Chest
Determinants of Maximum Exercise Capacity in Patients with Chronic Airflow Obstruction
Section snippets
MATERIALS AND METHODS
For the purposes of this study, we defined CAO as clinically stable primary pulmonary disease with the following characteristics: (1) ratio of FEV1/FVC less than 0.70; (2) TLC greater than 80 percent of predicted; and (3) change in FEV1 after bronchodilator inhalation less than 15 percent.
In addition, we defined VLE as (1) fcmax less than 2 SD below predicted maximum; (2) primary symptom at maximal exercise consisting of dyspnea without other limiting symptom; and (3) exercise ventilation
RESULTS
The studied population (Table 1) consisted of 20 men with CAO ranging from mild to severe by expiratory spirometric data. They had a mean age of 56 ± 3 years (mean ± SE) and a mean ratio of FEV1/FVC of 0.50 ± 0.03. Racially, there were 18 white subjects and two black subjects.
The PIP and PEP for the sample equalled 70 ± 6 and 66 ± 6 percent of predicted from Black and Hyatt,16 respectively. The PIP and PEP fell below the lower limit of normal in 11 and eight patients, respectively.
All subjects
DISCUSSION
We developed a multiple linear regression model (equation 2) which describes in patients with CAO in terms of the resting pulmonary function parameters, FEV1, Dsb, and PIP. The use of PIP in multivariate prediction of has not previously been reported. In addition, we presented as a function of power output in watts (equation 1) for patients with CAO.
Equation 2 relates exercise capacity to the function of anatomic compartments of the respiratory system,
ACKNOWLEDGMENTS
We thank Mr. William A. Slivka, Mr. Thomas R. McCumber, and Mr. James A. Godville for technical assistance on this project.
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Presented in part at the 51st Annual Scientific Assembly, American College of Chest Physicians, New Orleans, Oct 30, 1985.
Supported by WRAMC Department of Clinical Investigation research protocol 1717.
The opinions contained herein represent solely the views of the authors and are not to be construed as representing the views of the Department of Defense or the Department of the Army.
Manuscript received September 12; revision accepted December 9.