Background: Lung ultrasonography is increasingly used in the emergency department (ED) as a standard adjunct in the evaluation of the breathless patient. The study objective was to ascertain the diagnostic accuracy of lung and cardiac ultrasound in undifferentiated dyspneic ED patients.
Methods: We conducted this prospective observational study on patients presenting with dyspnea in the ED of a tertiary hospital. The sonographers who performed lung and cardiac ultrasound according to a locally-designed protocol were blinded to clinical and radiologic results. Ultrasonographic findings were subsequently compared with the final adjudicated diagnoses.
Results: Between February and August 2015, 231 patients were recruited. There was male predominance (63.2%) with a mean age of 67.8 years. Overall, lung ultrasonography yielded correct diagnoses in 68.3% of patients. Our protocol had likelihood ratios of 3.63 [95% confidence interval (CI): 2.44-5.40], 3.73 (95% CI: 2.50-5.57) and 6.31 (95% CI: 3.72-10.72) for positive findings; and 0.42 (95% CI: 0.29-0.63), 0.35 (95% CI: 0.25-0.50), and 0.40 (95% CI: 0.28-0.56) for negative findings in the diagnoses of pneumonia, pulmonary edema, and chronic obstructive pulmonary disease or asthma, respectively. Addition of bedside echocardiography was able to differentiate cardiogenic from nephrogenic pulmonary edema in 70% of patients.
Conclusions: Lung ultrasonography, when complemented with other tools of investigation, aids evaluation, allows for earlier treatment and more accurate disposition of undifferentiated dyspneic patients in the ED. The addition of cardiac ultrasound was not able to reliably differentiate the causes of pulmonary edema.
Keywords: Emergency department (ED); dyspnea; pneumonia; pulmonary edema; ultrasonography.