IVC Variation After VT Challenge to Predict Fluid Responsiveness

Study Overview
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Brief Summary
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The purpose of the study was to evaluate the efficacy of using the respiratory variation in inferior vena cava diameters as an index of fluid responsiveness after tidal volume challenge in mechanically ventilated patients after cardiac surgery.

Detailed Description
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The tidal volume challenge is a novel test to predict fluid responsiveness in patents in shock, ventilated using low tidal volume without spontaneous breathing activity. The test involves transiently increasing tidal volume from 8 ml/kg PBW to 12 ml/kg PBW for one minute and observing the change in PPV or SVV. The aim of this study was to evaluate whether the respiratory variation in inferior vena cava diameter after tidal volume challenge can predict fluid responsiveness in cardiac surgical patients with mechanical ventilation

Official Title
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Can Respiratory Variation in Inferior Vena Cava Diameter After Tidal Volume Challenge Predict Fluid Responsiveness in Cardiac Surgical Patients With Mechanical Ventilation

Conditions
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Cardiac Surgery, Fluid Challenge, Fluid Responsiveness, Mechanical Ventilation

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: acute circulatory failure (low blood pressure or urine output, tachycardia, or mottling) clinical signs of organ hypoperfusion (renal dysfunction or hyperlactatemia) Exclusion Criteria: a contraindication to elevation of tidal volume evidence of cardiac arrhythmia left ventricular ejection fraction less than 50% echocardiographic examination that showed the existence of severe tricuspid or mitral regurgitation or right heart dysfunction intracardiac shunt pulmonary hypertension severe chronic obstructive pulmonary disease a contraindication to the passive leg raising (PLR) test air leakage through chest drains abdominal compartment syndrome portal hypertension pregnancy inability to perform ultrasonography

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 |
| --- | --- |
| fluid responders<br>Patients whose stroke volume index increase by ≥15% in response to a 500-ml fluid bolus was defined as fluid responders. | |
| fluid non-responders<br>Patients whose stroke volume index increase by <15% in response to a 500-ml fluid bolus was defined as fluid non-responders. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| fluid responsiveness | Patients will be classified as fluid responders if there is an increase in SV ≥15% after the fluid challenge, and the remaining patients are classified as fluid non-responders | after fluid challenge (30min) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| inferior vena cava variation | Ultrasound equipment with convex probe will be used to measure IVC diameters of the patients in supine position.The IVC sagittal section is described with the probe in the area of subxiphoid. IVC diameters at the junction point of the IVC and right atrium (2cm caudal) are standardized measurement. The maximum anterior-posterior dimension came out from end-inspiration (IVCi, mm), whereas the minimum IVC diameter was shown in end-expiration (IVCe, mm). The IVC variation (IVCV) is calculated using the formula: IVCV (%) = (IVCi - IVCe) / [(IVCi+ IVCe) / 2] ×100%. | After tidal volume challenge (1 minute) and fluid challenge (30 minute) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fluid responsiveness, Preload responsiveness, Functional hemodynamic monitoring, Cardiac surgery, inferior vena cava variation, Tidal volume challenge