Carotid and femoral Doppler do not allow the assessment of passive leg raising effects

Abstract

BackgroundThe hemodynamic effects of the passive leg raising (PLR) test must be assessed through a direct measurement of cardiac index (CI). We tested whether changes in Doppler common carotid blood flow (CBF) and common femoral artery blood flow (FBF) could detect a positive PLR test (increase in CI ≥ 10%). We also tested whether CBF and FBF changes could track simultaneous changes in CI during PLR and volume expansion. In 51 cases, we measured CI (PiCCO2), CBF and FBF before and during a PLR test (one performed for CBF and another for FBF measurements) and before and after volume expansion, which was performed if PLR was positive.ResultsDue to poor echogenicity or insufficient Doppler signal quality, CBF could be measured in 39 cases and FBF in only 14 cases. A positive PLR response could not be detected by changes in CBF, FBF, carotid nor by femoral peak systolic velocities (areas under the receiver operating characteristic curves: 0.58 ± 0.10, 0.57 ± 0.16, 0.56 ± 0.09 and 0.64 ± 10, respectively, all not different from 0.50). The correlations between simultaneous changes in CI and CBF and in CI and FBF during PLR and volume expansion were not significant (p = 0.41 and p = 0.27, respectively).ConclusionDoppler measurements of CBF and of FBF, as well as measurements of their peak velocities, are not reliable to assess cardiac output and its changes.Electronic supplementary materialThe online version of this article (10.1186/s13613-018-0413-7) contains supplementary material, which is available to authorized users.

Carotid Ultrasound to Predict Fluid Responsiveness

“…Four hundred sixty‐five articles were found through the systematic search. Of these, 17 were determined to meet inclusion for the study (Figure ) . A total of 956 patients were included in the identified studies.…”

“…These studies recorded either absolute values or the absolute change and relative percentage change of FTc after PLR. Other measures included CBF (4 of 17 [24%]), peak velocity or change in peak velocity with respiration (ΔCDPV; 6 of 17 [35%]), and carotid diameter (2 of 17 [12%]) . Most studies were done in either intensive care unit (ICU; 7 of 17 [41%]) or operating theater (3 of 17 [18%]) patients, although a large number were also done in healthy participants (4 of 17 [24%]) .…”

“…Other measures included CBF (4 of 17 [24%]), peak velocity or change in peak velocity with respiration (ΔCDPV; 6 of 17 [35%]), and carotid diameter (2 of 17 [12%]) . Most studies were done in either intensive care unit (ICU; 7 of 17 [41%]) or operating theater (3 of 17 [18%]) patients, although a large number were also done in healthy participants (4 of 17 [24%]) . Studies commonly used PLR (11 of 17 [65%]) or an intravenous fluid bolus (8 of 17 [47%]) as the fluid challenge.…”

“…Most studies were done in either intensive care unit (ICU; 7 of 17 [41%]) or operating theater (3 of 17 [18%]) patients, although a large number were also done in healthy participants (4 of 17 [24%]) . Studies commonly used PLR (11 of 17 [65%]) or an intravenous fluid bolus (8 of 17 [47%]) as the fluid challenge. Although outcomes were heterogeneous, and a formal meta‐analysis was not performed, there did not appear to be differences between studies that used either of these as a fluid challenge for any measure.…”

Emergency department non-invasive cardiac output study (EDNICO): an accuracy study

“…Previous studies on CCABF were conducted on healthy volunteers [57,58], ICU patients [18,[59][60][61], and peri-operative patients [62,63]. To our knowledge no studies have investigated the accuracy of SSAD in identifying fluid responders in spontaneously breathing patients in any clinical setting.…”