Welch Allyn Propaq Quick Start Guide For Co2 Waveforms - Quick Reference Guide - Manual (Page 2)

The Normal CO
2
Waveform
The “normal” capnogram shape consists of the following:
A-B Zero baseline – the beginning of exhalation
B-C Rapid, sharp rise – anatomical dead space gas replaced by more
distal airway gases that contain more CO
2
C-D Alveolar “plateau” – contains mixed alveolar gases
D End-Tidal CO
2
– highest concentration of exhaled CO
2
D-E Rapid, sharp downstroke – inhalation phase; fresh gas rapidly
replaces CO
2
60
30
0 A B
C D
E
QG_CO2.frm Page 2 Friday, February 13, 2004 4:26 PM