Positive End-expiratory Pressure (PEEP) in Predicting Fluid Responsiveness in Patients Undergoing One-lung Ventilation

Study Overview
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Brief Summary
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The present study is to evaluate the effect of positive end-expiratory pressure (PEEP) in predicting fluid responsiveness in patients undergoing one-lung ventilation.

Detailed Description
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Appropriate fluid challenge is crucial during lung surgery under one-lung ventilation. Applying PEEP in mechanically ventilating patients changes dynamic hemodynamic parameters (stroke volume variation, pulse pressure variation), which is more pronounced in hypovolemic patients. The aim of the present study is to evaluate the mechanically ventilating patients under one-lung ventilation requiring fluid resuscitation by applying PEEP to predict fluid responsiveness. The investigators hypothesized that applying PEEP in one-lung ventilating patients can also change dynamic parameters and the magnitude of the change of stroke volume variation, pulse pressure variation can predict fluid responsiveness. The investigator applied PEEP 10 mmHg in one-lung ventilating patients and observed the dynamic parameters including stroke volume variation, pulse pressure variation and then infused 6ml/kg of crystalloid for fluid challenge and diagnosed fluid responsiveness as 10% increase of stroke volume after fluid challenge.

Official Title
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The Influence of Positive End-expiratory Pressure (PEEP) in Predicting Fluid Responsiveness in Patients Undergoing One-lung Ventilation

Conditions
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Lung Cancer, Lung Diseases

Intervention / Treatment
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* Procedure: PEEP challenge


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients undergoing lung surgery under one-lung ventilation Exclusion Criteria: arrhythmia moderate to severe valvular heart disease moderate to severe pericardial effusion left ventricular ejection fraction < 40% moderate to severe chronic obstructive lung disease unable to insert oesophageal Doppler Monitor (ODM) probe ( esophageal stent, esophageal cancer, previous esophageal surgery, esophageal stricture, esophageal varices, pharyngeal pouch and severe coagulopathy ) patient refusal cannot understand the protocol less than 50kg or over 100kg in weight

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 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: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: fluid responder<br>patients with 10% or more increase in stroke volume after fluid challenge. Both arms receive PEEP challenge. | Procedure: PEEP challenge<br>* apply PEEP 10 mmHg in one-lung ventilating patients.<br>|
| Experimental: fluid non-responder<br>patients with no increase or less than 10% increase in stroke volume after fluid challenge. Both arms receive PEEP challenge | Procedure: PEEP challenge<br>* apply PEEP 10 mmHg in one-lung ventilating patients.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pulse pressure variation | Temporary increase of PEEP will be able to predict fluid responsiveness using increase of pulse pressure variation over 1%. | 5 minutes after PEEP challenge | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| stroke volume variation | Temporary increase of PEEP will be able to predict fluid responsiveness using increase of stroke volume variation over 1%. | 5 minutes after PEEP challenge |