A lung ultrasound sign allowing bedside distinction between pulmonary edema and COPD:: the comet-tail artifact

Objective: Acute cardiogenic pulmonary edema and exacerbation of chronic obstructive pulmonary disease (COPD) can have a similar clinical presentation, and X-ray examination does not always solve the problem of differential diagnosis. The potential of lung ultrasound to distinguish these two disorders was assessed. Design: Prospective clinical study. Setting: The medical ICU of a university-affiliated teaching hospital. Patients: We investigated 66 consecutive dyspneic patients: 40 with pulmonary edema and 26 with COPD. In addition, 80 patients without clinical and radiologic respiratory disorders were studied. Measurements: The sign studied was the comet-tail artifact arising from the lung wall interface, multiple and bilaterally disseminated to the anterolateral chest wall. Results: The feasibility was 100 %. The length of the examination was always under 1 min. The described pattern was present in all 40 patients with pulmonary edema. It was absent in 24 of 26 cases of COPD as well as in 79 of 80 patients without respiratory disorders. The sign studied had a sensitivity of 100 % and a specificity of 92 % in the diagnosis of pulmonary edema when compared with COPD. Conclusions: With a described pattern present in 100 % of the cases of pulmonary edema and absent in 92 % of the cases of COPD and in 98.75 % of the normal lungs, ultrasound detection of the comet-tail artifact arising from the lung-wall interface may help distinguish pulmonary edema from COPD.