A Modified Lung and Cardiac Ultrasound Protocol Saves Time and Rules in the Diagnosis of Acute Heart Failure

Background

Multiorgan ultrasound (US), which includes evaluation of the lungs and heart, is an accurate method that outperforms clinical gestalt for diagnosing acutely decompensated heart failure (ADHF). A known barrier to ultrasound use is the time needed to perform these examinations.

Objective

The primary goal of this study was to determine the test characteristics of a modified lung and cardiac US (LuCUS) protocol for the accurate diagnosis of ADHF.

Methods

This was a secondary analysis of a prospective observational study that enrolled adult patients presenting to the emergency department with undifferentiated dyspnea. Intervention consisted of a modified LuCUS protocol performed by experienced emergency physician sonographers. A positive modified LuCUS protocol was defined as the presence of B+ lines in both the left and right anterosuperior lung zones, plus a left ventricular ejection fraction <45%. If all three of these findings were not present, the modified LuCUS result was interpreted as negative for ADHF. The primary objective was measured by comparing US findings to final diagnosis independently determined by two physicians, both blinded to US findings and each other's final diagnosis.

Results

We analyzed data on 99 patients; 36% had a final diagnosis of ADHF. The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of the modified LuCUS protocol are 25% (95% confidence interval [CI] 14–41%), 100% (95% CI 94–100%), undefined, and 0.75 (95% CI 0.62–0.91%), respectively. This modified protocol takes on average 1 min and 32 sec to complete.

Conclusion

The point estimate for the specificity of the modified LuCUS protocol in this pilot study, accomplished by a reanalysis of data collected for a previously reported investigation of the full LuCUS protocol, was 100% for the diagnosis of ADHF.