AnesthesiaPhase 4PULSE OxNCT03552627
Perioperative UtiLisation of SupplEmental Oxygen
A Phase 4 study testing Oxygen in people with Anesthesia, run by University Hospital Southampton NHS Foundation Trust at 1 site in United Kingdom.
Trial summary
The World Health Organisation recommends that all patients having a general anaesthetic for surgery should be given 80% oxygen as this might reduce their risk of getting an infection after their operation. Read more about this study
- Who is it for?
- Ages 16 years and olderHealthy volunteers can take part
- Conditions the study is for
- Anesthesia
- What is being tested?
- Oxygen
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 28 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 Mar 2018to Dec 2026
- Phase
- Phase 4
- 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 16 years and older
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- Age ≥16yrs - no upper limit
- Undergoing elective surgical procedure
- Planned for placement of arterial line and central venous catheter as part of routine anaesthetic delivery
- Written informed consent
Who cannot join
- Withdrawal of written consent or unable to give informed written consent
- Pregnant at time of enrolment
- Neurosurgery, cardiothoracic surgery or any other operation involving 1 lung ventilation at any point during procedure
- Baseline SpO2 < 90%
- Severe COPD (3 or 4 on GOLD criteria), Interstitial lung disease or other severe respiratory inflammatory co-morbidity (including already on home oxygen)
- BMI > 35
Show all 11Show fewer
- Assessed as having a potentially difficult airway or being difficult to ventilate (defined as concern documented at anaesthetic assessment)
- Participating in another research trial with similar interventions or outcomes.
- Sickle cell disease
- Thalassemia Major
- Under custody
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University Hospital Southampton
Southampton, Hampshire, SO16 6YD
About this study
The World Health Organisation recommends that all patients having a general anaesthetic for surgery should be given 80% oxygen as this might reduce their risk of getting an infection after their operation. However there remains a lot of uncertainty about how much oxygen patients should be given whilst undergoing surgery. In other areas of medicine evidence is slowly emerging to suggest that giving less oxygen may be as safe or even safer than giving high amounts of oxygen (e.g. after a heart attack, patients unnecessarily given oxygen seem to do worse than those given air). The amount of oxygen currently given to patients having surgery varies widely; in a recent study of almost 400 procedures across 29 hospitals, we found values ranged from below 30% to almost 100% oxygen. The aim of this research is to explore if giving less oxygen will generate less strain on parts of the body, particularly the lungs as they are always exposed to all of the oxygen that enters the body. Participants undergoing major elective surgical procedures will be randomised to receive either 80%, 55% or 30% throughout their general anaesthetic and levels of inflammation, oxidative stress and perioperative recovery will all be measured for upto 7 days after surgery.
Read the detailed description
Over 3 million patients receive oxygen (O2) during general anaesthesia (GA) in the UK annually, and a large number of these also have co-morbid respiratory diseases such as Asthma or COPD. The World Health Organisation (WHO) recently recommended that all surgical patients receive 80% O2 throughout GA and for 6 hours in recovery to reduce Surgical Site Infections (SSIs). However, a recent Cochrane systematic review found no evidence of benefit from this approach and some evidence that harm could be increased (including mortality).
Excess oxygen has been associated with worse outcomes in many areas of medicine (including acute respiratory illnesses), possibly due to increased Reactive Oxygen Species (ROS) production: ROS can cause oxidative stress and damage proteins, DNA, and lipids. Observational data from our group shows most surgical patients currently receive nearer 55% O2 under GA. The effect of intraoperative O2 concentration on other surgical outcomes remains unknown.
This project will determine whether giving lower concentrations of oxygen to surgical patients during anaesthesia can reduce levels of oxidative stress during surgery (particularly in the lungs); investigate how this affects other organs; and evaluate the feasibility of performing a large (multi-centre) effectiveness study to define 'safe' oxygen administration concentrations during surgery.
Patient undergoing elective major surgery will be randomised to receive 80% (WHO's recommendation); 55% (current usual care) or 30% oxygen (intervention) throughout anaesthesia. Endotracheal aspirates will be sampled along with paired central venous and arterial blood samples throughout surgery to monitor levels of oxidative stress and organ function. Patients will be followed up for 7 days after surgery.
