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 relative to the ‘d’ wave which can (not pictured) lead to only diastolic filling. The ccFT increases significantly (+ 12 ms). B Three cardiac cycles before and during the second fluid challenge, following 1 L crystalloid. The jugular velocity is biphasic; the ‘s’ wave greater than the ‘d’ wave. With the rapid fluid challenge, the ‘s’ wave velocities fall, the ccFT again increases (+ 16 ms). C Two longer recordings before and during the second fluid challenge. D The entire second rapid fluid challenge. The green bars represent the ccFT per cardiac cycle, the red bars the VTIc per cardiac cycle. The green-shaded window labeled ‘pre’ is the average of all cardiac cycles within the window. The vertical, purple line is where the rapid fluid challenge begins. The blue-shaded window during the fluid challenge averages all cardiac cycles needed to calculate change with statistical significance; the window size is based on the coefficient of variation