Effect of End-inspiratory Pause on Gas Exchange During Mediastinal Mass Excision With CO2 Insufflation and One-lung Ventilation

" Mediastinal mass excision is typically performed via video-assisted thoracoscopic surgery (VATS). To secure a clear surgical field, the ipsilateral lung must be deflated, achieved through one-lung ventilation (OLV) and intrathoracic CO₂ insufflation. However, OLV increases intrapulmonary shunt due to continued perfusion of the non-ventilated lung, potentially leading to hypoxemia and hypercapnia.

When performed in the supine position, gas exchange becomes more challenging compared to lateral decubitus due to limited gravitational redistribution of blood flow. Although CO₂ insufflation aids surgical exposure through passive lung deflation, it may also increase CVP and PCWP, reduce cardiac output, and raise PaCO₂, contributing to respiratory acidosis.

End-inspiratory pause (EIP), a ventilatory setting that pauses airflow at end-inspiration, prolongs alveolar gas exchange and improves ventilation-perfusion matching. Prior studies show EIP can enhance gas exchange, reduce microatelectasis, and improve CO₂ clearance in patients with acute lung injury. We therefore aimed to assess the effect of EIP application during VATS mediastinal mass excicion.

Study Overview

• Status: Not yet recruiting
• Conditions: Mediastinal Mass Requiring Video-assisted Surgical Excision
• Intervention / Treatment: Procedure: EIP-first; Procedure: EIP-later

• Study Type: Interventional
• Enrollment (Estimated): 58
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Korea, Republic of
  • Seoul, Korea, Republic of
    • Severance Hospital

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adult patients aged 20 to 80 years scheduled for video-assisted thoracoscopic mediastinal tumor resection.
• American Society of Anesthesiologists (ASA) physical status classification of II (patients with mild systemic disease) or III (patients with severe systemic disease limiting activity).

Exclusion Criteria:

• Moderate to severe chronic obstructive pulmonary disease (COPD) according to GOLD criteria: defined as FEV₁/FVC < 0.7 and FEV₁ ≤ 80% of predicted on pulmonary function testing.
• Diffusion capacity of the lung for carbon monoxide (DLCO) < 80% of predicted.
• History of pneumothorax or presence of bullae or blebs on preoperative imaging.
• Inability to read or understand the subject information sheet and consent form.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: EIP-first group; EIP is applied for 20 minutes immediately after the initiation of one-lung ventilation, followed by conventional mechanical ventilation.	Procedure: EIP-first; EIP is applied for 20 minutes immediately after the initiation of one-lung ventilation, followed by conventional mechanical ventilation.
Active Comparator: EIP-later group; Conventional mechanical ventilation is applied for 20 minutes after the initiation of one-lung ventilation, followed by EIP application.	Procedure: EIP-later; Conventional mechanical ventilation is applied for 20 minutes after the initiation of one-lung ventilation, followed by EIP application.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
PaCO₂ at 20 minutes after each ventilation method	The study aimed to evaluate whether the application of EIP resulted in a significant intergroup difference in PaCO₂.	PaCO₂ is assessed at 20 minutes after each ventilation method

Collaborators and Investigators

• Sponsor: Yonsei University

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2025
• Primary Completion (Estimated): March 10, 2027
• Study Completion (Estimated): March 10, 2027

Study Registration Dates

• First Submitted: April 24, 2025
• First Submitted That Met QC Criteria: April 24, 2025
• First Posted (Actual): May 2, 2025

Study Record Updates

• Last Update Posted (Actual): May 2, 2025
• Last Update Submitted That Met QC Criteria: April 24, 2025
• Last Verified: April 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Respiratory Tract Diseases; Respiration Disorders; Respiratory Aspiration
• Other Study ID Numbers: 4-2025-0232

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