Dynamic Arterial Elastance: an Indirect Marker of the Critical Capillary Pressure at the Microcirculatory Level

Study Overview
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Brief Summary
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The measurement of dynamic arterial elastance (Eadyn) was proposed as a marker of vascular tone. It is calculated by the ratio of the respiratory variation of the pulse pressure and the respiratory variation of stroke volume. Despite several clinical studies, no study has really focused on the physiological significance of Eadyn. No study demonstrates at present, if this index is a reflect of macrocirculatory parameters (systemic resistances, blood pressure, arterial elastance, ventricular elastance, ventriculo-arterial coupling) or microcirculatory tone in the capillaries and small arterioles (critical capillary pressure or capillary resistance). the physicians don't know which variables are associated with this index. the hypothesis is that Eadyn is an indirect reflect of capillary pressure (PCC).

Detailed Description
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The measurement of dynamic arterial elastance (Eadyn) was proposed as a marker of vascular tone. It is calculated by the ratio of the respiratory variation of the pulse pressure and the respiratory variation of stroke volume. Despite several clinical studies, no study has really focused on the physiological significance of Eadyn. No study demonstrates at present, if this index is a reflect of macrocirculatory parameters (systemic resistances, blood pressure, arterial elastance, ventricular elastance, ventriculo-arterial coupling) or microcirculatory tone in the capillaries and small arterioles (critical capillary pressure or capillary resistance). the physicians don't know which variables are associated with this index. One hypothesis is that Eadyn is an indirect reflection of capillary pressure (PCC). The main objective of this project is to study the correlation between the measure of Eadyn and the PCC. The study begins when the physician in charge of the patient decides a hemodynamic treatment (either volume expansion or norepinephrine). The indication of the treatment is left to the discretion of the physician in charge of the patient: volume expansion or vasopressor agent. After verification of inclusion criteria, the physician collects demographic, ventilatory, hemodynamic, cardiac ultrasound data, and the type of treatment initiated (volume expansion, norepinephrine, and their dosages). 15 minutes after the introduction of the therapy and stabilization of the hemodynamic state, a new series of measurements of the aforementioned.

Official Title
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Dynamic Arterial Elastance: an Indirect Marker of the Critical Capillary Pressure at the Microcirculatory Level (POEME)

Conditions
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Arterial Disease

Intervention / Treatment
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* Other: volume expansion
* Other: norepinephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients admitted to intensive care, for whom the physician has decided, in accordance with the care protocols of the service, to provide treatment for preload dependence or post-operative vasoplegia syndrome, patients monitored by a central venous catheter, a measurement of blood pressure with continuous monitoring of cardiac output by calibrated analysis of the pulse wave contour (PICCO or EV1000), Patients with sinus heart rate, Patients covered by a social insurance system, Patients who have given their oral consent to participation after complete information Exclusion Criteria: Modification of therapies during the study period, Rhythm disorder with PM Appearance of cardiac rhythm disturbances (Ac / Fa, Tac / Fa, TV, FV).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Volume expansion<br> | Other: volume expansion<br>* Volume expansion when the patient has a dependent preload evaluated by a positive leg lever test (variation of more than 10% of the VES). It corresponds to the intravenous administration of 500 ml of Ringer lactate over 10 min.<br>|
| norepinephrine<br> | Other: norepinephrine<br>* Vasopressor agent when the patient has persistent arterial hypotension related to postoperative vasoplegia syndrome. Norepinephrine is administered during persistent hypotension (MAP <60mmHg) despite volume expansion. It corresponds to continuous intravenous norepinephrine administration to obtain a MAP of more than 70 mmHg<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| to assess correlation between Eadyn and PCC measure |  | 15 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vasoplegia, dynamic arterial elastance, microcirculation