Two‐minute tidal breathing methacholine bronchial challenge: Comparison of two jet nebulisers

2021 ◽  
Author(s):  
Zheng Zhu ◽  
Hongyu Wang ◽  
Yanqing Xie ◽  
Jiaying An ◽  
Jing Li ◽  
...  
Keyword(s):  
Tidal Breathing ◽  
Bronchial Challenge

Selected Contribution: Airway caliber in healthy and asthmatic subjects: effects of bronchial challenge and deep inspirations

2001 ◽  
Vol 91 (1) ◽  
pp. 506-515 ◽  
Author(s):  
Andrew Jensen ◽  
Haytham Atileh ◽  
Bela Suki ◽  
Edward P. Ingenito ◽  
Kenneth R. Lutchen
Keyword(s):  
Smooth Muscle ◽  
Healthy Subjects ◽  
Tidal Breathing ◽  
Bronchial Challenge ◽  
Lung Capacity ◽  
Single Breath ◽  
Airway Caliber ◽  
Lung Resistance ◽  
Before And After ◽  
Biological State

In 9 healthy and 14 asthmatic subjects before and after a standard bronchial challenge and a modified [deep inspiration (DI), inhibited] bronchial challenge and after albuterol, we tracked airway caliber by synthesizing a method to measure airway resistance (Raw; i.e., lung resistance at 8 Hz) in real time. We determined the minimum Raw achievable during a DI to total lung capacity and the subsequent dynamics of Raw after exhalation and resumption of tidal breathing. Results showed that even after a bronchial challenge healthy subjects can dilate airways maximally, and the dilation caused by a single DI takes several breaths to return to baseline. In contrast, at baseline, asthmatic subjects cannot maximally dilate their airways, and this worsens considerably postconstriction. Moreover, after a DI, the dilation that does occur in airway caliber in asthmatic subjects constricts back to baseline much faster (often after a single breath). After albuterol, asthmatic subjects could dilate airways much closer to levels of those of healthy subjects. These data suggest that the asthmatic smooth muscle resides in a stiffer biological state compared with the stimulated healthy smooth muscle, and inhibiting a DI in healthy subjects cannot mimic this.

scholarly journals Methacholine bronchial challenge using a dosimeter with controlled tidal breathing.

Thorax ◽  
1988 ◽  
Vol 43 (11) ◽  
pp. 896-900 ◽  
Author(s):  
M M Nieminen ◽  
A Lahdensuo ◽  
L Kellomaeki ◽  
J Karvonen ◽  
A Muittari
Keyword(s):  
Tidal Breathing ◽  
Bronchial Challenge

Airway reactivity in infants: a positive response to methacholine and metaproterenol

1987 ◽  
Vol 62 (3) ◽  
pp. 1155-1159 ◽  
Author(s):  
R. S. Tepper
Keyword(s):  
Challenge Test ◽  
Threshold Concentration ◽  
Base Line ◽  
Tidal Breathing ◽  
Airway Reactivity ◽  
Bronchial Smooth Muscle ◽  
Bronchial Challenge ◽  
Control Value ◽  
Residual Capacity ◽  
The Mean

Because the presence of bronchial smooth muscle reactivity in infants remains controversial, airway reactivity was assessed in 10 normal, asymptomatic male infants less than 15 mo of age by measuring the changes that occurred in the maximal expiratory flows at functional residual capacity (VmaxFRC) during a methacholine bronchial challenge test. Sleeping infants inhaled doubling concentrations of methacholine by 2 min of tidal breathing, starting with a concentration of 0.075 mg/ml, and the bronchial challenge was stopped when VmaxFRC decreased by at least 40%. The threshold concentration of methacholine required to produce a decrease in VmaxFRC by 2 SD's of the control value was 0.43 mg/ml (0.11–0.90). By a methacholine concentration of 1.2 mg/ml, all infants decreased VmaxFRC by at least 40% (range 40–75%), and the mean dose required to produce a 40% decrease was 0.72 mg/ml. The airway reactivity was not related to base-line flows. During the methacholine challenge, no infant developed wheezing, but the percent oxygen saturation for the group decreased significantly (P less than 0.05) from 94 to 92%. Following the methacholine, the infants inhaled the bronchodilator metaproterenol, and 10 min later, VmaxFRC returned to base line. This study demonstrates that infants exhibit airway reactivity as evidenced by bronchoconstriction with methacholine and the subsequent bronchodilation with metaproterenol.

