FiO2 and Outcomes After OPCAB (the CARROT Trial)

Study Overview
=================
Brief Summary
-----------------
Conventionally, a relatively high level of fraction of inspired oxygen (FiO2) has been used for secure a margin of safety in patients undergoing cardiac surgery including off-pump coronary artery bypass grafting (OPCAB). Since the potential adverse effects of hyperoxemia (via reactive oxygen species, vasocontriction, perfusion heterogeneity, myocardiac injury, etc.), various studies on this topic has been performed. However, the results are conflicting and inconsistent, and the consensus about whether the use of additional oxygen supply in cardiac surgery has not been reached among practitioners yet. This study is a multicenter study (Seoul National University, Asan Medical Center, Severance Hospital) where the effect of different level of FiO2 on postoperative clinical outcomes is evaluated.

Detailed Description
-----------------
A sub-study will also be conducted in part of patients of the present study. In 40 out of 500 (expected) patients, two different levels of FiO2 will be sequentially set with a 5-minute interval after the induction of general anesthesia. Mixed venous and regional cerebral oxygen saturation will then be recorded according to the change of FiO2.

Official Title
-----------------
Effect of Intraoperative Oxygen Tension on Patient Outcomes After Off-pump Coronary Artery Bypass Grafting (the CARROT Trial)

Conditions
-----------------
Coronary Artery Disease

Intervention / Treatment
-----------------
* Other: Fraction of inspired oxygen level


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: All patients scheduled for elective off-pump coronary artery bypass grafting Exclusion Criteria: emergency robot-assisted surgery minimally invasive cardiac surgery requiring thoracotomy/one-lung anesthesia preoperative pulmonary morbidity requiring oxygen therapy preoperative use of ECMO or IABP preoperative tracheal intubation or mechanical ventilation

Ages Eligible for Study
-----------------
Minimum Age: 19 Years

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

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

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

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: FiO2 0.3<br>Patients allocated to this group are going to receiving FiO2 of 0.3 during surgery | Other: Fraction of inspired oxygen level<br>* A fraction of inspired oxygen level during off-pump coronary artery bypass grafting will be set differently between the study groups: 0.3 vs 0.8.<br>|
| Active Comparator: FiO2 0.8<br>Patients allocated to this group are going to receiving FiO2 of 0.8 during surgery | Other: Fraction of inspired oxygen level<br>* A fraction of inspired oxygen level during off-pump coronary artery bypass grafting will be set differently between the study groups: 0.3 vs 0.8.<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| hospital LOS | length of hospital stay after off-pump coronary artery bypass grafting | From the beginning of surgery until the hospital discharge after surgery through study completion, an expected average of two weeks |