295, W288, F311 and M315. Representative compound 118 forms two H-bonds with Q119 and two H-bonds with Q295, with also a π - π stacking effect with F311, respectively. Meanwhile, as a supplementary tool to study the antagonists' conformation in the binding cavity, molecular dynamics (MD) simulation was also performed to further elucidate the changes in the ligand-receptor complex. We hope that the obtained models and information may help to provide an insight into the interaction mechanism of OTR antagonists and facilitate the design and optimization of novel antagonists for preventing premature birth.

Lima L, Silva AM, Camargos ACR, Neves CDC, Lacerda ACR, Leite HR. Cardiorespiratory and metabolic responses and reference equation validation to predict peak oxygen uptake for the incremental shuttle waking test in adolescent boys

BACKGROUND

Previous studies speculated that the Incremental Shuttle Walking Test (ISWT) is a maximal test in children and adolescents, however comparison between ISWT with cardiopulmonary exercise test has not yet performed. Furthermore, there is no regression equation available in the current literature to predict oxygen peak consumption (VO2 peak) in this population. This study aimed to assesses and correlate the cardiorespiratory responses of the ISWT with the cardiopulmonary exercise (CEPT) and to develop and validate a regression equation to predict VO2 peak in healthy sedentary adolescent boys.

METHODS

Forty-one participants were included in the study. In the first stage, the VO2 peak, respiratory exchange ratio (R peak), heart rate max (HR max) and percentage of predicted HR max (% predicted HR max) were evaluated in CEPT and ISWT (n = 26). Second, an equation was developed (n = 29) to predict VO2 peak. In both phases, the VO2 peak, respiratory exchange ratio R and hearth rate (HR) were evaluated. In the third stage, the validation equation was performed by another 12 participants.

RESULTS

Similar results in VO2 peak (P>0.05), R peak (P>0.05) and predicted maximum HR (P>0.05) were obtained between the ISWT and CEPT. Both tests showed moderate significant correlations of VO2 peak (r = 0.44, P = 0.002) e R peak (r = -0.53, P < 0.01), as well as the agreement of these measurements by Bland-Altman analysis (VO2 peak, bias = -0.13; R peak, bias = 0.0). Distance walked was the variable that explained 42.5% (R2 = 0.425, p = 0.0001) of the variance in VO2 peak. The equation was VO2 peak (predicted) = 20.94 + (0.02 x distance walked). The results obtained by the equation were not significantly different compared to the values obtained by the gas analyzer and the Bland-Altman analysis showed agreement (bias = 1.6).

CONCLUSION

The ISWT produced maximal cardiorespiratory responses comparable to the CEPT, and the developed equation showed viability for the prediction of VO2 peak in healthy sedentary adolescent boys.

PSYCHOMETRIC PROPERTIES OF FUNCTIONAL CAPACITY TESTS IN CHILDREN AND ADOLESCENTS: SYSTEMATIC REVIEW

OBJECTIVES

To identify studies that evaluated psychometric properties of functional capacity tests in children and adolescents, and to verify which of these have satisfactory properties of measurement.

DATA SOURCES

Searches on MEDical Literature Analysis and Retrieval System Online (MEDLINE), Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Scientific Electronic Library Online (SciELO) databases without limiting period or language. Two investigators independently selected articles based on the following inclusion criteria: children and/or adolescent population (healthy or with cardiorespiratory diseases); and assessment of psychometric properties of functional capacity tests. Studies with (I) adult samples, (II) sample with neurological diseases, and (III) on reference values or prediction equations only were excluded.

DATA SYNTHESIS

From the total of 677 articles identified, 11 were selected. These evaluated the psychometric properties of the following tests: 6-minute walk test (6MWT) (n=7); 6MWT and the 3-minute step test (3MST) (n=1); and Incremental Shuttle Walk Test (ISWT) (n=3). Reproducibility and reliability were good for 6MWT and ISWT, and moderate for 3MST. The ISWT showed high validity measures for both healthy children and children with chronic respiratory disease. The validity of 6MWT varied across studies, and should be analyzed according to the health conditions of test takers. The validity of 3MST is unclear, and further studies in pediatric population are required.

CONCLUSIONS

Most studies investigated 6MWT measurement properties. Validity of 6MWT varied according to different pediatric populations. The use of 6MWT, ISWT and 3MST tests to measure clinically important changes in children and adolescents with cardiorespiratory diseases is still unclear.

