Study objective: Systemic administration of β-agonist and anticholinergic drugs markedly impair normal autonomic heart rate control. The purpose of this study was to quantify and compare the effects of therapeutic doses of inhaled albuterol and ipratropium on autonomic control of the cardiovascular system.
Design: Randomized, double-blind, placebo-controlled, crossover design study.
Setting: Tertiary-care hospital.
Subjects: Twelve healthy male volunteers.
Interventions: Subjects self-administered four puffs through a spacer device from one of three identical inhalers containing albuterol (100 µg per puff), ipratropium (20 µg per puff), or placebo in three different testing sessions.
Measurements: ECG and noninvasive continuous BP traces were recorded at baseline and from 45 to 75 min after administration of the drug. Autonomic control of the cardiovascular system was quantified by analysis of spontaneous baroreflex sensitivity and power spectral analysis of heart rate variability.
Results: Neither albuterol nor ipratropium caused a significant alteration in baroreflex sensitivity, normalized low-power frequency, or normalized high-power frequency. No adverse effects were reported by subjects.
Conclusions: Inhalation of four puffs of albuterol (400 µg) or ipratropium (80 µg) does not alter the autonomic control of the cardiovascular system in young, healthy male subjects.