Airway Response to Inhaled Methacholine in Normal Human Subjects

Jubber, Akeel; Foster, R W; Hassan, Nageeb; Carpenter, John R.; Small, R.C.

doi:10.1006/pulp.1993.1024

Cited by 6 publications

(5 citation statements)

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“…Three characteristics of the doseresponse curve need to be distinguished, as they describe phenomena that may vary independently of each other [Jubber et al 1993] and are likely the results of different pathophysiologic mechanisms. The curve is sigmoid in shape and can be characterized by (a) its position, measuring sensitivity, (b) its slope, measuring reactivity, and (c) its plateau, measuring the maximal response [Sterk and Bel, 1991;Woolcock et al 1984].…”

Section: Bronchoconstrictor Doseresponse Curvesmentioning

confidence: 99%

Noninflammatory mechanisms of airway hyper-responsiveness in bronchial asthma: an overview

Baroffio

Barisione

Crimi

et al. 2009

Ther Adv Respir Dis

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Airway hyper-responsiveness (AHR) is a cardinal feature of asthma. Its absence has been considered useful in excluding asthma, whereas it may be present in other diseases such as atopic rhinitis and chronic obstructive pulmonary disease. AHR is often considered an epiphenomenon of airway inflammation. Actually, the response of airways to constrictor stimuli is modulated by a complex array of factors, some facilitating and others opposing airway narrowing. Thus, it has been suggested that AHR, and perhaps asthma, might be present even without or before the development of airway inflammation. We begin this review by highlighting some terminological and methodological issues concerning the measurement of AHR. Then we describe the neurohumoral mechanisms controlling airway tone. Finally, the pivotal role of airway smooth muscle and internal and external modulation of airway caliber in vivo are discussed in detail.

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Section: Bronchoconstrictor Doseresponse Curvesmentioning

confidence: 99%

Noninflammatory mechanisms of airway hyper-responsiveness in bronchial asthma: an overview

Baroffio

Barisione

Crimi

et al. 2009

Ther Adv Respir Dis

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“…Although there are conflicting observations regarding the role of the baseline airway calibre in influencing airway responsiveness in normal subjects (83,84), the situation is more clear‐cut in asthmatics. Boulet et al (85) established a correlation between airway wall thickness and airway responsiveness in asthmatic patients with fixed airway obstruction.…”

Section: Obesity and Airway Responsiveness/asthmamentioning

confidence: 99%

Respiratory complications of obesity

Jubber¹

2004

International Journal of Clinical Practice

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103

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Obesity is known to be a major risk factor of a whole range of cardiovascular, metabolic and respiratory disorders. It has been recognised that the pattern of regional fat distribution plays an important role in the pre-disposition of obese subjects to certain obesity-related complications. Derangement of parameters of lung function is determined to a large extent by the quantity and distribution of excess body fat with its potential to interfere with the mechanics of pulmonary physiology. Clinical, laboratory and epidemiological observations have established links between obesity and several breathing problems including obstructive sleep apnoea, obesity hypoventilation syndrome and asthma. However, in many respects, the pathophysiology of these links is not fully explored. In this article, the impact of obesity on pulmonary physiology and its association with the above-mentioned clinical conditions is discussed.

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“…Third, we chose a cut-off for sGaw at PC 40 , but other cut-offs have been suggested. 6,8,9,[12][13][14]30,31 While these different cut-offs would change the results slightly, we do not think they would change the main finding of the study. Fourth, we acknowledge that the numerical results of our study are relevant only to the specific nebulizer and protocol we used, and since the protocol was conducted prior to the 2017 bronchial challenge standards, we are not able to report specific doses of methacholine.…”

Section: Discussionmentioning

confidence: 81%

“…The mean (SD) age of the group was 53 (11) years, with 141 women (67%) and 70 men (33%). The median (25-75 IQR) BMI was 29 (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) kg/m 2 . There were 80 (38%) current or former smokers, with a median use history of 15 The distribution of demographics among the four groups is shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…However, we tried to validate the clinical diagnosis based on the prescription of medications related to asthma in the year following the MCT (see Table S1 in the Supporting Information). Third, we chose a cut‐off for sGaw at PC 40 , but other cut‐offs have been suggested 6,8,9,12–14,30,31 . While these different cut‐offs would change the results slightly, we do not think they would change the main finding of the study.…”

Section: Discussionmentioning

confidence: 99%

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Validation of the clinical utility of sGaw as a response variable in methacholine challenge testing

et al. 2022

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Background and Objective Airway hyperresponsiveness (AHR) is commonly assessed by a methacholine challenge test (MCT), during which a provocative concentration causing a 20% reduction in forced expiratory volume in 1 second (FEV1) (PC20) < 8 mg/ml is considered a positive response. However, a fall in specific airway conductance (sGaw) may also have clinical significance. The purpose of this study was to assess whether AHR determined by a provocative concentration causing a 40% reduction in sGaw (PC40) < 8 mg/ml corresponds to a clinical diagnosis of asthma. Methods We analysed the changes in spirometry, lung volumes and sGaw during MCT in 211 randomly selected patients being evaluated for AHR to support a clinical diagnosis of asthma. Results The mean (SD) age of the group was 53 (15) years, with 141 women (67%). Overall lung function was normal, with FEV1 = 92 (15) % predicted, total lung capacity = 97 (13) % predicted and sGaw = 0.19 (0.15–0.23) L/s/cm H2O/L, (median, 25–75 IQR). There were many more patients who responded by PC40 only (n = 120) than who responded by PC20 (n = 52). There was no significant difference in asthma diagnosis between the PC20 (98%) and PC40 (93%) groups, and we estimate 34% of patients with a diagnosis of asthma would have been classified as having no AHR if only the FEV1 criterion was used. Conclusion Changes in sGaw during MCT indicate clinically significant AHR in support of a clinical diagnosis of asthma among patients being evaluated for asthma.

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Airway Response to Inhaled Methacholine in Normal Human Subjects

Cited by 6 publications

References 0 publications

Noninflammatory mechanisms of airway hyper-responsiveness in bronchial asthma: an overview

Noninflammatory mechanisms of airway hyper-responsiveness in bronchial asthma: an overview

Respiratory complications of obesity

Validation of the clinical utility of sGaw as a response variable in methacholine challenge testing

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