Normal end tidal CO2 is approximately?

Normal end tidal CO2 is approximately?

• A. 20 torr
• B. 40 torr
• C. 50 torr
• D. 30 torr

Answer: (D)

End-tidal CO2 represents the CO2 level in the air at the end of a breath and serves as a noninvasive indicator of ventilation efficiency. In healthy individuals, this value typically falls in the 35–45 mmHg range, with about 40 mmHg being the most common target in clinical monitoring. The small difference between ETCO2 and arterial CO2 (PaCO2) is normal, and the exact gradient can widen with lung disease, ventilation-perfusion mismatch, or poor perfusion. Among the given options, the value closest to normal is 40 torr, making it the best choice. Values like 20 or 30 are distinctly low and indicate hypoventilation or measurement issues, while 50 would indicate hypercapnia.

End-tidal CO2 represents the CO2 level in the air at the end of a breath and serves as a noninvasive indicator of ventilation efficiency. In healthy individuals, this value typically falls in the 35–45 mmHg range, with about 40 mmHg being the most common target in clinical monitoring. The small difference between ETCO2 and arterial CO2 (PaCO2) is normal, and the exact gradient can widen with lung disease, ventilation-perfusion mismatch, or poor perfusion. Among the given options, the value closest to normal is 40 torr, making it the best choice. Values like 20 or 30 are distinctly low and indicate hypoventilation or measurement issues, while 50 would indicate hypercapnia.