Simultaneous venous–arterial Doppler during preload augmentation: illustrating the Doppler Starling curve

Figures

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  Fig. 1. The wireless, wearable Doppler biosensor. A The device on a healthy volunteer. B The carotid artery Doppler spectrogram with the area under the velocity time curve, or velocity time integral (VTI), and flow time (FT) demarcated by the onset and end of systole. The FT is corrected for heart rate by the equation of Wodey to give the carotid corrected flow time (ccFT). The VTI for a single cardiac cycle represents the distance traveled by the blood, in centimeters, per beat. The ccFT is the duration of mechanical systole in milliseconds, corrected for heart rate by the equation of Wodey [22]

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  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…

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  Fig. 3. The results of the rapid fluid challenges (assessments) in patient 2. A Three cardiac cycles from before and during the first rapid fluid challenge; the venous morphology evolves from higher velocity, continuous to pulsatile, ‘s’ > ‘d’ wave which follows the right atrial pressure trace. Briefly, as the jugular vein changes from a collapsed, ellipsoid structure in cross-section, the Doppler spectrogram changes from a higher velocity, minimally undulating morphology into a pulsatile pattern that adopts the right atrial pressure waveform. Atrial kick, ‘a’ wave, creates a velocity minimum at end-diastole and may be accompanied by a visible S4 on the spectrogram. This is followed by the x’-descent, generating the venous Doppler systolic ‘s’ wave. The pooling venous blood in the right atrium as systole progresses creates the v wave in the pressure waveform; this corresponds to a velocity minimum that cleaves the venous Doppler into the ‘s’ and the diastolic ‘d’ wave at the onset of the y-descent (tricuspid valve opening). With rising right atrial pressure and/or tricuspid regurgitation, the x’-descent magnitude shrinks relative to the y-descent; thus, the Doppler ‘s’ wave falls…

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  Fig. 4. The ‘Doppler Starling curve’. The ‘normal’ and ‘abnormal’ curves represent extremes of cardiac function. A patient 1 begins in quadrant 3 with jugular Doppler spectrogram consistent with low central venous pressure; there is also low ccFT (baseline). With passive leg raise (PLR), the jugular spectrogram changes with rising central venous pressure, but ccFT falls. B patient 2 begins in quadrant 1 (baseline1); the first rapid fluid challenge (RFC1) changes both jugular venous and carotid arterial spectrograms in a manner consistent with rising central venous pressure and stroke volume, respectively. Baseline2 and RFC2 show the effects of the second fluid challenge