Oxygen Reserve Index to Reduce Hyperoxia

Study Overview
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Brief Summary
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Excessive oxygen administration is known to cause oxidative stress, and absorption atelectasis. Hyperoxia is very common in general anesthesia settings. Even though there are concerns in using excessive oxygen during general anesthesia, the optimal fraction of inspired oxygen (FiO2) for general anesthesia is not well studied. The oxygen reserve index (ORI) is a parameter which can evaluate partial pressure of oxygen (PaO2) rating from 0 to 1. There are growing evidences in ORI that it might be helpful to reduce hyperoxia in critically ill patients in the intensive care unit, as well as in general anesthesia. The aim of this study is to evaluate efficacy of oxygen reserve index to reduce hyperoxemia in major abdominal surgery.

Official Title
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Efficacy of Oxygen Reserve Index (ORI) to Reduce Hyperoxia in Major Abdominal Surgery

Conditions
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Hyperoxemia

Intervention / Treatment
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* Procedure: Titration of fraction of inspired oxygen (FiO2) guided by SpO2
* Procedure: Titration of fraction of inspired oxygen (FiO2) guided by ORI and SpO2


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients scheduled for elective major abdominal surgery expected to last more than 2hours. Patients who are scheduled for invasive arterial cannulation during surgery. Exclusion Criteria: Abnormal pulmonary function test Pregnancy Saturation of oxygen (SpO2) is below 92% in room air

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard group<br>Fraction of inspired oxygen (FiO2) is titrated guided by SpO2. | Procedure: Titration of fraction of inspired oxygen (FiO2) guided by SpO2<br>* Titration of fraction of inspired oxygen (FiO2) guided by SpO2<br>* Other names: SpO2;|
| Experimental: ORI group<br>Fraction of inspired oxygen (FiO2) is titrated guided by SpO2 and ORI | Procedure: Titration of fraction of inspired oxygen (FiO2) guided by ORI and SpO2<br>* Titration of fraction of inspired oxygen (FiO2) guided by ORI and SpO2<br>* Other names: ORI+SpO2;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure of arterial oxygen (PaO2) after 1 hour of surgery. | Pressure of arterial oxygen is obtain from arterial blood gas analysis as usual practice. | After 1 hour of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure of arterial oxygen (PaO2) after 2 hours of surgery. | Pressure of arterial oxygen is obtain from arterial blood gas analysis as usual practice. | After 2 hours of surgery | 
| Pressure of arterial oxygen (PaO2) after 3 hours of surgery. | Pressure of arterial oxygen is obtain from arterial blood gas analysis as usual practice. | After 3 hours of surgery | 
| Minimal and maximal value of PaO2 throughout the surgery | Pressure of arterial oxygen is obtain from arterial blood gas analysis as usual practice. | 1 hour after the end of surgery | 
| Fraction of inspired oxygen (FiO2) | Fraction of inspired oxygen (FiO2) administered during the surgery | 1 hour after the end of surgery | 
| Oxygen reserve index (ORI) | Oxygen reserve idex shown from the monitoring device during the surgery | 1 hour after the end of surgery |