Are tidal breathing indices useful in infant bronchial challenge tests?

1994 ◽  
Vol 17 (4) ◽  
pp. 225-230 ◽  
Author(s):  
Hazel Aston ◽  
Jane Clarke ◽  
Michael Silverman
Keyword(s):  
Tidal Breathing ◽  
Bronchial Challenge ◽  
Challenge Tests

Airway Responses to Deep Inspiration in Asthma by Different Bronchial Challenge

2012 ◽  
Vol 18 (2) ◽  
pp. 75-80
Author(s):  
Chang-Wook Min ◽  
An-Soo Jang ◽  
Young-Seok Ji ◽  
Nam-Jun Cho ◽  
Kang-Hyug Choi ◽  
...  
Keyword(s):  
Deep Inspiration ◽  
Bronchial Challenge ◽  
Airway Responses

Convective exchange between the nose and the atmosphere

1988 ◽  
Vol 64 (6) ◽  
pp. 2575-2581 ◽  
Author(s):  
F. R. Haselton ◽  
P. G. Sperandio
Keyword(s):  
Oscillatory Flow ◽  
High Efficiency ◽  
Underlying Mechanism ◽  
Ambient Atmosphere ◽  
Tidal Exchange ◽  
Upper Respiratory Tract ◽  
Oscillating Flows ◽  
Tidal Breathing ◽  
Convective Exchange ◽  
Upper Respiratory

It is generally accepted that there is little rebreathing of gas exhaled through the nose. A detailed physical model system has been used to quantify and identify the mechanisms responsible for this phenomenon. By the use of a cast of the upper respiratory tract and oscillating flows with a Reynolds number of 500 and nondimensional frequency of 1.6, corresponding to quiet tidal breathing through the nose, dye dilution measurements indicated an efficiency of tidal exchange of 0.95. Flow visualization studies performed to trace the expiratory flow, as well as the streamlines during steady inspiratory flow, support the hypothesis that the high efficiency of exchange is due to radical differences in the velocity fields between inspiratory and expiratory phases of this oscillatory flow. These findings confirm that convective gas exchange between the nose and the atmosphere is highly efficient; however, the underlying mechanism responsible for this exchange also maximizes the exposure of the respiratory system to aerosols contained in the ambient atmosphere.

Development and maintenance of force and stiffness in airway smooth muscle

2015 ◽  
Vol 93 (3) ◽  
pp. 163-169 ◽  
Author(s):  
Bo Lan ◽  
Brandon A. Norris ◽  
Jeffrey C.-Y. Liu ◽  
Peter D. Paré ◽  
Chun Y. Seow ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Solid State ◽  
Airway Smooth Muscle ◽  
Deep Inspiration ◽  
Contractile Apparatus ◽  
Tidal Breathing ◽  
Actomyosin Interaction ◽  
Filament Network

Airway smooth muscle (ASM) plays a central role in the excessive narrowing of the airway that characterizes the primary functional impairment in asthma. This phenomenon is known as airway hyper-responsiveness (AHR). Emerging evidence suggests that the development and maintenance of ASM force involves dynamic reorganization of the subcellular filament network in both the cytoskeleton and the contractile apparatus. In this review, evidence is presented to support the view that regulation of ASM contraction extends beyond the classical actomyosin interaction and involves processes within the cytoskeleton and at the interfaces between the cytoskeleton, the contractile apparatus, and the extracellular matrix. These processes are initiated when the muscle is activated, and collectively they cause the cytoskeleton and the contractile apparatus to undergo structural transformation, resulting in a more connected and solid state that allows force generated by the contractile apparatus to be transmitted to the extracellular domain. Solidification of the cytoskeleton also serves to stiffen the muscle and hence the airway. Oscillatory strain from tidal breathing and deep inspiration is believed to be the counter balance that prevents hypercontraction and stiffening of ASM in vivo. Dysregulation of this balance could lead to AHR seen in asthma.

Lower thresholds for bronchial challenge testing

Allergy ◽  
2004 ◽  
Vol 59 (10) ◽  
pp. 1125-1126 ◽  
Author(s):  
Tom Fardon ◽  
Graeme Currie ◽  
Daniel Lee ◽  
Brian Lipworth
Keyword(s):  
Bronchial Challenge ◽  
Challenge Testing
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