Exercise testing and chronic lung diseases in children

The PAY test: a new approach for assessing functional performance in children and adolescents with asthma

OBJECTIVE

To develop, validate, and test the reproducibility of a new test capable of assessing functional performance in children and adolescents (PAY test: Performance Activity in Youth).

METHODS

participants without and with asthma were included in the development and validation phases, respectively. The PAY test includes five activities: transition from sitting to standing, walking 10 m, step climbing, shoulder extension and flexion, and star jumps. Participants underwent the Pediatric Glittre test (TGlittre-P test time), modified shuttle test (MST), and cardiopulmonary exercise test (CPET).

OUTCOMES

PAY test and TGlittre-P test times, oxygen uptake (VO2peak), and distance walked in the MST.

RESULTS

8 healthy volunteers, aged 12 (7 - 15) years old were included in the development phase and 34 participants with asthma, aged 11 (7 -14) years old, in the validation phase. The PAY test elicited greater physiological responses (VO2peak 33.5 ± 6.9 mL/kg) than the TGlittre-P (VO2peak: 27.4 ± 9.0 mL/kg), but lower than the MST (VO2peak: 48.9 ± 14.2 mL/kg) and CPET (VO2peak: 42.0 ± 8.8 mL/kg), p < .05. Moderate correlation between the PAY test time and the TGlittre-P time (r = 0.70, p < .001) and distance walked in the MST (r = -0.72, p < .001). The PAY test time was longer in participants with asthma than in healthy participants (3.1 [3.0 - 3.3] min vs. 2.3 [2.1 - 2.4 min]), p < .001.; and the test was reproducible (ICC 0.78, CI 95% 0.55-0.90, p < .001).

CONCLUSIONS

The PAY test is a valid and reproducible tool for assessing functional performance in children and adolescents with asthma.

Lung growth and pulmonary function after prematurity and bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) still carries a heavy burden of morbidity and mortality in survivors of extreme prematurity. The disease is characterized by simplification of the alveolar structure, involving a smaller number of enlarged alveoli due to decreased septation and a dysmorphic pulmonary microvessel growth. These changes lead to persistent abnormalities mainly affecting the smaller airways, lung parenchyma, and pulmonary vasculature, which can be assessed with lung function tests and imaging techniques. Several longitudinal lung function studies have demonstrated that most preterm-born subjects with BPD embark on a low lung function trajectory, never achieving their full airway growth potential. They are consequently at higher risk of developing a chronic obstructive pulmonary disease-like phenotype later in life. Studies based on computer tomography and magnetic resonance imaging, have also shown that in these patients there is a persistence of lung abnormalities like emphysematous areas, bronchial wall thickening, interstitial opacities, and mosaic lung attenuation also in adult age. This review aims to outline the current knowledge of pulmonary and vascular growth in survivors of BPD and the evidence of their lung function and imaging up to adulthood.

FUNCTIONAL CAPACITY IN ADOLESCENT IDIOPATHIC SCOLIOSIS DURING THE POSTOPERATIVE PERIOD

ABSTRACT Introduction: Patients with Adolescent Idiopathic Scoliosis (AIS) show reduced exercise capacity during the Incremental Shuttle Walk Test (ISWT). However, we not know how patients behave in the late postoperative (LPO) period. Objective: The aim of this study was to evaluate the ISWT distance (ISWTD) and physiological responses during ISWT in AIS patients during the LPO period. Methods: We included 22 patients with AIS in the LPO period (SG) and 21 adolescents in the Control Group (CG). We assessed pulmonary function (FVC and FEV1). During ISWT, a gas analyzer was used to assess peak oxygen (VO2) and submaximal relations: Oxygen Uptake Efficiency Slope (OUES) and the breathing pattern (ΔVT/ΔlnVE). Results: Significantly lower values were observed in SG: VO2 (22 ± 5 vs. 27 ± 4), ISWTD (567 ± 94 vs.604 ± 86), FVC (2.70 ± 0.47 vs. 3.33 ± 0.52) and FEV1 (2.41 ± 0.46 vs. 2.84 ± 0.52). There were significant correlations between ISWTD and VO2/Kg (r = 0.80); between OUES and ΔVT/ΔlnVE (r = 0.65); and between the main thoracic curve with VO2/Kg (r= −0.61). Conclusion: AIS patients in the LPO period have significantly reduced exercise capacity associated with reduced lung function, residual spinal curve and cardiovascular deconditioning. Level of Evidence III; Prognostic Studies - Investigation of the effect of characteristic of a patient on the outcome of the disease.

