What is the normal value associated with EtCO2?

What is the normal value associated with EtCO2?

• A. 20-30 mmHg
• B. 35-45 mmHg
• C. 50-60 mmHg
• D. 60-70 mmHg

Answer: (B)

End-tidal CO2 (EtCO2) is the CO2 level at the end of a exhaled breath, measured by capnography. In healthy lungs, this value mirrors arterial CO2 and sits in a normal range of about 35–45 mmHg. This range is the standard reference used in field care to assess ventilation and airway function. Values below this range suggest too much ventilation or reduced CO2 delivery (hypoventilation is opposite; wait, correction: below 35 indicates hypocapnia from hyperventilation, low CO2 production, or poor perfusion; values above 45 indicate hypercapnia from hypoventilation or increased CO2 production). Note that EtCO2 is typically a few mmHg lower than PaCO2 because of dead space. This monitoring helps verify airway placement, gauge ventilation effectiveness, and detect changes during emergencies, including potential return of circulation during CPR if EtCO2 rises.

End-tidal CO2 (EtCO2) is the CO2 level at the end of a exhaled breath, measured by capnography. In healthy lungs, this value mirrors arterial CO2 and sits in a normal range of about 35–45 mmHg. This range is the standard reference used in field care to assess ventilation and airway function. Values below this range suggest too much ventilation or reduced CO2 delivery (hypoventilation is opposite; wait, correction: below 35 indicates hypocapnia from hyperventilation, low CO2 production, or poor perfusion; values above 45 indicate hypercapnia from hypoventilation or increased CO2 production). Note that EtCO2 is typically a few mmHg lower than PaCO2 because of dead space. This monitoring helps verify airway placement, gauge ventilation effectiveness, and detect changes during emergencies, including potential return of circulation during CPR if EtCO2 rises.