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

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: Not yet recruiting
• Conditions: Hypoxemia
• Intervention / Treatment: Other: 100% oxygen concentration inhaled; Other: 30% oxygen concentration inhaled

• Study Type: Interventional
• Enrollment (Estimated): 590
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Sanqing Jin; Phone Number: +86 13719366863; Email: sanqingjin@hotmail.com
• Study Contact Backup: Name: Yanna Pi; Phone Number: +86 18819186153; Email: piyanna@126.com

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China
      • The sixth affiliated hospital of Sun Yat-Sen University
      • Contact: Sanqing Jin; Phone Number: +86 13719366863; Email: sanqingjin@hotmail.com

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Time Frame
Incidence of hypoxemia	At the day of surgery from tracheal extubation to leaving the post-anesthesia care unit

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of post operative pulmonary-related complications		Within 7 days after surgery
Incidence of severe hypoxemia		At the day of surgery from tracheal extubation to leaving the post-anesthesia care unit
Arterial partial pressure of oxygen (PaO2)		At the day of surgery after tracheal extubation in the post-anesthesia care unit
Score of lung ultrasound	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		At the day of surgery after tracheal extubation
Number of patients unplanned transfers to the ICU		30 days after surgery
Length of postoperative stay		At hospital discharge
Number of patients return to the hospital after discharge		30 days after surgery
Number of deaths		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.		30 days after surgery

Collaborators and Investigators

• Sponsor: Sixth Affiliated Hospital, Sun Yat-sen University

Study record dates

Study Major Dates

• Study Start (Estimated): December 30, 2025
• Primary Completion (Estimated): May 30, 2026
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: November 18, 2025
• First Submitted That Met QC Criteria: December 16, 2025
• First Posted (Actual): December 19, 2025

Study Record Updates

• Last Update Posted (Actual): December 19, 2025
• Last Update Submitted That Met QC Criteria: December 16, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: atelectasis; hypoxemia; oxygen concentration
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Signs and Symptoms, Respiratory; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hypoxia; Pulmonary Atelectasis
• Other Study ID 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