1. Capnography: Defined and Clinical Applications
Becky Logiudice, RN, MS, CCRN
Mount Auburn Hospital

2. What is Capnograhy?
Continuous graphic display and recording of carbon dioxide concentrations during the respiratory cycle
Capnography provides:
Numerical value for end tidal CO2 (EtCO2)
CO2 waveform for each breath
Respiratory rate (RR) sampled directly from the airway
EtCO2 value + Waveform + RR = Ventilation/ Airway status

3. History
Fundamentals of capnography were established in 1943 by Karl Luft, a German Bio-engineer
CO2 could absorb infrared radiation
1978: Capnography first used in Holland during anesthesia
In 1998 the ASA (American Society of Anesthesiologists) Committee on Standards of Care = Mandatory during general anesthesia
Present: Standard of care during anesthesia and being used more during emergency care and procedural sedation

4. Infrared Spectography
The infrared light received is compared
to the infrared light transmitted.
The difference is then converted
by calculations into the partial pressure
that you see on the monitor.

5. Chemical Colorimetric Analysis
Uses pH to detect CO2
Good for a quick indicator

6. Physiology

7. Process of Respiration
Note: Ventilation and Oxygenation are separate, but related, processes

8. Capnography

9. Question?
Are oxygenation and ventilation separate?
How?

10. Oxygenation
Ventilation

11. Clinical uses for capnography
1. Monitoring of airway /ventilation during:
Moderate sedation
General anesthesia
Use of a PCA
2. Endotrachial tube placement verification
3. Detect breathing/apnea
4. Ventilator malfunction
5. Estimate cardiac output
6. Monitor adequacy of CPR
7. Identify ROSC (Return of Spontaneous Circulation)

12. Normal Values and Waveforms
ABGs
Normal CO2 values:
35 – 45 mmHg
Capnography
Normal EtCO2 values:
30 – 40 mmHg

13. Procedural Sedation
Depressed ventilation is common, but clinical observation of RR is inadequate
Capnography acts as an early warning for a disasterous respiratory event
Pulse oximetry/electrocardiography give late warnings

14. Why Capnography in a code?
Background:
The 2010 American Heart Association Guidelines for ACLS now recommends using quantitative waveform capnography with intubated patients receiving chest compressions
Purpose: Waveform capnography in intubated patients
monitors:
CPR quality
Optimizes chest compressions
Can detect return of circulation during chest
compressions

15. CO2 and Cardiac Output

16. Equipment Needed for Waveform Capnography Ambu Bag Capnography Unit
Capnography filter tubing
ET Tube

17. How the Pieces Connect Ambu attaches to Capnography Filter tubing
The other end of filter
Capnography Filter tubing
connects to unit here
Filter line ribbed end attaches to ET tube

18. The Capnography Device Screen
On/Off switch
PETCO2
Reading here
O2 sat here
PETCO2 waveform
here

19. What the Numbers Mean? Under normal conditions: During CPR:
PETCO2 = 35 to 45mmHg
During CPR:
PETCO mmHg = High quality chest
Results that require Action:
1. PETCO2: < 10mmHG:
* Check endotrachial tube placement:
* Check breath sounds
* Evaluate quality of chest compressions
* Consider switching compressor role
2. PETCO2: mmHg
* Assess for return of spontaneous circulation (ROSC)
* Check pulse, check rhythm

20. Factors affecting CO2 levels
Increase in ETCO2
Increased muscular activity (shivering)
Increased Metabolism:
Sepsis
Fever
Malignant Hypothermia
Increased Cardiac output (during resuscitation)
Decreased minute ventilation ( total lung ventilation per minute. Tidal volume and respiratory rate)
Two main causes:
Increased CO2 production
Decreased excretion / alveolar ventilation

21. Factors affecting CO2 levels
Decrease in ETCO2
Decreased muscular activity
Hypothermia
Decreased cardiac output
Pulmonary Embolism
Bronchospasm
Increased minute ventilation (RR and tidal volume)
Two Main Causes
Decreased Production
Increased Excretion or alveolar ventilation

22. Case Studies If intubated: Kinked ET tube ET tube dislodged
Airway obstruction

23. Rapidly decreasing waveform
Sudden hypotension
Early sign of cardiac
arrest
Pulmonary Embolism
Increase in RR

24. Rising Waveform Rising body temp Increased metabolism Increased BP
Decrease in RR

25. Capnography low (20 mmHg)
Hypothermia
Sedation / Anesthesia
Chest compressions