Analysis of End-Tidal CO2 Variability During Plateau Waves Episodes: An Information Theoretic Approach

Area of Science:

• Neuroscience and Critical Care Medicine
• Physiology and Biomedical Engineering

Background:

• Plateau waves (PWs) are dangerous intracranial pressure (ICP) surges in traumatic brain injury (TBI) that compromise cerebral perfusion pressure (CPP) and blood flow.
• End-tidal carbon dioxide (etCO2) serves as a non-invasive surrogate for arterial CO2 (PaCO2), reflecting cerebral blood flow and metabolic regulation.
• Understanding CO2 dynamics during PWs is crucial for managing TBI and improving patient outcomes.

Purpose of the Study:

• To investigate the dynamics of etCO2 during PWs using entropy-based measures.
• To explore the relationship between etCO2 variations, ICP, and cerebral hemodynamics during TBI-related PWs.

Main Methods:

• Analysis of etCO2 dynamics during PWs using entropy, information storage (IS), and complexity measures.
• Correlation of etCO2 patterns with ICP fluctuations and cerebral hemodynamic changes.

Main Results:

• A slight increase in etCO2 was observed preceding PWs, potentially triggering ICP elevation.
• Median etCO2 increased during PWs, possibly amplifying vasodilation and ICP.
• Elevated etCO2 entropy and complexity during PWs suggest increased cerebral hemodynamic irregularity and reduced perfusion.
• Increased etCO2 IS post-PW indicates activation of recovery mechanisms.

Conclusions:

• etCO2 dynamics, analyzed through entropy measures, provide valuable insights into the pathophysiology of PWs in TBI.
• Changes in etCO2 patterns during PWs reflect critical alterations in cerebral blood flow and intracranial pressure regulation.
• Incorporating etCO2 analysis into TBI monitoring can enhance understanding and management of PW episodes.