ObesityORiNCT07097662
Evaluation of the Effectiveness of Oxygen Reserve Index Monitoring During Pre-oxygenation in Obese Patients
An observational study of Obesity, run by Irem Caner at 1 site in Turkey (Türkiye).
Trial summary
In obese patients, the risk of perioperative complications such as rapid desaturation, atelectasis, difficult mask ventilation, difficult intubation, and hypoxia is higher compared to the normal population. Therefore, preoxygenation is even more critical in the obese patient group. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Obesity
- How many people
- 60 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 1 Feb 2024to 1 Jan 2025
- How long will I take part?
- 1 Day
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Between February 2024 and July 2024, 60 patients aged 18 to 75 years, with an ASA physical status classification of II-III, a body mass index (BMI) greater than 35 kg/m², and scheduled for elective surgery under general anesthesia, were included in our study after obtaining verbal and written informed consent.
Who may be able to join
- Patients with a body mass index (BMI) >35 kg/m² scheduled for elective surgery
- ASA (American Society of Anesthesiologists) physical status classification I-III
- Patients aged 18 years and older
Who cannot join
- Patients with ASA physical status classification IV-V,
- Psychiatric disorders
- Severe cardiac arrhythmias
- Patients with an ejection fraction below 30%
- Chronic obstructive pulmonary disease (COPD)
- Those receiving home oxygen therapy
- Patients requiring supraglottic airway devices, and emergency cases
Trial locations and contacts
1 site in 1 country.
About this study
In obese patients, the risk of perioperative complications such as rapid desaturation, atelectasis, difficult mask ventilation, difficult intubation, and hypoxia is higher compared to the normal population. Therefore, preoxygenation is even more critical in the obese patient group. In clinical practice, ETO2 is used as a practical indicator to evaluate sufficient oxygenation during preoxygenation. The Oxygen Reserve Index (ORiⓇ) is a new oxygenation monitoring parameter that is continuously and non-invasively measured by a specialized pulse oximetry device (Masimo, Irvine, CA).The primary objective of the investigators was to observe the correlation between ORIⓇ monitoring and ETO₂ during preoxygenation in obese patients.The secondary objective of the investigators was to evaluate the correlation of ORIⓇ with SpO₂ and PaO₂ in this patient population.
Read the detailed description
Obesity is a chronic, progressive, and recurrent disease characterized by abnormal fat accumulation that adversely affects health and increases morbidity and mortality.
According to World Health Organization (WHO) data, the prevalence of obesity among adults aged 18 years and older is reported to be 16%.
Obese patients have an increased risk of perioperative complications compared to the general population, including rapid desaturation, atelectasis, difficult mask ventilation, difficult intubation, and hypoxia.
Therefore, preoxygenation is particularly important in obese patient populations.
The goal of preoxygenation is to maximize the duration during which the patient can tolerate apnea, thereby providing the anesthesiologist with crucial time to secure the airway in cases of planned or unanticipated "cannot ventilate, cannot intubate" scenarios.
In clinical practice, end-tidal oxygen concentration (ETO₂) is frequently used as a practical indicator to evaluate the adequacy of preoxygenation.
However, achieving a tight-fitting face mask and obtaining accurate ETO₂ measurements can sometimes be challenging.
Thus, alternative monitoring parameters may be needed to evaluate the effectiveness of preoxygenation.
The Oxygen Reserve Index (ORIⓇ) is a novel, continuous, and non-invasive oxygenation monitoring parameter provided by a specialized pulse oximeter (Masimo, Irvine, CA).
While SpO₂ is useful in assessing hypoxia and normoxia, and PaO₂ can evaluate a wide range of oxygenation states, arterial blood gas (ABG) analysis is limited due to its intermittent and invasive nature.
ORIⓇ offers real-time visibility into moderate hyperoxic states (PaO₂ between 100-200 mmHg), which SpO₂ cannot detect.
Several studies have investigated the use of ORIⓇ monitoring to evaluate preoxygenation efficacy in various patient populations.
It has been reported in the literature that ORIⓇ may serve as an early warning indicator of hypoxia and help predict unwanted hyperoxic episodes.
The primary objective of the investigators was to observe the correlation between ORIⓇ monitoring and ETO₂ during preoxygenation in obese patients.The secondary objective of the investigators was to evaluate the correlation of ORIⓇ with SpO₂ and PaO₂ in this patient population.
