Temporal variability in the responses of individual canine airways to methacholine

Robert H Brown; David W Kaczka; Katherine Fallano; Sining Chen; Wayne Mitzner

doi:10.1152/japplphysiol.01348.2007

Back

Temporal variability in the responses of individual canine airways to methacholine

Journal article

Peer reviewed

Temporal variability in the responses of individual canine airways to methacholine

Robert H Brown, David W Kaczka, Katherine Fallano, Sining Chen and Wayne Mitzner

Journal of applied physiology (1985), Vol.104(5), pp.1381-1386

05/2008

DOI: 10.1152/japplphysiol.01348.2007

PMCID: PMC3154018

PMID: 18309091

View Online

Abstract

Previous work showed that individual airway size, before any spasmogen, varied widely in the same animals on different days. The effect of this variable baseline size on the airway response to a subsequent challenge is unknown. The present study examined how the variability in individual airway baseline size in dogs was related to that after methacholine challenge on 4 different days using high-resolution computed tomography scans. Dogs were anesthetized and ventilated, and on 4 separate days randomly varying between 1 and 8 wk apart, baseline scans were acquired, followed by a continuous intravenous infusion of methacholine at three rates in increasing order (17, 67, and 200 microg/min). As the measure of variability, we used the coefficient of variation (CV) of the four airway luminal measurements of each airway at baseline and at each dose of methacholine. For most airways, there was wide variability both between and within dogs in the response to a given dose of methacholine (CV = 33-38%). Airways with any level of methacholine stimulation had greater variability than those at baseline. The airway variability was greatest at the lowest dose of methacholine administered but was elevated at all the doses. In conclusion, there was substantial day-to-day variability in baseline airway size. Most importantly, the same dose of methacholine to the same individual airway showed even greater variability than that at baseline. If we consider that increased heterogeneity may potentiate clinical symptoms, then airway response variability may play an important role in the manifestation of airway disease.

Regression Analysis

Data Interpretation, Statistical

Animals

Asthma - physiopathology

Image Processing, Computer-Assisted

Time Factors

Methacholine Chloride - pharmacology

Dogs

Respiratory System - drug effects

Bronchodilator Agents - pharmacology

Tomography, X-Ray Computed

Infusions, Intravenous

Details

Title: Subtitle: Temporal variability in the responses of individual canine airways to methacholine
Creators: Robert H Brown - Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Public Health, Baltimore, MD 21205, USA. rbrown@jhsph.edu
David W Kaczka
Katherine Fallano
Sining Chen
Wayne Mitzner
Resource Type: Journal article
Publication Details: Journal of applied physiology (1985), Vol.104(5), pp.1381-1386
DOI: 10.1152/japplphysiol.01348.2007
PMID: 18309091
PMCID: PMC3154018
NLM abbreviation: J Appl Physiol (1985)
ISSN: 8750-7587
eISSN: 1522-1601
Publisher: United States
Grant note: HL 10342 / NHLBI NIH HHS P01 HL010342 / NHLBI NIH HHS P01 HL010342-40 / NHLBI NIH HHS
Language: English
Date published: 05/2008
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Radiology; Anesthesia
Record Identifier: 9984006365302771

Metrics

24 Record Views

11 Times Cited - Web of Science