The furosemide test in diagnosis of the cause of bronchial obstruction

The authors studied the rate of relief in cases of moderate, reversible airway obstruction after Furosemide administration. They examined 25 patients with bronchial asthma and chronic obstructive bronchitis (mean age 49 years). They found out that intravenous administration of Furosemide to patients with chronic obstructive bronchitis has a significant bronchodilating effect. The reduction of interstitial lung water and the decrease in congestion of airways mucosa in latent left ventricular failure may be the possible explanations of this phenomenon. After administration of Furosemide by inhalation, a mild decrease in airway obstruction was observed in asthmatic patients. The influence of Na+/K+/Cl- transport in the bronchial epithelium, or changes in PGE2 are supposed to represent the effective mechanisms. The authors conclude that Furosemide given intravenously to patients with moderate airflow limitation in connection with lung function tests may be helpful in the diagnosis of the nature of airway obstruction.