Surgeries Undergoing General AnesthesiaIntraOp OxNCT07224243
Impact of Intraoperative Oxygenation Practices on Patient Outcomes
A study testing Lower FiO2, Intermediate FiO2 and Higher FiO2 in people with Surgeries Undergoing General Anesthesia, run by Frederic T Billings IV at 4 sites in United States.
Trial summary
This multicenter, cluster-randomized, cluster-crossover clinical trial evaluates the impact of three intraoperative FiO2 (Fraction of Inspired Oxygen) oxygenation strategies-lower (FiO₂ 0.21-0.40), intermediate (FiO₂ 0.40-0.80), and higher (FiO₂ 0.80-1.00)-on postoperative organ injury and mortality in adult surgical… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Surgeries Undergoing General Anesthesia
- What is being tested?
- Lower FiO2, Intermediate FiO2 and Higher FiO2
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 54,000 participants
- Where
- 4 sitesUnited States
- Study dates
- 1 Dec 2025to Apr 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patient located in a participating operating room
- Planned surgery includes tracheal intubation
Who cannot join
- Patient is known to be less than 18 years old
- Patient is known to be pregnant
- Patient is known to be a prisoner.
- Patient is American Society of Anesthesiologists (ASA) classification-6 (i.e., organ donor)
- Patient's planned surgical case includes open heart surgery, defined as surgery on the heart or ascending aorta requiring sternotomy or thoracotomy.
- Patient's planned procedure requires prolonged apnea, bronchoscopy, airway surgery, or one-lung ventilation.
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- Patient's planned surgical case includes use of extracorporeal membrane oxygenation (ECMO).
- Patient is known to have a history of bleomycin treatment.
- Patient was enrolled in the trial in the prior 30 days.
Trial locations and contacts
4 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States4 sites, 4 recruiting
- Recruiting
University of Michigan Hospital
Ann Arbor, Michigan, 48109
Rebecca Pantis, MHSA, 734-834-8318, repantis@med.umich.edu
Christa Vaughn, MD
- Recruiting
Vanderbilt University Medical Center
Nashville, Tennessee, 37212
Tracie Baker, CCRA, 6158751852, tracie.d.baker@vumc.org
Meredith Kingeter, MD
- Recruiting
Nebraska Medical Center
Omaha, Nebraska, 68105
Emely Sanchez, BS, 402-559-8299, emsanchezrodriguez@unmc.edu
Levi Zehr, MD
- Recruiting
University of Utah Huntsman Cancer Institute
Salt Lake City, Utah, 84112
Anne Mackey, MD, 801-580-6886, Anne.mackey@utah.edu
Caroline Ruminski, MD
About this study
This multicenter, cluster-randomized, cluster-crossover clinical trial evaluates the impact of three intraoperative FiO2 (Fraction of Inspired Oxygen) oxygenation strategies-lower (FiO₂ 0.21-0.40), intermediate (FiO₂ 0.40-0.80), and higher (FiO₂ 0.80-1.00)-on postoperative organ injury and mortality in adult surgical patients. The trial aims to determine the optimal oxygenation strategy to improve perioperative outcomes.
Read the detailed description
The Intraop Ox trial will enroll adult patients undergoing surgery with tracheal intubation. Participating hospitals will be randomly assigned (as a unit) to administer one of three oxygenation strategies during maintenance anesthesia (lower FiO₂ [0.21-0.40], intermediate FiO₂ [0.40-0.80], or higher [FiO₂ 0.80-1.00] each period (month). The primary outcome is a composite of organ injury (acute kidney injury, myocardial injury, lung injury, stroke) or death within 30 days. Secondary outcome is 30-day mortality. Exploratory outcomes are individual components of the composite primary endpoint, surgical site infection, length of stay, and hypoxemia. The study is conducted under a waiver of informed consent due to minimal incremental risk of participating and impracticability of obtaining consent in this cluster-randomized design.
