Controlled Delivery of 80mg Aerosol Furosemide Does Not Achieve Consistent Dyspnea Relief in Patients.

Abstract

Aerosol furosemide may be an option to treat refractory dyspnea, though doses, methods of delivery, and outcomes have been variable. We hypothesized that controlled delivery of high dose aerosol furosemide would reduce variability of dyspnea relief in patients with underlying pulmonary disease. Seventeen patients with chronic exertional dyspnea were recruited. Patients rated recently recalled breathing discomfort on a numerical rating scale (NRS) and the multidimensional dyspnea profile (MDP). They then performed graded exercise using an arm-ergometer. The NRS was completed following each exercise grade, and the MDP was repeated after a pre-defined dyspnea threshold was reached. During separate visits, patients received either aerosol saline or 80mg of aerosol furosemide in a randomized, double-blind, crossover design. After treatment, graded exercise to the pre-treatment level was repeated, followed by completion of the NRS and MDP. Treatment effect was defined as the difference between pre- and post-treatment NRS at end exercise, expressed in absolute terms as % Full Scale. "Responders" were defined as those showing treatment effect ≥ 20% of full scale. Final analysis included 15 patients. Neither treatment produced a statistically significant change in NRS and there was no significant difference between treatments (p = 0.45). There were four "responders" and one patient whose dyspnea worsened with furosemide; two patients were responders with saline, of whom one also responded to furosemide. No adverse events were reported. High dose controlled delivery aerosol furosemide was not statistically different from saline placebo at reducing exercise-induced dyspnea. However, a clinically meaningful improvement was noted in some patients.