Changes in PPV Induced by PLR Test to Predict Fluid Responsiveness in ICU

Study Overview
=================
Brief Summary
-----------------
The passive leg raising (PLR) test is a reversible preload challenge of around 300 mL of blood that can be repeated as frequently as required without infusing a drop of fluid. Two recent meta-analyses of many studies have confirmed the reliability of the PLR test to predict fluid responsiveness in patients with acute circulatory failure. Nevertheless, the effects of the PLR must be assessed by the direct measurement of cardiac output since changes in arterial pressure do not allow the assessment of the PLR hemodynamic effects with reliability. Moreover, cardiac output must be measured continuously and in real time. In clinical practice, cardiac output measurement can be difficult for different reasons such as the unavailability of the echocardiography machine, or the absence of any continuous cardiac output monitoring technique at the time of acute circulatory failure occurrence. Recently, it was shown that the decrease in pulse pressure variation (PPV) induced by the mini-fluid challenge (100 mL of colloid solution infused in 1 min) was able to predict fluid responsiveness with reliability in patients ventilated with low tidal volume (<8 mL/kg of ideal body weight). Therefore, the investigators hypothesize that the changes in PPV induced by PLR test could be able to predict fluid responsiveness with reliability in mechanically ventilated patients with acute circulatory failure.

Official Title
-----------------
Changes in Pulse Pressure Variations Induced by Passive Leg Raising Test to Predict Fluid Responsiveness in ICU

Conditions
-----------------
Acute Circulatory Failure

Intervention / Treatment
-----------------
* Other: Fluid loading of 500 mL of crystalloid solution
* Other: Passive Leg Raising test


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Mechanically ventilated patients Patients in whom the physician decides to perform a fluid challenge based on the presence of one of the following criteria: (1) systolic arterial pressure <90 mmHg, mean arterial pressure <65 mmHg, or the need for vasopressor infusion; (2) skin mottling; (3) urine output <0.5 mL/Kg/h for more than or equal to 2 hours; (4) lactate concentrations > 2 mmol/L Patients in whom the physician decides to perform a PLR test to predict fluid responsiveness Arterial catheter should be in place for invasive monitoring of arterial pressure and PPV Non inclusion Criteria: Age <18 yrs Pregnancy Moribund patients Risk of fluid loading induced pulmonary edema Cardiac arrhythmias Contraindication to perform PLR (intracranial hypertension, pelvic fractures) Exclusion Criteria : Changes in vasopressor and sedation agents dosages during the protocol Changes in ventilatory parameters during the protocol

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

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

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

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

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Acute circulatory failure<br>Mechanically ventilated patients displaying acute circulatory failure in whom the physician decides to perform a fluid challenge (fluid loading of 500 mL of crystalloid solution) and a passive leg raising test to predict fluid responsiveness. | Other: Fluid loading of 500 mL of crystalloid solution<br>* Infusion of 500 mL of crystalloid solution in less than 15 minutes<br>Other: Passive Leg Raising test<br>* This intervention is done before the fluid loading in order to predict fluid responsiveness.<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Increase in cardiac output in all mechanically ventilated patients | The primary endpoint is the increase in cardiac output of more than or equal to 15% after 500 mL of volume expansion. All included patients are concerned by the primary outcome. | Cardiac output will be measured immediately after the end of the volume expansion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Increase in cardiac output in mechanically ventilated patients with spontaneous breathing activities | The secondary endpoint is the increase in cardiac output of more than or equal to 15% after 500 mL of volume expansion. Only patients with spontaneous breathing activities are concerned by this secondary outcome. | Cardiac output will be measured immediately after the end of the volume expansion | 
| Increase in cardiac output in mechanically ventilated patients with low tidal ventilation and/or low respiratory compliance | The secondary endpoint is the increase in cardiac output of more than or equal to 15% after 500 mL of volume expansion. Only patients with low tidal ventilation (<8mL/kg of ideal body weight) and/or low respiratory compliance (<30mL/cmH2O) are concerned by this secondary outcome. | Cardiac output will be measured immediately after the end of the volume expansion | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Fluid responsiveness, Passive leg raising, Pulse pressure variation