Value of continuous waveform quantitative end-tidal CO2 monitoring in cardiac arrest
- A sudden decrease or loss of ETCO2 may indicated the need for CPR to be started
- ETCO2 is an indirect assessment of quality of chest compressions (location, rate, depth); adequate chest compressions correlate with ETCO2 pressures of ≥20mmHg.
- A rise of ETCO2 >20mmHg is highly specific for ROSC in patients with PEA arrest; on average, patients with ROSC after CPR had an average ETCO2 level of 25 mmHg in one meta-analysis
- An up-trending ETCO2 during resuscitation suggests continuing resuscitative efforts unless there is overwhelming clinical evidence to the contrary
- Confirmation of airway placement and subsequent guide for adequate delivery of breaths using BVM or supraglottic device and ventilation rates for ETT with more immediate feedback than oxygen saturation monitoring
- A general “rule” is that if the ETCO2 is consistently <10mmHg for 3-5 minutes after 20 minutes of high quality CPR and resuscitative efforts, ROSC is unlikely to be achieved; however this is not a sensitive test and should be used only as an adjunctive data point in decisions of termination of resuscitation efforts
- There are multiple potential confounders that can elevate or decrease ETCO2 levels (see chart below), so extreme or trending values may be more useful than unwavering mid-range levels
- A sudden flattening of the ETCO2 waveform may be due to cardiac arrest, ventilator disconnection, esophageal intubation, capnography obstruction or dislodged airway device
The Podcast: EM Quick Hits 45 ETCO2 in Cardiac Arrest, Organ Donation, Paraphimosis, Medicolegal Myths, QI Corner
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