At this year's EMS State of the Sciences Conference, organizers grouped a handful of capnography-themed presentations into a "mini-symposium" on end-tidal CO2 monitoring. Its concepts included:
EtCO2 analysis as the "gold standard" for airway management
Oklahoma's Emergency Medical Services Authority (EMSA) really believes in capnography to verify tube placement: In 2009, it began suspending providers for not using it. Per a 2008 memo from the office of EMSA's medical director, "All tracheal intubations will have EtCO2 confirmation within 60 seconds of ETT insertion and continuous monitoring of lung ventilation." A protocol for confirmation of tube placement followed in 2009, with 30 days off and remedial airway education for medics who failed to utilize timely continuous post-intubation waveform capnography. In the state's largest cities, Oklahoma City and Tulsa, the mandate covered more than 1,200 intubations in 2010.
Using EtCO2 analysis in sepsis syndromes
Sepsis is the 10th-leading cause of American deaths, and severe sepsis can have a mortality rate of 30%–40%. Early goal-directed therapy begun in the ED and aimed at quickly reversing global tissue hypoxia is the best current strategy against such mortality.
That hypoxia begins early in the sepsis process and may precede changes in vital signs. A key finding is elevated serum lactate levels: As oxygen demand exceeds supply and tissue becomes hypoxic, these levels will rise, eventually resulting in lactic acidosis. EGDT is triggered with a lactate level greater than 4 mmol/L in conjunction with systolic BP less than 90 and two or more criteria for Systemic Inflammatory Response Syndrome (temperature less than 36°C or greater than 38°C; heart rate greater than 90 bpm; respiratory rate greater than 20 or PCO2 less than 32 mmHg; white blood cell count less than 4,000 or greater than 12,000). It cuts mortality by roughly a third.
Beginning this trajectory is an important opportunity for EMS, argued Orange County (FL) EMS medical director George Ralls, MD. Ralls cited an Orlando-based study that found a "significant association" between EtCO2 levels and in-hospital mortality in ED patients with suspected sepsis, and that EtCO2 levels correlated inversely with lactate levels in these patients. "With future studies," authors concluded, "[EtCO2 monitoring] may be used as a potential risk and non-invasive stratification tool for predicting sepsis severity in this patient population."