Effects of nebulized morphine sulfate on the exercise tolerance of the ventilatory limited COPD patient.

We have shown previously that the administration of morphine (0.8 mg/kg) to patients with COPD increases the VO2max by 19.3 percent. A recent study demonstrated that the administration of low-dose nebulized morphine (approximately 2 mg) increased the endurance time of patients with severe lung disease by 1 min (35 percent) with few systemic side effects. This double-blind crossover study evaluated the effects of various doses of nebulized morphine (0, 1, 4, and 10 mg) on the exercise tolerance and the psychologic status of COPD patients. In the present study, eight COPD patients (FEV1 = 0.90 +/- 0.26 L, workload max = 76 +/- 29 W, VO2max = 950 +/- 264 ml, VEmax = 34 +/- 7 L), who were ventilatory limited were tested on four separate days. On each testing day, the patients underwent incremental exercise testing and psychologic testing before and 45 min after receiving the nebulized solution. The mean changes (+/- SD) in the exercise test results after each of the four different regimens were as follows: [table: see text] Although there tended to be larger increases in the workload, VO2max, and VEmax after the largest dose of morphine, none of the changes was statistically significant. Likewise, there were no significant differences in spirometry, resting metabolic measurements, or psychologic test scores after the four different regimens. We conclude that aerosolized morphine in the doses used in this study has no significant beneficial effect on the exercise tolerance of patients with COPD.

Effects of buspirone on anxiety levels and exercise tolerance in patients with chronic airflow obstruction and mild anxiety.

The objective of this study was to determine if buspirone would alleviate anxiety and improve exercise tolerance of anxious patients with chronic airflow obstruction (CAO). Eleven male patients with mild to moderate anxiety and CAO completed this study comparing buspirone, 10 to 20 mg given three times a day, with placebo. Patients were evaluated with State Trait Anxiety Inventory, spirometry, 12-min walk, incremental exercise on a cycle ergometer to symptom limitation and measurement of dyspnea with a modified Borg scale at exercise levels and the end of each 2 min on 12-min walk. There were no significant differences in anxiety scores, work load, maximum oxygen consumption per minute, maximum expired volume per minute, PETCO2, PETO2, 12-min walking distance or dyspnea scores after 6 weeks of buspirone or placebo therapy. We conclude that administration of buspirone has no significant effect on anxiety levels, exercise capabilities or PETO2 or PETCO2 in patients with CAO and mild anxiety.

Reanalysis of the 12-minute walk in patients with chronic obstructive pulmonary disease.

The purpose of this study was to determine the correlation between different intervals in the 12-min walk test, to determine which of the intervals best correlated with maximal oxygen intake (VO2max) and maximal CO2 expelled (VCO2max) and to determine the degree of correlation between changes in the VO2max and changes in the walk test and spirometry. Nine elderly (age, 67 +/- 4 years) patients with moderate COPD (FEV1, 1.32 +/- 0.28 L) who were ventilatory limited were seen 6 times over a 14-week period. At each visit they performed spirometry, a 12-min walk, and a symptom-limited maximal exercise test. During the 12-min walk the distances traversed in each 2-min interval were recorded. A Borg score was obtained at the end of each 2 min. The distances that the patients walked in each 2-min interval were very similar, but the mean Borg score became higher the longer the patient walked. The Borg score after 2 min was 1.64 +/- 1.15, while the Borg score after 12 min was 5.70 +/- 3.59. The correlation coefficients between the distance walked at various intervals and the oxygen consumption (VO2)/kg (approximately 0.65) and the VCO2/kg (approximately 0.52) were very similar. However, changes in the VO2/kg were more closely correlated with changes in the 12-min walk (r = 0.72), than with changes in the 6-min walk (r = 0.64), the 4-min walk (r = 0.59), or the 2-min walk (r = 0.53). This latter observation suggests that the 12-min walk may be preferable to tests in which the patient walks 4 or 6 min for documenting changes in the exercise capabilities.