An interventional study of ORi-Guided FiO₂ Titration and SpO₂-Guided FiO₂ Titration in Hyperoxemia, Intraoperative Oxygen Therapy and Beach Chair Position, sponsored by Fatih Sultan Mehmet Training and Research Hospital. Not yet recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-11.
Sponsored by Fatih Sultan Mehmet Training and Research Hospital · Not applicable, Interventional, and Prevention
This study aims to evaluate whether guidance by the Oxygen Reserve Index (ORi) improves inspiratory oxygen fraction (FiO₂) titration compared with conventional pulse oximetry (SpO₂)-guided oxygen administration in adult patients undergoing surgery in the beach chair position.
Oxygen therapy is routinely used during general anesthesia to prevent hypoxemia; however, excessive oxygen administration may result in hyperoxia, which has been associated with adverse cardiovascular and pulmonary effects. Standard pulse oximetry may not adequately detect hyperoxia when oxygen saturation values are high.
In this prospective comparative study, patients will receive oxygen titration guided either by SpO₂ alone or by combined ORi and SpO₂ monitoring. The primary outcome is the incidence of intraoperative hyperoxemia, assessed by arterial blood gas analysis. Secondary outcomes include intraoperative oxygenation parameters and hemodynamic variables.
This prospective study will be conducted in adult patients (ASA physical status I-III) undergoing elective orthopedic surgery in the beach chair position under general anesthesia. Following approval by the institutional ethics committee and acquisition of written informed consent, eligible patients will be included in the study.
Standard monitoring will include electrocardiography, noninvasive blood pressure, peripheral oxygen saturation (SpO₂), bispectral index (BIS), perfusion index (PI), pleth variability index (PVI), near-infrared spectroscopy (NIRS), and multiwavelength pulse co-oximetry for Oxygen Reserve Index (ORi) monitoring. Invasive arterial blood pressure monitoring will be established via radial arterial cannulation to allow continuous hemodynamic monitoring and arterial blood gas sampling.
General anesthesia will be induced with intravenous propofol, fentanyl, and rocuronium, followed by orotracheal intubation. Mechanical ventilation will be applied in volume-controlled mode with lung-protective settings. Anesthesia will be maintained using sevoflurane and remifentanil infusion, targeting bispectral index values between 40 and 60.
From anesthesia induction onward, inspiratory oxygen fraction (FiO₂) will be titrated either according to SpO₂ values alone or using combined ORi and SpO₂ guidance. In the ORi-guided group, FiO₂ adjustments will aim to maintain ORi values between 0.2 and 0.5, with reassessment at regular intervals. In the SpO₂-guided group, FiO₂ will be adjusted to maintain SpO₂ values at or above 98%, in accordance with routine clinical practice.
Hemodynamic parameters, oxygenation variables, ORi values, and cerebral oxygenation assessed by NIRS will be recorded at predefined time points during surgery and recovery. Arterial blood gas analysis will be performed to determine PaO₂ and arterial oxygen saturation.
Hyperoxemia will be defined as a PaO₂ value of 100 mmHg or greater and classified as mild or severe. The primary outcome of the study is the incidence of intraoperative severe hyperoxemia. Secondary outcomes include overall oxygenation profiles and intraoperative hemodynamic stability.
The results of this study are expected to provide evidence regarding the utility of ORi-guided oxygen titration in reducing unnecessary hyperoxia during surgery performed in the beach chair position.
115 studies on the registry are indexed under Hyperoxia; 13 are open to participants now.
This study's planned enrollment of 80 is above the median of 48 across 82 interventional studies indexed under Hyperoxia.
Browse Hyperoxia studies →Fatih Sultan Mehmet Training and Research Hospital is the lead sponsor of 120 studies on the registry; 34 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Inspiratory oxygen fraction (FiO₂) will be titrated using combined Oxygen Reserve Index (ORi) and peripheral oxygen saturation (SpO₂) monitoring throughout surgery.
Other: ORi-Guided FiO₂ Titration
Inspiratory oxygen fraction (FiO₂) will be titrated based on peripheral oxygen saturation (SpO₂) values according to routine clinical practice.
Other: SpO₂-Guided FiO₂ Titration
Inspiratory oxygen fraction (FiO₂) will be adjusted throughout surgery using combined Oxygen Reserve Index (ORi) and peripheral oxygen saturation (SpO₂) monitoring. FiO₂ will be titrated to maintain ORi values between 0.2 and 0.5, with reassessment every 2-3 minutes.
FiO₂ will be adjusted to maintain SpO₂ at or above 98% throughout surgery.
Incidence of Intraoperative Severe Hyperoxemia
Severe hyperoxemia will be defined as an arterial partial pressure of oxygen (PaO2) ≥200 mmHg, measured by arterial blood gas analysis at predefined intraoperative time points.
Time frame: Perioperative/Periprocedural
Mean Peripheral Oxygen Saturation (SpO2) During Surgery
Peripheral oxygen saturation (SpO2) measured continuously during surgery using standard pulse oximetry.
Time frame: Perioperative/Periprocedural
Mean Oxygen Reserve Index (ORi) During Surgery
Oxygen Reserve Index (ORi) values recorded intraoperatively to evaluate oxygenation status.
Time frame: Perioperative/Periprocedural
Mean Fraction of Inspired Oxygen (FiO₂) During Surgery
Mean fraction of inspired oxygen (FiO₂) expressed as percentage (%), averaged over the surgical period.
Time frame: Perioperative/Periprocedural
Mean Cerebral Oxygen Saturation Measured by Near-Infrared Spectroscopy During Surgery
Cerebral regional oxygen saturation values measured intraoperatively using near-infrared spectroscopy.
Time frame: Intraoperative period (from induction of anesthesia to end of surgery)
Start is estimated for Feb 2026; primary completion for Jun 2026, 4 months later.
Of 37 non-industry interventional studies with no phase under Hyperoxia, half reached primary completion within 16 months of starting (the median), counting those still running; a quarter within 5 and three quarters within 33. This study's planned 4 months is below that.
Counting every sponsor, half of 39 studies reached it within 12 months; a quarter within 5 and three quarters within 33.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
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Fatih Sultan Mehmet Training and Research Hospital →