Pre-Hospital Lung Ultrasound Impact on Diagnosis

Prospective, randomized study using a phased implementation on patients being transported by EMS to the hospital for acute dyspnea. The investigators will include adults (>17yo) with a chief complaint of dyspnea and at least one of the following: bilateral lower extremity edema, orthopnea, wheezing or rales on auscultation, increased work of breathing, tachypnea (RR>20) or hypoxia (oxygen saturation <92%). Patients with fever (>100.4F), systolic blood pressure <90mmHg, those requiring immediate intubation, those found to have ST elevation myocardial infarction on EKG, or pregnant will be excluded. Eligible patients will be enrolled in the pre-hospital setting over a 12-month period. Randomization that will occur at the ambulance level using a stepped wedge cluster randomization trial design. Twenty-six full-time paramedics previously trained in LUS will perform a 2 or 4-view imaging protocol and interpret images in real-time to guide acute management. The diagnosis of AHF on LUS will be defined as bilateral B-lines (>2 B-lines in a zone in each hemi-thorax). A hospital diagnosis of AHF versus not HF will be determined through independent chart review by two blinded physicians and will serve as the criterion standard for final diagnosis. Diagnosis by paramedics, whether LUS was used, and treatment given pre-hospital will be tracked in ESO (an online EMS clinical documentation system). For the primary aim the investigators will compare pre-hospital provider diagnosis to final diagnosis to determine accuracy with and without the use of LUS.

Expected Results: The investigators anticipate the use of prehospital LUS will improve diagnostic accuracy for detecting AHF. This pilot study will set the groundwork for future larger studies assessing the clinical impact of prehospital LUS.