Effectiveness of CPR and Prognosis in Cardiac Arrest
During cardiac arrest, when alveolar ventilation and metabolism are essentially constant, end tidal CO2 (EtCO2) reflects pulmonary blood flow.
EtCO2 can be used as a gauge of the effectiveness of cardiac compressions. As effective CPR leads to a higher cardiac output, EtCO2 will rise, reflecting the increase in perfusion.
In a study conducted by Wallbrecht et al. (2007), the results demonstrated that deeper chest compressions correlated with higher EtCO2 levels, and that changes in EtCO2 during the resuscitation event may be reflective of the CPR quality being delivered.
Return of spontaneous circulation:
EtCO2 can be used as a gauge of the effectiveness of cardiac compressions. As effective CPR leads to a higher cardiac output, EtCO2 will rise, reflecting the increase in perfusion.
In a study conducted by Wallbrecht et al. (2007), the results demonstrated that deeper chest compressions correlated with higher EtCO2 levels, and that changes in EtCO2 during the resuscitation event may be reflective of the CPR quality being delivered.
Return of spontaneous circulation:
- During cardiac arrest, EtCO2 is the earliest indicator of the return of spontaneous circulation.
- When the heart restarts, the dramatic increase in cardiac output, and resulting increase in perfusion, leads to a rapid increase in EtCO2 as the CO2 that has accumulated during cardiac arrest is effectively transported to the lungs and exhaled. This process manifests as a sudden rise in EtCO2.
The American Heart Association guidelines for cardiac resuscitation emphasize the importance of continuing chest compressions without interruption until a perfusing rhythm is reestablished.
Capnographic waveform monitoring helps eliminate the need to stop chest compressions to check for pulses.
Results from other studies indicated that EtCO2 levels of ≤10 mmHg measured 20 minutes after the initiation of advanced cardiac life support accurately predicted death in adult patients with cardiac arrest.
Capnographic waveform monitoring helps eliminate the need to stop chest compressions to check for pulses.
- Reestablishment of a perfusing rhythm is accompanied immediately be a dramatic increase in EtCO2.
- Once this rise in EtCO2 is noted, chest compressions can be safely stopped while cardiac rhythm and blood pressure are assessed.
Results from other studies indicated that EtCO2 levels of ≤10 mmHg measured 20 minutes after the initiation of advanced cardiac life support accurately predicted death in adult patients with cardiac arrest.