Postoperative HypoxemiaPhase 4OPERANCT01887015
Optiflow® to Prevent Post-Extubation Hypoxemia afteR Abdominal Surgery (the OPERA Trial)
A Phase 4 study testing Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand) in people with Postoperative Hypoxemia, run by University Hospital, Clermont-Ferrand at 1 site in France.
Trial summary
To evaluate whether early application of nasal high flow oxygen therapy after extubation can reduce the incidence of postoperative hypoxemia (defined as a PaO2/FiO2 ratio <300) after abdominal surgery in patients with intermediate to high risk of postoperative pulmonary complications. Read more about this study
- Who is it for?
- Ages 19 years and older
- Conditions the study is for
- Postoperative Hypoxemia
- What is being tested?
- Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 220 participants
- Where
- 1 siteFrance
- Study dates
- Jun 2013to Mar 2015
- Phase
- Phase 4
- Are there results?
- None posted in the registry
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 19 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Planned or unplanned surgical procedures
- Abdominal or abdominal and thoracic surgery
- Expected duration ≥2 hours
- ARISCAT score ≥26 points
Who cannot join
- Age <18 years
- Body mass index >35 kg/m2
- Sleep apnea syndrome
- Patient refusal
- Pregnancy and/or lactation
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Early Nasal High Flow Oxygen Therapy for Prevention of Postoperative Hypoxemia After Abdominal Surgery: A Multicenter Randomized Controlled Trial
To evaluate whether early application of nasal high flow oxygen therapy after extubation can reduce the incidence of postoperative hypoxemia (defined as a PaO2/FiO2 ratio <300) after abdominal surgery in patients with intermediate to high risk of postoperative pulmonary complications.
Read the detailed description
Postoperative hypoxemia complicates between 30 to 50% of patients after abdominal surgery. Loss of functioning alveolar units and development of atelectasis after abdominal surgery have been recognized as the underlying mechanisms responsible for postoperative hypoxemia. Supplemental Oxygen administration is therefore widely recommended after extubation in the postoperative period, especially in patients with high risk of postoperative respiratory complications. Although oxygen therapy is effective in preventing the vast majority of severe postoperative hypoxemia after extubation in surgical patients, respiratory failure may occur, thus requiring endotracheal intubation and mechanical ventilation or therapeutic use of non-invasive positive pressure ventilation (NPPV). In patients with postoperative hypoxemia (defined as patients with a PaO2/FiO2 ratio <300), application of NPPV was found to decrease the incidence of endotracheal intubation after abdominal surgery. Nevertheless, use of NPPV in the postoperative period is responsible for organizational constraints and increases healthcare utilization.
Nasal high flow cannula (NHFC) has been described as an attractive and well-tolerated method of non-invasive oxygen delivery. Previous studies have shown that NHFC generates a low level of positive airway pressure, increases end-expiratory lung volume and reduces airway resistance, thus contributing to a reduction in work of breathing. To date, however, no clinical trials have compared NHFC to standard oxygen therapy in the prevention of postoperative hypoxemia after abdominal surgery in patients with intermediate to high risk of postoperative pulmonary complications.
The primary objective of the study is to compare: 1- Standard oxygen therapy; 2- Nasal high flow oxygen therapy after extubation in patients with intermediate to high risk of postoperative pulmonary complications after abdominal surgery.
Our hypothesis is that, compared with standard oxygen therapy, early application of nasal high flow oxygen therapy can reduce the need for postoperative NPPV for postoperative hypoxemia (defined as PaO2/FiO2 ratio <300).
- Conditions
- Postoperative Hypoxemia
- Being tested
- Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand)
- Keywords
- Postoperative pulmonary complications, Oxygen therapy, Nasal high flow oxygen therapy, Nasal high flow cannula
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand)Device
Also called Nasal high flow oxygen therapy versus standard oxygen therapy
| Study group | Role | What they receive |
|---|---|---|
| Standard oxygen therapy | Experimental | Our hypothesis is that, compared with standard oxygen therapy, early application of nasal high flow oxygen therapy can reduce the need for postoperative NPPV for postoperative hypoxemia (defined as PaO2/FiO2 ratio <300). Receives: Device: Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand) |
| nasal high flow oxygen therapy | Other | Our hypothesis is that, compared with standard oxygen therapy, early application of nasal high flow oxygen therapy can reduce the need for postoperative NPPV for postoperative hypoxemia (defined as PaO2/FiO2 ratio <300). Receives: Device: Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand) |
What is being measured
The primary outcome is the main question the study is designed to answer.
percentage of patients who developed postoperative hypoxemia (defined as PaO2/FiO2 ratio <300)
Measured: 1 hour after tracheal extubation (day 1)
Secondary outcomes (5)
Postoperative gas exchange (PaO2, PaCO2)
Measured: 1H after extubation and after surgery (at day 1)
Need for supplemental oxygen therapy beyond postoperative day 1 (defined as arterial oxygen saturation by pulse oximetry (SpO2) <93% in room air)
Measured: at day 1
Need for endotracheal intubation or non-invasive ventilation for postoperative acute respiratory failure (ARF)
ARF (acute respiratory failure) is defined by one of the hypoxemic criteria (SpO2 <92% while breathing at least 10 L/min oxygen, PaO2 <60 mmHg on air or <80 mmHg while breathing any supplemental oxygen) and at least 1 of the following criteria: severe respiratory distress with dyspnea, accessory muscle recruitment and paradoxical abdominal or thoracic motion, respiratory rate >25 breaths/min, respiratory acidosis with pH <7.30 and PaCO2 > 50 mmHg.
