Evaluation of diuretic therapy response in patients with pulmonary edema in the emergency department using the Reverse-FALLS protocol: A prospective observational study

Abstract

Cardiogenic pulmonary edema (CPE) is a serious condition that can result in impaired gas exchange and acute respiratory failure, often leading to high mortality. Diuretics are considered to be the cornerstone of CPE treatment. The doses of furosemide should be individualized according to the patient status and response. Lung ultrasonography has emerged as a reliable bedside tool for diagnosing and monitoring pulmonary congestion. By considering the extent of extravascular lung water and the inferior vena cava (IVC) size, clinicians can obtain objective data to guide them in determining the appropriate level of diuresis for the safe and effective treatment of pulmonary edema. However, data on the use of structured ultrasound protocols, such as the Reverse-FALLS protocol, to guide and monitor diuretic therapy in the emergency department are limited. This prospective, single-center observational study was conducted between April 1 and June 30, 2023, in an emergency department. Adult patients diagnosed with acute CPE were included. Bedside lung ultrasonography and IVC measurements were performed using the Reverse-FALLS protocol before and after intravenous loop diuretic therapy. The number of B-lines in 4 lung regions and IVC diameter changes were recorded. The primary outcome was the change in B-line counts following diuretic treatment. Secondary outcomes included IVC diameter changes and clinical outcomes. A total of 40 patients (mean age 73.7 +/- 12.7 years; 65% female) were included. After diuretic therapy, 82.5% of patients demonstrated a significant reduction in B-lines on lung ultrasonography. B-line counts decreased significantly in all lung regions (right upper P = .005, right lower P = .013, left upper P < .001, left lower P < .001). The mean interval between ultrasound assessments was 6.2 +/- 3.4 hours. Changes in IVC diameter were not statistically significant (P = .061). Higher brain natriuretic peptide levels were significantly associated with worse clinical outcomes (P = .021). Bedside lung ultrasonography using the Reverse-FALLS protocol effectively demonstrated a reduction in pulmonary congestion following diuretic therapy in patients with CPE. Monitoring B-line changes may allow individualized diuretic management without significant intravascular volume depletion, supporting the clinical utility of ultrasound-guided treatment in the emergency department.