Cerebral tissue oxygenation measured by two different probes: challenges and interpretation

Area of Science:

• Neuroscience
• Critical Care Medicine

Background:

• Cerebral tissue oxygenation (PbrO(2)) monitoring is crucial for managing patients with traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH).
• The Licox CC1.SB (LX) system is commonly used, but the Neurovent-PTO (NV) probe is a newer alternative.
• Prospective comparative data in clinical settings are lacking.

Purpose of the Study:

• To compare the performance of LX and NV probes for measuring PbrO(2) in comatose patients with TBI or SAH.
• To evaluate probe comparability during dynamic changes in inspired oxygen fraction (FiO(2)) and mean arterial pressure (MAP).

Main Methods:

• Continuous PbrO(2) monitoring using side-by-side LX and NV probes in 11 patients.
• Standardized challenges involving increases in FiO(2) and MAP.
• Data analysis using logistic functions and Bland-Altman methods.

Main Results:

• Significant differences in PbrO(2) values were observed between LX and NV probes.
• The LX probe demonstrated faster responses to changes in FiO(2) and MAP.
• Limits of agreement were wide (-32.1 to 20.0 mmHg), with LX values averaging 6.1 mmHg lower than NV.

Conclusions:

• LX and NV probes yield different PbrO(2) measurements in clinical routine and during physiological challenges.
• The findings do not support the interchangeable use of LX and NV probes.
• Preliminary results suggest caution due to the small sample size.