B-lines are vertical echogenic artifacts seen on lung ultrasound that allow bedside diagnosis of pulmonary edema. The BLUE protocol, published by Lichtenstein and Mezière, suggests that cardiogenic pulmonary edema is sufficiently ruled out in the ICU setting when B-lines are not predominant in the anterior chest (the B-profile). Our analysis sought to evaluate the sensitivity of the B-profile for ruling out pulmonary edema in the ED patient population.
The ultrasound lung scans of patients with confirmed official diagnoses of acute decompensated heart failure (ADHF) from two ED databases were retrospectively analyzed. 170 acutely dyspneic patients had complete studies (130 from one database and 40 from the other). The scans were reviewed using the B-profile definition for ruling out pulmonary edema and comparing that to an alternate scanning protocol that includes ultrasound evaluation of the lateral and anterior chest.
Of the 170 ED patients with ADHF diagnoses, the B-profile missed 16.5% (n = 28) for a sensitivity of 83.5% (95% CI 77–89%). These 28 patients did not show anterior bilateral B-lines that fit the criteria for positive under the BLUE protocol. Moreover, 25% (7/28) of these missed patients had only lateral B-lines on their lung scans and B-lines would have been detected only by including scans of the lateral zones.
Limiting the sonographic lung examination to the anterior chest areas only will miss cases of ADHF in the dyspneic ED patients. The BLUE protocol (B-profile) may need to be modified to include examination of the lateral chest as necessary for ED patients with ADHF.