Flow limitation and dysanapsis in children and adolescents with exertional dyspnea

Pianosi, Paul

doi:10.1016/j.resp.2018.03.013

Cited by 3 publications

(3 citation statements)

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“…Expiratory flow limitation occurred at some point during exercise in 87 (59%) subjects, over 49 ± 21% (mean ± SD) of tidal volume. Onset of EFL during exercise occurred in lighter exercise in those with more obstruction (greater concavity of resting maximum expiratory FVL) but not until peak exercise in those with normal spirometry (Pianosi, 2018b). Subjects with EFL achieved higher values for peak V˙O2 with concomitant higher minute volume and O 2 pulse at peak exercise (Table 2).…”

Section: Resultsmentioning

confidence: 99%

Ventilatory Limitation of Exercise in Pediatric Subjects Evaluated for Exertional Dyspnea

Pianosi

Smith

2019

Front. Physiol.

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Purpose: Attribution of ventilatory limitation to exercise when the ratio of ventilation (trueV˙E) at peak work to maximum voluntary ventilation (MVV) exceeds 0.80 is problematic in pediatrics. Instead, expiratory flow limitation (EFL) measured by tidal flow-volume loop (FVL) analysis – the method of choice – was compared with directly measured MVV or proxies to determine ventilatory limitation.Methods: Subjects undergoing clinical evaluation for exertional dyspnea performed maximal exercise testing with measurement of tidal FVL. EFL was defined when exercise tidal FVL overlapped at least 5% of the maximal expiratory flow-volume envelope for > 5 breaths in any stage of exercise. We compared this method of ventilatory limitation to traditional methods based on MVV or multiples (30, 35, or 40) of FEV1. Receiver operating characteristic curves were constructed and area under curve (AUC) computed for peak trueV˙E/MVV and peak trueV˙E/x⋅FEV1.Results: Among 148 subjects aged 7–18 years (60% female), EFL was found in 87 (59%). Using EFL shown by FVL analysis as a true positive to determine ventilatory limitation, AUC for peak trueV˙E/30⋅FEV1 was 0.84 (95% CI 0.78–0.90), significantly better than AUC 0.70 (95% CI 0.61–0.79) when 12-s sprint MVV was used for peak trueV˙E/MVV. Sensitivity and specificity were 0.82 and 0.70 respectively when using a cutoff of 0.85 for peak trueV˙E/30⋅FEV1 to predict ventilatory limitation to exercise.Conclusion: Peak trueV˙E/30⋅FEV1 is superior to peak trueV˙E/MVV, as a means to identify potential ventilatory limitation in pediatric subjects when FVL analysis is not available.

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Section: Resultsmentioning

confidence: 99%

Ventilatory Limitation of Exercise in Pediatric Subjects Evaluated for Exertional Dyspnea

Pianosi

Smith

2019

Front. Physiol.

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“…Thus, these data may not be widely generalisable to all BPD. Second, to obtain the measurement of DR we used static recoil pressures at 50% of lung volume (Pst(l) 50 ) extrapolated from adult values [ 23 ] as has been previously described [ 18 , 19 , 24 ]. However, given the lung growth that occurs from birth through early childhood, the assumption of a linear relationship of Pst(l) 50 values with age in early childhood may not be entirely valid [ 15 ].…”

Section: Discussionmentioning

confidence: 99%

“…We used data from T urner et al . [ 23 ] to extrapolate Pst(l) 50 based on the equation Pst(l) 50 = −0.056×age (years)+6.3038, as previously described in both adults [ 18 , 19 ] and children [ 24 ]. The DR is inversely related to dysanaptic lung growth, i.e.…”

Section: Methodsmentioning

confidence: 99%

Bronchodilator responsiveness and dysanapsis in bronchopulmonary dysplasia

et al. 2022

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Question addressedThe incidence of bronchopulmonary dysplasia (BPD) following preterm birth is increasing. Bronchodilators are often used to treat patients with BPD with little evidence to guide therapy. To test the hypothesis that there are infant pulmonary function test (iPFT) parameters that can predict subsequent bronchodilator response in infants with BPD.MethodsSubjects in this study are part of a patient group in whom we reported 3 BPD phenotypes (obstructive, restrictive and mixed) based on iPFT data. From that group, a cohort of 93 patients with iPFT data including bronchodilator response were eligible for this study.ResultsBronchodilator responsiveness was found in 59 (63%) of the cohort. There were no differences in demographics between the responders and non-responders. There was no difference in forced vital capacity (FVC) between the two groups. Responders had significantly lower FEV0.5 and FEV0.5/FVC (p<0.005) and greater indices of hyperinflation than did non-responders (p<0.005). Logistic regression modeling found that pre-bronchodilator FEV0.5 and FRC/TLC were significantly associated with bronchodilator response. The magnitude of response to bronchodilators was negatively correlated (R = −0.49; R2 = 0.24; p<0.001) with the FEV0.5. The median dysanapsis ratio in responders (0.08; 95% CI 0.05–0.19) was significantly (p = 0.005) smaller than in non-responders (0.18; 95% CI 0.06–0.38).Answer to the questionThese findings demonstrate that there are pulmonary function test parameters associated with bronchodilator response. Responders had evidence of greater dysanaptic lung growth than do non-responders.

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Exertional Dyspnea in Childhood: Is There an Iceberg Beneath the Apex?

Pianosi

2018

Pediatric Exercise Science

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This essay expounds on fundamental, quantitative elements of the exercise ventilation in children, which was the subject of the Tom Rowland Lecture given at the NASPEM 2018 Conference. Our knowledge about how much ventilation rises during aerobic exercise is reasonably solid; our understanding of its governance is a work in progress, but our grasp of dyspnea and ventilatory limitation in children (if it occurs) remains embryonic. This manuscript summarizes ventilatory mechanics during dynamic exercise, then proceeds to outline our current understanding of mechanisms of dyspnea, particularly during exercise (exertional dyspnea). Most research in this field has been done in adults, and the vast majority of these studies in patients with chronic obstructive pulmonary disease. To what extent conclusions drawn from this literature apply to children and adolescents—both healthy and those with cardiopulmonary disease—will be discussed. The few, recent, pertinent, pediatric studies will be reviewed in an attempt to provide an empirical basis for proposing a hypothetical model to study exertional dyspnea in youth. Just as somatic growth will have consequences for ventilatory and exercise capacity, so too will neural developmental plasticity and experience affect perception of dyspnea. Our path to understand how these evolving inputs and influences summate during a child’s life will be Columbus’ India.

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Flow limitation and dysanapsis in children and adolescents with exertional dyspnea

Cited by 3 publications

References 39 publications

Ventilatory Limitation of Exercise in Pediatric Subjects Evaluated for Exertional Dyspnea

Ventilatory Limitation of Exercise in Pediatric Subjects Evaluated for Exertional Dyspnea

Bronchodilator responsiveness and dysanapsis in bronchopulmonary dysplasia

Exertional Dyspnea in Childhood: Is There an Iceberg Beneath the Apex?

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