-
The Journal of Allergy and Clinical... Oct 1996
Topics: Adolescent; Adult; Cholinergic Agents; Female; Humans; Male; Methacholine Chloride; Physical Exertion; Sex Factors; Skin Tests; Urticaria
PubMed: 8876564
DOI: 10.1016/s0091-6749(96)70137-9 -
Journal of Investigational Allergology... 2016
Topics: Adolescent; Adult; Asthma; Bronchial Provocation Tests; Bronchoconstrictor Agents; Cost-Benefit Analysis; Female; Humans; Male; Methacholine Chloride; Middle Aged
PubMed: 27164632
DOI: 10.18176/jiaci.0026 -
American Journal of Respiratory and... Oct 2014
Topics: Airway Resistance; Bronchial Provocation Tests; Bronchoconstriction; Bronchoconstrictor Agents; Humans; Inhalation; Male; Methacholine Chloride; Muscle, Smooth
PubMed: 25317460
DOI: 10.1164/rccm.201409-1651ED -
Airway responsiveness to methacholine and deep inhalations in subjects with rhinitis without asthma.The Journal of Allergy and Clinical... Feb 2008Airway hyperresponsiveness in asthma is believed to be caused in part by the inability of deep inspirations to modulate airway narrowing.
BACKGROUND
Airway hyperresponsiveness in asthma is believed to be caused in part by the inability of deep inspirations to modulate airway narrowing.
OBJECTIVE
We investigated whether deep inspirations taken before or after methacholine inhalation attenuate bronchoconstriction in subjects with rhinitis. The results were compared with a group of healthy subjects.
METHODS
Ten subjects with rhinitis without asthma and 10 healthy subjects were studied on 3 different occasions at random. Bronchial challenges were performed with a single dose of methacholine known to decrease the FEV(1) by 17% to 40%. Challenges were performed with avoidance of deep inspirations, or with 5 deep inspirations preceding or following the inhalation of methacholine. Lung function measurements were specific airway conductance, forced expiratory flow at 30% to 40% of vital capacity on a maneuver started from end-tidal inspiration (partial flow), and residual volume (partial residual volume).
RESULTS
In healthy subjects, deep inspirations taken after methacholine caused less changes in specific airway conductance, partial flow, and partial residual volume (P < .005 for all) than deep inspirations taken before methacholine or avoidance. In subjects with rhinitis, methacholine produced similar functional changes independently of the presence or absence of any deep inspirations. Compared with normal subjects, the attenuating effects of deep inspirations after methacholine on partial flow and partial residual volume were blunted in the subjects with rhinitis (P = .02 and P = .05, respectively).
CONCLUSION
The ability to dilate methacholine-constricted airways by deep inspirations is impaired in subjects with rhinitis, possibly because of an abnormal behavior of airway smooth muscle.
Topics: Administration, Inhalation; Adult; Bronchi; Bronchial Provocation Tests; Bronchoconstrictor Agents; Female; Humans; Inhalation; Male; Methacholine Chloride; Pulmonary Ventilation; Residual Volume; Rhinitis
PubMed: 17980415
DOI: 10.1016/j.jaci.2007.09.009 -
Chest Oct 2002
Topics: Bronchial Hyperreactivity; Bronchial Provocation Tests; Dose-Response Relationship, Drug; Female; Forced Expiratory Volume; Humans; Male; Methacholine Chloride; Respiratory Function Tests; Retrospective Studies; Sensitivity and Specificity
PubMed: 12377897
DOI: 10.1378/chest.122.4.1499 -
World Journal of Pediatrics : WJP Oct 2017Bronchial hyperresponsiveness (BHR) is a fundamental pathophysiological characteristic of asthma. Although several factors such as airway caliber can affect BHR, no...
BACKGROUND
Bronchial hyperresponsiveness (BHR) is a fundamental pathophysiological characteristic of asthma. Although several factors such as airway caliber can affect BHR, no study has established age-dependent cutoff values of BHR to methacholine for the diagnosis of asthma in children. We investigated the cutoff values of the methacholine challenge test (MCT) in the diagnosis of asthma according to age.
