Diagnostic Accuracy of Lung Point-Of-Care Ultrasonography for Acute Heart Failure Compared With Chest X-Ray Study Among Dyspneic Older Patients in the Emergency Department

Abstract

Background: Acute heart failure and exacerbation of chronic obstructive pulmonary disease (COPD) are sometimes difficult to differentiate in the emergency department (ED).

Objectives: We sought to determine the classification performance of lung point-of-care ultrasound (POCUS) compared with chest x-ray study to identify acute heart failure in an older population.

Methods: We conducted a cohort study with additional health records review between March and September 2017. We included consecutive patients aged 50 years and older with shortness of breath from suspected acute heart failure or COPD. The reference standard was discharged diagnosis, ED diagnosis with confirmation by another physician, or diagnosis made by health record reviews. We calculated the classification performance of lung POCUS to diagnose acute heart failure as well as that of chest x-ray study, and compared them by exact McNemar test.

Results: There were 81 patients evaluated with lung POCUS, and 67 had acute heart failure. Emergency physicians identified acute heart failure by lung POCUS with sensitivity of 92.5% (95% confidence interval [CI] 83.4-97.5%) and specificity of 85.7% (95% CI 57.2-98.2%). The radiology reading of chest x-ray study had sensitivity of 63.6% (95% CI 50.9-75.1%) and specificity of 92.9% (95% CI 66.1-99.8%). The sensitivity of lung POCUS was significantly higher than that of chest x-ray study (p = 0.0003).

Conclusions: Lung POCUS in a real clinical setting was highly sensitive and specific in identifying acute heart failure, and performed better than chest x-ray in an older population.

Keywords: acute heart failure; emergency medicine; point-of-care ultrasonography; shortness of breath.