Death, BrainAPNEAFLO2WNCT07640009
Efficacy of High-Flow Humidified Oxygen (HFHO) in Apneic Oxygenation for Apnea Testing: A Comparison With Continuous Positive Airway Pressure (CPAP)
A study testing Apnea test under HHFO followed by an apnea test under CPAP. and Apnea test under CPAP followed by an apnea test under HHFO. in people with Death, Brain, run by Centre Hospitalier Régional d'Orléans at 4 sites in France.
Trial summary
Brain death (BD) is characterized by a severe brain injury resulting in irreversible loss of all brain and brainstem functions, while other organs may remain viable. The diagnosis of BD is based on the presence of coma, absence of brainstem reflexes, and absence of spontaneous breathing confirmed by an apnea test. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Death, Brain
- What is being tested?
- Apnea test under HHFO followed by an apnea test under CPAP. and Apnea test under CPAP followed by an apnea test under HHFO.
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 28 participants
- Where
- 4 sitesFrance
- Study dates
- 15 Sep 2026to 15 Sep 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
- Adult intensive care unit patients
- fulfilling all criteria for clinical brain death, for whom confirmation of the absence of spontaneous breathing requires performance of an apnea test
- And for whom consent to participate in the study was sought from a trusted person or a family member
Who cannot join
- History of chronic obstructive pulmonary disease (COPD) classified as GOLD stage III or IV.
- Current extracorporeal life support, including veno-arterial (VA) or veno-venous (VV) extracorporeal membrane oxygenation (ECMO).
- PaO₂/FiO₂ ratio ≤ 150 on the most recent arterial blood gas analysis, obtained within 24 hours prior to the screening visit.
- Presence of at least one clear or absolute contraindication to the procurement of at least one organ.
- Presence of a high cervical spinal cord injury.
- Patient in the prone position and/or with a contraindication to placement in the supine position at 30°.
Show all 12Show fewer
- Minor patient.
- Protected adult under legal guardianship or curatorship.
- Individual under judicial protection (safeguard of justice).
- Individuals deprived of liberty.
- Individual not covered by a social security or health insurance system.
- Pregnant or breastfeeding woman.
Trial locations and contacts
4 sites in 1 country. Contact the study team or a site near you to ask about taking part.
France4 sites
Chu Angers
Angers
Aurore ARMAND, MD, auarmand@chu-angers.fr
Aurore ARMAND, MD
Chu de Nantes
Nantes
jaen-Baptiste LASCARROU, MD, jeanbaptiste.lascarrou@chu-nantes.fr
Jean-Baptiste LASCARROU, MD
Chu Orleans
Orléans
Damien BARRIER, damien.barrier@chu-orleans.fr
Damien BARRIER
Chru de Tours
Tours
Sophie JACQUIER, MD, s.jacquier@chu-tours.fr
Sophie JACQUIER, MD
About this study
Official title: Efficacy of High-Flow Humidified Oxygen in Apneic Oxygenation During Apnea Testing Compared With Continuous Positive Airway Pressure: A Randomized Multicenter Crossover Trial
Brain death (BD) is characterized by a severe brain injury resulting in irreversible loss of all brain and brainstem functions, while other organs may remain viable. The diagnosis of BD is based on the presence of coma, absence of brainstem reflexes, and absence of spontaneous breathing confirmed by an apnea test. In France, the apnea test is mandatory prior to organ procurement. The apnea test aims to demonstrate that hypercapnia, a strong ventilatory stimulus, does not induce any respiratory movements.
In current practice, the apnea test is performed by disconnecting the patient from mechanical ventilation for 8-10 minutes while administering oxygen. Oxygenation strategies during apnea vary across French centers. Although the use of continuous positive airway pressure (CPAP) is recommended, a substantial proportion of tests are still performed without positive end-expiratory pressure (PEEP) effect, using either an open T-piece or an intratracheal oxygen catheter. These methods are associated with a higher risk of complications, such as hypoxemia, and potential adverse effects on organ function, which is particularly relevant in the context of organ donation.