- Conditions
- Anesthesia
- Being tested
- Oxygen
- Keywords
- hyperoxia, oxygen, surgery, perioperative
- Medical subject headings
- Hyperoxia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
OxygenDrug
Medical Oxygen
| Study group | Role | What they receive |
|---|---|---|
| 80% Oxygen | Active comparator | Patients will receive 80% oxygen throughout anaesthesia in accordance with current World Health Organisation Recommendations Receives: Drug: Oxygen |
| 55% Oxygen | Active comparator | Patients will receive 55% oxygen throughout anaesthesia in accordance with current UK clinical practice Receives: Drug: Oxygen |
| 30% Oxygen | Experimental | Patients will receive 30% oxygen throughout anaesthesia in accordance with this research's hypothesis that lowering intraoperative oxygen concentrations may benefit patients Receives: Drug: Oxygen |
What is being measured
The primary outcome is the main question the study is designed to answer.
Total Free Thiols
A measure of (Anti)oxidant capacity
Measured: End of surgery
Secondary outcomes (6)
Other oxidative stress markers
A panel of other markers of oxidative stress
Measured: Within 7 days of surgery
Acute cardiac events
Elevations in troponin levels
Measured: Within 7 days of surgery
Acute Kidney Injury
Elevations in creatinine or NGAL-1
Measured: Within 7 days of surgery
Acute Liver Injury
Elevations in ALT
Measured: Within 7 days of surgery
Post-operative Cognitive Recovery
PQRS score
Measured: 7 days after surgery
Postoperative Morbidity
Post Operative Morbidity Survey score
Measured: 7 days after surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Jun 2018
- Study start1 Mar 2018
- Primary completionDec 2026 (estimated)
- Study completionDec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for 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 4
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 28 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital Southampton NHS Foundation Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Andrew Cumpstey, BM BCh, Principal investigator, University Hospital Southampton NHS Foundation Trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03552627
- Sponsor's protocol ID
- CRI0358
- Acronym
- PULSE Ox
- Status last verified
- Jan 2024
- First submitted
- 29 May 2018
- Last updated
- 9 Jan 2024
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Cumpstey AF, Clark AD, Minnion M, Crosby SF, Nogueira RC, Moyses H, Martin D, Tanus-Santos JE, Jackson AA, Edwards M, Grocott MPW, Feelisch M. How hyperoxia affects systemic redox state: insights from PULSE-Ox, a randomised double-blind mechanistic feasibility trial. BJA Open. 2026 May 28;18:100563. doi: 10.1016/j.bjao.2026.100563. eCollection 2026 Jun.
PubMed 42256649
Study at a glance
From the registry record, last updated by the sponsor on 9 Jan 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Perioperative UtiLisation of SupplEmental Oxygen
- ClinicalTrials.gov ID
- NCT03552627
- Acronym / sponsor ID
- PULSE Ox / CRI0358
- Conditions
- Anesthesia
- Keywords
- hyperoxia, oxygen, surgery, perioperative
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 28 participants (actual)
- Lead sponsor
- University Hospital Southampton NHS Foundation TrustUniversity, hospital or other
- Study start
- 1 Mar 2018 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Dec 2026 (estimated)
- First posted
- 12 Jun 2018 (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.
The World Health Organisation recommends that all patients having a general anaesthetic for surgery should be given 80% oxygen as this might reduce their risk of getting an infection after their operation. However there remains a lot of uncertainty about how much oxygen patients should be given whilst undergoing surgery. In other areas of medicine evidence is slowly emerging to suggest that giving less oxygen may be as safe or even safer than giving high amounts of oxygen (e.g. after a heart attack, patients unnecessarily given oxygen seem to do worse than those given air). The amount of oxygen currently given to patients having surgery varies widely; in a recent study of almost 400 procedures across 29 hospitals, we found values ranged from below 30% to almost 100% oxygen. The aim of this research is to explore if giving less oxygen will generate less strain on parts of the body, particularly the lungs as they are always exposed to all of the oxygen that enters the body. Participants undergoing major elective surgical procedures will be randomised to receive either 80%, 55% or 30% throughout their general anaesthetic and levels of inflammation, oxidative stress and perioperative recovery will all be measured for upto 7 days after surgery.
