Ventilatory DepressionNCT05379673
The Effect of Hyperoxia on Ventilation During Recovery From General Anesthesia
A study testing Oxygen Gas for Inhalation in people with Ventilatory Depression and Postoperative Respiratory Failure, run by Stanford University at 1 site in United States.
Trial summary
In this randomized-controlled trial the investigators will examine the effect of oxygen supplementation on the recovery of breathing for 90 minutes in the immediate post-anesthesia period starting from extubation of the trachea. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Ventilatory Depression, Postoperative Respiratory Failure
- What is being tested?
- Oxygen Gas for Inhalation
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteUnited States
- Study dates
- 4 Oct 2022to 31 Dec 2026
- 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 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- American Society of Anesthesiologists (ASA) physical status I-III
- Body mass index (BMI) less than 40 kg/m2
- Scheduled to undergo robotic-assisted radical laparoscopic nephrectomy or prostatectomy.
Who cannot join
- Patients with a diagnosis of chronic obstructive pulmonary disorder (COPD), severe neurological, cardiopulmonary, psychiatric, or untreated thyroid disorder
- Chronic pain condition that is being treated with opioids
- Patients with a hematocrit lower than 30% at the end of surgery, or those with an excessive blood loss, requiring transfusion of blood products during surgery.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Stanford University School of Medicine
Stanford, California, 94305
Anthony Doufas, MD, PhD, (650) 498-7699, agdoufas@stanford.edu
Anthony Doufas, MD, PhD
About this study
Official title: Recovery of Ventilation After General Anesthesia for Robotic-Assisted Laparoscopic Nephrectomy or Prostatectomy: The Effect of Oxygen Supplementation
In this randomized-controlled trial the investigators will examine the effect of oxygen supplementation on the recovery of breathing for 90 minutes in the immediate post-anesthesia period starting from extubation of the trachea.
Read the detailed description
In a pilot randomized-controlled trial (NCT04723433) the investigators found that hyperoxia, compared with standard O2 supplementation, enhanced ventilation, as estimated by the fraction of time at a transcutaneous PCO2 (TcPCO2) > 45 mmHg.
More specifically, patients treated with hyperoxia (O2 titrated to: SpO2 > 96%, N=10; Liberal O2) for 90 minutes post-anesthesia, spent 61.2% of the time at TcPCO2 > 45 mmHg, compared with 80.6% of the time in those receiving standard O2 supplementation (O2 titrated to: SpO2 between 90-94%, N=9; Conservative O2 - between-group difference of 19.4% (95% CI: -18.7% to 57.6%), ANCOVA adjusted P = 0.140]. Results were consistent across the 90-min monitoring period. With an observed effect size of 0.73, it was estimated that 30 participants per group are required, to demonstrate this difference with a power of 80% at a two-sided alpha of 5%.
In the present confirmative randomized controlled trial, the investigators plan to estimate and compare the cumulative segment of time during which the transcutaneous partial pressure of carbon dioxide will exceed an upper limit of 45 mmHg (i.e., TcPCO2 > 45 mmHg) for the 90-min-long post-anesthesia period, between the conventional (titrated to an oxygen saturation > 96%) and the conservative (titrated to O2 saturation 90-94%) O2 supplementation interventions.
Hypothesis: Conservative use of O2 (titrated to an SpO2: 90 - 94%), will be associated with more hypoventilation (i.e., more time spent with an TcPCO2 > 45 mmHg) during recovery from general anesthesia, compared to liberal O2 supplementation (SpO2 > 96%).
- Being tested
- Oxygen Gas for Inhalation
- Medical subject headings
- Respiratory Insufficiency
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Oxygen Gas for InhalationOther
Oxyhemoglobin saturation (SpO2) higher than 96% vs SpO2 between 90% and 94%.
| Study group | Role | What they receive |
|---|---|---|
| "Conservative O2 Supplementation" | Active comparator | Oxygen administration will be titrated to a oxyhemoglobin saturation (SpO2) between 90 and 94%. Receives: Other: Oxygen Gas for Inhalation |
| "Liberal O2 Supplementation" | Experimental | Oxygen administration will be titrated to an SpO2 > 96%. Receives: Other: Oxygen Gas for Inhalation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Transcutaneous partial pressure of carbon dioxide (TcPCO2)
The cumulative segment of time during which the transcutaneous partial pressure of carbon dioxide (TcPCO2: primary outcome) will exceed an upper limit of 45 mmHg (i.e., TcPCO2 > 45 mmHg)
Measured: Ninety -minute period beginning immediately post-anesthesia.
Secondary outcomes (1)
Apnea / hypopnea index (AHI)
The number of apnea /hypopnea episodes detected using respiratory inductance plethysmography and nasal pressure.
Measured: Ninety -minute period beginning immediately post-anesthesia.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 May 2022
- Study start4 Oct 2022
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Ventilatory DepressionStudies of the same condition, open and under way.
- More trials run by Stanford UniversityThe 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 N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- In the post-anesthesia care unit (PACU), participants will be randomized to receive conservative (titrated to an SpO2 between 90 and 94%) versus liberal (titrated to SpO2 \> 96%) oxygen supplementation, via a non-rebreather mask.
