Relation Between Mixed Venous Oxygen Saturation and Cerebral Oxygen Saturation Measured by Absolute and Relative Near-infrared Spectroscopy During Off-pump Coronary Artery Bypass Grafting.

Study Overview
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Brief Summary
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In this clinical study the investigators compared mixed venous oxygen saturation (SmvO2) with relative and absolute cerebral oxygen saturation (rScO2) measurements. They hypothesized that previously reported contradictory results regarding the equivalence of SmvO2 and rScO2 might be related to time delay issues and to the measurement technology. 42 consenting patients undergoing elective off-pump coronary artery bypass grafting were included. 4 disposable oxygenation sensors were applied bilaterally on the patient's forehead for continuous, non-invasive registration of rScO2. The sensors of one monitor were placed just above the eyebrows, and the sensors of the other monitor were placed just above the former sensors. The sensors placement was determined at random by a computerized randomization list. SmvO2 was measured continuously via a pulmonary artery catheter. All variables were recorded continuously. The study ended at the end of the operation.

Official Title
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Relation Between Mixed Venous Oxygen Saturation and Cerebral Oxygen Saturation Measured by Absolute and Relative Near-infrared Spectroscopy During Off-pump Coronary Artery Bypass Grafting.

Conditions
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Elective Off-pump Coronary Artery Bypass Grafting

Intervention / Treatment
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* Procedure: Relative and absolute cerebral oxygen saturation (rScO2) measurements.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing elective off-pump coronary artery bypass grafting for at least 3-vessel coronary artery disease were eligible. Exclusion Criteria: Patients with arteriovenous shunts, intracardiac shunts, a previous history of cerebrovascular accident, or stenosis of the internal carotid artery of > 60% were excluded.

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 100 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Relative + absolute cerebral oxygen saturation.<br> | Procedure: Relative and absolute cerebral oxygen saturation (rScO2) measurements.<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation and time delay between mixed venous and cerebral oxygen saturation during off-pump coronary artery bypass grafting. | Mixed venous oxygen saturation was measured continuously via a pulmonary artery catheter. Cerebral oxygen saturation was measured with near-infrared spectroscopy; the INVOS monitor to obtain relative measurements, and the Foresight monitor to obtain absolute data. | 4 hours during an operation of average 5 hours (during off-pump coronary artery bypass grafting). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The response of cerebral oxygen saturation to major haemodynamic disturbances. | Percentage difference between the cerebral oxygen saturation value just before heart retraction and the value at the different time moments. | 2 hours after start of operation (during placement of deep pericardial stitches). | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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bypass grafting