Central Venous Pressure (CVP) Changes do Not Predict Preload Unresponsiveness

Study Overview
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Brief Summary
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Passive leg raising (PLR) is routinely used to predict preload responsiveness in critically ill patients. However, real-time measurements of cardiac output are required to assess its effects. Some authors have suggested that in fluid non-responders, central venous pressure (CVP) increased markedly. By analogy with the CVP rules proposed by Weill et al to assess a fluid challenge, it has been hypothesized that an increase in CVP ≥ 5 mmHg during PLR can predict preload unresponsiveness. Objective Investigation of whether an increase in CVP ≥ 5 mmHg during PLR predict preload unresponsiveness diagnosed by the absence of increase in velocity-time integral (VTI) of the flow in the left ventricular outflow tract by more than 10% (4). Methods Critically ill patients with a central venous catheter in place and for whom the physician decided to test preload responsiveness by PLR were prospectively included. Transthoracic echocardiography was performed to obtain VTI. The CVP and VTI were measured before and during PLR.

Official Title
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Central Venous Pressure (CVP) Changes do Not Predict Preload Unresponsiveness

Conditions
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Cardiovascular Shock

Intervention / Treatment
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* Diagnostic Test: preload responsiveness


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ADULTS Patients presenting with shock or other signs of circulatory failure (tachycardia, oliguria) Need for the physician to test preload responsiveness Patients already equipped by a central venous catheter for the measurement of CVP Exclusion Criteria: patients<18 years old pregnancy instaility justifying rapid increase in cathecolamines
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 |
| --- | --- |
| preload responsive<br>defined as an increase in Velocity time integral of the sub-aortic flow greater or equal to 10% | Diagnostic Test: preload responsiveness<br>* We investigated whether an increase in CVP ≥ 5 mmHg during PLR predict preload unresponsiveness diagnosed by the absence of increase in velocity-time integral (VTI) of the flow in the left ventricular outflow tract by more than 10%<br>|
| preload unresponsive<br>defined as an increase in Velocity time integral of the sub-aortic flow lower than 10% | Diagnostic Test: preload responsiveness<br>* We investigated whether an increase in CVP ≥ 5 mmHg during PLR predict preload unresponsiveness diagnosed by the absence of increase in velocity-time integral (VTI) of the flow in the left ventricular outflow tract by more than 10%<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the predictive value of changes in CVP to determine preload responsiveness | Systolic, diastolic and mean arterial pressure will be assessed before and after the PLR test | ONE MINUTE TEST |