- Conditions
- Obesity
- Medical subject headings
- Obesity
What is being measured
The primary outcome is the main question the study is designed to answer.
Evaluation of the Effectiveness of Oxygen Reserve Index Monitoring During Pre-oxygenation in Obese Patients
Non-invasive ORiⓇ values and ETO₂ levels measured every minute during tidal volume breathing in the preoxygenation period will be analyzed for correlation.
Measured: During 5-minute preoxygenation
Secondary outcomes (2)
Correlation between ORiⓇ and arterial oxygen pressure (PaO₂) at multiple time points after intubation
ORiⓇ values will be compared with simultaneously obtained arterial blood gas measurements (PaO₂) at predefined time points to assess correlation.
Measured: 30, 60, 90, and 120 minutes after intubation
Correlation between ORiⓇ and peripheral oxygen saturation (SpO₂) at multiple time points after intubation
ORiⓇ values will be compared with corresponding SpO₂ measurements from pulse oximetry to evaluate correlation.
Measured: 30, 60, 90, and 120 minutes after intubation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Jul 2025
- Study start1 Feb 2024
- Primary completion31 Jul 2024
- Study completion1 Jan 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Cross-sectional
- Enrolment
- 60 participants (actual)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Irem Caner
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Irem Caner, Kocaeli University
- Investigators
- İrem Caner, Principal investigator, Kocaeli University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07097662
- Sponsor's protocol ID
- KocaeliUIC
- Acronym
- ORi
- Status last verified
- Jul 2025
- First submitted
- 17 Jul 2025
- Last updated
- 31 Jul 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Hirata N, Nishimura M, Chaki T, Yoshikawa Y, Yamakage M. Comparison between oxygen reserve index and end-tidal oxygen concentration for estimation of oxygenation during pre-oxygenation via a tight-fitted face mask: A prospective observational study. Eur J Anaesthesiol. 2021 Mar 1;38(3):313-315. doi: 10.1097/EJA.0000000000001358. No abstract available.
PubMed 33538433
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of the Effectiveness of Oxygen Reserve Index Monitoring During Pre-oxygenation in Obese Patients
- ClinicalTrials.gov ID
- NCT07097662
- Acronym / sponsor ID
- ORi / KocaeliUIC
- Conditions
- Obesity
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 60 participants (actual)
- Lead sponsor
- Irem CanerUniversity, hospital or other
- Study start
- 1 Feb 2024 (actual)
- Primary completion
- 31 Jul 2024 (actual)
- Study completion
- 1 Jan 2025 (actual)
- First posted
- 31 Jul 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
In obese patients, the risk of perioperative complications such as rapid desaturation, atelectasis, difficult mask ventilation, difficult intubation, and hypoxia is higher compared to the normal population. Therefore, preoxygenation is even more critical in the obese patient group. In clinical practice, ETO2 is used as a practical indicator to evaluate sufficient oxygenation during preoxygenation. The Oxygen Reserve Index (ORiⓇ) is a new oxygenation monitoring parameter that is continuously and non-invasively measured by a specialized pulse oximetry device (Masimo, Irvine, CA).The primary objective of the investigators was to observe the correlation between ORIⓇ monitoring and ETO₂ during preoxygenation in obese patients.The secondary objective of the investigators was to evaluate the correlation of ORIⓇ with SpO₂ and PaO₂ in this patient population.
Detailed description
Obesity is a chronic, progressive, and recurrent disease characterized by abnormal fat accumulation that adversely affects health and increases morbidity and mortality.
According to World Health Organization (WHO) data, the prevalence of obesity among adults aged 18 years and older is reported to be 16%.
Obese patients have an increased risk of perioperative complications compared to the general population, including rapid desaturation, atelectasis, difficult mask ventilation, difficult intubation, and hypoxia.
Therefore, preoxygenation is particularly important in obese patient populations.
The goal of preoxygenation is to maximize the duration during which the patient can tolerate apnea, thereby providing the anesthesiologist with crucial time to secure the airway in cases of planned or unanticipated "cannot ventilate, cannot intubate" scenarios.
In clinical practice, end-tidal oxygen concentration (ETO₂) is frequently used as a practical indicator to evaluate the adequacy of preoxygenation.
However, achieving a tight-fitting face mask and obtaining accurate ETO₂ measurements can sometimes be challenging.
Thus, alternative monitoring parameters may be needed to evaluate the effectiveness of preoxygenation.
