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NCT Number: NCT07720778

ORI-Guided Oxygen Therapy During One-Lung Ventilation

High inspired oxygen concentrations (FiO₂) are commonly administered during general anesthesia to prevent hypoxemia. However, excessive oxygen administration may result in hyperoxemia, which has been associated with impaired hypoxic pulmonary vasoconstriction, increased oxidative stress, ventilation-perfusion mismatch, and postoperative pulmonary complications.

During one-lung ventilation (OLV) for thoracic surgery, higher FiO₂ is often required because of increased intrapulmonary shunting, making hyperoxemia a frequent occurrence. The Oxygen Reserve Index (ORI) is a noninvasive pulse oximetry-derived parameter that reflects moderate hyperoxemia (PaO₂ approximately 100-200 mmHg) and may facilitate more precise oxygen titration than pulse oximetry alone.

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Key information

Conditions

Thoracic Surgery With One-lung Ventilation Hyperoxia Pathological Conditions, Signs and Symptoms Signs and Symptoms Signs and Symptoms, Respiratory

Age range

19 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Konkuk University Medical Center

Seoul, Gwangjin-gu, 05030, South Korea

About this study

This prospective, randomized, assessor-blinded clinical trial aims to determine whether FiO₂ titration guided by both ORI and peripheral oxygen saturation (SpO₂) reduces the incidence of hyperoxemia compared with conventional SpO₂-guided FiO₂ titration during OLV in patients undergoing thoracic surgery. Participants will be randomly assigned to either an ORI-guided group or a conventional SpO₂-guided group. The primary outcome is the incidence of hyperoxemia (PaO₂ >125 mmHg) after OLV. Secondary outcomes include SpO₂, ORI, PaO₂, and FiO₂ measured

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged ≥19 years
  • Scheduled for elective lung surgery requiring one-lung ventilation
  • Written informed consent

Exclusion criteria

  • Severe pulmonary hypertension.
  • Left ventricular systolic dysfunction.

Withdrawal Criteria:

  • The participant or legally authorized representative requests withdrawal from the study.
  • An adverse event occurs that precludes continued participation in the study.
  • The planned surgery or study procedures are not performed (e.g., ORI monitoring is not applied or arterial blood gas analysis is not performed).
  • Perfusion Index is less than 2 during the study.
  • A major violation of the inclusion or exclusion criteria is identified after enrollment.
  • The participant fails to comply with the study protocol, potentially affecting the validity of the study outcomes.
  • Continued participation is considered not to be in the participant's best interest.
  • In the investigator's judgment, any other condition arises that makes continued participation inappropriate.

Treatment and study plan

ORI-Guided FiO2 Titration

Other

During one-lung ventilation, FiO₂ is adjusted according to both ORI and SpO₂. FiO₂ is titrated to maintain SpO₂ ≥98% while keeping ORI above 0 to minimize hyperoxemia.

Conventional SpO₂-Guided FiO₂ Titration

Other

During one-lung ventilation, FiO₂ is adjusted according to SpO₂ alone. FiO₂ is titrated to maintain SpO₂ ≥98% according to the institutional standard of care.

Primary outcomes

  1. Incidence of hyperoxemia during one-lung ventilation

    Time frame: 10 min after initiation of one-lung ventilation during operation

    Hyperoxemia is defined as an arterial partial pressure of oxygen (PaO₂) greater than 125 mmHg measured after initiation of one-lung ventilation.

Secondary outcomes

  1. Peripheral oxygen saturation (SpO₂)

    Time frame: 10 mins after two-lung ventilation, 10 mins after initiation of one-lung ventilation, and 10 mins after resumption of two-lung ventilation, all time frames are included in anesthesia time

    Peripheral oxygen saturation

  2. Oxygen Reserve Index (ORI)

    Time frame: 10 mins after two-lung ventilation, 10 mins after initiation of one-lung ventilation, and 10 mins after resumption of two-lung ventilation, all time frames are included in anesthesia time

    Oxygen Reserve Index measured during anesthesia.

  3. Arterial oxygen tension (PaO₂)

    Time frame: 10 mins after two-lung ventilation, 10 mins after initiation of one-lung ventilation, and 10 mins after resumption of two-lung ventilation, all time frames are included in anesthesia time

    Arterial partial pressure of oxygen measured by arterial blood gas analysis.

  4. Fraction of inspired oxygen (FiO₂)

    Time frame: 10 mins after two-lung ventilation, 10 mins after initiation of one-lung ventilation, and 10 mins after resumption of two-lung ventilation, all time frames are included in anesthesia time

    Fraction of inspired oxygen administered during anesthesia.

Study contacts

Contact information is provided by the study sponsor or research team.

Chungsik Oh

CONTACT

[email protected]

Tae-Yop Kim

CONTACT

[email protected]

82-10-8811-6942

Sponsors and collaborators

Lead sponsor

Konkuk University Medical Center

Other

Registry information

Official study title

Effect of Oxygen Reserve Index-Guided Fraction of Inspired Oxygen Titration on the Incidence of Hyperoxemia During One-Lung Ventilation

Acronym: ORI-OLV

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
Jul 22, 2026
Registry last updated
Jul 22, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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