Effect of Different Inspired Oxygen Concentrations on Intraoperative Recruitment Outcomes in Patients Undergoing Abdominal Surgery

February 22, 2026 updated by: Ju Gao, Northern Jiangsu People's Hospital

This study intends to evaluate the effect of different inhaled oxygen concentrations on the effect of lung recruitment in patients undergoing abdominal surgery. During perioperative mechanical ventilation, higher FiO2 is usually given to prevent the occurrence of hypoxemia, but there are no conclusions about the setting of optimal FiO2 during surgery.

Dynamic pulmonary compliance enables real-time monitoring of alveolar changes and is used to assess pulmonary function in intraoperative patients. The value of compliance represents the number of air-containing alveoli; the more alveoli are trapped, the less air-containing tissue there is and the lower the compliance. Lung recruitment, as part of a lung-protective ventilation strategy, is effective in opening alveoli and improving oxygenation. This single-center, randomized controlled trial will explore the optimal inspired oxygen concentration that allows patients to benefit from lung recruitment and the duration of improvement in lung compliance after lung recruitment.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

95

Phase

  • 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 Locations

  • China
    • Jiangsu
      • Yangzhou, Jiangsu, China, 225001
        • Northern Jiangsu People's Hospital

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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • ASA physical status classification: I or II.
  • Adults aged 18 to 64 years, regardless of gender.
  • BMI between 18 kg/m² and 25 kg/m².
  • Patients undergoing elective abdominal surgery under general anesthesia.
  • Patients with estimated operating time ≥1.5h and intraoperative bleeding ≤500ml.
  • Patients who have provided written informed consent after understanding the study purpose, procedures, and potential risks.

Exclusion Criteria:

  • Previous thoracic surgery.
  • Chest X-ray or CT suggestive of pneumothorax or alveoli.
  • Lung disease: chronic bronchitis, asthma, moderate to severe obstructive ventilatory dysfunction.
  • Preoperative pulse oxygen saturation (SpO2) <90% on breathing air or SpO2 <95% on oxygen.
  • Contraindications to lung reanimation: high intracranial pressure, hypovolemic shock, right heart failure.
  • Severe heart disease (New York Heart Association, NYHA class III or IV.
  • Acute coronary syndrome or sustained ventricular tachyarrhythmia).
  • Participation in other interventional studies or refusal of enrollment.

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: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: A: FiO2 = 30%
FiO2 of group A = 30%. If SPO2 < 94%, improve FiO2; if FiO2≥40%, eliminate the patient.
Behavioral: Fraction of inspiration O2(FiO2)
After the patient was admitted to the room, anesthesia induction was performed after pre-oxygenation for 3 minutes. Tracheal intubation was carried out once the medication had fully taken effect. After the surgery began, the inspired oxygen concentration was adjusted for each group. The first lung recruitment maneuver was performed 10 minutes later, and subsequent lung recruitment maneuvers were conducted when pulmonary compliance returned to baseline levels. This process was repeated, with all patients undergoing one final lung recruitment maneuver immediately at the end of the surgery.
Experimental: B: FiO2＝40%
FiO2＝40%
Behavioral: Fraction of inspiration O2(FiO2)
After the patient was admitted to the room, anesthesia induction was performed after pre-oxygenation for 3 minutes. Tracheal intubation was carried out once the medication had fully taken effect. After the surgery began, the inspired oxygen concentration was adjusted for each group. The first lung recruitment maneuver was performed 10 minutes later, and subsequent lung recruitment maneuvers were conducted when pulmonary compliance returned to baseline levels. This process was repeated, with all patients undergoing one final lung recruitment maneuver immediately at the end of the surgery.
Experimental: C: FiO2＝60%
FiO2＝60%
Behavioral: Fraction of inspiration O2(FiO2)
After the patient was admitted to the room, anesthesia induction was performed after pre-oxygenation for 3 minutes. Tracheal intubation was carried out once the medication had fully taken effect. After the surgery began, the inspired oxygen concentration was adjusted for each group. The first lung recruitment maneuver was performed 10 minutes later, and subsequent lung recruitment maneuvers were conducted when pulmonary compliance returned to baseline levels. This process was repeated, with all patients undergoing one final lung recruitment maneuver immediately at the end of the surgery.
Experimental: D: FiO2＝80%
FiO2＝80%
Behavioral: Fraction of inspiration O2(FiO2)
After the patient was admitted to the room, anesthesia induction was performed after pre-oxygenation for 3 minutes. Tracheal intubation was carried out once the medication had fully taken effect. After the surgery began, the inspired oxygen concentration was adjusted for each group. The first lung recruitment maneuver was performed 10 minutes later, and subsequent lung recruitment maneuvers were conducted when pulmonary compliance returned to baseline levels. This process was repeated, with all patients undergoing one final lung recruitment maneuver immediately at the end of the surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Duration of improvement in lung compliance
Time Frame: during the surgery
Time to return to baseline levels of lung compliance after lung recruitment
during the surgery

Secondary Outcome Measures

Outcome Measure
Time Frame
Incidence of hypoxemia during PACU
Time Frame: From the time of entry to the PACU to the time of exit from the PACU
From the time of entry to the PACU to the time of exit from the PACU
Incidence of pulmonary complications within 3 days after surgery
Time Frame: From the end of surgery to 3 days after surgery
From the end of surgery to 3 days after surgery
Incidence of pulmonary atelectasis at the end of surgery
Time Frame: Surgery complete, extubation immediate
Surgery complete, extubation immediate

Collaborators and Investigators

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

Sponsor

Northern Jiangsu People's Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

April 1, 2025

Primary Completion (Actual)

January 29, 2026

Study Completion (Actual)

January 30, 2026

Study Registration Dates

First Submitted

December 17, 2024

First Submitted That Met QC Criteria

December 20, 2024

First Posted (Actual)

December 24, 2024

Study Record Updates

Last Update Posted (Actual)

February 24, 2026

Last Update Submitted That Met QC Criteria

February 22, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2024ky310

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data (IPD) will be shared. Data will include demographic characteristics, procedural details, and outcome measures. Access will be granted to qualified researchers upon request via a secure data repository.

IPD Sharing Time Frame

De-identified individual participant data (IPD) will be available starting 6 months after the publication of the primary study results. Data will remain available for 3 years.

IPD Sharing Access Criteria

Qualified researchers affiliated with academic, governmental, or non-profit institutions may request access to the IPD. Requests must include a detailed research proposal, institutional review board (IRB) approval (if applicable), and a signed data-sharing agreement. Access will be provided to de-identified data relevant to the study objectives, including demographic information, procedural details, and primary/secondary outcome measures. Data will be shared via a secure repository upon approval of the request.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • ANALYTIC_CODE
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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