The Oxygen Reserve Index (ORIⓇ) is a novel, continuous, and non-invasive oxygenation monitoring parameter provided by a specialized pulse oximeter (Masimo, Irvine, CA).
While SpO₂ is useful in assessing hypoxia and normoxia, and PaO₂ can evaluate a wide range of oxygenation states, arterial blood gas (ABG) analysis is limited due to its intermittent and invasive nature.
ORIⓇ offers real-time visibility into moderate hyperoxic states (PaO₂ between 100-200 mmHg), which SpO₂ cannot detect.
Several studies have investigated the use of ORIⓇ monitoring to evaluate preoxygenation efficacy in various patient populations.
It has been reported in the literature that ORIⓇ may serve as an early warning indicator of hypoxia and help predict unwanted hyperoxic episodes.
The primary objective of the investigators was to observe the correlation between ORIⓇ monitoring and ETO₂ during preoxygenation in obese patients.The secondary objective of the investigators was to evaluate the correlation of ORIⓇ with SpO₂ and PaO₂ in this patient population.
Study design
- Observational model
- Other
- Time perspective
- Cross-sectional
- Target follow-up
- 1 Day
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Between February 2024 and July 2024, 60 patients aged 18 to 75 years, with an ASA physical status classification of II-III, a body mass index (BMI) greater than 35 kg/m², and scheduled for elective surgery under general anesthesia, were included in our study after obtaining verbal and written informed consent.
Key inclusion criteria (3 listed)
- Patients with a body mass index (BMI) >35 kg/m² scheduled for elective surgery
- ASA (American Society of Anesthesiologists) physical status classification I-III
- Patients aged 18 years and older
Key exclusion criteria (7 listed)
- Patients with ASA physical status classification IV-V,
- Psychiatric disorders
- Severe cardiac arrhythmias
- Patients with an ejection fraction below 30%
- Chronic obstructive pulmonary disease (COPD)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Evaluation of the Effectiveness of Oxygen Reserve Index Monitoring During Pre-oxygenation in Obese Patients
Time frame: During 5-minute preoxygenation
Non-invasive ORiⓇ values and ETO₂ levels measured every minute during tidal volume breathing in the preoxygenation period will be analyzed for correlation.
2 secondary outcomes
Correlation between ORiⓇ and arterial oxygen pressure (PaO₂) at multiple time points after intubation
Time frame: 30, 60, 90, and 120 minutes after intubation
Correlation between ORiⓇ and peripheral oxygen saturation (SpO₂) at multiple time points after intubation
Time frame: 30, 60, 90, and 120 minutes after intubation
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Jul 2025.
- Results publication: PubMed 33538433Hirata N, Nishimura M, Chaki T, Yoshikawa Y, Yamakage M. Comparison between oxygen reserve index and end-tidal oxygen concentration for estimation of oxygenation during pre-oxygenation via a tight-fitted face mask: A prospective observational study. Eur J Anaesthesiol. 2021 Mar 1;38(3):313-315. doi: 10.1097/EJA.0000000000001358. No abstract available.
- Individual participant dataSharing planned: No
Related trials for Obesity
RecruitingObservational study
Endoscopic Sleeve Gastroplasty (ESG) Prospective Trial for Obesity (EGO-Trial)
Obesity
Active, not recruitingPhase 4
Effects of Sequential Therapy With Mexidol® (Intravenous) and Mexidol® FORTE 250 (Oral) on Functional Brain Activity Assessed by Functional Magnetic Resonance Imaging and Biochemical Parameters in Patients With Chronic Cerebral Ischemia: A Comparison of Patients With and Without Metabolic Disorders
Metabolic Abnormalities, Obesity & Overweight
Recruiting
Exercise Training and Vitamin D Metabolism
Obesity & Overweight, Vitamin D
Recruiting
Metabolic Health, Bones and Nuts During Weight Loss in Adults
Weight Loss, Bone Density
Active, not recruiting
Effect of Probiotics on Insulin Sensitivity in Overweight and Obese Pregnancy
Obesity & Overweight, Gestational Diabetes Mellitus (GDM)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
İrem Caner principal investigator
Kocaeli University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Obesity, run by Irem Caner at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 31 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Evaluation of the Effectiveness of Oxygen Reserve Index Monitoring During Pre-oxygenation in Obese Patients (time frame: During 5-minute preoxygenation). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07097662, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Jul 2025.