Intracranial Pressure and Brain Tissue Oxygen Trajectories after Cardiac Arrest

Area of Science:

• Neurology
• Critical Care Medicine
• Neurocritical Care

Background:

• Brain tissue hypoxia and elevated intracranial pressure worsen hypoxic-ischemic brain injury (HIBI) after cardiac arrest.
• Pathophysiological changes vary between and within patients over time, leading to distinct HIBI phenotypes.
• Understanding these variations is crucial for targeted treatment strategies.

Purpose of the Study:

• To identify distinct trajectories of PbtO2 and ICP in patients surviving cardiac arrest.
• To characterize the clinical features associated with each identified trajectory.
• To explore the relationship between these trajectories and patient outcomes.

Main Methods:

• A single-center retrospective study involving 43 patients who survived cardiac arrest and underwent invasive neuromonitoring.
• Group-based trajectory modeling was used to analyze PbtO2 and ICP over the first 72 hours post-arrest.
• Clinical characteristics and outcomes were described for each trajectory group.

Main Results:

• Three distinct ICP trajectories were identified: normal, high-normal, and rapidly increasing/pathologically elevated.
• Three PbtO2 trajectories were identified: persistent hypoxia, mostly normal, and linearly increasing.
• The PbtO2 group with linearly increasing oxygen levels showed lower survival and more severe HIBI, despite similar ICP and CPP compared to other groups.

Conclusions:

• Distinct PbtO2 and ICP trajectories exist after cardiac arrest, suggesting variable HIBI physiology.
• These trajectories may represent distinct clinical phenotypes of HIBI.
• This research provides a basis for future studies investigating HIBI heterogeneity.