B-lines with Lung Ultrasound: The Optimal Scan Technique at Rest and During Stress.
AIM The purpose of this study was to compare lung ultrasound findings in both the supine and upright positions in heart failure patients presenting with dyspnea or chest pain. METHODS AND RESULTS We performed lung ultrasonography on 50 heart failure patients in the emergency department. Each subject underwent eight-zone lung sonography in the seated upright position, followed by a repeat ultrasound in the supine position. Each ultrasound video clip was later assigned a score (0-2 B-lines=0 points, 3-7 B-lines=1 point, >7 B-lines=2 points) by a physician who was blinded to patient position, chest zone, and clinical information. The median B-line score on eight-zone lung ultrasound was significantly higher in the supine (6, interquartile range (IQR) 2-10) vs the sitting position (5, IQR 1-8; p<0.001). Subjects with vascular congestion or pulmonary edema on chest x-ray (CXR) (n=29) also had higher median eight-zone B-line scores in the supine position (6, IQR 4-10) compared to the sitting position (5, IQR 2-8; p=0.002). Subjects without any acute pulmonary findings on CXR (n=19) had similar median eight-zone B-line scores in sitting (4, IQR 1-7) and supine positions (4, IQR 1-9, p=0.093). CONCLUSION Our findings suggest that patient positioning may impact the number of B-lines on lung ultrasound in a heart failure population. A consistent approach to patient positioning during lung ultrasonography may be necessary in order to monitor dynamic changes in heart failure.