METHODS
A total of 2383 individuals aged from 6 to 15 years old were included in this study. MCTs using the five-breath technique were performed in 350 children with suspected asthma based on symptoms by pediatric allergists and in 2033 healthy children from a general population-based cohort. We determined the provocative concentration of methacholine producing a 20% decrease in forced expiratory volume in 1 second from baseline (PC). A modified Korean version of the International Study of Asthma and Allergies in Childhood questionnaire was used to distinguish asthmatics and healthy subjects. Receiver-operator characteristic curve analysis was used to assess the cutoff value of PC for the diagnosis of asthma.
RESULTS
Cutoff values of methacholine PC, which provided the best combination of diagnostic sensitivity and specificity, showed an increasing pattern with age: 5.8, 9.1, 11.8, 12.6, 14.9, 21.7, 23.3, 21.1, 21.1, and 24.6 mg/mL at ages 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15 years, respectively.
CONCLUSION
The application of different cutoff values of methacholine PC depending on age might be a practical modification for the diagnosis of asthma in children and adolescents with asthmatic symptoms.
Topics: Adolescent; Age Factors; Asthma; Bronchial Provocation Tests; Child; Female; Humans; Male; Methacholine Chloride; Muscarinic Agonists
PubMed: 28276002
DOI: 10.1007/s12519-017-0026-5 -
PloS One 2015To evaluate the changes in airway responsiveness to methacholine inhalation test (MIT) when performed after an eucapnic voluntary hyperpnea challenge (EVH) in athletes. (Clinical Trial)
Clinical Trial
AIM
To evaluate the changes in airway responsiveness to methacholine inhalation test (MIT) when performed after an eucapnic voluntary hyperpnea challenge (EVH) in athletes.
METHODS
Two MIT preceded (visit 1) or not (visit 2) by an EVH, were performed in 28 athletes and 24 non-athletes. Twelve athletes and 13 non-athletes had airway hyperresponsiveness (AHR) to methacholine, and 11 athletes and 11 non-athletes had AHR to EVH (EVH+).
RESULTS
The MIT PC20 post-EVH was significantly lower compared to baseline MIT PC20 by 1.3±0.7 doubling-concentrations in EVH+ athletes only (p<0.0001). No significant change was observed in EVH- athletes and EVH+/EVH- non-athletes. A significant correlation between the change in MIT PC20 post-EVH and EVH+/EVH- status and athlete/nonathlete status was found (Adjusted R2=0.26 and p<0.001). Three (11%) athletes and one (4%) non-athlete had a change in the diagnosis of AHR when MIT was performed consecutively to EVH.
CONCLUSION
The responsiveness to methacholine was increased by a previous indirect challenge in EVH+ athletes only. The mechanisms for such increase remain to be determined. MIT and EVH should ideally be performed on separate occasions as there is a small but possible risk to obtain a false-positive response to methacholine when performed immediately after the EVH.
TRIAL REGISTRATION
ClinicalTrials.gov NCT00686491.
Topics: Athletes; Bronchial Hyperreactivity; Bronchial Provocation Tests; Bronchoconstriction; Exercise; Female; Forced Expiratory Volume; Humans; Male; Methacholine Chloride; Respiratory System; Young Adult
PubMed: 25789614
DOI: 10.1371/journal.pone.0121781 -
American Journal of Physiology. Lung... Feb 2022There are renewed interests in using the parameter K of Salazar-Knowles' equation to assess lung tissue compliance. K either decreases or increases when the lung's...
