Airway resistance variability and response to bronchodilator in children with asthma

Lall, Carolyn A.; Cheng, Natalie; Hernández, Paul; Pianosi, Paul; Zhang, Dali; Abouzied, Alyaa; Maksym, Geoffrey N.

doi:10.1183/09031936.00064006

Cited by 41 publications

(54 citation statements)

References 46 publications

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“…Using end-inspiratory values may theoretically decrease the contribution of flow to RRSi, yet, transition from RRSi to RRSe would have to be smooth enough to accurately identify undistorted near zero flow values (14). That the ⌬RRS DI could not be recovered in a significant proportion of subjects may induce a bias in interpreting the case-control difference, for instance, expressing the fact that asthmatic children may show lower RRS repeatability (41), but the overall proportion of data rejected was very similar in asthma and controls. Moreover, it may be argued that some sensitization of the ⌬RRS DI might have resulted from taking a through instead of mean RRSi after the DI, but the difference between asthma and control was significant after exercise and not at baseline.…”

Section: Discussionmentioning

confidence: 99%

Airway Response to Exercise by Forced Oscillations in Asthmatic Children

et al. 2010

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Forced expiratory volume in 1 s (FEV 1 ) detection of exercise-induced bronchoconstriction (EIB) to identify asthma has good specificity but rather low sensitivity. The aim was to test whether sensitivity may be improved by measuring respiratory resistance (RRS) by the forced oscillation technique (FOT). Forty-seven asthmatic and 50 control children (5-12 y) were studied before and after running 6 min on a treadmill. RRS in inspiration (RRSi) and expiration (RRSe), FEV 1 and RRSi response to a deep inhalation (DI) were measured before and after exercise. In asthmatics versus controls, exercise induced significantly larger increases in RRSi (p Ͻ 0.001) and larger decreases in FEV 1 (p ϭ 0.004). Asthmatics but not controls showed more bronchodilation by DI after exercise (p ϭ 0.02). At specificity Ͼ0.90, sensitivity was 0.53 with 25% increase RRSi and 0.45 with 27% increase RRSe or 5% decrease FEV 1 . It is concluded that the FOT improves sensitivity of exercise challenge, and the RRSi response to DI may prove useful in identifying the mechanism of airway obstruction. (Pediatr Res 68: 537-541, 2010) E xercise-induced bronchoconstriction (EIB) is closely linked to airway inflammation and unlikely to develop in healthy children (1), so that detecting airway hyperresponsiveness to exercise in the lung function laboratory is considered highly specific of asthma, i.e. it is associated with low rate of false-positive responses. A limitation is the rather low sensitivity of the test (2,3). EIB has been identified in primary school children by changes in forced expiratory volume in 1 s (FEV 1 ) or peak expiratory flow, and decision levels were mostly based on the former parameter (3). Respiratory resistance (RRS) measured by the forced oscillation technique (FOT) offers an alternative assessment of airway caliber, the time variations of which may be characterized for instance using a single excitation frequency (4). Computing RRS separately in inspiration and expiration (RRSi and RRSe, respectively) rather than over the whole breathing cycle may be of interest because the upper airways, which may represent a confounding factor in assessing the intrathoracic airways, are known to contribute differently to airway mechanics in inspiration and expiration (5,6). Furthermore, the RRS change in relation to volume history, more specifically the bronchomotor alteration that follows a deep inhalation (DI), has potential relevance in identifying the mechanism of EIB (7-9). Indeed, stretching the acutely contracted bronchial smooth muscle promotes bronchial wall relaxation, which in turn could be taken as an indicator of the magnitude of the airway response (10). To the best of our knowledge, a systematic analysis of diagnostic value of single-frequency RRS has not been performed during case-control identification of EIB in the lung function laboratory at school age.Therefore, the aim of this study was to assess the value of the FOT in identifying EIB in asthmatic children. More specifically, RRSi and RRSe and the change in...

