How hyperoxia affects systemic redox state: insights from PULSE-Ox, a randomised double-blind mechanistic feasibility...

Area of Science:

• Anesthesiology
• Critical Care Medicine
• Biochemistry

Background:

• Intraoperative oxygen administration recommendations vary, with the WHO suggesting 80% to reduce surgical site infections.
• Potential harm from high oxygen concentrations, such as oxidative stress, remains unclear.

Purpose of the Study:

• To investigate the impact of varying intraoperative oxygen concentrations (FiO2=0.3, 0.55, 0.8) on whole-body redox state in major cancer surgery patients.
• To determine if redox profiling can differentiate between oxygen administration groups.

Main Methods:

• Randomized controlled trial involving 28 adult cancer surgery patients allocated to three oxygen concentration groups.
• Monitoring of peripheral oxygen saturation (SpO2) and oxygen reserve index.
• Analysis of blood samples for lipid peroxides, protein carbonyls, free thiols, antioxidants, and nitroso species using advanced analytical techniques.

Main Results:

• Higher oxygen concentrations (FiO2=0.8) led to decreased systemic oxygen utilization despite unchanged SpO2.
• Significant increases in nitrosation and diminished reductive power were observed with higher oxygen concentrations.
• Administration of 80% oxygen was associated with significant oxidative stress.

Conclusions:

• High intraoperative oxygen concentrations challenge the body's redox balance, potentially increasing vulnerability.
• Redox profiling shows promise for early identification of patients at risk of complications and guiding individualized oxygen therapy.
• Further clinical studies are needed to evaluate optimal oxygen therapy targets.