Read more
Humidified high-flow oxygen (HHFO), delivered via a specialized device connected to the endotracheal tube, provides high flow rates (up to 60 L/min), allows precise adjustment of the fraction of inspired oxygen (FiO₂ up to 1.0), and generates a minimal PEEP effect. HHFO is routinely used in intensive care units. While its feasibility during apnea testing has been reported, its efficacy during BD diagnosis has not been well evaluated.
Preliminary observations in intensive care patients with clinical brain death suggest that HHFO can be safely used during the apnea test, allowing achievement of hypercapnia and confirmation of absence of spontaneous respiration while maintaining better oxygenation compared with conventional oxygen delivery via an open T-piece.
This study aims to evaluate the efficacy of HHFO for apneic oxygenation during the apnea test, in comparison with the recommended method using CPAP.
Read the detailed description
The study strategy is based on performing two consecutive apnea tests in patients with clinical brain death, conducted in a randomized order. Only patients in whom the first apnea test confirms the absence of spontaneous breathing will proceed to the second apnea test. Consistency of clinical brain death at the end of the first apnea test are defined by the absence of any respiratory movement and the presence of either an arterial partial pressure of carbon dioxide (PaCO₂) ≥ 60 mmHg or an increase in PaCO₂ > 20 mmHg compared with the PaCO₂ measured at the end of the preoxygenation period.
Each of the two apnea tests will be preceded by a standardized 15-minute preoxygenation period using assisted controlled ventilation with a tidal volume of 6mL/kg of predicted body weight.
The two consecutive apnea tests will be performed in randomized order under CPAP and under HHFO with standardized parameters.
As per routine clinical practice, an arterial blood gas sample will be obtained before disconnection from the ventilator at the end of the preoxygenation period to confirm normocapnia, defined as 35 mmHg ≤ PaCO₂ ≤ 45 mmHg. A second arterial blood gas sample will be obtained at the end of the apnea test, prior to reconnection to the ventilator, to measure PaCO₂ and arterial partial pressure of oxygen (PaO₂).
Specifically for the purposes of the study, during each apnea test, the investigator will perform arterial blood gas sampling every 2 minutes to measure PaO₂, PaCO₂, and pH. At the same time points, arterial blood pressure, heart rate, pulse oximetry, and catecholamine infusion doses will be recorded.
In addition to these measurements required to meet the study objectives, demographic and clinical data will be collected primarily from the medical records to characterize the study population.
- Conditions
- Death, Brain
- Being tested
- Apnea test under HHFO followed by an apnea test under CPAP., Apnea test under CPAP followed by an apnea test under HHFO.
- Keywords
- Intensive Care Unit, Humidified high-flow oxygen therapy, Continuous positive airway pressure, Apnea testing, Brain death
- Medical subject headings
- Brain Death
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Apnea test under HHFO followed by an apnea test under CPAP.Other
For each 10-minute apnea test, regardless of the oxygenation device used, arterial blood gas will be analysed and heart rate, arterial pressure, and pulse oximetry will be recorded in 2-minute intervals.
Apnea test under CPAP followed by an apnea test under HHFO.Other
For each 10-minute apnea test, regardless of the oxygenation device used, arterial blood gas will be analysed and heart rate, arterial pressure, and pulse oximetry will be recorded in 2-minute intervals.
| Study group | Role | What they receive |
|---|---|---|
| Arm HHFO in first | Experimental | HHFO in first: in this arm, the first of the two consecutive apnea tests is performed under HHFO, followed by a second apnea test under CPAP. Receives: Other: Apnea test under HHFO followed by an apnea test under CPAP.; Other: Apnea test under CPAP followed by an apnea test under HHFO. |
| Arm CPAP in first. | Experimental | CPAP in first: in this arm, the first of the two consecutive apnea tests is performed under CPAP, followed by a second apnea test under HHFO. Receives: Other: Apnea test under HHFO followed by an apnea test under CPAP.; Other: Apnea test under CPAP followed by an apnea test under HHFO. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in PaO₂ (mmHg) between the beginning and the end of an apnea test under HHFO and CPAP
To demonstrate the non-inferiority of humidified high-flow oxygen compared to continuous positive airway pressure in apneic oxygenation for apnea testing.