Measured: within the first 7 days after surgery
Postoperative pulmonary complications (PPCs)
PPCs(Postoperative pulmonary complications ) are scored using a grade scale ranging from 0 to 4, with grade 0 representing the absence of any complications and grade 1 through 4 representing successively the worse forms of complications.
Measured: within the first 7 days after surgery
Respiratory discomfort using a numerical rating scale (NRS) ranging from 0 (no discomfort) to 10 (maximum imaginable discomfort).
Discomfort symptoms are assessed by evaluating dryness of the nose, mouth and throat.
Measured: within the first 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 posted26 Jun 2013 (estimated)
- Study startJun 2013
- Primary completionMar 2015
- Study completionMar 2015
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for Postoperative HypoxemiaStudies of the same condition, open and under way.
- More trials run by University Hospital, Clermont-FerrandThe sponsor's other registered studies.
- 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
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 220 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Clermont-Ferrand
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Emmanuel FUTIER, MD, Ph D, Principal investigator, University Hospital, Clermont-Ferrand
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01887015
- Sponsor's protocol ID
- CHU-0157
- Other IDs
- 2013-A00030-45
- Acronym
- OPERA
- Status last verified
- Jul 2026
- First submitted
- 24 Jun 2013
- Last updated
- 3 Aug 2026
- Results posted
- No
Publications
Futier E, Paugam-Burtz C, Godet T, Khoy-Ear L, Rozencwajg S, Delay JM, Verzilli D, Dupuis J, Chanques G, Bazin JE, Constantin JM, Pereira B, Jaber S; OPERA study investigators. Effect of early postextubation high-flow nasal cannula vs conventional oxygen therapy on hypoxaemia in patients after major abdominal surgery: a French multicentre randomised controlled trial (OPERA). Intensive Care Med. 2016 Dec;42(12):1888-1898. doi: 10.1007/s00134-016-4594-y. Epub 2016 Oct 22.
PubMed 27771739Futier E, Paugam-Burtz C, Constantin JM, Pereira B, Jaber S. The OPERA trial - comparison of early nasal high flow oxygen therapy with standard care for prevention of postoperative hypoxemia after abdominal surgery: study protocol for a multicenter randomized controlled trial. Trials. 2013 Oct 18;14:341. doi: 10.1186/1745-6215-14-341.
PubMed 24138710
Study at a glance
From the registry record, last updated by the sponsor on 3 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Early Nasal High Flow Oxygen Therapy for Prevention of Postoperative Hypoxemia After Abdominal Surgery: A Multicenter Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT01887015
- Acronym / sponsor ID
- OPERA / CHU-0157
- Conditions
- Postoperative Hypoxemia
- Keywords
- Postoperative pulmonary complications, Oxygen therapy, Nasal high flow oxygen therapy, Nasal high flow cannula
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 220 participants (actual)
- Lead sponsor
- University Hospital, Clermont-FerrandUniversity, hospital or other
- Study start
- Jun 2013
- Primary completion
- Mar 2015 (actual)
- Study completion
- Mar 2015 (actual)
- First posted
- 26 Jun 2013 (estimated)
- 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.
To evaluate whether early application of nasal high flow oxygen therapy after extubation can reduce the incidence of postoperative hypoxemia (defined as a PaO2/FiO2 ratio <300) after abdominal surgery in patients with intermediate to high risk of postoperative pulmonary complications.
Detailed description
Postoperative hypoxemia complicates between 30 to 50% of patients after abdominal surgery. Loss of functioning alveolar units and development of atelectasis after abdominal surgery have been recognized as the underlying mechanisms responsible for postoperative hypoxemia. Supplemental Oxygen administration is therefore widely recommended after extubation in the postoperative period, especially in patients with high risk of postoperative respiratory complications. Although oxygen therapy is effective in preventing the vast majority of severe postoperative hypoxemia after extubation in surgical patients, respiratory failure may occur, thus requiring endotracheal intubation and mechanical ventilation or therapeutic use of non-invasive positive pressure ventilation (NPPV). In patients with postoperative hypoxemia (defined as patients with a PaO2/FiO2 ratio <300), application of NPPV was found to decrease the incidence of endotracheal intubation after abdominal surgery. Nevertheless, use of NPPV in the postoperative period is responsible for organizational constraints and increases healthcare utilization.
