An interventional study of Perioperative Oxygen Strategy - Normoxia and Perioperative Oxygen Strategy-Hyperoxia in Hyperoxia, Perioperative Care and Oxidative Stress, sponsored by Istanbul University. Completed at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-04-13.
Sponsored by Istanbul University · Not applicable, Interventional, and Basic science
This single-center randomized interventional study evaluated the biological effects of two perioperative oxygen strategies in adults undergoing elective laparoscopic lower abdominal surgery under standardized general anesthesia. Participants were assigned to receive either normoxia (FiO2 0.35) or hyperoxia (FiO2 0.80) after intubation and throughout the intraoperative period. The study assessed perioperative changes in circulating biomarkers related to pulmonary epithelial stress, endothelial glycocalyx injury, oxidative stress, and inflammation, together with blood gas and hemodynamic parameters. The study was completed before registration and is being registered retrospectively.
Perioperative oxygen administration is widely used during general anesthesia, but the biological effects of liberal oxygen exposure remain uncertain. This randomized parallel-group study compared a normoxic strategy (FiO2 0.35) with a hyperoxic strategy (FiO2 0.80) in adult patients undergoing elective laparoscopic lower abdominal surgery. The assigned inspired oxygen fraction was initiated immediately after tracheal intubation and maintained intraoperatively under volume-controlled ventilation with otherwise standardized anesthetic management.
The primary objective was to compare perioperative changes in circulating biomarkers reflecting endothelial glycocalyx injury and inflammatory activation. Biomarkers assessed included syndecan-1, sialic acid, surfactant protein-A, ischemia-modified albumin, tumor necrosis factor-alpha, and total protein. Secondary assessments included arterial and venous blood gas variables, lactate, mean arterial pressure, and heart rate.
This study was completed before registry submission and is being entered retrospectively for transparency.
115 studies on the registry are indexed under Hyperoxia; 13 are open to participants now.
This study's enrollment of 76 is above the median of 48 across 82 interventional studies indexed under Hyperoxia.
Browse Hyperoxia studies →Istanbul University is the lead sponsor of 511 studies on the registry; 78 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 1 (20%) have results posted.
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.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
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.
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.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
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.
Intraoperative inspired oxygen fraction (FiO2) of 0.35 under standardized general anesthesia and volume-controlled ventilation.
Other: Perioperative Oxygen Strategy - Normoxia
Intraoperative inspired oxygen fraction (FiO2) of 0.80 under standardized general anesthesia and volume-controlled ventilation.
Other: Perioperative Oxygen Strategy-Hyperoxia
Normoxia arm: FiO2 0.35 Intervention started immediately after intubation and maintained intraoperatively
Hyperoxia arm: FiO2 0.80 Intervention started immediately after intubation and maintained intraoperatively
Concentration of syndecan-1
Serum syndecan-1 concentration measured in duplicate.
Time frame: 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation
Concentration of sialic acid
Serum sialic acid concentration measured in duplicate.
Time frame: 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation
Concentration of surfactant protein-A
Serum surfactant protein-A concentration measured in duplicate.
Time frame: 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation
Concentration of ischemia-modified albumin
Serum ischemia-modified albumin concentration measured in duplicate.
Time frame: 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation
Concentration of TNF-alpha
Serum TNF-alpha concentration measured in duplicate.
Time frame: 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation
Concentration of total protein
Serum total protein concentration measured in duplicate.
Time frame: 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation
Arterial oxygen tension (PaO2)
Time frame: 10 minutes after establishment of assigned oxygen fraction
Intraoperative mean arterial pressure
Time frame: Immediately after intubation and every 15 minutes up to 90 minutes
Intraoperative heart rate
Time frame: Immediately after intubation and every 15 minutes up to 90 minutes
Arterial oxygen tension (PaO2)
Arterial partial pressure of oxygen.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Arterial pH
Arterial pH measured on blood gas analysis.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Arterial carbon dioxide tension (PaCO2)
Arterial partial pressure of carbon dioxide.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Venous oxygen tension (PvO2)
Venous partial pressure of oxygen.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Venous carbon dioxide tension (PvCO2)
Venous partial pressure of carbon dioxide.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Arterial oxygen saturation (SaO2)
Arterial oxygen saturation measured on blood gas analysis.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Venous oxygen saturation (SvO2)
Venous oxygen saturation measured on blood gas analysis.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Arteriovenous oxygen difference
Difference between arterial and venous oxygen saturation.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Lactate concentration
Blood lactate concentration measured on blood gas analysis.
Time frame: 10 minutes after establishment of assigned oxygen fraction
Plan to share: No
Ran from Jul 2017 to primary completion in Jan 2019, 18 months.
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 18 months is above 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 completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
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