Introduction: Inhaled anticholinergic drugs are often
recommended for use as a first-line therapy for patients with COPD
because they provide similar or more effective bronchodilating actions,
as well as fewer side effects. It is not known, however, which class of
bronchodilators is more advantageous for pulmonary hemodynamics,
particularly during exercise.
Objectives: To compare
the effects of oxitropium and fenoterol on pulmonary hemodynamics in
patients with COPD at rest and during exercise.
Patients: The study participants consisted of 20
consecutive male patients with stable COPD, a mean (± SD) age of
68 ± 8 years old, and an FEV1/FVC ratio of
47.5 ± 10.0%.
Methods: Eleven patients inhaled two
puffs of oxitropium, and nine patients inhaled two puffs of fenoterol.
Seven members of each group performed incremental exercise using a
cycle ergometer. The hemodynamic measurements with right heart
catheterization were performed by taking the average of three
consecutive respiratory cycles before and after the administration of
inhaled bronchodilators at rest and during exercise.
Results: At rest, despite a similar improvement of
spirometric data with the two drugs, fenoterol, not oxitropium, caused
significant increases in heart rate and cardiac output, a decrease in
pulmonary vascular resistance, and a deteriorated
Pao2. During exercise, however, both drugs
similarly attenuated elevations in the mean pulmonary arterial pressure
(40 ± 12 to 38 ± 10 mm Hg by oxitropium, and 41 ± 9 to
36 ± 9 mm Hg by fenoterol), the mean pulmonary capillary wedge
pressure, and the mean right atrial pressure.
Conclusion: Our findings indicate that both classes of
bronchodilators are equally beneficial in the attenuation of right
heart afterload during exercise in patients with
BPM = beats per minute; CI = cardiac index; CO = cardiac output;
HR = heart rate; PAP = pulmonary arterial pressure;Δ
PAP = change in mean pulmonary arterial pressure;
PCWP = pulmonary capillary wedge pressure;
Pvo2 = mixed venous oxygen tension;
PVR = pulmonary vascular resistance; RAP = right atrial pressure;
SBP = systemic blood pressure