[Effects of inhaled and intravenous furosemide on bronchial hyperresponsiveness in patients with chronic congestive heart failure].
We studied the effects of inhaled and intravenous furosemide (40 mg) on bronchial responsiveness to acetylcholine (ACh) in patients with chronic congestive heart failure. The measurement of bronchial responsiveness was performed by inhaling doses of ACh and calculating the provocative concentration of ACh needed to cause a 20% fall in FEV1.0 (PC20-ACh). Intravenous furosemide (N = 11) had a marked diuretic effect (urine output 1014 ml (SEM 156) in 2 hours), but had no effect on resting pulmonary function and PC20-ACh. In contrast, inhaled furosemide (N = 10) had no effect on urine output and resting pulmonary function, but caused significant increase in PC20-ACh from 2.74 (GSEM 1.28) to 8.47 (GSEM 1.22) mg/ml (p less than 0.05). We conclude that inhaled furosemide, but not intravenous furosemide reduces bronchial hyperresponsiveness to ACh in patients with chronic congestive heart failure. The mechanism of this effect appears to be related to the ion transport system of airway epithelium.