Informed consent was obtained from 14 patients with COPD who were referred to this study by their physician and from six healthy nonsmoking volunteers obtained from laboratory personel. All patients with COPD had been heavy smokers but all had stopped a minimum of five years earlier; none of the healthy group was a smoker. Each subject underwent a complete physical examination, including a 12-lead ECG, complete pulmonary function test, and arterialized capillary blood gas determinations and pH analysis. The patients with COPD were randomly divided into a control and a treatment group. All subjects were to perform weekly maximum expiratory flow volume (MEFV) curves, pulmonary diffusing capacity (Deo), and graded exercise protocol with oximetry (SoxiOJ over a 21-week period. The data collected during the first three weeks would serve to establish baseline values. Then subjects in the treatment group and healthy group would take 400 mg of pentoxifylline three times daily for the ensuing 12 weeks. Each patient would be followed up for the six weeks after treatment with the medication was stopped.
One of the patients with COPD stopped taking pentoxifylline after two weeks because of gastric complaints. One of the control patients with COPD left the project after the third week. Three female and three male patients with COPD, ranging in age from 38 years to 71 years (mean = 57 years), completed the full 21-week therapeutic protocol. Three female and three male patients with COPD, ranging in age from 57 to 70 years (mean = 64 years), completed the 21-week control protocol. All six healthy volunteers (five men and one woman), ranging in age from 27 years to 50 years (mean = 40 years), completed their protocol. (Table 1 summarizes the pertinent clinical data from the patients with COPD: percent FEV, values were those of Knudson and coworkers; the values for predicted residual volume are from Goldman and Becklake.) cialis super active
Table 1—Description of COPD Population
Maximum expiratory flow volume curves were performed in triplicate. The curve with the highest sum of forced vital capacity (FVC) and 1-second forced expiratory volume (FEV,) was stored for further analysis. Total lung capacity (TLC) was calculated from the sum of the residual volume (measured by helium dilution) and vital capacity. Pulmonary diffusion capacity (Deo) was measured using the single breath method. Preexercise Deo values were measured in duplicate with a minimum of 20 minutes separating the two trials. The postexercise Deo was measured within one minute of the subject stopping exercise. Breath-hold time and alveolar volume were measured in accord with the Epidemiology Standardization Project.