Oxidative injury of the pulmonary circulation in the perinatal period: Short- and long-term consequences for the human cardiopulmonary system

Development of the pulmonary circulation is a complex process with a spatial pattern that is tightly controlled. This process is vulnerable for disruption by various events in the prenatal and early postnatal periods. Disruption of normal pulmonary vascular development leads to abnormal structure and function of the lung vasculature, causing neonatal pulmonary vascular diseases. Premature babies are especially at risk of the development of these diseases, including persistent pulmonary hypertension and bronchopulmonary dysplasia. Reactive oxygen species play a key role in the pathogenesis of neonatal pulmonary vascular diseases and can be caused by hyperoxia, mechanical ventilation, hypoxia, and inflammation. Besides the well-established short-term consequences, exposure of the developing lung to injurious stimuli in the perinatal period, including oxidative stress, may also contribute to the development of pulmonary vascular diseases later in life, through so-called "fetal or perinatal programming." Because of these long-term consequences, it is important to develop a follow-up program tailored to adolescent survivors of neonatal pulmonary vascular diseases, aimed at early detection of adult pulmonary vascular diseases, and thereby opening the possibility of early intervention and interfering with disease progression. This review focuses on pathophysiologic events in the perinatal period that have been shown to disrupt human normal pulmonary vascular development, leading to neonatal pulmonary vascular diseases that can extend even into adulthood. This knowledge may be particularly important for ex-premature adults who are at risk of the long-term consequences of pulmonary vascular diseases, thereby contributing disproportionately to the burden of adult cardiovascular disease in the future.

Health-related quality of life in adolescent survivors of bronchopulmonary dysplasia

BACKGROUND AND OBJECTIVE

Bronchopulmonary dysplasia (BPD) is the most common chronic lung disease of infancy in the developed countries. Outcomes for BPD patients have traditionally been assessed using physiological parameters such as lung function, and no data are available on the health-related quality of life (HRQOL) for adolescents with BPD. The aim of this study was to assess HRQOL in adolescents with BPD, in comparison with age-matched and sex-matched control groups of healthy volunteers and asthmatic subjects.

METHODS

We enrolled 27 BPD patients (age range 11-19 years), 27 asthmatic patients and 27 healthy controls. HRQOL was assessed by the Short Form 36 (SF-36) questionnaire. Lung function was assessed by spirometry.

RESULTS

The BPD group did not differ significantly from the healthy controls in any scale or dimension of the SF-36 (the BPD group's summary scores were as follows: physical component summary mean 55.6 + 4.98 and mental component summary 51.8 + 7.75 vs 55.8 + 6.25 and 49.2 + 9.45 for the healthy control group, P > 0.5 and P = 0.26, respectively). Asthmatic adolescents scored lower than those of both healthy controls and patients with BPD in several SF-36 dimensions despite adolescents with BPD having lower lung function. No correlation emerged between lung function and HRQOL in BPD subjects.

CONCLUSION

Despite their impaired lung function, BPD patients have an HRQOL comparable with healthy peers and better than asthmatic patients. We did not find any association between HRQOL and lung function parameters.

Respiratory morbidity, lung function and fitness assessment after bronchopulmonary dysplasia

OBJECTIVE

To examine respiratory morbidity and exercise capacity at school age in children after bronchopulmonary dysplasia (BPD).

STUDY DESIGN

Former preterm children after BPD (n=23), without BPD (n=33) and term controls (n=33) were compared using respiratory health questionnaire, spirometry and six-minute walk test (6MWT).

RESULT

Wheezing was more frequent in BPD group (61%) vs non-BPD group (24%; P<0.001) and controls (15%; P<0.001) in the first year of life and until a year before inclusion. The children after BPD had lower mean value (P<0.001) for forced expiratory volume in 1 s (75.3%) vs non-BPD (89.8%) and controls (91.1%). Six-minute walking distance was lower after BPD by 58.3 m compared with non-BPD group (P=0.002) and by 53.7 m compared with controls (P=0.005). After adjusting for confounding factors the difference was not significant anymore.

CONCLUSION

More frequent wheezing and reduced lung function persist into school age after BPD.

Reference Equation for the Incremental Shuttle Walk Test in Children and Adolescents

OBJECTIVE

To determine a prediction equation for distance walked of incremental shuttle walk test (ISWT) and test its reliability in children and adolescents.

