Carolyn Kanter, MD | Emergency Ultrasound Fellow
The Article:
Point-of-Care Ultrasonography for Evaluation of Acute Dyspnea in the ED. Zanobetti et al. (2017). Chest. 151(6): 1295-1301.
The Idea:
To determine the feasibility and diagnostic accuracy of bedside emergency ultrasound in the management of ED patients presenting with acute dyspnea.
The Study:
A prospective, blinded, observational study at one teaching hospital of all patients over age 18 who presented to the ED with any degree of dyspnea who were admitted to the hospital and whose symptoms were not of traumatic origin. All patients were assessed physician with a history, exam, EKG and other studies as ordered by the treating physician. The treating physician then notified a blinded sonographer who performed a lung ultrasound (LUS), ECHO and IVC ultrasound on each patient. Both the sonographer and the treating physician (blinded to the US results) filled out a standardized form where they identified a maximum of 2 most likely diagnoses: CHF, ACS, pneumonia, pleural effusion, pericardial effusion, PE, COPD/asthma, pneumothorax, ARDS, or other. The ED & US diagnoses were compared with a final diagnosis made by 2 EM physicians who retrospectively reviewed the entire patient chart from ED presentation to hospital discharge. Time to US diagnosis and time to ED diagnosis were recorded and compared.
The Findings:
Of the 3487 patients with dyspnea evaluated between Jan-Dec 2013, 2683 were included in the study. Bedside US was performed on every study patient with an average time of 7 minutes (3 min LUS, 4min ECHO). The average time to US diagnosis was significantly less than the ED diagnosis (24min vs 186min, P=0.025). Concordance between US & ED diagnoses was optimal (0.8 < k < 1) for CHF, pericardial effusion, COPD/asthma, pneumothorax and good (0.6 < k < 0.8) for ACS, pneumonia, pleural effusion and other. Overall concordance across all diagnoses was good (k=0.71). In comparison with the final diagnosis, US was more sensitive than the standard ED evaluation in diagnosing CHF and less sensitive in diagnosing COPD/asthma and PE. There was no statistically significant difference between sensitivities & specificities of the US & ED diagnoses for ACS, pneumonia, PE, pericardial effusion, pleural effusion, pneumothorax and other causes. The US diagnosis was highly sensitive & specific for pneumothorax, pneumonia and pericardial effusion. The US diagnosis was very specific for ACS, pleural effusion, PE and other causes.
The Takeaway:
Bedside emergency US is a reliable and accurate adjunct in the ED evaluation of acute dyspnea and can lead to earlier diagnosis and rapid initiation of appropriate therapy.