Chest
Clinical InvestigationsCholinergic Bronchomotor Tone in COPD: Estimates of Its Amount in Comparison with That in Normal Subjects
Section snippets
Subjects and Methods
All subjects were recruited from Hines VA Hospital. Those with COPD were outpatients who had chronic bronchitis and/or emphysema as defined by recently revised criteria of the American Thoracic Society.8 All had airflow limitation (FEV, less than 70 percent of the predicted value) and a history of cigarette smoking equivalent to at least one pack per day for ten years. Patients with any features of asthma, allergies, peripheral eosinophilia or elevated serum IgE levels were excluded. None was
Results
General features of the 41 subjects are present in Table 1. For simplicity they are divided into four groups based on their baseline FEV1 values. The normal subjects could be divided without overlap of baseline FEV, into smokers and nonsmokers, and the patients with COPD were divided into “mild” and “moderate” by virtue of a baseline FEV, of above or below 55 percent of predicted. Although none of the subjects in this study had baseline FEV, values below 31 percent of predicted, it should be
Discussion
The principal aim of this study was to estimate cholinergic tone in patients with COPD in comparison with normal subjects. We estimated cholinergic tone by measuring the increment in FEV, when cholinergic tone is abolished by an anticholinergic agent, atropine methonitrate. We consider first some factors which might confound the premise that the FEV, increment following anticholinergic administration can be equated with cholinergic tone.
First, performance of an FEV, requires an inspiration to
ACKNOWLEDGMENTS
We thank Donald P. Tashkin, M.D., UCLA School of Medicine, for helpful suggestions and David Smith, Ph.D., for valuable advice on statistical methods and analyses.
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Cited by (0)
Manuscript received November 21 1988; revision accepted March 15
Supported in part by Veterans Administration Research Service, Hines VA Hospital.