The Best Peak Expiratory Flow Is Flow-Limited and Effort-Independent in Normal Subjects

Tantucci, Claudio; Duguet, Alexandre; Giampiccolo, Pietro; Similowski, Thomas; Zelter, Marc; Derenne, Jean‐Philippe

doi:10.1164/rccm.2012008

Cited by 28 publications

(22 citation statements)

References 16 publications

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“…The extrinsic mechanical compression on the lung together with the thorax might also be the leading mechanism of a decreased FEV in our study. Because the PEF is limited by force-velocity characteristics of expiratory muscles instead of mechanical properties of the lung and airways, insufficient force would lead to flow limitation (27).…”

Section: Discussionmentioning

confidence: 99%

The Effect of Obesity Degree on Childhood Pulmonary Function Tests

Torun¹,

Çakır²,

Özgüç³

et al. 2014

Balkan Med J

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Background:Childhood obesity has become a global epidemic. It is related to several chronic diseases such as essential hypertension, type 2 diabetes mellitus, and renal disease. The relationship between the degree of obesity and lung functions is well defined in adults, but limited information is available about the childhood period. Aims: This study aims to determine the impact of the degree of obesity on the pulmonary functions of school children and adolescents. Study Design: Cross sectional study. Methods: Included in the study were a total of 170 school children and adolescents (9-17 years old) referred to our paediatric outpatient clinic. Of these subjects, 42 were lean and non-obese (BMI % <85), 30 subjects were overweight (BMI % ˃85, <95), 34 subjects were obese (BMI % ˃95, <97), and 64 subjects were morbidly obese (BMI % ˃97). Anthropometric measurements were taken and spirometry was performed on all subjects. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV 1 ), forced vital capacity ) and peak expiratory flow (PEF) were used to measure the ventilatory functions for all the subjects. Results: The groups showed no significant differences in age or gender. Despite no statistically significant differences in FEV 1 , FVC, or FEV 1 /FVC, there were significant reductions in PEF (p<0.001) and FEV 25-75 (p<0.001) in the overweight, obese and morbidly obese subjects, when compared with those who were non-obese. Conclusion: Overweight, obese and morbidly obese children have no obstructive abnormalities compared with healthy lean subjects. (Balkan Med J 2014;31:235-8).

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Section: Discussionmentioning

confidence: 99%

The Effect of Obesity Degree on Childhood Pulmonary Function Tests

Torun¹,

Çakır²,

Özgüç³

et al. 2014

Balkan Med J

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“…k 1 was set proportional to each subject's FEF and k 2 was set to 1.9 for all the subjects. P m was added to the driving pressure from V PEF to the lowest simulated lung volumes, i.e., over the region where flow is limited [22,23].…”

Section: Methodsmentioning

confidence: 99%

Simulation of Forced Expiration in a Biophysical Model, With Homogeneous and Clustered Bronchoconstriction

Hedges

Tawhai

2016

Journal of Biomechanical Engineering

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One limitation of forced spirometry is that it integrates the contribution of the complex and dynamic behavior of all of the airways and tissue of the lung into a single exhaling unit, hence, it is not clear how spirometric measures are affected by local changes to the airways or tissue such as the presence of "ventilation defects." Here, we adapt a wavespeed limitation model to a spatially distributed and anatomically based airway tree that is embedded within a deformable parenchyma, to simulate forced expiration in 1 s (FEV 1 ). This provides a model that can be used to assess the consequence of imposed constrictions on FEV 1 . We first show how the model can be parameterized to represent imaging and forced spirometry data from nonasthmatic healthy young adults. We then compare the effect of homogeneous and clustered bronchoconstriction on FEV 1 in six subject-specific models (three male and three female). The model highlights potential sources of normal subject variability in response to agonist challenge, including the interaction between sites of airway constriction and sites of flow limitation at baseline. The results support earlier studies which proposed that the significant constriction of nondefect airways must be present in order to match to clinical measurements of lung function.

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“…Therefore, traditional teaching indicated that early expiration is primarily limited by effort dependent muscle strength. However, a recent model in normal individuals showed that peak expiratory flow was limited by mechanical properties of the lung (in accordance with the wave speed mechanism), and not by muscle strength (Tantucci, C., 2002). As peak flow normally occurs at around 80% of total lung capacity, the wave speed theory can be used to explain expiratory flow limitation from a vital capacity of 80% and less.…”

Section: Wwwintechopencommentioning

confidence: 96%