What is the normal End-Tidal CO2 value?

What is the normal End-Tidal CO2 value?

• A. 25-35 mmHg
• B. 35-45 mmHg
• C. 45-55 mmHg
• D. 60-70 mmHg

Answer: (B)

End-tidal CO2 is the CO2 level measured at the end of an exhaled breath, reflecting how effectively the lungs are removing CO2 through ventilation. In a healthy adult, the normal end-tidal CO2 value is about 35 to 45 mmHg. This range sits slightly below arterial CO2 because the exhaled gas comes from ventilated alveoli and a small amount of CO2 remains in the blood and in dead-space air before complete gas exchange. Values outside this window point to ventilation or perfusion problems: higher ETCO2 suggests hypoventilation or rebreathing, while lower ETCO2 can indicate hyperventilation, reduced pulmonary perfusion, or increased dead-space ventilation. Capnography is routinely used during anesthesia, CPR, and airway management to monitor ventilation and verify proper tube placement.

End-tidal CO2 is the CO2 level measured at the end of an exhaled breath, reflecting how effectively the lungs are removing CO2 through ventilation. In a healthy adult, the normal end-tidal CO2 value is about 35 to 45 mmHg. This range sits slightly below arterial CO2 because the exhaled gas comes from ventilated alveoli and a small amount of CO2 remains in the blood and in dead-space air before complete gas exchange. Values outside this window point to ventilation or perfusion problems: higher ETCO2 suggests hypoventilation or rebreathing, while lower ETCO2 can indicate hyperventilation, reduced pulmonary perfusion, or increased dead-space ventilation. Capnography is routinely used during anesthesia, CPR, and airway management to monitor ventilation and verify proper tube placement.