- Conditions
- Surgeries Undergoing General Anesthesia
- Being tested
- Lower FiO2, Intermediate FiO2, Higher FiO2
- Keywords
- Intraoperative oxygenation, oxygen, surgery, anesthesia, mechanical ventilation, organ injury, acute kidney injury, myocardial injury, lung injury, stroke, pragmatic, cluster
- Medical subject headings
- Acute Kidney Injury, Lung Injury, Stroke
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Lower FiO2Other
FiO₂ 0.21-0.40 or lowest FiO₂ to maintain SpO₂ ≥ 94% during maintenance anesthesia
Intermediate FiO2Other
FiO₂ 0.40-0.80 or lowest FiO₂ to maintain SpO₂ ≥ 94% during maintenance anesthesia
Higher FiO2Other
FiO₂ > 0.80 to maintain SpO₂ ≥ 94% during maintenance anesthesia
| Study group | Role | What they receive |
|---|---|---|
| Lower FiO2 | Experimental | Not described Receives: Other: Lower FiO2 |
| Intermediate FiO2 | Experimental | Not described Receives: Other: Intermediate FiO2 |
| Higher FiO2 | Experimental | Not described Receives: Other: Higher FiO2 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Composite of organ injury or in-hospital death within 30 days of surgery
This composite outcome measures the number of participants experiencing at least one of the following organ injuries or death within the defined study period:
- Acute Kidney Injury (AKI), defined according to creatinine based Kidney Disease Improving Global Outcomes criteria, specifically a 0.3 mg/dL or greater increase within 48 hours or a 50% or greater increase from baseline within seven days of surgery.
- Myocardial injury, defined as >99th percentile of normal based on site-specific troponin assay within 72 hours of surgery.
- Lung injury, defined using international classification of diseases, ninth revision or tenth revision (ICD-9 or ICD-10) diagnosis codes
- Stroke, defined using international classification of diseases, ninth revision or tenth revision (ICD-9 or ICD-10) diagnosis codes
- Death within 30 days of surgery
Measured: 30 days post-surgery
Secondary outcomes (1)
30-day mortality
Death from any cause within 30 days of surgery
Measured: 30 days post-surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Nov 2025
- Study start1 Dec 2025
- Primary completionFeb 2028 (estimated)
- Study completionApr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Surgeries Undergoing General AnesthesiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Cluster randomized, cluster crossover
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 54,000 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Frederic T Billings IV
- Sponsor type
- University, hospital or other
- Collaborators
- Multicenter Perioperative Outcomes Group, University of Michigan, The Association of University Anesthesiologists
- Responsible party
- Sponsor-investigator, Frederic T Billings IV, Vanderbilt University Medical Center
- Investigators
- Frederic T Billings, MD, Principal investigator, Vanderbilt University Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07224243
- Sponsor's protocol ID
- 241806
- Acronym
- IntraOp Ox
- Status last verified
- Sep 2026
- First submitted
- 31 Oct 2025
- Last updated
- 16 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data cannot be removed from the MPOG servers where they are stored and analysed. We will review requests for data analyses that use individual patient data, but it would have to be performed inside these servers - i.e., IPD cannot not be shared with others.
Study at a glance
From the registry record, last updated by the sponsor on 16 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Intraoperative Oxygenation Practices on Patient Outcomes
- ClinicalTrials.gov ID
- NCT07224243
- Acronym / sponsor ID
- IntraOp Ox / 241806
- Conditions
- Surgeries Undergoing General Anesthesia
- Keywords
- Intraoperative oxygenation, oxygen, surgery, anesthesia, mechanical ventilation, organ injury, acute kidney injury, myocardial injury
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 54,000 participants (estimated)
- Lead sponsor
- Frederic T Billings IVUniversity, hospital or other
- Collaborators
- Multicenter Perioperative Outcomes Group, University of Michigan, The Association of University Anesthesiologists
- Study start
- 1 Dec 2025 (actual)
- Primary completion
- Feb 2028 (estimated)
- Study completion
- Apr 2028 (estimated)
- First posted
- 4 Nov 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This multicenter, cluster-randomized, cluster-crossover clinical trial evaluates the impact of three intraoperative FiO2 (Fraction of Inspired Oxygen) oxygenation strategies-lower (FiO₂ 0.21-0.40), intermediate (FiO₂ 0.40-0.80), and higher (FiO₂ 0.80-1.00)-on postoperative organ injury and mortality in adult surgical patients. The trial aims to determine the optimal oxygenation strategy to improve perioperative outcomes.
