Q: Why its called "End-Tidal" CO2?
Answer: It's the point in the respiratory cycle where CO2 is at the highest level (End of the tide)
There are five phases of respiration when it comes to end-tidal Co2 analysis
- Dead space ventilation
- Ascending expiratory phase
- Alveolar Plateau
- End-tidal CO2
- Descending inspiratory phase
These five phases are marked in the pic as
A - B: Dead space ventilation
B - C: Ascending expiratory phase
C - D: Alveolar Plateau
D: End-tidal CO2 (highest)
D - E: Descending inspiratory phase
#pulmonary
#procedures
References:
1. Krauss B, Deykin A, Lam A, et al. Capnogram shape in obstructive lung disease. Anesth Analg 2005; 100:884. Copyright © 2005 Lippincott Williams & Wilkins.
2. Zwerneman K. End-tidal carbon dioxide monitoring: a VITAL sign worth watching. Crit Care Nurs Clin North Am. 2006 Jun;18(2):217-25, xi. doi: 10.1016/j.ccell.2006.02.002. PMID: 16728308.
3. Benumof JL. Abnormal end-tidal CO2 waveforms. Can J Anaesth. 2003 Aug-Sep;50(7):754. doi: 10.1007/BF03018728. PMID: 12944461.