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Section: Discussionmentioning

confidence: 99%

Airway Response to Exercise by Forced Oscillations in Asthmatic Children

et al. 2010

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“…This is a useful tool in evaluating lung function in young children with limited ability to cooperate 1 and older children. [2][3][4] FOT has been shown to be applicable in the clinical evaluation of preschool children with cystic fibrosis 5 as well as older children with cystic fibrosis during a respiratory tract exacerbation. 6 Lung function measured with FOT has also been evaluated in children born prematurely with or without neonatal chronic lung disease.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9] FOT has also been shown to be a valid tool in the assessment of bronchodilator response (BDR) in different populations of patients, especially asthmatic or wheezing children. 4,[10][11][12][13][14] Before FOT can be introduced into clinical practice as a routine test, appropriate reference values from healthy populations are needed. Although, a number of data sets from children have been published these are likely to be specific to the equipment used and to the study population.…”

Section: Introductionmentioning

confidence: 99%

Respiratory impedance and bronchodilator response in healthy Italian preschool children

Calogero¹,

Parri²,

Baccini³

et al. 2010

Pediatric Pulmonology

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Summary. Objective: To define normal values for respiratory resistance (R rs ) and reactance (X rs ) and bronchodilator response (BDR) in a population of healthy Italian preschool children using a commercially available forced oscillation device. Methods: R rs and X rs were measured in kindergartens in Viterbo, Italy. Regression analysis was performed taking into account height, weight, age, gender, and reference equations calculated. The coefficient of repeatability (CR) between two tests performed 15 min apart was calculated in a subset of children. BDR was assessed by repeating the measurements 15 min after the administration of 200 mg of inhaled salbutamol and calculated as an absolute change in R rs and X rs at 8 Hz, as a percent change in baseline, and as a change in Z-score calculated from the reference equations. Results: Lung function was attempted in 175 healthy children and successful in 163 (81 male, median age 4.8, range 2.9-6.1 years). R rs and X rs at 6, 8, and 10 Hz were related to height but not other variables. The CR was 1.53 hPa s L À1 for R rs8 and 0.91 hPa s L À1 for X rs8 . The 5th percentile for absolute R rs8 BDR was À3.16 hPa s L À1, whereas the 95th percentile for absolute X rs8 BDR was 2.25 hPa s L À1. These cut-off values corresponded to a change in the Z-score of À1.88 and 2.48, respectively. Conclusions: We have established reference equations for R rs and X rs in healthy Italian preschool children using forced oscillations. We recommend a change in Z-score of À1.88 for R rs8 and 2.48 for X rs8 as cut-off values for a positive BDR.

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“…In 2001, Que and colleagues demonstrated that respiratory system resistance measured by FOT was more variable in patients with asthma than in healthy control subjects, even across time spans as short as 15 minutes (66). This variability has subsequently been demonstrated in a number of other studies involving both adults and children (22,(67)(68)(69). One study has even suggested that home monitoring of FOT for just 2 minutes a day over only 8 days could yield sufficient information to calculate a conditional probability of lung function deterioration over the subsequent week (70).…”

Section: More Sensitive Lung Function Measures?mentioning

confidence: 98%

Systems Biology and Clinical Practice in Respiratory Medicine. The Twain Shall Meet

Thamrin

Frey

Kaminsky

et al. 2016

Am J Respir Crit Care Med

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Respiratory diseases are highly complex, being driven by host-environment interactions and manifested by inflammatory, structural, and functional abnormalities that vary over time. Traditional reductionist approaches have contributed vastly to our knowledge of biological systems in health and disease to date; however, they are insufficient to provide an understanding of the behavior of the system as a whole. In this Pulmonary Perspective, we discuss systems biology approaches, especially but not limited to the study of the lung as a complex system. Such integrative approaches take into account the large number of dynamic subunits and their interactions found in biological systems. Borrowing methods from physics and mathematics, it is possible to study the collective behavior of these systems over time and in a multidimensional manner. We first examine the physiological basis for complexity in the respiratory system and its implications for disease. We then expand on the potential applications of systems biology methods to study complex systems, within the context of diagnosis and monitoring of respiratory diseases including asthma, chronic obstructive pulmonary disease (COPD), and critical illness. We summarize the significant advances made in recent years using systems approaches for disease phenotyping, applied to data ranging from the molecular to clinical level, obtained from large-scale asthma and COPD networks. We describe new studies using temporal complexity patterns to characterize asthma and COPD and predict exacerbations as well as predict adverse outcomes in critical care. We highlight new methods that are emerging with this approach and discuss remaining questions that merit greater attention in the field.

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Airway resistance variability and response to bronchodilator in children with asthma

Cited by 41 publications

References 46 publications

Airway Response to Exercise by Forced Oscillations in Asthmatic Children

Airway Response to Exercise by Forced Oscillations in Asthmatic Children

Respiratory impedance and bronchodilator response in healthy Italian preschool children

Systems Biology and Clinical Practice in Respiratory Medicine. The Twain Shall Meet

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