Lung ultrasound for monitoring cardiogenic pulmonary edema

Several studies address the accuracy of lung ultrasound (LUS) in the diagnosis of cardiogenic pulmonary edema (CPE) evaluating the interstitial syndrome, which is characterized by multiple and diffuse vertical artifacts (B-lines), and correlates with extravascular lung water. We studied the potential role of LUS in monitoring CPE response to therapy, by evaluating the clearance of interstitial syndrome within the first 24 h after Emergency Department (ED) admission. LUS was performed at arrival (T0), after 3 (T3) and 24 (T24) hours. Eleven regions were evaluated in the antero-lateral chest; the B-lines burden was estimated in each region (0 = no B-lines, 1 = multiple B-lines, 2 = confluent B-lines/white lung) and a mean score (B-Score, range 0-2) was calculated. Patients received conventional CPE treatment. Blood chemistry, vital signs, blood gas analysis, diuresis at T0, T3, T24 were also recorded. A complete echocardiography was obtained during hospitalization. Forty-one patients were enrolled. Respiratory and hemodynamic parameters improved in all patients between T0 and T3 and between T3 and T24. Mean B-score significantly decreased at T3 (from 1.59 +/- 0.40 to 0.73 +/- 0.44, P < 0.001) and between T3 and T 24 (from 0.73 +/- 0.44 to 0.38 +/- 0.33, P < 0.001). B-score was higher in the lower pulmonary regions at any time. At final evaluation (T24) 75 % of apical and only 38 % of basal regions were cleared. LUS allows one to assess the clearance of interstitial syndrome and its distribution in the early hours of treatment of CPE, thus representing a possible tool to guide therapy titration.