Effect of Tidal Volume Change on Pressure-based Prediction of Fluid Responsiveness in Children

Study Overview
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Brief Summary
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This study evaluates predictability of fluid responsiveness of pressure-based dynamic variables such as pulse pressure variation and systolic pressure variation, according to tidal volume change in patients undergoing cardiac surgery.

Detailed Description
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Pressure-based dynamic variables such as pulse pressure variation(PPV) and systolic pressure variation(SPV) are known to be unreliable for prediction of fluid responsiveness in children. The hypothesis is that tidal volume change in mechanically ventilated children undergoing anesthesia would affect reliability of aforementioned dynamic variables in prediction of fluid responsiveness, especially in the way that reliability increases for high tidal volume. In children undergoing cardiac surgery, tidal volume is changed to 6mL/kg, 10mL/kg and 14mL/kg after closure of sternum, followed by measurement of PPV, SPV. We also measure the respiratory variation of aortic blood peak velocity(△Vpeak) via transesophageal echocardiography, which is known to best predict fluid responsiveness. Afterward, 10mL/kg of crystalloid solution is administered for fluid loading. 'Fluid responder' is defined as subjects with increase of stroke volume index more than 15% after fluid loading of 10mL/kg. With these data, whether the predictability of fluid responsiveness of PPV and SPV changes according to change in tidal volume is evaluated by comparing the area under the curve of the receiver-operating characteristics curve between themselves and △Vpeak.

Official Title
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Effect of Tidal Volume Change on Pressure-based Prediction of Fluid Responsiveness in Children

Conditions
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Plasma Volume, Tidal Volume

Intervention / Treatment
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* Procedure: Tidal volume_6mL/kg
* Procedure: Tidal volume_10mL/kg
* Procedure: Tidal volume_14mL/kg
* Procedure: Fluid loading


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Children younger than 6 years old planned to undergo ventricular septal defect closure or atrial septal defect closure under general anesthesia Exclusion Criteria: Children with other complex cardiac defects Children with arrhythmia Children with preoperatively measured ejection fraction of less than 30% Children with underlying pulmonary disease

Ages Eligible for Study
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Maximum Age: 5 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: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study group<br>Measure pulse pressure variation and systolic pressure variation after each set of tidal volume to 6mL/kg, 10mL/kg and 14mL/kg. Measure respiratory variation of aortic blood flow peak velocity via transesophageal echocardiography at tidal volume of 10mL/kg. Measure stroke volume index via transesophageal echocardiography before and 5 min after fluid loading with 10mL/kg of crystalloid. | Procedure: Tidal volume_6mL/kg<br>* Set tidal volume to 6mL/kg for 1 minute<br>Procedure: Tidal volume_10mL/kg<br>* Set tidal volume to 10mL/kg for 1 minute<br>Procedure: Tidal volume_14mL/kg<br>* Set tidal volume to 10mL/kg for 1 minute<br>Procedure: Fluid loading<br>* Administer 10mL/kg of crystalloid for 5 minutes<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Stroke volume index | Define subject that shows increase of stroke volume index more than 15% after 10mL/kg of fluid loading as fluid responder, otherwise as non-responder | From sternal closure to 5 minutes after fluid loading | 
| Predictability_PPV and SPV | Area under the curve of the receiver-operative characteristic curve for prediction of fluid responder of pulse pressure variation and systolic pressure variation after each change of set tidal volume | From sternal closure to 5 minutes after fluid loading | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Predictability_△Vpeak | Area under the curve of the receiver-operative characteristic curve for prediction of fluid responder of respiratory variation of aortic blood flow peak velocity measured via transesophageal echocardiography at tidal volume of 10mL/kg | From sternal closure to 5 minutes after fluid loading | 
| Grey zone | Compare the range that the prediction of fluid responsiveness is unreliable (grey zone) for each variable in each set tidal volume | From sternal closure to 5 minutes after fluid loading | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fluid Therapy, Hemodynamic Monitoring