Effect of Inspired Oxygen Concentration on Postoperative Atelectasis After VATS Right Lobectomy

Effect of Inspired Oxygen Concentration on Postoperative Atelectasis in Patients Undergoing Elective Thoracoscopic Right Pulmonary Lobectomy Based on Perioperative Lung Protection Strategy: A Randomized Controlled Trial

This study aims to investigate whether using 50% FiO₂ during one-lung ventilation, compared with 100% FiO₂, reduces postoperative atelectasis in the non-dependent (healthy) lung of patients undergoing VATS right pulmonary lobectomy, based on individualized PEEP titration. This is a single-center, prospective, assessor- and patient-blinded randomized controlled trial. A total of 100 patients (50 per group, including a pilot phase of 10 per group) will be enrolled and randomized 1:1 to the high-oxygen group (FiO₂=100%) and the low-oxygen group (FiO₂=50%). The primary endpoint is the percentage of atelectasis volume in the non-operated lung relative to the total non-operated lung volume, assessed by CT at 90±10 minutes postoperatively.

Study Overview

• Status: Not yet recruiting
• Conditions: Atelectasis; Postoperative Pulmonary Complications
• Intervention / Treatment: Procedure: High inspired oxygen concentration (FiO₂=100%) during one-lung ventilaion; Procedure: Low inspired oxygen concentration (FiO₂=50%) during one-lung ventilation

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Yi Feng, Ph.D; Phone Number: 010-88325590; Email: doc_yifeng@163.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Age 18-65 years Elective thoracoscopic (VATS) right pulmonary lobectomy Anticipated one-lung ventilation duration >1 hour ASA physical status I-III

Exclusion Criteria:

Previous lobectomy or lung volume reduction surgery Pre-existing significant atelectasis (large collapse on preoperative CT) Contraindications to PEEP: intracranial hypertension, bronchopleural fistula, hypovolemic shock, right heart failure, giant bullae, pneumothorax FiO₂ restrictions: preoperative continuous oxygen therapy or mechanical ventilation, moderate-severe COPD BMI ≥ 30 kg/m² Patient refusal to participate

Withdrawal Criteria / Major Protocol Deviations:

Surgery changed to simple wedge resection Severe pleural adhesions (found intraoperatively) Ventilation protocol interrupted Intraoperative blood loss >500 ml Severe hypotension (MAP<55 mmHg despite high-dose vasopressors) Unexpected non-thoracic surgical procedure FiO₂ exposure <80% of planned time (experimental group) Postoperative CT not completed or image quality unusable

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: High-Oxygen Group (FiO₂=100%); FiO₂=100% throughout one-lung ventilation.	Procedure: High inspired oxygen concentration (FiO₂=100%) during one-lung ventilaion; Ventilation with FiO₂=100% throughout one-lung ventilation, combined with individualized PEEP titration (decremental PEEP titration selecting the highest PEEP corresponding to the lowest driving pressure).
Experimental: Low-Oxygen Group (FiO₂=50%); Initial FiO₂=50% during one-lung ventilation (maintaining SpO₂≥92%) with individualized PEEP titration. If SpO₂<92%, increase FiO₂ by 10% increments; if SpO₂<90% and FiO₂ already at 100%, initiate rescue ventilation.	Procedure: Low inspired oxygen concentration (FiO₂=50%) during one-lung ventilation; Ventilation with initial FiO₂=50% during one-lung ventilation, combined with individualized PEEP titration. Oxygen concentration is dynamically adjusted based on SpO₂; ventilation duration at each FiO₂ level and total oxygen exposure burden are recorded.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Non-operated lung atelectasis volume percentage	Chest CT at 60±10 minutes after tracheal extubation	CT scans were performed at 60 ± 10 minutes after tracheal extubation to assess the volume ratio of atelectasis in the contralateral lung.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of postoperative pulmonary complications	PPC defined as Melbourne Postoperative Pulmonary Complication score ≥4	Postoperative days 1-3
QoR-15 quality of recovery score	15-item Quality of Recovery questionnaire score	Postoperative days 1-3
Arterial blood gas analysis (oxygenation index)	PaO₂/FiO₂ ratio at specified time points	Multiple time points: preop room air; 5 minutes after one lung ventilation start; 1 hour after one lung ventilation ; pre-postanesthesia care unit discharge
Intraoperative oxygen saturationo	Oxygen saturation (pulse oxygen)	Intraoperative (during one lung ventilation)
Oxygen concentration exposure burden	Sum of FiO₂ × time; incidence and frequency of FiO₂ increase	Intraoperative (during one lung ventilation)
Incidence of intraoperative adverse events	Incidence of hypoxemia	During surgery
Oxidative stress marker (MDA)	Arterial blood malondialdehyde (MDA) level at 1 hour after one lung ventilation	1 hour after one lung ventilation

Collaborators and Investigators

• Sponsor: Peking University People's Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: July 18, 2026
• First Submitted That Met QC Criteria: July 22, 2026
• First Posted (Actual): July 23, 2026

Study Record Updates

• Last Update Posted (Actual): July 23, 2026
• Last Update Submitted That Met QC Criteria: July 22, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: One-lung ventilation; Lung recruitment maneuver; Inspired oxygen concentration
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Pulmonary Atelectasis
• Other Study ID Numbers: 2026PHBXXX

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data will be available upon reasonable request after publication
• IPD Sharing Time Frame: Immediately following publication, for 3 years
• IPD Sharing Access Criteria: Researchers with a reasonable research purpose, subject to a data use agreement
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No