Impact of Positive End-expiratory Pressure on Hepatic Venous Flow

Study Overview
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Brief Summary
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The purpose of this study is to determine the difference in the impact of moderate positive end-expiratory pressure (PEEP) on hepatic venous flow Doppler in patients undergoing cardiac surgery: conventional versus protective ventilation strategy The possible changes in forward and backward flows (Doppler profiles) of hepatic venous flow at different degrees of PEEP in conventional and protective ventilation strategies are analyzed by using intraoperative transesophageal echocardiography (TEE) in patients undergoing cardiac surgery .

Detailed Description
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Following data would be determined after 5 min-exposure volume controlled ventilation employing tidal volume of 10 ml/kg and 6 ml/kg with low PEEP (with 2 mmHg) and moderate PEEP (7 mmHg) during remifentanil-based anesthesia (1.0 mcg/kg/min) for cardiac surgery (n=12) sum of forward hepatic venous flow sum of backward hepatic venous flow peak velocity of diastolic hepatic venous flow lung compliance peak airway pressure mean airway pressure other pressure derived hemodynamic parameters:heart rate; systolic, diastolic, and mean blood pressures; systolic, diastolic, and mean pulmonary artery pressures; central venous pressure (CVP), pulmonary capillary

Official Title
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Impact of Moderate Positive End-expiratory Pressure on Hepatic Venous Flow in Patients Undergoing Cardiac Surgery

Conditions
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Valvular Heart Disease

Intervention / Treatment
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* Procedure: low PEEP conventional ventilation
* Procedure: moderate PEEP conventional ventilation
* Procedure: low PEEP protective ventilation
* Procedure: moderate PEEP protective ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing cardiac surgery Patients provide written informed consents Exclusion Criteria: Re-do or tri-do surgery Patients with active infection Patients with endocrine disease Patients ischemic heart disease patients with tricuspid valve regurgitation greater than mild degree

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 65 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: Supportive Care
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: low PEEP conventional ventilation<br>PEEP 2 mmHg tidal volume 10ml/kg | Procedure: low PEEP conventional ventilation<br> <br> |
| Experimental: moderate PEEP conventional ventilation<br>PEEP 7 mmHg tidal volume 10ml/kg | Procedure: moderate PEEP conventional ventilation<br> <br> |
| Experimental: low PEEP protective ventilation<br>PEEP 2 mmHg with tidal volume 6 ml/kg | Procedure: low PEEP protective ventilation<br> <br> |
| Experimental: moderate PEEP protective ventilation<br>PEEP 7 mmHg tidal volume 6ml/kg | Procedure: moderate PEEP protective ventilation<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| forward hepatic venous flow | Hepatic venous flow Doppler, cm/sec, by transesophageal echocardiography | 3 min after intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| reversed hepatic venous flow | Reversed hepatic venous flow Doppler, cm/sec, by transesophageal echocardiography | 3 min after intervention |