Nasal high flow cannula (NHFC) has been described as an attractive and well-tolerated method of non-invasive oxygen delivery. Previous studies have shown that NHFC generates a low level of positive airway pressure, increases end-expiratory lung volume and reduces airway resistance, thus contributing to a reduction in work of breathing. To date, however, no clinical trials have compared NHFC to standard oxygen therapy in the prevention of postoperative hypoxemia after abdominal surgery in patients with intermediate to high risk of postoperative pulmonary complications.
The primary objective of the study is to compare: 1- Standard oxygen therapy; 2- Nasal high flow oxygen therapy after extubation in patients with intermediate to high risk of postoperative pulmonary complications after abdominal surgery.
Our hypothesis is that, compared with standard oxygen therapy, early application of nasal high flow oxygen therapy can reduce the need for postoperative NPPV for postoperative hypoxemia (defined as PaO2/FiO2 ratio <300).
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Standard oxygen therapy | Experimental | Device: Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand)Our hypothesis is that, compared with standard oxygen therapy, early application of nasal high flow oxygen therapy can reduce the need for postoperative NPPV for postoperative hypoxemia (defined as PaO2/FiO2 ratio <300). |
| nasal high flow oxygen therapy | Other | Device: Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand)Our hypothesis is that, compared with standard oxygen therapy, early application of nasal high flow oxygen therapy can reduce the need for postoperative NPPV for postoperative hypoxemia (defined as PaO2/FiO2 ratio <300). |
Who may qualify
- Ages
- 19 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Planned or unplanned surgical procedures
- Abdominal or abdominal and thoracic surgery
- Expected duration ≥2 hours
- ARISCAT score ≥26 points
Key exclusion criteria (5 listed)
- Age <18 years
- Body mass index >35 kg/m2
- Sleep apnea syndrome
- Patient refusal
- Pregnancy and/or lactation
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 |
|---|---|---|
| Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand)Also: Nasal high flow oxygen therapy versus standard oxygen therapy | Device | Standard oxygen therapy, nasal high flow oxygen therapy |
Primary outcome
percentage of patients who developed postoperative hypoxemia (defined as PaO2/FiO2 ratio <300)
Time frame: 1 hour after tracheal extubation (day 1)
5 secondary outcomes
Postoperative gas exchange (PaO2, PaCO2)
Time frame: 1H after extubation and after surgery (at day 1)
Need for supplemental oxygen therapy beyond postoperative day 1 (defined as arterial oxygen saturation by pulse oximetry (SpO2) <93% in room air)
Time frame: at day 1
Need for endotracheal intubation or non-invasive ventilation for postoperative acute respiratory failure (ARF)
Time frame: within the first 7 days after surgery
Postoperative pulmonary complications (PPCs)
Time frame: within the first 7 days after surgery
Respiratory discomfort using a numerical rating scale (NRS) ranging from 0 (no discomfort) to 10 (maximum imaginable discomfort).
Time frame: within the first 7 days after surgery
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Aug 2026.
- Results publication: PubMed 27771739Futier E, Paugam-Burtz C, Godet T, Khoy-Ear L, Rozencwajg S, Delay JM, Verzilli D, Dupuis J, Chanques G, Bazin JE, Constantin JM, Pereira B, Jaber S; OPERA study investigators. Effect of early postextubation high-flow nasal cannula vs conventional oxygen therapy on hypoxaemia in patients after major abdominal surgery: a French multicentre randomised controlled trial (OPERA). Intensive Care Med. 2016 Dec;42(12):1888-1898. doi: 10.1007/s00134-016-4594-y. Epub 2016 Oct 22.
- Derived from this study: PubMed 24138710Futier E, Paugam-Burtz C, Constantin JM, Pereira B, Jaber S. The OPERA trial - comparison of early nasal high flow oxygen therapy with standard care for prevention of postoperative hypoxemia after abdominal surgery: study protocol for a multicenter randomized controlled trial. Trials. 2013 Oct 18;14:341. doi: 10.1186/1745-6215-14-341.
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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.
Emmanuel FUTIER, MD, Ph D principal investigator
University Hospital, Clermont-Ferrand
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 Nasal high flow cannula (OptiflowTM, MR850 heated humidified, Fisher & Paykel Healthcare, Auckland, New Zealand) in people with Postoperative Hypoxemia, run by University Hospital, Clermont-Ferrand at 1 site in France.
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 5 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: finished, as of the sponsor's last update on 3 Aug 2026. 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 France. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
percentage of patients who developed postoperative hypoxemia (defined as PaO2/FiO2 ratio <300) (time frame: 1 hour after tracheal extubation (day 1)). 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 NCT01887015, which also lists 2 linked publications.
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 3 Aug 2026.