Endothelial Glycocalyx Injury, Hyperoxia, Oxidative Stress, Perioperative Care
Conditions
Keywords
Hyperoxia, Normoxia, Perioperative Oxygen Therapy, Syndecan-1, Sialic Acid, Surfactant Protein-A, TNF-alpha, Randomized Trial
Brief summary
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.
Detailed description
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.
Interventions
OTHERPerioperative Oxygen Strategy - Normoxia
Normoxia arm: FiO2 0.35 Intervention started immediately after intubation and maintained intraoperatively
OTHERPerioperative Oxygen Strategy-Hyperoxia
Hyperoxia arm: FiO2 0.80 Intervention started immediately after intubation and maintained intraoperatively
Sponsors
Istanbul University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* Adults aged 18 to 70 years * Scheduled for elective laparoscopic lower abdominal surgery * Expected surgery duration of at least 90 minutes * ASA physical status I to III * Body mass index 18.5 to 35 kg/m2 * Planned management under standardized general anesthesia with volume-controlled ventilation
Exclusion criteria
* Known chronic pulmonary disease, including chronic obstructive pulmonary disease or asthma requiring regular medication * Baseline peripheral oxygen saturation below 92% on room air * Significant cardiovascular instability * Severe hepatic or renal dysfunction * Active infection or systemic inflammatory disease * Use of systemic corticosteroids or immunosuppressive therapy * Pregnancy * Inability to provide informed consent * Anticipated difficult airway * Expected need for postoperative mechanical ventilation
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Concentration of syndecan-1 | 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation | Serum syndecan-1 concentration measured in duplicate. |
| Concentration of sialic acid | 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation | Serum sialic acid concentration measured in duplicate. |
| Concentration of surfactant protein-A | 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation | Serum surfactant protein-A concentration measured in duplicate. |
| Concentration of ischemia-modified albumin | 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation | Serum ischemia-modified albumin concentration measured in duplicate. |
| Concentration of TNF-alpha | 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation | Serum TNF-alpha concentration measured in duplicate. |
| Concentration of total protein | 10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation | Serum total protein concentration measured in duplicate. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Arterial oxygen tension (PaO2) | 10 minutes after establishment of assigned oxygen fraction | — |
| Intraoperative mean arterial pressure | Immediately after intubation and every 15 minutes up to 90 minutes | — |
| Intraoperative heart rate | Immediately after intubation and every 15 minutes up to 90 minutes | — |
| Arterial pH | 10 minutes after establishment of assigned oxygen fraction | Arterial pH measured on blood gas analysis. |
| Arterial carbon dioxide tension (PaCO2) | 10 minutes after establishment of assigned oxygen fraction | Arterial partial pressure of carbon dioxide. |
| Venous oxygen tension (PvO2) | 10 minutes after establishment of assigned oxygen fraction | Venous partial pressure of oxygen. |
| Venous carbon dioxide tension (PvCO2) | 10 minutes after establishment of assigned oxygen fraction | Venous partial pressure of carbon dioxide. |
| Arterial oxygen saturation (SaO2) | 10 minutes after establishment of assigned oxygen fraction | Arterial oxygen saturation measured on blood gas analysis. |
| Venous oxygen saturation (SvO2) | 10 minutes after establishment of assigned oxygen fraction | Venous oxygen saturation measured on blood gas analysis. |
| Arteriovenous oxygen difference | 10 minutes after establishment of assigned oxygen fraction | Difference between arterial and venous oxygen saturation. |
| Lactate concentration | 10 minutes after establishment of assigned oxygen fraction | Blood lactate concentration measured on blood gas analysis. |
Countries
Turkey (Türkiye)
Outcome results
None listed