Twenty-eight patients were entered into the study, and all completed the four days of evaluation. There were 14 in each group and no patient had to be withdrawn because of side effects or lack of response. Three patients in each group had a less than 15 percent increase in FEVj during the study period. These patients were all current or former smokers, were considered to have COPD, and were not included in this report. Table 1 shows a comparison of the demographic characteristics and results of pulmonary function tests on entry, in the two groups of patients with reversible airways obstruction. This was an elderly population; there were six smokers in group A and seven in group B; the mean smoking histories were equal. The values for spirometric studies showed a moderate obstructive defect that was similar in both groups. pilocarpine eye drops
The overall response to therapy was good, based on clinical data and the mean change in pulmonary function test results. Figure 1 shows the day-by-day change in FEVX (percent predicted). The largest increase occurred during the first day; thereafter the improvement was more gradual, and at the end of the study both groups had reached mean values of FEV! close to the lower limit of normal. Although the mean FE Vx was somewhat lower for group B at the beginning of the study, there was no significant difference in the original values or the magnitudes of change between groups (p = 0.17). A slight decline in FEV! occurred from day 3 to day 4 in the group receiving IV therapy; a similar, as yet unexplained, effect has been found by other investigators. The response in the FVC, FEF25-75%, and PEFR was along the same lines (Table 2). The rate of improvement in PEFR in the first 24 hours was not different between groups (data not shown).
The dyspnea and wheezing indices were equal at the onset of the study and improved to similar degrees in both groups. The mean DI in each group was close to 5 initially, which represents dyspnea on the least exertion and intermittently at rest. At the end of the study, the dyspnea index had improved similarly to approximately 3, ie, dyspnea only on walking stairs or > 90 m on level ground. Again, the improvement was slightly greater in group B, but the difference was not significant. Both groups showed a similar improvement in auscultatory evidence of wheezing. The initial wheezing index was approximately 3 in both groups, representing inspiratory and expiratory wheezing, and had improved similarly to about 1 at the conclusion of the study, ie, wheezing only on forced exhalation.
The initial values for arterial blood gases showed moderate hypoxia and respiratory alkalosis in both groups. No patient was severely hypoxic. The mean Pa02 was 69.2 mm Hg in group A and 69.5 mm Hg in group B and improved to similar degrees (Table 2). The mean values for serum theophylline levels were slightly below the conventional therapeutic range in both groups on entry, but were therapeutic at the end of the study (Fig 2). Minor side effects of treatment were noted in four patients in group B, two of whom complained of insomnia and two of palpitations, while one patient in group A complained of sleeplessness. None was of a serious nature, and no change in therapy was required.
Table 1—Patients and Pulmonary Function on Entry to Study
|Measurement||Group A||Group B|
|Age, yr||64.7± 11.1||61.5± 10.1|
|Smoking history, pack-years (n)||27.3 ± 12.1(6)||30± 13.6(9)|
|FVC, % pred||59.5 ±15.3||52.4 ±8.3|
|FEVb % pred||50.6 ±15.4||41.9± 15.2|
|FEV/FVC, %||57.5 ±7.1||56.8 ±13.9|
|FEF25-75, % pred||30.1 ±14.6||22.5 ±13.0|
|Pa02, mm Hg||69.2 ±7.3||69.5 ±8.1|
|PaC02, mm Hg||29.0 ±3.5||30.4 ±2.5|
Table 2—Changes in Pulmonary Function
|Measurement||Group A||Group B|
|FVC, % pred||+ 24.1 ±13.0||+ 28.7± 11.7|
|FEV,, % pred||+ 29.5± 11.3||+ 37.2 ±14.3|
|FEVj/FVC, %||+14.6± 12.3||+12.5±8.1|
|PEFR, L/min||+ 152.7 ±69.4||+ 164.5 ±63.7|
|FEF25-75, % pred||+ 30.1 ±19.6||+ 29.6 ±9.9|
|Pa02, mm Hg||+ 6.7±9.3||+ 9.9±8.1|
Figure 1. Daily change in mean values for FEVj (% predicted) for groups A (open squares) and B (closed squares) from start to finish.
Figure 2. Mean serum theophylline concentration on entry and after four days of treatment. Brackets, SD.