Methacholine-induced volume dependence of respiratory resistance in preschool children

Marchal, François; Loos, Nathalie; Monin, Philippe; Peslin, R

doi:10.1183/09031936.99.14511679

Cited by 30 publications

(20 citation statements)

References 30 publications

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“…In calculating tidal fluctuation in resistance the authors used measurements at instants of zero flow, at end inspiration and end expiration, which allowed the volume dependent changes in resistance to be measured independently of any flow-related effects. Using a linear regression model, MARCHAL et al [17] have also demonstrated the volume dependence of resistance during tidal breathing at baseline and after methacholine challenge in children with airway hyperresponsiveness to methacholine.…”

Section: Discussionmentioning

confidence: 99%

Airway re-narrowing following deep inspiration in asthmatic and nonasthmatic subjects

Salome¹,

Thorpe²,

Diba³

et al. 2003

Eur Respir J

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After bronchoconstriction, deep inspiration (DI) causes dilatation followed by airway re-narrowing. Re-narrowing may be faster in asthmatic than nonasthmatic subjects. This study investigated the relationship between re-narrowing and the magnitude of both DI-induced dilatation and the volume-dependence of respiratory system resistance (Rrs) during tidal breathing.In 25 asthmatic and 18 nonasthmatic subjects the forced oscillation technique was used to measure Rrs at baseline and after methacholine challenge, during 1 min of tidal breathing, followed by DI to total lung capacity (TLC) and passive return to functional residual capacity (FRC). Dilatation was measured as the decrease in Rrs between end tidal inspiration and TLC, re-narrowing as Rrs at FRC immediately after DI, as per cent Rrs at end-tidal expiration, and volume dependent tidal fluctuation as the difference between mean Rrs at end-expiration and end-inspiration.Asthmatic subjects had greater re-narrowing, less dilatation, and greater tidal fluctuations both at baseline and after challenge. Re-narrowing correlated with baseline tidal fluctuation and inversely with dilatation. Both baseline tidal fluctuation and dilatation were significant independent predictors of re-narrowing.Following deep inspiration-induced dilatation, faster airway re-narrowing in asthmatic than nonasthmatic subjects is associated not only with reduced deep inspiration-induced dilatation but also with some property of the airways that is detectable prior to challenge as an increased volume dependence of resistance. It is well recognised that the response of the airways to deep inspiration (DI) differs in asthmatic and nonasthmatic subjects. Following airway narrowing induced by inhaled methacholine, DI causes dilatation of the airways in both asthmatic and nonasthmatic subjects. However, the magnitude of the dilatation is usually less in asthmatic than in nonasthmatic subjects [1,2]. It has been suggested that the inability of DI to overcome bronchoconstriction is a fundamental abnormality of asthma, and could contribute to airway hyperresponsiveness [1].The amount of residual dilatation measured after a DI is likely to be determined both by the degree to which the airways distend in response to the inflationary pressure of a DI and by the rate at which they re-narrow following the release of the distending force. After a single DI, it can take more than a minute for the airways of a healthy subject to renarrow to pre-DI calibre [3]. Using the forced oscillation technique to measure airway resistance continuously throughout a DI, JENSEN et al.[4] measured the extent of both dilatation and re-narrowing, and found that asthmatic subjects both dilated less and re-narrowed more than healthy subjects. They concluded that these differences were attributable to differences in the behaviour of airway smooth muscle (ASM), most likely due to an increase in the stiffness of asthmatic ASM making it unresponsive to stretch. These findings imply that there is an inverse correlation b...