Measured: From ventilator disconnection to 10th minute of the apnea test
Secondary outcomes (9)
Evolution of arterial blood PaO2 parameters during the apnea test under HHFO and the apnea test with CPAP
Recording of PaO2 values measured in 2-minute intervals during the apnea test under HHFO and apnea test with CPAP
Measured: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of arterial blood PaCO2 parameters during the apnea test under HHFO and the apnea test with CPAP
Recording of PaCO2 values measured in 2-minute intervals during the apnea test under HHFO and apnea test with CPAP
Measured: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of arterial blood pH parameters during the apnea test under HHFO and the apnea test with CPAP
Recording of pH values measured in 2-minute intervals during the apnea test under HHFO and apnea test with CPAP
Measured: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of arterial blood pressure during the apnea test under HHFO and the apnea test with CPAP
Recording of arterial blood pressure measured in 2-minute intervals during the apnea test under HHFO and with CPAP.
Measured: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of heart rate during the apnea test under HHFO and the apnea test with CPAP
Recording of heart rate measured in 2-minute intervals during the apnea test under HHFO and with CPAP.
Measured: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of pulse oximetry during the apnea test under HHFO and the apnea test with CPAP
Recording of pulse oximetry measured in 2-minute intervals during the apnea test under HHFO and with CPAP.
Measured: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Time required to reach the hypercapnia thresholds necessary to confirm brain death during an apnea test under HHFO and with CPAP
Time required to exceed 60mmHg of PaCO2 or for which PaCO2 increases by more than 20mmHg compared to the PaCO2 before disconnection during an apnea test under HHFO and with CPAP
Measured: From ventilator disconnection until the hypercapnia threshold is reached
Occurrence of apnea test interruptions during HHFO and CPAP.
Documentation of apnea test interruptions under HHFO and CPAP.
Measured: From ventilator disconnection until apnea test termination due to intolerance
Nurse-rated numeric scale evaluations of Humidified High Flow Oxygen and Continuous Positive Airway Pressure use for each enrolled patient
Nurse-rated ease of use will be assessed using a 4-point numeric scale (range: 0-3). The minimum score is 0 and the maximum score is 3. A score of 0 corresponds to very difficult use, and a score of 3 corresponds to very easy use. Higher scores indicate greater ease of use
Measured: Within 1 hour after each apnea test.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Jun 2026
- Study start15 Sep 2026 (estimated)
- Primary completion15 Sep 2028 (estimated)
- Study completion15 Sep 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Death, BrainStudies 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
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized controlled crossover multi-center trial
- Masking
- None (open label)
- Enrolment
- 28 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Centre Hospitalier Régional d'Orléans
- Sponsor type
- University, hospital or other
- Collaborators
- Fisher and Paykel Healthcare
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07640009
- Sponsor's protocol ID
- CHUO-2025-05
- Acronym
- APNEAFLO2W
- Status last verified
- Jul 2026
- First submitted
- 5 Jun 2026
- Last updated
- 10 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 10 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacy of High-Flow Humidified Oxygen in Apneic Oxygenation During Apnea Testing Compared With Continuous Positive Airway Pressure: A Randomized Multicenter Crossover Trial
- ClinicalTrials.gov ID
- NCT07640009
- Acronym / sponsor ID
- APNEAFLO2W / CHUO-2025-05
- Conditions
- Death, Brain
- Keywords
- Intensive Care Unit, Humidified high-flow oxygen therapy, Continuous positive airway pressure, Apnea testing, Brain death
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 28 participants (estimated)
- Lead sponsor
- Centre Hospitalier Régional d'OrléansUniversity, hospital or other
- Collaborators
- Fisher and Paykel Healthcare
- Study start
- 15 Sep 2026 (estimated)
- Primary completion
- 15 Sep 2028 (estimated)
- Study completion
- 15 Sep 2028 (estimated)
- First posted
- 10 Jun 2026 (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.
