![]() ![]() Hemodynamic measurementsĪll patients were equipped with a jugular or subclavian venous catheter and a thermistor-tipped femoral arterial catheter (PV2024, Pulsion Medical Systems). Patients were excluded if the PLR maneuver was contraindicated (intracranial hypertension), if PLR was supposed to be unreliable (venous compression stocking and intraabdominal hypertension) or if it was impossible to perform vascular Doppler measurements. Patients were included in the study if they met the following criteria:Ī PiCCO2 device (Pulsion Medical Systems, Feldkirchen, Germany) already in place for clinical purposes.ĭecision to perform a PLR test made by the attending physicians. It took place at a 25-bed medical intensive care unit of a university hospital between June and November 2016. All patients or their relatives accepted to participate in the study. The second was to investigate the ability of carotid and femoral Doppler measurements to track the changes in cardiac index, during PLR and fluid administration.īefore starting the study, we obtained the agreement of our institutional review board ( Comité pour la protection des personnes Ile- de-France VI, ref # 2016-A00959-42). The first was to test whether changes in carotid and femoral Doppler measurements were able to detect a positive PLR test. Nevertheless, contradictory results have been published regarding this issue. The Doppler measurement of blood flow and its velocity in the carotid as well as in the femoral arteries may be interesting for estimating the changes in cardiac output during a PLR test, since changes in arterial blood flow and in cardiac output might be proportional. However, it must be coupled with a direct and real-time measurement of cardiac output, which is often invasive. By transferring a consistent amount of venous blood from the legs and the splanchnic compartment toward the intrathoracic compartment, it increases the mean systemic pressure, the cardiac preload and consequently cardiac output in the case of preload responsiveness of both ventricles. It consists in lifting the legs passively at 45° and moving the trunk down horizontally, starting from a semi-recumbent position. In order to predict the response of cardiac output to fluid infusion, the passive leg raising (PLR) test has been validated. The decision to give fluids must be guided by a reliable prediction of fluid responsiveness as only 50% of patients respond to fluid administration by increasing cardiac output. Since it has been demonstrated that fluid overload can be deleterious in patients with acute respiratory distress syndrome and severe sepsis, it is of paramount importance to avoid excessive fluid administration in such cases. ![]() Conclusionĭoppler measurements of CBF and of FBF, as well as measurements of their peak velocities, are not reliable to assess cardiac output and its changes. 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). 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). Resultsĭue to poor echogenicity or insufficient Doppler signal quality, CBF could be measured in 39 cases and FBF in only 14 cases. 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. We also tested whether CBF and FBF changes could track simultaneous changes in CI during PLR and volume expansion. 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%). The hemodynamic effects of the passive leg raising (PLR) test must be assessed through a direct measurement of cardiac index (CI). ![]()
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