A consideration was undertaken to ...

A consideration was undertaken to compare the cardiac and ventilatory rejoinders to different types of exercise between 12 patients with COPD and ten normal age-matched repress subjects. Both groups attained comparable heart rates and the percentage of their maximum predicted heart rate. Patients had a higher heart rate and VE with a lower [Osub2]P at each level of work load. Patients had a mean VT which approximated their [FEVsub1] and increased their VE predominantly by way of increasing their respiratory frequency. During the gentle intensity test, despite the differences in work load, the patients had comparable heart rates and VE No resting spirometric value accurately predicted work load, VE or maximal [VOsub2] We deduce that patients have a reduc work tolerance that is not adequately explained on their reduced lung function. Thus, cardiac factors, deconditioning, and the dyspneic sensation may be determinants of exercise limitation in any patients. (Chest 1989; 96:11-17)

Patients with obstructive lung disease exhibit several ventilatory abnormalities which may affect their ability to exercise. These include: an increased dead space ventilation, a reduc ventilatory keep an increased work of breathing, and mechanical question at issues related to the position of the diaphragm.[1-4]

While there is an abundance of literature concerning exercise abnormalities in patients with COPD there are hardly any studies in which age-matched reign over subjects are compared with patients with COPD In particular, there is a paucity of studies in which patients with COPD are compared with normal age-matched bridle subjects with regard to exercise of varying intensity and duration. For these reasons, we designed a contemplation to compare patients with COPD and normal repress subjects in a maximal incremental ordeal a high intensity steady state exercise exhibition and a more prolonged cheap intensity exercise test. Our objective was to compare noninvasively the ventilatory and cardiac answers between patients with moderate to stiff obstructive lung disease and normal age-matched sway subjects to these three marks of exercise.

There are several formulae for predicting the maximal exercise VE[5-8] and the [MVOsub2][9-11] However, the relationship between these formulae and the actual values obtained during exercise in individual patients with obstructive lung disease is les than whole Moreover, the relationship between the maximal VE and [MVOsub2] to actual work performed has been level more variable.[12,13] This give an inkling ofs that factors other than ventilatory abnormalities may contribute to exercise limitation, at least in near patients.

A secondary goal of our subject of attention was to examine mechanisms of exercise limitation in patients with obstructive lung disease. The contemplation was approved by the Clinical Investigation and Human Use Committees at Brooke Army Medical Center

Methods

Patient Selection

The COPD patients consisted of 12 patients randomly pick outed from our clinic population. Patients had to have an [FEVsub1] les than 75 percent of predicted, an [FEVsub1]/FVC ratio les than 65 percent and no known cardiac disease on history, physical examination or ECG They had to be male patients, without a history of bronchospasm, without a latter illness, and had to be able to walk up undivided flight of stairs. All patients had entire pulmonary function studies performed forward a Cardiopulmonary Instruments 5000 Computerized Pulmonary Function Laboratory. The spirometric standards of Morris et al,[14] modified for back extrapolation, were utilized. The unbroken study was performed 1 to 30 days prior to the day of the exercise contemplation The control subjects consisted of randomly chooseed male patients completing an over-40 physical examination. They had to be without known cardiopulmonary disease by means of history, physical examination or ECG They also had to have a normal chest roentgenogram and normal spirometry.

meditation Protocol

Each control underwent the three types of exercise testing with a 20-minute interval period between each test. The exposes presented to the pulmonary function laboratory after a 3-h fast. Patients taking oral bronchodilators were instructed to take their medications at the regular time. Inhaled medications were withheld for 3 h or longer prior to the exercise proof Baseline spirometry was performed 30 to 60 min prior to the exercise examples The first test was a maximal IT. After 2 min of resting measurements, the enslaves started exercising at 25 W work. The work load was increased on 15 W each minute and terminated when the patient could not continue. We used the formula, maximal heart rate = 210 - 065 x age, to calculate the maximal predicted heart rate.[1] The other test consisted of a steady state high intensity standard (SS 75%). The bring under rules exercised for 6 min at 75 percent of the work load achieved upon the IT. The third exhibition consisted of a steady state cheap intensity test (SS 50%). The controls exercised for 20 min at 50 percent of the work load achieved forward the IT.