Can Atelectasis Be Prevented With Oxygen Reserve Index (ORI) Monitoring?

NCT07050719 | Completed

• 1 other identifier: AEAHAE001
• Study Type: interventional
• Target: 58
• Locations: 1 country
• Sites: 1

Brief Summary

This single-center randomized controlled trial aims to evaluate whether intraoperative monitoring using the Oxygen Reserve Index (ORI) reduces the incidence of postoperative atelectasis, as assessed by lung ultrasound (LUS), in adult patients undergoing elective robotic surgery under general anesthesia.

Conditions

Atelectasis; Hyperoxia; Lung Ultrasonography Score

Keywords

Atelectasis; ORI; robotic surgery; lung ultrasound score; hyperoxia

Outcome Measures

Primary Outcomes (1)

• Postoperative LUS score at 30 min

  Lung ultrasound (LUS) measurements will be performed by an anesthesiologist blinded to the study groups, who is experienced in lung ultrasonography with at least 100 prior examinations. LUS will be performed and recorded 30 minutes before surgery while patients are in the supine position, using a linear probe (6-12 MHz). The total LUS score will be calculated as the sum of the scores for the 12 quadrants of each hemithorax (range: 0-36). Higher scores will indicate more severe loss of aeration. Loss of aeration will be scored as follows: * 0: Presence of A-lines or fewer than two B-lines * 1: Three or more well-defined B-lines * 2: Presence of multiple coalescent B-lines * 3: Presence of lung consolidation characterized by dynamic air bronchograms

  At 30 minutes following tracheal extubation at the end of surgery

Secondary Outcomes (5)

• Preoperative LUS score

  30 minutes prior to patient transfer to the operating room

• Intraoperative arterial partial pressure of oxygen (PaO₂)

  At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively

• Intraoperative fraction of inspired oxygen (FiO₂)

  At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively

• Intraoperative Oxygen Reserve Index (ORI)

  At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively

• Number of episodes with severe hyperoxia (PaO₂ > 200 mmHg)

  At baseline (immediately before incision), and at 1st, 2nd, and 3rd hour intraoperatively

Study Arms (2)

Peripheral Oxygen Saturation (SpO₂) Group

ACTIVE COMPARATOR

FiO₂ adjusted based on pulse oximetry to maintain SpO₂ ≥98%

Procedure: Peripheral Oxygen Saturation (SpO₂) Group

Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group

ACTIVE COMPARATOR

FiO₂ adjusted using both SpO₂ and ORI to maintain ORI between 0-0.3

Procedure: Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group

Interventions

Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group PROCEDURE

FiO₂ adjusted using both SpO₂ and ORI to maintain ORI between 0-0.3

Peripheral Oxygen Saturation and Oxygen Reserve Index (SpO₂-ORI) Group

Peripheral Oxygen Saturation (SpO₂) Group PROCEDURE

FiO₂ adjusted based on pulse oximetry to maintain SpO₂ ≥98%

Peripheral Oxygen Saturation (SpO₂) Group

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• American Society of Anesthesiologists Physical Status Classification System (ASA) physical status I-III
• Elective robotic surgery under general anesthesia
• Surgery duration \>2 hours
• Requires invasive arterial cannulation
• Signed informed consent

You may not qualify if:

• ASA IV or higher
• Room air SpO₂ \<92%
• Chronic pulmonary disease
• Hemoglobinopathy
• Pregnancy
• Refusal to participate

Sponsors & Collaborators

• Antalya Training and Research Hospital: lead

Study Sites (1)

Antalya Training and Research Hospital

Antalya, Muratpasa, 07100, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Pulmonary Atelectasis; Hyperoxia

Interventions

Oxygen Saturation; Lactoperoxidase; Population Groups

Condition Hierarchy (Ancestors)

Lung Diseases; Respiratory Tract Diseases; Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Metabolism; Peroxidases; Oxidoreductases; Enzymes; Enzymes and Coenzymes; Demography; Population Characteristics

Study Officials

• NILGUN KAVRUT OZTURK, PROFESSOR MD

  Antalya Training and Research Hospital

  STUDY CHAIR

• AYSE MERVE ERDEM, RESIDENT

  Antalya Training and Research Hospital

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER GOV
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PROFESSOR MD

Study Record Dates

• First Submitted: June 22, 2025
• First Posted: July 3, 2025
• Study Start: July 15, 2025
• Primary Completion: December 8, 2025
• Study Completion: December 8, 2025
• Last Updated: December 10, 2025

Record last verified: 2025-12

Locations

TU (1)