Effect of Different Oxygen Concentrations Before Extubation After General Anesthesia on Hypoxemia After Extubation in Post-anesthesia Care Unit

December 16, 2025 updated by: SanQing Jin, Sixth Affiliated Hospital, Sun Yat-sen University

Effect of Different Oxygen Concentrations During the Recovery Period Before Extubation After General Anesthesia on Hypoxemia After Extubation in Post-anesthesia Care Unit

Before extubation during the anesthesia recovery period, 100% oxygen is routinely inhaled to increase the oxygen reserves, maximizing the time window for anesthesiologists to adjust strategies when they encounter hypoxemia after extubation.

However, even inhaling a short period of pure oxygen can cause absorptive atelectasis, and may even impair the effectiveness of intraoperative protective ventilation measures continuing to post-operative period. The purpose of this study is to determine whether 30% oxygen before extubation after abdominal surgery could reduce hypoxemia incidence after extubation during the recovery period or not, compared to 100% oxygen. 590 patients scheduled to abdominal surgeries, will be randomly assigned to receive 30% or 100% oxygen concentration from the end of surgery to extubation after general anesthesia in the post-anesthesia care unit. The incidence of hypoxemia (SpO2 < 90%) from extubation to leaving the post-anesthesia care unit (PACU) is the primary outcome.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
590

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • China
    • Guangdong
      • Guangzhou, Guangdong, China
        • The Sixth Affiliated Hospital of Sun Yat-sen University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients aged 18-65 years old, scheduled for elective abdominal surgery in general anesthesia with endotracheal intubation; ASA I-III grade; cardiac function 1-2 grade; 18 kg/m2 < BMI < 28 kg/m2; Preoperative SpO2 ≥ 94% without oxygen supplementation at rest; pre-anesthesia assessment shows no difficult airway, no difficulty with mask ventilation, no difficulty in intubation during tracheal insertion, and no difficulty in extubation as expected.

Exclusion Criteria:

  • Respiratory infection recently, or atelectasis, inflammation, fibrosis, or pleural effusion by chest CT preoperatively.

History thoracic surgery and fractures of the sternum or ribs, chest deformity, difficulty in raising both upper limbs, or scoliosis.

High risk of reflux aspiration. Severe hepatic or renal dysfunction (e.g., Child-Pugh class C liver disease, or requiring dialysis).

Limb movement disorders. Mask ventilation or intubation difficulty during anesthesia induction. Occurrence of severe allergy, massive bleeding, suspected pulmonary embolism, pulmonary edema, myocardial injury, or cardiopulmonary arrest during surgery.

Currently participating in other clinical studies, which may have an impact on this study.

Inability to cooperate well for mental disorder, or hypophrenia.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Control group : 100% oxygen concentration
Patients will inhale 100% oxygen from the end of surgery to tracheal extubation in the recovery period.
Other: 100% oxygen concentration inhaled
Oxygen concentration inhaled from the end of surgery to tracheal extubation after general anesthesia in the recovery period is 100%.
Experimental: Experimental group: 30% oxygen concentration
Patients will inhale 30% oxygen from the end of surgery to extubation in the recovery period.
Other: 30% oxygen concentration inhaled
Oxygen concentration inhaled from the end of surgery to tracheal extubation after general anesthesia in the recovery period is 30%.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Incidence of hypoxemia
Time Frame: At the day of surgery from tracheal extubation to leaving the post-anesthesia care unit
At the day of surgery from tracheal extubation to leaving the post-anesthesia care unit

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Incidence of post operative pulmonary-related complications
Time Frame: Within 7 days after surgery
Within 7 days after surgery
Incidence of severe hypoxemia
Time Frame: At the day of surgery from tracheal extubation to leaving the post-anesthesia care unit
At the day of surgery from tracheal extubation to leaving the post-anesthesia care unit
Arterial partial pressure of oxygen (PaO2)
Time Frame: At the day of surgery after tracheal extubation in the post-anesthesia care unit
At the day of surgery after tracheal extubation in the post-anesthesia care unit
Score of lung ultrasound
Time Frame: At the day of surgery after tracheal extubation in the post-anesthesia care unit
The score of lung ultrasound ranges from 0 to 36, and a higher score means a worse ventilation.
At the day of surgery after tracheal extubation in the post-anesthesia care unit
Area of atelectasis shown on chest CT
Time Frame: At the day of surgery after tracheal extubation
At the day of surgery after tracheal extubation
Number of patients unplanned transfers to the ICU
Time Frame: 30 days after surgery
30 days after surgery
Length of postoperative stay
Time Frame: At hospital discharge
At hospital discharge
Number of patients return to the hospital after discharge
Time Frame: 30 days after surgery
30 days after surgery
Number of deaths
Time Frame: 30 days after surgery
30 days after surgery
Number of patients with important organ disfunction after surgery, including arrhythmia, acute myocardial injury, heart failure, renal function injury, liver function injury, and cerebrovascular accident.
Time Frame: 30 days after surgery
30 days after surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sixth Affiliated Hospital, Sun Yat-sen University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 30, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 30, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
June 30, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 18, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 16, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 19, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 19, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 16, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025ZSLYSC-630

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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