Assessment of Arterial Dynamic Elastance as a Function Variable of Arterial Load

Study Overview
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Brief Summary
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The goal of the study is to determine Eadyn as a functional measure of arterial load, in conjunction with other actual afterload indices, derived from both invasive arterial pressure tracing and non-invasive signals, such as arterial saturation, non-invasive cardiac output obtained by bio-reactance, and non-invasive stroke volume. A secondary aim is the correlation of the different non-invasive signals with the invasive arterial pressure tracing characteristics.

Detailed Description
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Fifteen patients, who provide written informed consent, will be included. All of them are scheduled for a major surgical intervention, in whom standard haemodynamic monitoring includes arterial pressure monitoring. Non-invasive wired patches, connected to a Cheetah cardiac output monitor, will be installed, as well as traditional haemodynamic monitoring (ECG, SaO2, non-invasive blood pressure). A computer link between a Philips monitor (MP50 or MP70) is made, to obtain selected curves in a digital format for post-intervention processing. After awake insertion of an arterial catheter in the radial or brachial artery and induction of anaesthesia, patient becomes intubated and mechanically ventilated. Before surgery, following data will be registered for 5 min.: ECG, invasive arterial pressure tracing, cardiac output (Cheetah monitor), SaO2 tracing, arterial pressure tracing and pulse pressure and stroke volume variation (Nexfin). When SVV > 15%, the operation table will be put in Passive Leg Raising (PLR) to optimize the filling status of the patient (test of preload dependency). When positive haemodynamic reaction is present, the patients will obtain a rapid infusion bolus of 250 ml of crystalloids.

Official Title
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Assessment of Arterial Dynamic Elastance as a Function Variable of Arterial Load, Derived From Both Non-invasive and Invasive Haemodynamic Variables.

Conditions
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Hypovolemia

Intervention / Treatment
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* Device: arterial line
* Device: Cheetah®


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients scheduled for a major surgical intervention, in whom standard haemodynamic monitoring includes arterial pressure monitoring. Exclusion Criteria: Minor surgery and absence of arterial pressure monitoring

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: arterial line<br>invasive haemodynamic monitoring | Device: arterial line<br>* In mechanically ventilated patients systolic pressure variation will be captured and passive leg raising with positive result fluid filling will be initiated.<br>Device: Cheetah®<br>* In mechanically ventilated patients systolic pressure variation will be captured and passive leg raising with positive result fluid filling will be initiated.<br>|
| Experimental: Cheetah®<br>non-invasive cardiac output | Device: arterial line<br>* In mechanically ventilated patients systolic pressure variation will be captured and passive leg raising with positive result fluid filling will be initiated.<br>Device: Cheetah®<br>* In mechanically ventilated patients systolic pressure variation will be captured and passive leg raising with positive result fluid filling will be initiated.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dynamic Elastance | determination of stroke volume and pulse pressure variation: ratio of SPV/SVV | 2 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stroke volume variation (SVV) | Variation of stroke volume (area under the arterial or oxygen saturation curve) during mechanical ventilation | 2 minutes | 
| Systolic pressure variation (SPV) | Variation of systolic pressure or peak oxygen saturation during mechanical ventilation | 2 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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elastance, fluid responsiveness