Pulse Pressure Variation (PPV) to Predict Fluid Responsiveness During Cardiac Displacement in Patients Undergoing Off-pump Coronary Artery Bypass Surgery (OPCAB)

Study Overview
=================
Brief Summary
-----------------
Pulse pressure variation (PPV) known as a dynamic preload index is increasingly being used for guide of fluid management under various clinical situations. We hypothesized that PPV could play a role as a predictor of fluid responsiveness during displacement of the heart in patients undergoing off-pump coronary artery bypass surgery (OPCAB).

Detailed Description
-----------------
The aim of this study was to investigate the ability of PPV to predict fluid responsiveness during displacement of the heart in patients undergoing off-pump coronary artery bypass surgery. After anesthesia, we will measure mean arterial pressure, heart rate, central venous pressure, mean pulmonary artery pressure, pulmonary arterial occlusion pressure, mixed venous oxygen saturation, PPV and cardiac index in patients receiving elective OPCAB. All parameters will be recorded at 5 minutes after the left anterior descending artery anastomosis, immediately after the displacement of the heart for the left circumflex artery anastomosis, and 10 minutes after fluid loading with hydroxyethyl starch 6%(10 mL/kg). Patients whose cardiac index increased by >15% to fluid loading will be defined as responders. To test the abilities of central venous pressure, pulmonary artery occlusion pressure and PPV to predict fluid responsiveness during heart displacement, areas under the receiver operating characteristics curves of the responders will be calculated and compared.

Official Title
-----------------
Pulse Pressure Variation to Predict Fluid Responsiveness During Cardiac Displacement in Patients Undergoing Off-pump Coronary Artery Bypass Surgery

Conditions
-----------------
Ischemic Heart Disease

Intervention / Treatment
-----------------
* Procedure: fluid loading


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: patients undergoing elective off-pump coronary artery bypass surgery Exclusion Criteria: unstable angina, preoperative arrhythmia, reduced ventricular function (ejection fraction < 40%), more than mild degree valvular heart disease, preoperative use of vasopressors or mechanical assist devices, intra-cardiac shunt, pulmonary artery hypertension, severe peripheral vascular obstructive disease, or esophageal pathology precluding the use of transesophageal echocardiography (TEE)

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: OPCAB<br> | Procedure: fluid loading<br>* fluid loading will be performed by using 6% hydroxyethyl starch solution , at 10 mL/kg.<br>* Other names: HES 130/0.4; Voluven; Fresenius Kabe, Stans, Switzerland;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pulse pressure variation |  | during displacement of the heart in OPCAB |