Brain death (BD) is characterized by a severe brain injury resulting in irreversible loss of all brain and brainstem functions, while other organs may remain viable. The diagnosis of BD is based on the presence of coma, absence of brainstem reflexes, and absence of spontaneous breathing confirmed by an apnea test. In France, the apnea test is mandatory prior to organ procurement. The apnea test aims to demonstrate that hypercapnia, a strong ventilatory stimulus, does not induce any respiratory movements.
In current practice, the apnea test is performed by disconnecting the patient from mechanical ventilation for 8-10 minutes while administering oxygen. Oxygenation strategies during apnea vary across French centers. Although the use of continuous positive airway pressure (CPAP) is recommended, a substantial proportion of tests are still performed without positive end-expiratory pressure (PEEP) effect, using either an open T-piece or an intratracheal oxygen catheter. These methods are associated with a higher risk of complications, such as hypoxemia, and potential adverse effects on organ function, which is particularly relevant in the context of organ donation.
Humidified high-flow oxygen (HHFO), delivered via a specialized device connected to the endotracheal tube, provides high flow rates (up to 60 L/min), allows precise adjustment of the fraction of inspired oxygen (FiO₂ up to 1.0), and generates a minimal PEEP effect. HHFO is routinely used in intensive care units. While its feasibility during apnea testing has been reported, its efficacy during BD diagnosis has not been well evaluated.
Preliminary observations in intensive care patients with clinical brain death suggest that HHFO can be safely used during the apnea test, allowing achievement of hypercapnia and confirmation of absence of spontaneous respiration while maintaining better oxygenation compared with conventional oxygen delivery via an open T-piece.
This study aims to evaluate the efficacy of HHFO for apneic oxygenation during the apnea test, in comparison with the recommended method using CPAP.
Detailed description
The study strategy is based on performing two consecutive apnea tests in patients with clinical brain death, conducted in a randomized order. Only patients in whom the first apnea test confirms the absence of spontaneous breathing will proceed to the second apnea test. Consistency of clinical brain death at the end of the first apnea test are defined by the absence of any respiratory movement and the presence of either an arterial partial pressure of carbon dioxide (PaCO₂) ≥ 60 mmHg or an increase in PaCO₂ > 20 mmHg compared with the PaCO₂ measured at the end of the preoxygenation period.
Each of the two apnea tests will be preceded by a standardized 15-minute preoxygenation period using assisted controlled ventilation with a tidal volume of 6mL/kg of predicted body weight.
The two consecutive apnea tests will be performed in randomized order under CPAP and under HHFO with standardized parameters.
As per routine clinical practice, an arterial blood gas sample will be obtained before disconnection from the ventilator at the end of the preoxygenation period to confirm normocapnia, defined as 35 mmHg ≤ PaCO₂ ≤ 45 mmHg. A second arterial blood gas sample will be obtained at the end of the apnea test, prior to reconnection to the ventilator, to measure PaCO₂ and arterial partial pressure of oxygen (PaO₂).
Specifically for the purposes of the study, during each apnea test, the investigator will perform arterial blood gas sampling every 2 minutes to measure PaO₂, PaCO₂, and pH. At the same time points, arterial blood pressure, heart rate, pulse oximetry, and catecholamine infusion doses will be recorded.
