Fig. 2

The results of the passive leg raise maneuver in patient 1. A The user display of the wearable Doppler ultrasound. The green bars represent the ccFT per cardiac cycle, the red bars the VTIc per cardiac cycle. The green-shaded window labeled ‘pre’ averages all cardiac cycles within the window. The vertical, purple line is where the leg raise begins. The blue-shaded ‘post’ window during the PLR averages all cardiac cycles within the window and is compared to the ‘pre’ value to calculate change. The window size is based on the coefficient of variation and can be moved by the clinician. B Two strips of the carotid and jugular spectrograms above and below the x-axis, respectively, before and during the leg raise. C 3 cardiac cycles before the leg raise with higher resolution. The jugular velocity is high, and the amplitude (brightness) is low, suggesting a collapsed vein. D 3 cardiac cycles during the leg raise. The venous Doppler velocity falls and the amplitude (brightness) increases—suggesting a distended vein. The venous velocity becomes pulsatile with venous systole (‘s’ wave) preceding arterial systole (carotid upstroke) illustrating interventricular delay (‘ivd’) consistent with the patient’s known incomplete left bundle branch block. Compare the temporal relationship of the venous ‘s’ and ‘d’ waves with patient 2