Paramedic identification of acute pulmonary edema in a metropolitan ambulance service.

INTRODUCTION: Acute pulmonary edema (APE) is a common cause of acute dyspnea. In the prehospital setting, it is often difficult to differentiate APE from other causes of shortness of breath (SOB). Radiography and echocardiography aid in the identification of APE but are often not available. There is little information on how accurately ambulance paramedics identify patients with APE. Objectives. This study aimed to 1) describe the prehospital clinical presentation and management of patients with a clinical diagnosis of APE and 2) compare the accuracy of coding of APE by paramedics against the emergency department (ED) medical discharge diagnosis.
METHODS: This study included a retrospective cohort of all patients who had episodes identified as APE by ambulance paramedics and were transported to a metropolitan hospital ED in 2011. Two databases were used: an ambulance database and the Emergency Department Information System. The ED medical discharge diagnosis (using International Statistical Classification of Diseases and Related Problems, 10th Revision, Australian Modification [ICD-10-AM] codes) was used as the comparator with paramedic-assigned problem codes for APE. The outcomes for the study were the positive predictive value, i.e., the proportion of patients identified as having APE in the ambulance database who also had an ED discharge diagnosis of APE, and the sensitivity of paramedic identification of APE, i.e., the proportion of patients with an ED discharge diagnosis of APE that were correctly identified as APE by the ambulance paramedics.
RESULTS: Four hundred ninety-five patients were transported to an ED with APE identified by the paramedics as the primary problem code. Shortness of breath, crepitations, high systolic blood pressure, and chest pain were the most common presenting signs and symptoms. Pink frothy sputum was rare (3% of patient episodes of APE). One hundred eighty-six patients received an ED discharge diagnosis of APE, i.e., a positive predictive value of 41%. Of 631 ED presentations with APE, paramedics identified 186, i.e., a sensitivity of 29%.
CONCLUSION: Acute pulmonary edema is difficult to identify in the prehospital setting because of the variability in the signs and symptoms associated with this condition. Improved identification of APE is essential in the initiation of appropriate and timely care. Ambulance paramedics need to be aware of such variability when considering patients who may be suffering from APE. Key words: pulmonary edema; acute pulmonary edema; emergency medical services; ambulance; paramedics.