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Section: Discussionmentioning

confidence: 99%

Airway re-narrowing following deep inspiration in asthmatic and nonasthmatic subjects

Salome¹,

Thorpe²,

Diba³

et al. 2003

Eur Respir J

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“…The removal of glottic influences appears to be made feasible by controlling the variation of R~ and Xrs with respiratory phase MARCHAL et al, 1999). These monofrequency studies have assessed pre-school children during bronchoconstriction using Z~s,G.…”

Section: Recent Applications Of Fot In Paediatric Subjectsmentioning

confidence: 99%

“…The partitioning of Raw from tissue components is often of interest. Also, the potential to measure Zrs during sleep and artificial ventilation is of great value, and uncooperative pre-school children can also be assessed (LEBECQUE and STANESCU, 1997;JACKSON et al, 1996;STOCKS, 1996;MARCHAL et al, 1999;LOOS et al, 2000;DELACOURT et al, 2000).…”

Section: Clinical Aspects Of Impedance Measurementsmentioning

confidence: 99%

Respiratory input impedance measurement: Forced oscillation methods

MacLeod

Birch

2001

Med. Biol. Eng. Comput.

152

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The paper reviews how forced oscillation techniques (FOT) for measuring respiratory input impedance Zrs,in have recently been used in clinical applications. Zrs,in is clinically relevant, as it provides data on both the resistive, Rrs, and nonresistive, Xrs, components of the respiratory system. Additionally, when excitatory test signals extending into low- (<4 Hz) or high-frequency (>100 Hz) ranges are used, reliable partitioning of lung tissue from airway components is feasible. Adult and paediatric studies examining the use of Zrs,in for routine lung-function assessment, sleep and mechanical ventilation are reviewed. For clinicians, Zrs,in repeatable and sensitive to airway resistance. It is helpful for assessing unco-operative and severely obstructed patients, for monitoring mechanics during artificial ventilation and for tracking airway closure during sleep studies. For paediatricians, longitudinal studies of the growth and development of the respiratory system can also be made using Zrs,in. Forced oscillation techniques, however, require further standardisation, and Zrs,in is limited by upper-airway shunt artifacts. In conclusion, measurement of Zrs,in using FOT is an important and sophisticated non-invasive lung-function test, showing good potential for future clinical applications.

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“…Rrs also changes with flow associated with turbulence and other effects and in anaesthetised children can change two-fold with a three-fold change in flow under isovolumetric conditions [38]. Agonists can modulate the volume dependence of Rrs [39,40], which may have contributed to the changes in Rrs and Rrs SD in asthma and with BD. However, the effects of a BD on median Rrs were similar in both groups and no changes were observed in tidal volume with BD or between asthma and controls.…”

Section: Variation In Rrsmentioning

confidence: 99%

Airway resistance variability and response to bronchodilator in children with asthma

Lall¹,

Cheng²,

Hernández³

et al. 2007

European Respiratory Journal

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Variability of airway function is a feature of asthma, spanning timescales from months to seconds. Short-term variation in airway resistance (Rrs) is elevated in asthma and is thought to be due to increased variation in the contractile activation of airway smooth muscle. If true, then variation in Rrs should decrease in response to bronchodilators, but this has not been investigated.Using the forced oscillation technique, Rrs and the variation in Rrs from 4-34 Hz were measured in 39 children with well-controlled mild-to-moderate asthma and 31 healthy controls (7-13 yrs) before and after an inhaled bronchodilator (200 mg salbutamol) or placebo.In agreement with other findings, baseline Rrs at all frequencies and the SD of Rrs (Rrs SD) below 14 Hz were found to be elevated in asthma while neither forced expiratory volume in one second nor the mean forced expiratory flow between 25 and 75% of forced vital capacity were different compared with controls. The present authors found that Rrs SD changed the most of any measurement in asthma, and this was the only measurement that changed significantly more in children with asthma following bronchodilator administration.The present results show that like airway narrowing, short-term airway variability of resistance may be a characteristic feature of asthma that may be useful for monitoring response to therapy.

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Methacholine-induced volume dependence of respiratory resistance in preschool children

Cited by 30 publications

References 30 publications

Airway re-narrowing following deep inspiration in asthmatic and nonasthmatic subjects

Airway re-narrowing following deep inspiration in asthmatic and nonasthmatic subjects

Respiratory input impedance measurement: Forced oscillation methods

Airway resistance variability and response to bronchodilator in children with asthma

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