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Anthony Doufas, Stanford University
- Investigators
- Anthony Doufas, MD, PhD, Principal investigator, Professor, Department of Anesthesiology, Stanford University Medical School
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05379673
- Sponsor's protocol ID
- IRB-63878
- Status last verified
- Jun 2026
- First submitted
- 12 May 2022
- Last updated
- 24 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Recovery of Ventilation After General Anesthesia for Robotic-Assisted Laparoscopic Nephrectomy or Prostatectomy: The Effect of Oxygen Supplementation
- ClinicalTrials.gov ID
- NCT05379673
- Acronym / sponsor ID
- IRB-63878
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Study start
- 4 Oct 2022 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 18 May 2022 (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.
In this randomized-controlled trial the investigators will examine the effect of oxygen supplementation on the recovery of breathing for 90 minutes in the immediate post-anesthesia period starting from extubation of the trachea.
Detailed description
In a pilot randomized-controlled trial (NCT04723433) the investigators found that hyperoxia, compared with standard O2 supplementation, enhanced ventilation, as estimated by the fraction of time at a transcutaneous PCO2 (TcPCO2) > 45 mmHg.
More specifically, patients treated with hyperoxia (O2 titrated to: SpO2 > 96%, N=10; Liberal O2) for 90 minutes post-anesthesia, spent 61.2% of the time at TcPCO2 > 45 mmHg, compared with 80.6% of the time in those receiving standard O2 supplementation (O2 titrated to: SpO2 between 90-94%, N=9; Conservative O2 - between-group difference of 19.4% (95% CI: -18.7% to 57.6%), ANCOVA adjusted P = 0.140]. Results were consistent across the 90-min monitoring period. With an observed effect size of 0.73, it was estimated that 30 participants per group are required, to demonstrate this difference with a power of 80% at a two-sided alpha of 5%.
In the present confirmative randomized controlled trial, the investigators plan to estimate and compare the cumulative segment of time during which the transcutaneous partial pressure of carbon dioxide will exceed an upper limit of 45 mmHg (i.e., TcPCO2 > 45 mmHg) for the 90-min-long post-anesthesia period, between the conventional (titrated to an oxygen saturation > 96%) and the conservative (titrated to O2 saturation 90-94%) O2 supplementation interventions.
Hypothesis: Conservative use of O2 (titrated to an SpO2: 90 - 94%), will be associated with more hypoventilation (i.e., more time spent with an TcPCO2 > 45 mmHg) during recovery from general anesthesia, compared to liberal O2 supplementation (SpO2 > 96%).
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- In the post-anesthesia care unit (PACU), participants will be randomized to receive conservative (titrated to an SpO2 between 90 and 94%) versus liberal (titrated to SpO2 > 96%) oxygen supplementation, via a non-rebreather mask.
| Arm | Type | Receives |
|---|---|---|
| "Conservative O2 Supplementation" | Active comparator | Other: Oxygen Gas for InhalationOxygen administration will be titrated to a oxyhemoglobin saturation (SpO2) between 90 and 94%. |
| "Liberal O2 Supplementation" | Experimental | Other: Oxygen Gas for InhalationOxygen administration will be titrated to an SpO2 > 96%. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- American Society of Anesthesiologists (ASA) physical status I-III
- Body mass index (BMI) less than 40 kg/m2
- Scheduled to undergo robotic-assisted radical laparoscopic nephrectomy or prostatectomy.
Key exclusion criteria (3 listed)
- Patients with a diagnosis of chronic obstructive pulmonary disorder (COPD), severe neurological, cardiopulmonary, psychiatric, or untreated thyroid disorder
- Chronic pain condition that is being treated with opioids
- Patients with a hematocrit lower than 30% at the end of surgery, or those with an excessive blood loss, requiring transfusion of blood products during surgery.
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 |
|---|---|---|
| Oxygen Gas for InhalationOxyhemoglobin saturation (SpO2) higher than 96% vs SpO2 between 90% and 94%. | Other | "Conservative O2 Supplementation", "Liberal O2 Supplementation" |
Primary outcome
Transcutaneous partial pressure of carbon dioxide (TcPCO2)
Time frame: Ninety -minute period beginning immediately post-anesthesia.
The cumulative segment of time during which the transcutaneous partial pressure of carbon dioxide (TcPCO2: primary outcome) will exceed an upper limit of 45 mmHg (i.e., TcPCO2 > 45 mmHg)
1 secondary outcome
Apnea / hypopnea index (AHI)
Time frame: Ninety -minute period beginning immediately post-anesthesia.
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 24 Sep 2026.
- Individual participant dataSharing planned: No
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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.
Anthony Doufas, MD, PhD principal investigator
Professor, Department of Anesthesiology, Stanford University Medical School
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Oxygen Gas for Inhalation in people with Ventilatory Depression and Postoperative Respiratory Failure, run by Stanford University at 1 site 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 3 inclusion and 3 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 24 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 1 site 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 Anthony Doufas, MD, PhD (650-498-7699, agdoufas@stanford.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Transcutaneous partial pressure of carbon dioxide (TcPCO2) (time frame: Ninety -minute period beginning immediately post-anesthesia.). 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 24 Sep 2026.