Targeted temperature management and P_btO₂ in traumatic brain injury

Area of Science:

• Neuroscience
• Critical Care Medicine
• Physiology

Background:

• Targeted Temperature Management (TTM) to normothermia is a common intervention for patients with traumatic brain injury (TBI).
• Understanding the physiological consequences of TTM in TBI is crucial for optimizing patient care.
• Multimodality monitoring is essential for assessing brain oxygenation and intracranial pressure in TBI patients.

Purpose of the Study:

• To investigate the physiological effects of TTM to normothermia in TBI patients (GCS≤12) using multimodality monitoring.
• To determine if changes in physiological parameters occur when brain oxygenation deteriorates during TTM in TBI patients.

Main Methods:

• Retrospective study of 102 TBI patients with continuous intracranial pressure (ICP) and brain oxygen tension (PbtO2) monitoring.
• Inclusion of non-continuous arterial carbon dioxide (PaCO2) and oxygen (PaO2) tensions, and core body temperature (Tc).
• Comparison of physiological parameters 8 hours before and after transition to normothermia in 39 patients.

Main Results:

• Normothermia reduced ICP and core body temperature but did not significantly change overall PbtO2.
• A subgroup of 18 patients experienced a fall in PbtO2 during normothermia.
• This PbtO2 decrease was associated with reductions in ICP and temperature-corrected PaCO2.

Conclusions:

• TTM to normothermia may lead to a decrease in PbtO2 in a subset of TBI patients.
• This finding suggests potential occult hyperventilation related to temperature changes.
• pH-stat correction of ventilation should be considered in future TTM protocols for TBI.