STUDY DESIGN

Cross-sectional study, which included 108 healthy volunteers between 6 and 18 years old. Those who had an abnormal spirometry or had a history of chronic disease were excluded. Two ISWT were performed. Heart rate and peripheral capillary oxygen saturation (SpO2) were continuously measured during the test. Dyspnea and lower limb fatigue were assessed by Borg scale before and after the tests.

RESULTS

Boys walked longer distances compared with girls (1066.4 ± 254.1 m vs 889.7 ± 159.6 m, respectively, P < .0001). Except for dyspnea, there were no significant differences in the other outcomes measured (heart rate, lower limb fatigue, SpO2, and distance walked) at the peak of the two ISWT. The variables included in the predicted equation were age, body mass index, and sex. The predicted equation is: ISWTpred = 845.559 + (sex * 193.265) + (age * 47.850) - (body mass index * 26.179). The distance walked had an excellent reliability between the two ISWT, 0.98 (95% CI 0.97-0.99). The Bland-Altman plot shows agreement between tests (range from -40 to 45 m).

CONCLUSIONS

We established a prediction equation for ISWT. It can be used as a reference to evaluate exercise capacity for children and adolescents. ISWT has excellent repeatability and it is a maximal-effort field test for this age group.

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

[Purpose] The aim of this study was to compare functional capacity and peripheral muscle strength in preterm children with bronchopulmonary dysplasia (BPD) with those of age-matched full-term healthy controls. [Subjects and Methods] Eighteen BPD subjects and 20 healthy subjects were enrolled in the study. Pulmonary function testing was performed. Body composition was determined using the skinfold method. An analysis of posture was scored. Muscle strength was evaluated using a dynamometer. Functional capacity was assessed using the six-minute walking test (6MWT). [Results] Pulmonary function testing parameters, 6MWT distance, and quadriceps strength of the children with BPD were significantly lower than those of healthy peers. The scores of posture analysis of the children with BPD were significantly higher than those of healthy subjects. Exercise heart rate was significantly higher in the children with BPD compared to healthy children. The 6MWT distance correlated with height, fat-free mass, exercise dyspnea perception, and hand grip strength in BPD children. [Conclusion] The study showed that preterm children with BPD had disturbed pulmonary and extrapulmonary characteristics. BPD had lower fat free mass, reduced lung function, worsen postural function, a shorter 6MWT distance, and lower quadriceps strength than healthy children. These features may provide insights into the choice of outcome measures for pulmonary rehabilitation for BPD.

Association between preterm birth and thoracic musculoskeletal static alterations in adolescents

OBJECTIVE

To compare thoracic musculoskeletal static alterations in adolescents born prematurely with those born at term and investigate neonatal and post-neonatal variables associated with thoracic alterations.

METHOD

This is a cross-sectional study with 57 adolescents aged 10-15 years born prematurely and 57 adolescents born at term paired by gender and age. Photographs of the head and thorax in the front, back, and right side views were studied using a computer program. The two groups were compared in regards to: elevation of clavicles, elevation of shoulders, protrusion of the head, and anteroposterior and mediolateral thoracic length. Factor associated with thoracic disorders were evaluated by linear regression analysis.

RESULTS

The Preterm group had mean gestational age of 32.0±2.8 weeks and the birth weight was 1462±338 and 3342±430 g for the Preterm and Term adolescents, respectively. Preterm adolescents had higher elevation of the left shoulder (22.7±5.4° vs. 20.6±5.3°;sim, p=0.038) and the right shoulder (22.2±4.4° vs. 18.5±5.7°; p<0.001). Smaller protrusion of the head (27.8±6.1° vs. 32.4±7.9°; p=0.008), mediolateral thoracic length (22.9±2.3 cm vs. 25.1±3.1 cm; p<0.001) and anteroposterior thoracic length (19.7±2.2 cm vs. 21.1±3.4 cm; p<0.001) were found in preterm adolescents. By multiple regression analysis, factors associated with higher shoulder elevation were birth weight <1500 g (p<0.001) and mechanical ventilation during neonatal period >5 days (p=0.009).

CONCLUSION

Adolescents born prematurely presented greater thoracic musculoskeletal static alterations compared to those born at term. Factors associated with these alterations were: very low birth weight and longer duration of mechanical ventilation in the neonatal unit.