Pulse Pressure Variation in Spontaneously Breathing Patients

Study Overview
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Brief Summary
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The investigators hypothesized that pulse pressure variation (PPV) could predict fluid responsiveness in spontaneously breathing patients undergoing anesthesia induction.

Detailed Description
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Pulse pressure variation (PPV) is known to be a dynamic indicator to predict fluid responsiveness in mechanically ventilating patients. PPV is generated by cardiopulmonary interaction with respiratory cycles. In spontaneous breathing, the cardiopulmonary interaction may lead to PPV by inverted manner. In this study, the investigators will evaluate the ability of PPV to predict fluid responsiveness in spontaneously breathing patients. Before induction of anesthesia, radial artery cannulation is performed, and FloTrac/Vigileo (Edwards Lifesciences Corp., Irvine, USA) system is connected. And then, the investigators will measure baseline data including invasive blood pressure, pulse pressure, cardiac index, stroke volume variation in two different conditions: during tidal spontaneous breathing and during forced spontaneous breathing. All hemodynamic measurement will be repeated after infusion of fluid using 6mL/kg of hydroxyethyl starch solution (Voluven), and will be averaged over 3 minutes. Patients whose cardiac index increased by >15% to fluid infusion is defined as responders. The investigators will compare the hemodynamic parameters between responders and non-responders. To evaluate the ability to predict volume responsiveness, receiver operating characteristics curves of the PPV will be calculated.

Official Title
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The Ability of Pulse Pressure Variation to Predict Fluid Responsiveness in Spontaneously Breathing Patients Undergoing Thoracic Surgery

Conditions
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Pulse Pressure Variation, Spontaneously Breathing

Intervention / Treatment
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* Procedure: Hydroxyethyl starch solution (Voluven) infusion


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients undergoing thoracic surgery Exclusion Criteria: preoperative arrhythmia left ventricular ejection fraction <40% intra-cardiac valve disease intra-cardiac shunt pulmonary artery hypertension severe peripheral vascular obstructive disease decreased pulmonary function

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: Treatment
Intervention Model: Single Group Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: fluid infusion<br> | Procedure: Hydroxyethyl starch solution (Voluven) infusion<br>* fluid loading will be performed by hydroxyethyl starch solution (Voluven), at 6 mL/kg<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pulse pressure variation |  | three respiratory cycles, an expected average of 30 seconds | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| hemodynamic parameters | systolic blood pressure (SBP), dyastolic BP, mean BP, heart rate, cardiac index, stroke volume varation | before and after fluid loading, 1 mimute |