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.

Exercise-induced bronchoconstriction in school-age children born extremely preterm

BACKGROUND

School children born preterm often show airway hyperresponsiveness to methacholine or histamine. Less attention has been paid to their airway response to exercise, an important point because of the role of exercise in the child's daily life. The aim of this study was to describe the characteristics of, and potential determinants to, the airway response to exercise in children born extremely preterm.

METHODS

Forty-two nonasthmatic nonatopic children born before 32 wk gestation were compared with 27 healthy nonasthmatic nonatopic term children at age 7. Spirometry and respiratory impedance were measured at baseline and repeated after a single-step 6-min treadmill exercise in a climate-controlled room.

RESULTS

The preterm group showed significant broncho-constriction induced by exercise. Prematurity, but not low baseline lung function, neonatal oxygen supplementation, mechanical ventilation, chronic lung disease, or maternal smoking, was a determinant of exercise-induced bronchoconstriction.

CONCLUSION

Children born extremely preterm present significant exercise-induced airway obstruction at age 7. The response has different characteristics from that occurring in asthmatics and is likely to express airway noneosinophilic inflammation.

Forced expiratory volume predicts all-cause and cancer mortality in Mumbai, India: results from a population-based cohort study

BACKGROUND

Reduction in pulmonary function, as estimated by forced expiratory volume in 1 s (FEV(1)), has been found to predict all-cause mortality in developed-country populations. This study was designed to examine the association between FEV(1) and mortality in an urban developing-country population.

METHODS

Data from the large, well-characterized Mumbai Cohort Study (Maharashtra, India) were used to compute hazard ratios (HRs; deaths/100-ml FEV(1)) and 95% confidence intervals (CIs) from Cox proportional hazards regression models in which age, tobacco use, education, height and relative body weight were controlled.

RESULTS

A total of 13,261 deaths occurred in this cohort of 148,173 individuals. After controlling for important covariates, there was a 1.7% reduction in risk of overall death in women for each 100-ml increment in FEV(1) (HR = 0.983; 95% CI = 0.980-0.986) and a 1.5% reduction in men (HR = 0.985; 95% CI = 0.984-0.986). There was a 1.6% reduction in cancer deaths in women (HR = 0.984; 95% CI = 0.973-0.996) and a 0.8% reduction in men (HR = 0.992; 95% CI = 0.987-0.997). The largest reductions in women were observed in tuberculosis deaths (3.7%/100-ml increment in FEV(1)), and in men in respiratory system deaths (3.2%).

CONCLUSIONS

In a densely populated urban Indian population, FEV(1) predicted overall and cancer mortality. Effects were larger in women and were not attenuated by exclusion of smokers or restricting analyses to subjects dying >2 years from recruitment. Because FEV(1) may be affected by air pollution, which is worsening in urban areas of most developing countries, further research is recommended to deepen understanding of these factors in relation to mortality.

Optimal level of physical activity in children with chronic lung diseases

AIM

To determine the optimal level of physical activity and its relationship with disease severity in children with chronic lung diseases (CLD).

METHODS

Pulmonary function and exercise tests were compared between 18 CLD children (aged 13.5 +/- 2.4 years, 33% male) and 18 healthy controls without any history of lung diseases (age and sex matched).

RESULTS

CLD children had lower forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV)(1), forced expiratory flow rate between 25% and 75% of vital capacity (FEF)(25-75%) and total lung capacity (TLC) and higher residual volume (RV)/TLC ratio than controls (77.3 +/- 22.6 vs. 97.9 +/- 12.5%pred; p = 0.002, 74.3 +/- 17.6 vs. 104.0 +/- 12.6%pred; p < 0.001, 49.9 +/- 23.1 vs. 75.6 +/- 18.6%pred; p < 0.001, 82.8 +/- 18.6 vs. 95.6 +/- 9.8%pred; p = 0.04, 30.8 +/- 10.2 vs. 24.4 +/- 5.9%; p = 0.04, respectively). Oxygen consumption at anaerobic threshold (AT) and optimal level of physical activity (metabolic equivalents [METs] at AT) were not different between the two groups and between mild and moderate to severe CLD. However, when the exercise was continued beyond the AT, CLD children demonstrated poorer exercise performance than normal controls.

CONCLUSION

Children with CLD demonstrated the same level of optimal physical activity as normal children despite their lower lung function. The optimal level of physical activity was not related to disease severity. The exercise test and exercise should not be performed beyond the AT by the CLD children. Proper exercise test should be done to determine their optimal exercise activity.