Peripheral Oxygen Saturation (SpO2) Directed Oxygen Therapy

Study Overview
=================
Brief Summary
-----------------
Investigators hypothesized that a relative low SpO2 directed oxygen therapy would reduced the mortality in patients staying longer than 72 hours in ICUs.

Detailed Description
-----------------
In fear of harmful effect of hypoxia, oxygen therapy is commonly used, especially in critically ill patients in intensive care units (ICUs). However, hyperoxia can be harmful too. Examples are myocardial infarction (MI) patients and patients resuscitated to return of spontaneous circulation after cardiac arrest. In Air Versus Oxygen in Myocardial Infarction (AVOID) trial, Meyhoff and colleagues proved hyperoxia caused more cardiac injury in patients with ST-elevation MI but without hypoxia. Kilgannon and colleagues found that arterial hyperoxia following resuscitation from cardiac arrest were associated with increased in-hospital mortality, and a pulse oxygen saturation (SpO2) of 94-98% was recommended. Recently, Panwar and colleagues found that compared to liberal oxygen strategy (SpO2 ≥96%), conservative oxygen strategy (SpO2 of 88%-92%) was feasible in patients receiving invasive mechanical ventilation. Girardis and colleagues found control oxygen therapy (targeting SpO2 of 94%-98% or PaO2 of 70-100mmHg) resulted lower ICU mortality than conventional oxygen therapy (SpO2 ≥97%) in the randomized clinical trial called Oxygen-ICU. However, the Oxygen-ICU trial was single-centered, early-terminated with only 480 patients included and led to an unplanned interim analysis. In this larger multicenter trial, investigators hypothesized that a relative low SpO2 directed oxygen therapy was safe and would reduced the 28-day mortality in patients staying longer than 72 hours in ICUs.

Official Title
-----------------
Effect of Low vs High Peripheral Oxygen Saturation (SpO2) Directed Oxygen Therapy on Mortality Among Critically Ill Patients

Conditions
-----------------
Critical Illness

Intervention / Treatment
-----------------
* Other: SpO2 directed oxygen therapy


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: aged 18 years or older and admitted into ICU, with expected stay in ICU more than 72 hours or longer. Exclusion Criteria: under 18 years old, expected stay in ICU less than 72 hours, unconsented inclusion, ICU readmission, patients with acute exacerbation of chronic obstruction disease, patients with severe acute respiratory distress syndrome (defined as PaO2/FiO2 ≤ 100mmHg and PEEP ≥10cmH2O), decision to withhold life-sustaining treatment, physician forgetting to screen during 12 hours after admission, pregnancy, patients with acute myocardial infarction, paraquat poisoning and patients on extracorporeal membrane oxygenation (ECMO) or planned to be on ECMO.

Ages Eligible for Study
-----------------
Minimum Age: 18 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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low SpO2 group<br>SpO2 90-95%, with FiO2 as low as possible. | Other: SpO2 directed oxygen therapy<br>* Oxygen therapy was administered to achieve targeted SpO2.<br>|
| Active Comparator: High SpO2 group<br>SpO2 96-100%, with FiO2 no lower than 30%. | Other: SpO2 directed oxygen therapy<br>* Oxygen therapy was administered to achieve targeted SpO2.<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 28-day mortality | Death within 28 days after inclusion | 28 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ventilator-free time | Hours free from ventilator | 14 days | 
| RRT-free time | Hours free from renal replacment therapy | 14 days |