Around 1 million Americans with acute heart failure (ADHF) visit the emergency department (ED) annually [1], many of whom are transported to the hospital by ambulance. Assessments commonly used by prehospital providers, such as chest auscultation, capnography, and oxygen saturation, perform poorly at differentiating ADHF from other causes of dyspnea [2]. A recent meta-analysis found the sensitivity of a stethoscope, physical exam, and medical history was only 37% accurate for correctly diagnosing respiratory conditions [3].

Differentiating ADHF from other causes of dyspnea is crucial, as the treatment pathway for different diseases differs greatly [1]. Patients experiencing ADHF who are treated for chronic obstructive pulmonary disease (COPD) require more aggressive therapy later in the disease course and have longer hospital stays [4,5]. Additionally, early diagnosis and aggressive treatment for ADHF is associated with improved mortality and decreased hospital (LOS) [[6], [7], [8]].

Lung ultrasound (LUS) has emerged as a key tool to facilitate earlier and more accurate diagnosis and a reduced time to appropriate treatment. A diagnostic meta-analysis and analysis of test-treatment thresholds in ADHF found that of all the diagnostic strategies including history, exam and chest radiography, LUS was the only binary test with sufficient accuracy to immediately direct the start of ADHF treatment on its own [9]. Moreover, in a recent randomized trial, LUS led to a >20-fold reduction in time to accurate diagnosis in ED patients with undifferentiated dyspnea [10].

With the limitations of the prehospital environment and the importance of prompt disease-specific treatment, several emergency medical service (EMS) agencies have piloted programs utilizing LUS to help guide prehospital diagnosis and clinical decision making [[11], [12], [13], [14]]. Yet limited evidence exists regarding the diagnostic accuracy of LUS performed by prehospital providers for the diagnosis of ADHF. The goal of this systematic review and meta-analysis was to evaluate the diagnostic accuracy and clinical impact of prehospital LUS for the diagnosis of ADHF.