2
2
QG_CO2.frm Page 1 Friday, February 13, 2004 4:26 PM
Propaq
®
Vital Signs Monitor
Quick Guide for CO
Waveforms
2
60
C
D
30
0
This Guide is intended for quick reference only. It is strongly recommended that clinicians new to capnography also
refer to published educational literature on this subject.
All waveform illustrations in this guide apply to both
Mainstream CO
Sidestream CO
waveforms tend to be slightly more defined, especially on the upstroke, plateau, downstroke;
2
waveforms are more rounded.
2
AB
Mainstream CO
E
and Sidestream CO
with intubated patients.
QG_CO2.frm Page 2 Friday, February 13, 2004 4:26 PM
The Normal CO
Waveform
2
60
C
D
30
0
The “normal” capnogram shape consists of the following:
AB
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
C-D Alveolar “plateau” – contains mixed alveolar gases
D End-Tidal CO
– highest concentration of exhaled CO
2
D-E Rapid, sharp downstroke – inhalation phase; fresh gas rapidly
replaces CO
2
E
2
2
QG_CO2.frm Page 3 Friday, February 13, 2004 4:26 PM
Endotracheal Tube In Esophagus
60
30
0
If inadvertent esophageal intubation occurs, the capnogram indicates the
endotracheal tube is incorrectly positioned and ventilation is not taking place.
Look for:
• No CO
• Only small, short-lived capnograms displayed
measured
2
QG_CO2.frm Page 4 Friday, February 13, 2004 4:26 PM
Endotracheal Tube “Leaks”
60
Rounded
30
0
If air leaks around the endotracheal tube cuff, the alveolar (end-tidal) CO
diluted. The alveolar plateau is blunted, and it blends with the downstroke of the
capnogram. Look for:
•A deflated or leaky endotracheal or tracheal tube cuff
• An artificial airway that is too small for the patient
gas is
2
QG_CO2.frm Page 5 Friday, February 13, 2004 4:26 PM
Decreased Muscle Relaxant Effect Or Breathing
Against Ventilator
60
Cleft
30
0
The “cleft” in the far right portion of the alveolar plateau indicates that the
diaphragm is moving and causing entrainment of fresh air. A cleft can occur in
any part of the alveolar plateau when the patient attempts to breath against the
ventilator. Look for:
• Clefts in the capnogram (may not be on every waveform)
• “Humped” waveforms (indicating attempts at spontaneous breathing
QG_CO2.frm Page 6 Friday, February 13, 2004 4:26 PM
Endotracheal Tube Kinked Or Airway Obstructed
60
30
Kinking
0
If exhaled CO
ascending limb of the capnogram has little or no alveolar plateau. Look for:
•Partially kinked or occluded artificial airway
• Herniated endotracheal or tracheal tube cuff
• Bronchospasm, chronic obstructive pulmonary disease
•Foreign body in the upper airway
gas is completely or partially obstructed, the slope of the
2
QG_CO2.frm Page 7 Friday, February 13, 2004 4:26 PM
Rebreathing CO
2
60
30
0
If the patient is rebreathing previously exhaled CO
and the baseline elevates. The waveform does not return to zero at the end of
inspiration. Look for:
• Inadequate expiratory time
• Malfunctioning inspiratory valve
• Other errors/malfunctions in breathing circuit
• Insufficient inspiratory flow rate
, ETCO
2
values increase
2
QG_CO2.frm Page 8 Friday, February 13, 2004 4:26 PM
Beaverton, Oregon USA
Within USA, toll free:
Phone: (800) 289-2500
Phone Technical Services: (800) 289-2501
WorldWide: Phone: (1) 503 530-7500
Fax: (1) 503 526-4200
Fax Technical Services: (1) 503 526-4970
Internet: http://www.monitoring.welchallyn.com
©2004 Printed in USA
P/N: 810-0466-03 Rev A 2/04
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