Effect of Individualized Positive End-expiratory Pressure (PEEP) in Patients Who Have an Intrinsic PEEP During One-lung Ventilation

Effects of Individualized Positive End-expiratory Pressure (PEEP) on Intrinsic PEEP and Stroke Volume During One-lung Ventilation: a Single-center, Randomized Crossover Study

This study investigates the effects of three extrinsic PEEP settings-5 cmH2O, 0 cmH2O, and an individualized PEEP (70% of the measured intrinsic PEEP)-on intrinsic PEEP and hemodynamic stability in patients with intrinsic PEEP undergoing lung resection surgery, using a randomized, crossover design.

Study Overview

• Status: Not yet recruiting
• Conditions: Pulmonary Disease (COPD), Chronic Obstructive; Lung Resection Surgery
• Intervention / Treatment: Procedure: PEEP0; Procedure: PEEP5; Procedure: PEEPi

Detailed Description

Intrinsic positive end-expiratory pressure (iPEEP) frequently occurs during one-lung ventilation (OLV), which is essential for lung resection. This occurrence is driven by three primary factors. First, a significant portion of patients undergoing lung surgery have concomitant chronic obstructive pulmonary disease (COPD) and thus possess a baseline intrinsic PEEP. Second, high-frequency ventilation applied to prevent carbon dioxide accumulation during OLV shortens the expiratory time, thereby generating intrinsic PEEP. Third, the use of a narrow-bore double-lumen endobronchial tube for OLV increases airway resistance, accelerating the development of intrinsic PEEP. Intrinsic PEEP causes lung hyperinflation and elevates intrathoracic pressure, which can subsequently decrease venous return and lead to abrupt hypotension. However, research remains insufficient regarding the optimal level of extrinsic PEEP for patients who develop intrinsic PEEP during OLV. While an extrinsic PEEP of around 5 cmH2O is generally applied during OLV, some guidelines recommend completely removing extrinsic PEEP (0 cmH2O) during OLV in COPD patients. Nevertheless, this recommendation lacks robust scientific evidence. Furthermore, whether the strategy of setting extrinsic PEEP at approximately 70% of intrinsic PEEP-as suggested by studies in critically ill patients-is equally valid in the intraoperative OLV environment remains unverified. Theoretically, if extrinsic PEEP exceeds intrinsic PEEP, it may exacerbate lung hyperinflation by increasing expiratory resistance. Conversely, an extrinsic PEEP that is too low may cause airway collapse during expiration, paradoxically worsening gas trapping. Therefore, this study aims to evaluate the effects of three extrinsic PEEP settings-5 cmH2O, 0 cmH2O, and an individualized PEEP (70% of the measured intrinsic PEEP)-on intrinsic PEEP and hemodynamic stability using a randomized, crossover design.

• Study Type: Interventional
• Enrollment (Estimated): 48
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hyun Joo Ahn, MD, PhD; Phone Number: +82234100784; Email: hyunjooahn@skku.edu
• Study Contact Backup: Name: Heejoon Jeong, MD; Phone Number: +82234100841; Email: heejoonjeong@skku.edu

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• American Society of Anesthesiologists Physical Status I - III
• The Eastern Cooperative Oncology Group Performance Status Grade 0 - 2
• Lung resection surgery requiring one-lung ventilation for over 60 minutes
• Indication of double-lumen endobronchial tube (female 35 Fr, male 37 Fr)
• Patient who is diagnosed with intrinsic PEEP during one-lung ventilation

Exclusion Criteria:

• Large bullae
• Emergency surgery
• Mechanical ventilation before surgery
• Hemodynamic instability before surgery
• Surgery requiring cardiopulmonary bypass
• Pregnancy, breastfeeding patient
• Patient's refusal to participate
• No intrinsic PEEP during one-lung ventilation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Experimental group; During one-lung ventilation, baseline intrinsic PEEP and stroke volume will be measured. All participants will receive three PEEP interventions: 0 cmH2O, 5 cmH2O, and 70% of the intrinsic PEEP value. The order of interventions is randomized. Each intervention will be maintained for 5 minutes, with a 5-minute washout period between interventions to minimize mutual interference. At the end of each intervention, two primary outcomes (intrinsic PEEP and stroke volume) will be measured.

Procedure: PEEP0; PEEP 0 (zero) means off-PEEP on the anesthesia machine.; Procedure: PEEP5; PEEP5 means setting the PEEP to 5 cmH2O on the anesthesia machine.; Procedure: PEEPi; PEEPi (individualized PEEP) means setting the PEEP to 70% of intrinsic PEEP on the anesthesia machine.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intrinsic positive end-expiratory airway pressure	During one-lung ventilation, each patient will randomly receive three PEEP interventions: 0 cmH2O, 5 cmH2O, and the 70% value of intrinsic PEEP. After each 5-minute intervention, intrinsic PEEP will be measured by the anesthesia machine.	During a 30-minute period from the start of one-lung ventilation to the completion of the intervention
Stroke volume	During one-lung ventilation, each patient will randomly receive three PEEP interventions: 0 cmH2O, 5 cmH2O, and the 70% value of intrinsic PEEP. After each 5-minute intervention, Stroke volume will be measured by an arterial pressure-based cardiac output monitor.	During a 30-minute period from the start of one-lung ventilation to the completion of the intervention

Collaborators and Investigators

• Sponsor: Samsung Medical Center
• Investigators: Principal Investigator: Hyun Joo Ahn, MD, PhD, Samsung Medical Center

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): May 31, 2027

Study Registration Dates

• First Submitted: May 21, 2026
• First Submitted That Met QC Criteria: June 4, 2026
• First Posted (Actual): June 10, 2026

Study Record Updates

• Last Update Posted (Actual): June 10, 2026
• Last Update Submitted That Met QC Criteria: June 4, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Chronic Disease; Disease Attributes; Respiratory Tract Diseases; Lung Diseases, Obstructive; Pathological Conditions, Signs and Symptoms; Lung Diseases; Pulmonary Disease, Chronic Obstructive
• Other Study ID Numbers: Individual PEEP trial

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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