There are renewed interests in using the parameter K of Salazar-Knowles' equation to assess lung tissue compliance. K either decreases or increases when the lung's parenchyma stiffens or loosens, respectively. However, whether K is affected by other common features of respiratory diseases, such as inflammation and airway smooth muscle (ASM) contraction, is unknown. Herein, male C57BL/6 mice were treated intranasally with either saline or lipopolysaccharide (LPS) at 1 mg/kg to induce pulmonary inflammation. They were then subjected to either a multiple or a single-dose challenge with methacholine to activate ASM to different degrees. A quasi-static pressure-driven partial pressure-volume (P-V) maneuver was performed before and after methacholine. The Salazar-Knowles' equation was then fitted to the deflation limb of the P-V loop to obtain K, as well as the parameter A, an estimate of lung volume (inspiratory capacity). The fitted curve was also used to derive the quasi-static elastance (E) at 5 cmHO. The results demonstrate that LPS and both methacholine challenges increased E. LPS also decreased A, but did not affect K. In contradistinction, methacholine decreased both A and K in the multiple-dose challenge, whereas it decreased K but not A in the single-dose challenge. These results suggest that LPS increases E by reducing the open lung volume (A) and without affecting tissue compliance (K), whereas methacholine increases E by decreasing tissue compliance with or without affecting lung volume. We conclude that lung tissue compliance, assessed using the parameter K of Salazar-Knowles' equation, is insensitive to inflammation but sensitive to ASM contraction.
Topics: Airway Resistance; Animals; Inflammation; Lipopolysaccharides; Lung; Lung Compliance; Male; Methacholine Chloride; Mice; Mice, Inbred C57BL; Muscle Contraction; Respiratory Mechanics
PubMed: 34936511
DOI: 10.1152/ajplung.00384.2021 -
Anesthesia and Analgesia Oct 1998It has been postulated that regional anesthesia, when feasible, is the best anesthetic approach in asthmatic patients. However, there are reports of severe bronchospasm...
UNLABELLED
It has been postulated that regional anesthesia, when feasible, is the best anesthetic approach in asthmatic patients. However, there are reports of severe bronchospasm during regional anesthesia. In the present study, we developed an experimental model of spinal (subarachnoid) anesthesia in guinea pigs and studied respiratory system responsiveness to aerosolized methacholine. The animals received sodium pentobarbital (50 mg/kg intraperitoneally), a tracheotomy, and mechanical ventilation. Four groups of animals were studied: guinea pigs that received spinal anesthesia with lidocaine (500 microL of 2% solution) (n = 7); guinea pigs that received spinal administration of isotonic sodium chloride solution (500 microL) (n = 7); guinea pigs that received an intraperitoneal injection of lidocaine (500 microL of 2% solution) (n = 6); and control guinea pigs (n = 7). The concentration of methacholine chloride that resulted in 50% of the maximal value of respiratory system elastance was lower in guinea pigs that received spinal anesthesia compared with the other three groups (P < 0.005 for control group, P < 0.01 for spinal saline group, and P < 0.05 for intraperitoneal lidocaine group). Our results suggest that spinal anesthesia results in an increase in pulmonary responsiveness to bronchoconstrictive stimuli.
IMPLICATIONS
Regional anesthesia has been considered the best anesthetic approach in asthmatic patients, although there are reports of severe bronchospasm. We developed an experimental model of spinal anesthesia with lidocaine in guinea pigs and studied respiratory responsiveness to methacholine, a bronchoactive agonist. Spinal anesthesia resulted in an increase in respiratory responsiveness.
Topics: Airway Resistance; Anesthesia, Spinal; Animals; Bronchoconstrictor Agents; Dose-Response Relationship, Drug; Guinea Pigs; Injections, Intraperitoneal; Lidocaine; Lung Volume Measurements; Male; Methacholine Chloride; Respiratory Mechanics
PubMed: 9768786
DOI: No ID Found -
The Journal of Allergy and Clinical... Nov 2007
Comparative Study Randomized Controlled Trial
Topics: Adult; Bronchial Provocation Tests; Bronchoconstrictor Agents; Female; Humans; Male; Methacholine Chloride; Nebulizers and Vaporizers
PubMed: 17637473
DOI: 10.1016/j.jaci.2007.06.020