Episode 144 Deep Dive: End Tidal CO2 in Cardiac Arrest

Prehospital end-tidal carbon dioxide (EtCO2) levels serve as a critical, yet often misunderstood, metric for managing out-of-hospital cardiac arrest. Research utilizing the ESO data collaborative reveals a U-shaped relationship between EtCO2 values and patient survival, where both excessively low and high readings correlate with increased mortality. Contrary to long-standing assumptions, EtCO2 values below 10 mmHg do not guarantee futility, as approximately 7% of patients in this range survive to hospital discharge. These findings underscore that EtCO2 should never dictate termination of resuscitation in isolation; instead, clinicians must integrate these values with broader patient characteristics and clinical trends. Future advancements in resuscitation science require shifting focus toward continuous waveform morphology and AI-driven pattern recognition to better inform real-time decision-making. Lead author Tanner Smida emphasizes the necessity of moving beyond static thresholds toward personalized, context-aware care to improve patient outcomes.