Detailed description
The Intraop Ox trial will enroll adult patients undergoing surgery with tracheal intubation. Participating hospitals will be randomly assigned (as a unit) to administer one of three oxygenation strategies during maintenance anesthesia (lower FiO₂ [0.21-0.40], intermediate FiO₂ [0.40-0.80], or higher [FiO₂ 0.80-1.00] each period (month). The primary outcome is a composite of organ injury (acute kidney injury, myocardial injury, lung injury, stroke) or death within 30 days. Secondary outcome is 30-day mortality. Exploratory outcomes are individual components of the composite primary endpoint, surgical site infection, length of stay, and hypoxemia. The study is conducted under a waiver of informed consent due to minimal incremental risk of participating and impracticability of obtaining consent in this cluster-randomized design.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
- Model description
- Cluster randomized, cluster crossover
| Arm | Type | Receives |
|---|---|---|
| Lower FiO2 | Experimental | Other: Lower FiO2 |
| Intermediate FiO2 | Experimental | Other: Intermediate FiO2 |
| Higher FiO2 | Experimental | Other: Higher FiO2 |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Patient located in a participating operating room
- Planned surgery includes tracheal intubation
Key exclusion criteria (9 listed)
- Patient is known to be less than 18 years old
- Patient is known to be pregnant
- Patient is known to be a prisoner.
- Patient is American Society of Anesthesiologists (ASA) classification-6 (i.e., organ donor)
- Patient's planned surgical case includes open heart surgery, defined as surgery on the heart or ascending aorta requiring sternotomy or thoracotomy.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Lower FiO2FiO₂ 0.21-0.40 or lowest FiO₂ to maintain SpO₂ ≥ 94% during maintenance anesthesia | Other | Lower FiO2 |
| Intermediate FiO2FiO₂ 0.40-0.80 or lowest FiO₂ to maintain SpO₂ ≥ 94% during maintenance anesthesia | Other | Intermediate FiO2 |
| Higher FiO2FiO₂ > 0.80 to maintain SpO₂ ≥ 94% during maintenance anesthesia | Other | Higher FiO2 |
Primary outcome
Composite of organ injury or in-hospital death within 30 days of surgery
Time frame: 30 days post-surgery
This composite outcome measures the number of participants experiencing at least one of the following organ injuries or death within the defined study period: * Acute Kidney Injury (AKI), defined according to creatinine based Kidney Disease Improving Global Outcomes criteria, specifically a 0.3 mg/dL or greater increase within 48 hours or a 50% or greater increase from baseline within seven days of surgery. * Myocardial injury, defined as >99th percentile of normal based on site-specific troponin assay within 72 hours of surgery. * Lung injury, defined using international classification of diseases, ninth revision or tenth revision (ICD-9 or ICD-10) diagnosis codes * Stroke, defined using international classification of diseases, ninth revision or tenth revision (ICD-9 or ICD-10) diagnosis codes * Death within 30 days of surgery
1 secondary outcome
30-day mortality
Time frame: 30 days post-surgery
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Sep 2026.
- Individual participant dataSharing planned: No. Individual participant data cannot be removed from the MPOG servers where they are stored and analysed. We will review requests for data analyses that use individual patient data, but it would have to be performed inside these servers - i.e., IPD cannot not be shared with others.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Frederic T Billings, MD principal investigator
Vanderbilt University Medical Center
4 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Lower FiO2, Intermediate FiO2 and Higher FiO2 in people with Surgeries Undergoing General Anesthesia, run by Frederic T Billings IV at 4 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 16 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Tracie Baker, CCRA (6158751852, tracie.d.baker@vumc.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Composite of organ injury or in-hospital death within 30 days of surgery (time frame: 30 days post-surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Sep 2026; AzTrials last refreshed its copy on 7 Nov 2026.