Respiratory Variation in Central Venous Oxygen Saturation Predicts Volume Responsiveness in Hemodynamically Unstable Patients Under Mechanical Ventilation : a Prospective Cohort Study

Study Overview
=================
Brief Summary
-----------------
Vascular filling is the main treatment of hypovolemia. Hypovolemia diagnosis can be difficult in some situations and need to be confirmed with other investigations. Venous oxymetry based on the ScvO2 values represent a valuable way to predict responsivness to fluid filling maneuver in patients with hemodynamic instability.

Detailed Description
-----------------
Vascular filling represent the milestone of the treatment of hypovolemia. Its main objective is to restore vascular volume and correct perfusion issues preventing the deleterious consequences of prolonged shock. Hypovolemia diagnosis is easy to made in obvious clinical situations such as hemorrhagic shock, deshydratation..., but there still many diagnostic difficulties regarding latent hypovolemia especially if associated with left ventricular dysfunction. In this situations, diagnostic of hypovolemia is hard to made and other investigations are needed. Central venous pressure (CVP) and pulmonary occlusion artery pressure (PAPO) are the mainly used parameters for indicating vascular filling but actually many studies underline their low liability in this situation. After vascular filling, outcome measurment is needed to evaluate the efficacity of the treatment. Outcome measurment based on hemodynamic criteria is still insufficient. In fact, tissue hypoxia persists if the cardio - respiratory system did not adapt to the metabolic needs, that's why a pathway based on therapeutic objectives like venous oxymetry is needed. Theorically, a filling maneuver is beneficial if associated with a ScvO2 amelioration. It reflects the amelioration of cardiac output and predicts the positive responsivness to the filling test.

Official Title
-----------------
Respiratory Variation in Central Venous Oxygen Saturation Predicts Volume Responsiveness in Hemodynamically Unstable Patients Under Mechanical Ventilation : a Prospective Cohort Study

Conditions
-----------------
Hemodynamic Instability

Intervention / Treatment
-----------------
* Drug: Sodium Chloride 0.9% Intravenous


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: patients aged above 18 year old hemodynamic instability (hypotension or shock) Exclusion Criteria: intra cardiac shunt severe arrythmia valvular regurgitation pacemaker pulmonary oedema

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: crystalloid solution<br>vascular filling with 500 ml of crystalloid solution within 10 minutes | Drug: Sodium Chloride 0.9% Intravenous<br>* vascular filling with 500 ml of crystalloid solution (sodium chloride 0.9%) over 30 minutes<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| central venous oxygen saturation (ScvO2) variation | the ScvO2 is first measured at baseline via a central venous catheter and blood gaz, then after vascular filling (500 ml of colloid solution (Plasmagel) over thirty minutes). | at baseline and after 10 minutes |