In addition to these measurements required to meet the study objectives, demographic and clinical data will be collected primarily from the medical records to characterize the study population.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Randomized controlled crossover multi-center trial
| Arm | Type | Receives |
|---|---|---|
| Arm HHFO in first | Experimental | Other: Apnea test under HHFO followed by an apnea test under CPAP., Other: Apnea test under CPAP followed by an apnea test under HHFO.HHFO in first: in this arm, the first of the two consecutive apnea tests is performed under HHFO, followed by a second apnea test under CPAP. |
| Arm CPAP in first. | Experimental | Other: Apnea test under HHFO followed by an apnea test under CPAP., Other: Apnea test under CPAP followed by an apnea test under HHFO.CPAP in first: in this arm, the first of the two consecutive apnea tests is performed under CPAP, followed by a second apnea test under HHFO. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Adult intensive care unit patients
- fulfilling all criteria for clinical brain death, for whom confirmation of the absence of spontaneous breathing requires performance of an apnea test
- And for whom consent to participate in the study was sought from a trusted person or a family member
Key exclusion criteria (12 listed)
- History of chronic obstructive pulmonary disease (COPD) classified as GOLD stage III or IV.
- Current extracorporeal life support, including veno-arterial (VA) or veno-venous (VV) extracorporeal membrane oxygenation (ECMO).
- PaO₂/FiO₂ ratio ≤ 150 on the most recent arterial blood gas analysis, obtained within 24 hours prior to the screening visit.
- Presence of at least one clear or absolute contraindication to the procurement of at least one organ.
- Presence of a high cervical spinal cord injury.
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 |
|---|---|---|
| Apnea test under HHFO followed by an apnea test under CPAP.For each 10-minute apnea test, regardless of the oxygenation device used, arterial blood gas will be analysed and heart rate, arterial pressure, and pulse oximetry will be recorded in 2-minute intervals. | Other | Arm CPAP in first., Arm HHFO in first |
| Apnea test under CPAP followed by an apnea test under HHFO.For each 10-minute apnea test, regardless of the oxygenation device used, arterial blood gas will be analysed and heart rate, arterial pressure, and pulse oximetry will be recorded in 2-minute intervals. | Other | Arm CPAP in first., Arm HHFO in first |
Primary outcome
Change in PaO₂ (mmHg) between the beginning and the end of an apnea test under HHFO and CPAP
Time frame: From ventilator disconnection to 10th minute of the apnea test
To demonstrate the non-inferiority of humidified high-flow oxygen compared to continuous positive airway pressure in apneic oxygenation for apnea testing.
9 secondary outcomes
Evolution of arterial blood PaO2 parameters during the apnea test under HHFO and the apnea test with CPAP
Time frame: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of arterial blood PaCO2 parameters during the apnea test under HHFO and the apnea test with CPAP
Time frame: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of arterial blood pH parameters during the apnea test under HHFO and the apnea test with CPAP
Time frame: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of arterial blood pressure during the apnea test under HHFO and the apnea test with CPAP
Time frame: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of heart rate during the apnea test under HHFO and the apnea test with CPAP
Time frame: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Evolution of pulse oximetry during the apnea test under HHFO and the apnea test with CPAP
Time frame: At 2-minute intervals from ventilator disconnection to the 10th minute of each apnea test
Time required to reach the hypercapnia thresholds necessary to confirm brain death during an apnea test under HHFO and with CPAP
Time frame: From ventilator disconnection until the hypercapnia threshold is reached
Occurrence of apnea test interruptions during HHFO and CPAP.
Time frame: From ventilator disconnection until apnea test termination due to intolerance
Nurse-rated numeric scale evaluations of Humidified High Flow Oxygen and Continuous Positive Airway Pressure use for each enrolled patient
Time frame: Within 1 hour after each apnea test.
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 10 Jul 2026.
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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.
4 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Apnea test under HHFO followed by an apnea test under CPAP. and Apnea test under CPAP followed by an apnea test under HHFO. in people with Death, Brain, run by Centre Hospitalier Régional d'Orléans at 4 sites 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 3 inclusion and 12 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: opening soon, as of the sponsor's last update on 10 Jul 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 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.
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?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in PaO₂ (mmHg) between the beginning and the end of an apnea test under HHFO and CPAP (time frame: From ventilator disconnection to 10th minute of the apnea test). 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 10 Jul 2026.