Oxygen Reserve Index (ORi) in Identifying Desaturation
The Role of Oxygen Reserve Index (ORi) in Identifying Early Desaturation During Endolaryngeal Surgery: A Randomized Clinical Trial
1 other identifier
interventional
80
1 country
1
Brief Summary
This randomized clinical trial investigates whether Oxygen Reserve Index (ORi) monitoring enables earlier detection of impending hypoxemia compared with conventional pulse oximetry during apneic intermittent ventilation in adult patients undergoing endolaryngeal surgery under general anesthesia. By providing continuous, noninvasive assessment of oxygen reserve in the hyperoxic range, ORi may offer an earlier warning of oxygen depletion before peripheral oxygen saturation declines. The study compares time to reventilation thresholds, arterial blood gas parameters, and perioperative respiratory outcomes between ORi-guided and standard SpO₂-guided monitoring strategies.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P50-P75 for not_applicable
Started Jan 2026
Shorter than P25 for not_applicable
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
January 27, 2026
CompletedStudy Start
First participant enrolled
January 27, 2026
CompletedFirst Posted
Study publicly available on registry
February 17, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
March 15, 2026
CompletedStudy Completion
Last participant's last visit for all outcomes
March 25, 2026
CompletedFebruary 17, 2026
January 1, 2026
2 months
January 27, 2026
February 15, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
Time to Reventilation Threshold
Time from the onset of apnea to the predefined reventilation threshold, defined as Oxygen Reserve Index (ORi) reaching zero in the ORi group and peripheral oxygen saturation (SpO₂) decreasing to 90% in the control group, measured in seconds.
From the onset of apnea until the predefined reventilation threshold is reached during the intraoperative period (within minutes).
Secondary Outcomes (4)
Arterial Blood Gas Parameters at Reventilation
From the onset of apnea until the predefined reventilation threshold is reached during the intraoperative period (within minutes).
Perioperative Lung Ultrasound Findings
Preoperatively (before anesthesia induction) and postoperatively in the post-anesthesia care unit (within 1 hour after surgery).
Postoperative Oxygenation
postoperatively in the post-anesthesia care unit (within 1 hour after surgery).
End-Tidal Carbon Dioxide (EtCO₂) Level
During the apneic period, measured at the time of reventilation during surgery.
Study Arms (2)
Oxygen Reserve Index
EXPERIMENTALParticipants in this arm will undergo continuous Oxygen Reserve Index (ORi) monitoring in addition to standard anesthesia monitoring during general anesthesia with apneic intermittent ventilation for endolaryngeal surgery. ORi values will be used to guide the timing of reventilation, with reventilation initiated when ORi reaches zero, indicating depletion of oxygen reserve. Standard clinical care and anesthesia management will otherwise be identical to the control group.
Peripheral oxygen saturation
NO INTERVENTIONParticipants in this arm will receive standard anesthesia monitoring, including continuous peripheral oxygen saturation (SpO₂) monitoring, during general anesthesia with apneic intermittent ventilation for endolaryngeal surgery. The timing of reventilation will be guided by SpO₂ values, with reventilation initiated when SpO₂ decreases to 90%. All other aspects of anesthesia care and perioperative management will be identical to the experimental arm.
Interventions
to determine whether ORi monitoring provides earlier and clinically meaningful warning of oxygen reserve depletion compared with conventional pulse oximetry, potentially improving patient safety during shared-airway surgery.
Eligibility Criteria
You may qualify if:
- Age 18 years or older
- Scheduled for elective endolaryngeal surgery
- Planned general anesthesia with apneic intermittent ventilation
- American Society of Anesthesiologists (ASA) physical status I-III
- Ability to provide written informed consent
You may not qualify if:
- Age under 18 years
- Preoperative chronic hypoxemia (baseline SpO₂ \< 95%)
- Patients transferred from the intensive care unit
- ASA physical status IV or higher
- Refusal or inability to provide informed consent
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Istanbul University, Department of anesthesiology
Istanbul, Fatih, 34093, Turkey (Türkiye)
Related Publications (2)
Fleming NW, Singh A, Lee L, Applegate RL 2nd. Oxygen Reserve Index: Utility as an Early Warning for Desaturation in High-Risk Surgical Patients. Anesth Analg. 2021 Mar 1;132(3):770-776. doi: 10.1213/ANE.0000000000005109.
PMID: 32815872RESULTSzmuk P, Steiner JW, Olomu PN, Ploski RP, Sessler DI, Ezri T. Oxygen Reserve Index: A Novel Noninvasive Measure of Oxygen Reserve--A Pilot Study. Anesthesiology. 2016 Apr;124(4):779-84. doi: 10.1097/ALN.0000000000001009.
PMID: 26978143RESULT
Study Officials
- PRINCIPAL INVESTIGATOR
ece naz demir, resident
Istanbul University
- STUDY DIRECTOR
demet altun, prof
Istanbul University
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- SINGLE
- Who Masked
- PARTICIPANT
- Masking Details
- Masking Description
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Professor
Study Record Dates
First Submitted
January 27, 2026
First Posted
February 17, 2026
Study Start
January 27, 2026
Primary Completion
March 15, 2026
Study Completion
March 25, 2026
Last Updated
February 17, 2026
Record last verified: 2026-01