Perioperative Hyperoxia vs Normoxia Biomarker Trial

Effects of Perioperative Hyperoxia Versus Normoxia on Pulmonary, Endothelial, and Inflammatory Biomarkers in Elective Laparoscopic Lower Abdominal Surgery

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.

Study Overview

• Status: Completed
• Conditions: Oxidative Stress; Perioperative Care; Hyperoxia; Endothelial Glycocalyx Injury
• Intervention / Treatment: Other: Perioperative Oxygen Strategy - Normoxia; Other: Perioperative Oxygen Strategy-Hyperoxia

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.

• Study Type: Interventional
• Enrollment (Actual): 76
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Istanbul University, Istanbul Faculty of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Normoxia; Intraoperative inspired oxygen fraction (FiO2) of 0.35 under standardized general anesthesia and volume-controlled ventilation.	Other: Perioperative Oxygen Strategy - Normoxia; Normoxia arm: FiO2 0.35 Intervention started immediately after intubation and maintained intraoperatively
Experimental: Hyperoxia; Intraoperative inspired oxygen fraction (FiO2) of 0.80 under standardized general anesthesia and volume-controlled ventilation.	Other: Perioperative Oxygen Strategy-Hyperoxia; Hyperoxia arm: FiO2 0.80 Intervention started immediately after intubation and maintained intraoperatively

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concentration of syndecan-1	Serum syndecan-1 concentration measured in duplicate.	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.	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.	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.	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.	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.	10 minutes after establishment of assigned oxygen fraction and immediately after surgery/post-extubation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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 oxygen tension (PaO2)	Arterial partial pressure of oxygen.	10 minutes after establishment of assigned oxygen fraction
Arterial pH	Arterial pH measured on blood gas analysis.	10 minutes after establishment of assigned oxygen fraction
Arterial carbon dioxide tension (PaCO2)	Arterial partial pressure of carbon dioxide.	10 minutes after establishment of assigned oxygen fraction
Venous oxygen tension (PvO2)	Venous partial pressure of oxygen.	10 minutes after establishment of assigned oxygen fraction
Venous carbon dioxide tension (PvCO2)	Venous partial pressure of carbon dioxide.	10 minutes after establishment of assigned oxygen fraction
Arterial oxygen saturation (SaO2)	Arterial oxygen saturation measured on blood gas analysis.	10 minutes after establishment of assigned oxygen fraction
Venous oxygen saturation (SvO2)	Venous oxygen saturation measured on blood gas analysis.	10 minutes after establishment of assigned oxygen fraction
Arteriovenous oxygen difference	Difference between arterial and venous oxygen saturation.	10 minutes after establishment of assigned oxygen fraction
Lactate concentration	Blood lactate concentration measured on blood gas analysis.	10 minutes after establishment of assigned oxygen fraction

Collaborators and Investigators

• Sponsor: Istanbul University

Publications and helpful links

General Publications

• Meyhoff CS, Wetterslev J, Jorgensen LN, Henneberg SW, Hogdall C, Lundvall L, Svendsen PE, Mollerup H, Lunn TH, Simonsen I, Martinsen KR, Pulawska T, Bundgaard L, Bugge L, Hansen EG, Riber C, Gocht-Jensen P, Walker LR, Bendtsen A, Johansson G, Skovgaard N, Helto K, Poukinski A, Korshin A, Walli A, Bulut M, Carlsson PS, Rodt SA, Lundbech LB, Rask H, Buch N, Perdawid SK, Reza J, Jensen KV, Carlsen CG, Jensen FS, Rasmussen LS; PROXI Trial Group. Effect of high perioperative oxygen fraction on surgical site infection and pulmonary complications after abdominal surgery: the PROXI randomized clinical trial. JAMA. 2009 Oct 14;302(14):1543-50. doi: 10.1001/jama.2009.1452.
• Lopez MG, Pandey AK, Hennessy C, Hughes CG, Absi TS, Shah AS, Shotwell MS, Harrison DG, Billings FT 4th; ROCS Trial Investigators. Effects of Oxygen on Perioperative Vascular Function: A Randomized Clinical Trial. J Am Heart Assoc. 2025 Aug 5;14(15):e041778. doi: 10.1161/JAHA.125.041778. Epub 2025 Jul 17.
• Farag E, Esa Y, Chehade NEH, Sleiman VB, Seif J. Endothelial glycocalyx in perioperative medicine current understanding and future direction. J Clin Anesth. 2026 Mar;110:112154. doi: 10.1016/j.jclinane.2026.112154. Epub 2026 Feb 16.
• Larvin J, Edwards M, Martin DS, Feelisch M, Grocott MPW, Cumpstey AF. Perioperative oxygenation-what's the stress? BJA Open. 2024 Mar 20;10:100277. doi: 10.1016/j.bjao.2024.100277. eCollection 2024 Jun.
• Elfeky A,Chen YF,Grove A,Couper K,Court R,Tomassini S,Wilson A,Hooper A,Buckle A,Vadeyar S,Thompson M,Uthman O,Yeung J

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2017
• Primary Completion (Actual): January 1, 2019
• Study Completion (Actual): February 1, 2019

Study Registration Dates

• First Submitted: March 30, 2026
• First Submitted That Met QC Criteria: April 10, 2026
• First Posted (Actual): April 13, 2026

Study Record Updates

• Last Update Posted (Actual): April 13, 2026
• Last Update Submitted That Met QC Criteria: April 10, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: TNF-alpha; Syndecan-1; Hyperoxia; Randomized Trial; Normoxia; Sialic Acid; Perioperative Oxygen Therapy; Surfactant Protein-A
• Additional Relevant MeSH Terms: Signs and Symptoms, Respiratory; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hyperoxia
• Other Study ID Numbers: 2017/771

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No