Detailed description
Over 3 million patients receive oxygen (O2) during general anaesthesia (GA) in the UK annually, and a large number of these also have co-morbid respiratory diseases such as Asthma or COPD. The World Health Organisation (WHO) recently recommended that all surgical patients receive 80% O2 throughout GA and for 6 hours in recovery to reduce Surgical Site Infections (SSIs). However, a recent Cochrane systematic review found no evidence of benefit from this approach and some evidence that harm could be increased (including mortality).
Excess oxygen has been associated with worse outcomes in many areas of medicine (including acute respiratory illnesses), possibly due to increased Reactive Oxygen Species (ROS) production: ROS can cause oxidative stress and damage proteins, DNA, and lipids. Observational data from our group shows most surgical patients currently receive nearer 55% O2 under GA. The effect of intraoperative O2 concentration on other surgical outcomes remains unknown.
This project will determine whether giving lower concentrations of oxygen to surgical patients during anaesthesia can reduce levels of oxidative stress during surgery (particularly in the lungs); investigate how this affects other organs; and evaluate the feasibility of performing a large (multi-centre) effectiveness study to define 'safe' oxygen administration concentrations during surgery.
Patient undergoing elective major surgery will be randomised to receive 80% (WHO's recommendation); 55% (current usual care) or 30% oxygen (intervention) throughout anaesthesia. Endotracheal aspirates will be sampled along with paired central venous and arterial blood samples throughout surgery to monitor levels of oxidative stress and organ function. Patients will be followed up for 7 days after surgery.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| 80% Oxygen | Active comparator | Drug: OxygenPatients will receive 80% oxygen throughout anaesthesia in accordance with current World Health Organisation Recommendations |
| 55% Oxygen | Active comparator | Drug: OxygenPatients will receive 55% oxygen throughout anaesthesia in accordance with current UK clinical practice |
| 30% Oxygen | Experimental | Drug: OxygenPatients will receive 30% oxygen throughout anaesthesia in accordance with this research's hypothesis that lowering intraoperative oxygen concentrations may benefit patients |
Who may qualify
- Ages
- 16 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (4 listed)
- Age ≥16yrs - no upper limit
- Undergoing elective surgical procedure
- Planned for placement of arterial line and central venous catheter as part of routine anaesthetic delivery
- Written informed consent
Key exclusion criteria (11 listed)
- Withdrawal of written consent or unable to give informed written consent
- Pregnant at time of enrolment
- Neurosurgery, cardiothoracic surgery or any other operation involving 1 lung ventilation at any point during procedure
- Baseline SpO2 < 90%
- Severe COPD (3 or 4 on GOLD criteria), Interstitial lung disease or other severe respiratory inflammatory co-morbidity (including already on home oxygen)
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 |
|---|---|---|
| OxygenMedical Oxygen | Drug | 30% Oxygen, 55% Oxygen, 80% Oxygen |
Primary outcome
Total Free Thiols
Time frame: End of surgery
A measure of (Anti)oxidant capacity
6 secondary outcomes
Other oxidative stress markers
Time frame: Within 7 days of surgery
Acute cardiac events
Time frame: Within 7 days of surgery
Acute Kidney Injury
Time frame: Within 7 days of surgery
Acute Liver Injury
Time frame: Within 7 days of surgery
Post-operative Cognitive Recovery
Time frame: 7 days after surgery
Postoperative Morbidity
Time frame: 7 days after 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 9 Jan 2024.
- Derived from this study: PubMed 42256649Cumpstey AF, Clark AD, Minnion M, Crosby SF, Nogueira RC, Moyses H, Martin D, Tanus-Santos JE, Jackson AA, Edwards M, Grocott MPW, Feelisch M. How hyperoxia affects systemic redox state: insights from PULSE-Ox, a randomised double-blind mechanistic feasibility trial. BJA Open. 2026 May 28;18:100563. doi: 10.1016/j.bjao.2026.100563. eCollection 2026 Jun.
- Individual participant dataSharing planned: Undecided
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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. This study is not recruiting at the moment.
Andrew Cumpstey, BM BCh principal investigator
University Hospital Southampton NHS Foundation Trust
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Oxygen in people with Anesthesia, run by University Hospital Southampton NHS Foundation Trust at 1 site in United Kingdom.
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 4 inclusion and 11 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: under way, not looking for participants, as of the sponsor's last update on 9 Jan 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. 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.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Total Free Thiols (time frame: End of surgery). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03552627, which also lists 1 linked publication.
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 9 Jan 2024.