Changes of respiratory function induced by furosemide in a group of mild cardiopathic patients

Respiratory function (with flow-volume curve) before and after acute e.v. administration of furosemide was studied in 22 mild cardiopathic patients without clinical and radiological signs of cardiac failure. A variable degree of small airways obstruction was present in 17 patients (i.e. abnormality in at least one of these parameters: MEF25, MEF50, ΔMEF50, IFV). Furosemide completely reversed the obstruction in 11 patients and improved it significantly in the remaining 6. The observed response to furosemide suggests that the increase of small airways resistance could depend on an increased pulmonary fluid content either due to interstitial edema or to vascular congestion alone, as a consequence of left ventricle failure. We suggest therefore that the measurement of small airways function before and after furosemide is a useful tool for the early detection of subclinical cardiac failure. ________________________________________