Cardiopulmonary exercise testing for pediatric exercise-induced dyspnea especially in patients whose asthma treatment failed

Use of cardiopulmonary exercise testing to identify mechanisms of exertional symptoms in children with long COVID

BACKGROUND

Little is known about the mechanisms of exercise intolerance and exertional symptoms in children with long COVID. Through utilization of cardiopulmonary exercise testing (CPET), this study is the first of its kind to evaluate exertional symptoms and attempt to identify potential mechanism of long COVID-19 in children.

OBJECTIVE

To determine if CPET will uncover potential reasons for persistent symptoms of long COVID when there is no indication of cardiopulmonary or upper airway disease.

METHODS

We performed a retrospective chart review study involving children 6-17 years of age with symptoms of long COVID at Phoenix Children''s Hospital from January 1, 2021, to June 1, 2022. Symptoms included but were not limited to exercise intolerance, fatigue, shortness of breath, dyspnea on exertion, and chest pain. We recorded any measurable abnormalities present on CPET after comparing it to established normal reference ranges. Range, median, and SD of data points were calculated and p values were determined using the Mann-Whitney U and Fisher's exact test.

RESULTS

Twenty-three children with exertional symptoms consistent with long COVID were identified. The most frequent symptoms reported during exercise include dyspnea on exertion (35%), followed by chest pain (30%) and dizziness (13%). Nearly half of the children (47%) demonstrated decreased exercise capacity with 30% displaying limitations due to deconditioning, 22% limited by body habitus, and 13% due to bronchospasm. Other contributing factors include ventilation to perfusion mismatch and volitional hyperventilation.

CONCLUSION

Decreased aerobic activity due to multiple factors was found in 47% of children with a history of COVID-19. This study illustrates the importance of ongoing research into this phenomenon to elucidate its mechanism and assist physicians in making decisions regarding referral to specialists for further testing.

Comparison of Exercise Protocols for Diagnosing Pediatric Unexplained Dyspnea on Exertion

PURPOSE

Clinicians evaluating pediatric patients with unexplained dyspnea on exertion (DOE) often obtain exercise testing with a treadmill-based exercise-induced bronchospasm (EIB) protocol measuring only changes in spirometry. We modified the EIB protocol to collect metabolic and lung volume endpoints as obtained in a cardiopulmonary exercise test (CPET). We tested the hypothesis that measuring metabolic data with the EIB protocol (EIB-CPET) would yield greater diagnostic information than the EIB protocol.

METHODS

Exercise test diagnosis for healthy children with DOE referred to the pulmonary exercise lab from January 2011 through July 2023 were retrospectively compared between those performing either the EIB or EIB-CPET protocols.

RESULTS

One hundred and twenty-seven patients with unexplained DOE were analyzed. Of the 72 patients tested on the EIB protocol, 49% had stridor and 5% with EIB. Of the 55 patients tested on the EIB-CPET protocol, 42% had stridor, 42% with normal physiologic limitation, 22% with dysfunctional breathing, 5% with deconditioning, 2% with EIB, and 2% with exercise-induced hypoxemia. Patients performing the EIB-CPET protocol had a significantly higher rate of any diagnosis compared with EIB (P = .0002).

CONCLUSIONS

There is a greater diagnostic yield in children with unexplained DOE performing the EIB-CPET protocol compared with patients performing the EIB protocol.

The Need for Testing-The Exercise Challenge Test to Disentangle Causes of Childhood Exertional Dyspnea

Exertional dyspnea is a common symptom in childhood which can induce avoidance of physical activity, aggravating the original symptom. Common causes of exertional dyspnea are exercise induced bronchoconstriction (EIB), dysfunctional breathing, physical deconditioning and the sensation of dyspnea when reaching the physiological limit. These causes frequently coexist, trigger one another and have overlapping symptoms, which can impede diagnoses and treatment. In the majority of children with exertional dyspnea, EIB is not the cause of symptoms, and in asthmatic children it is often not the only cause. An exercise challenge test (ECT) is a highly specific tool to diagnose EIB and asthma in children. Sensitivity can be increased by simulating real-life environmental circumstances where symptoms occur, such as environmental factors and exercise modality. An ECT reflects daily life symptoms and impairment, and can in an enjoyable way disentangle common causes of exertional dyspnea.

Exercise-induced bronchoconstriction in elite or endurance athletes:: Pathogenesis and diagnostic considerations

OBJECTIVE

To review the pathogenesis and evaluation of exercise-induced bronchoconstriction pertaining to the elite or endurance athlete, as well as propose a diagnostic algorithm based on the current literature.

DATA SOURCES

Studies were identified using Ovid MEDLINE and reference lists of key articles.

STUDY SELECTIONS

Randomized controlled trials were selected when available. Systematic reviews and meta-analyses of peer-reviewed literature were included, as were retrospective studies and observational studies of clinical interest.

RESULTS

Exercise-induced bronchoconstriction (EIB) is the physiologic entity in which exercise induces acute narrowing of the airways and occurs in patients both with and without asthma. It may present with or without respiratory symptoms, and the underlying cause is likely attributable to environment stressors to the airway encountered during exercise. These include the osmotic effects of inhaled dry air, temperature variations, autonomic nervous system dysregulation, sensory nerve reactivity, and airway epithelial injury. Deposition of allergens, particulate matter, and gaseous pollutants into the airway also contribute. Elite and endurance athletes are exposed to these stressors more frequently and in greater duration than the general population.

CONCLUSION

A greater awareness of EIB among elite and endurance athletes is needed, and a thorough evaluation should be performed if EIB is suspected in this population. We propose an algorithm to aid in this evaluation. Symptoms should not be solely relied on for diagnosis but should be taken into the context of bronchoprovocative challenges, which should replicate the competitive environment as closely as possible. Further research is needed to validate these tests' predictive values.