Capnography, or end-tidal carbon dioxide (ETCO2) monitoring, provides important information about a patient's ventilation and oxygenation. It can be used to verify endotracheal tube placement, monitor ventilation during CPR or anesthesia, and detect hypoventilation or hyperventilation based on the ETCO2 value and waveform shape. The normal ETCO2 range is 35-45 mmHg; values higher or lower may indicate hypoventilation or hyperventilation, respectively. Capnography is a vital sign that can help guide management of ventilation in intubated and non-intubated patients.

2. Oxygenation:
– oxygen is inhaled into the lungs and carried into the
blood
Ventilation:
– CO2 is transported back from the blood to the lungs
& exhaled

3. Relationship between CO2 & respiratory
rate (RR):
Increased RR = decreased CO2 =
HYPERventilation (ETCO2 < 35)
Resp. alkalosis
Decreased RR = increased CO2 =
HYPOventilation (ETCO2 > 45)
resp. acidosis

4. CAPNOGRAPHY =
“THE VENTILATION VITAL SIGN”:
”
INTUBATED APPLICATIONS:
Verification of ETT placement

5. NON-INTUBATED APPLICATIONS:
anaphylaxis
post-ictal
biofeedback monitor

6. 3 QUESTION TO ASK EVERY
TIME CAPNOGRAPHY IS USED:
1. IS THE ET TUBE IN THE TRACHEA
(rise and fall of detectable CO2)?
2. WHAT IS THE ETCO2 VALUE
(height of the waveform)?

7. 35 – 45 mm/hg
ETCO2 Less Than 35 mmHg =
– "Hyperventilation/Hypocapnia"
ETC02 Greater Than 45 mmHg =
– "Hypoventilation/Hypercapnia"

8.
B-C is the exhalation upstroke where dead space gas
D-E is the inspiration washout.

9. Phase I (A) = Respiratory Baseline
Phase II (B)= Expiratory upstroke
Phase III (C)= Expiratory plateau
(D)**ETCO2 Peak level
Phase IV (E) = Inspiratory downstroke

10. CAPNOGRAPHY WAVEFORM
ANALYSIS:
“Square box” waveform;
”
baseline CO2 = 0;
ETCO2 = 35-45 mm Hg

11. DISLODGED ETT:
–
– Replace ETT

12. ESOPHAGEAL INTUBATION:
–
ETCO2.
– Re-intubate

13. CPR:
– “Square box” waveform; baseline CO2 = 0;
ETCO2 = 10-15 mm Hg (possibly higher) with
adequate CPR
– Change rescuers if ETCO2 drops < 10

14.
Monitoring ETC02 measures cardiac output, thus monitoring ETCO2 is a
good way to measure the effectiveness of CPR.
In 1978, Kalenda “reported a decrease in ETC02 as the person performing
CPR fatigued, followed by an increase in ETCO2 as a new rescuer took
over, presumably providing better chest compressions.” –Gravenstein,
Capnography: Clinical Aspects, Cambridge Press, 2004
“Reductions in ETCO2 during CPR are associated with comparable
reductions in cardiac output....The extent to which resuscitation maneuvers,
especially precordial compression, maintain cardiac output may be more
readily assessed by measurements of ETCO2 than palpation of arterial
pulses.” -Max Weil, M.D., Cardiac Output and End-Tidal carbon dioxide,
Critical Care Medicine, November 1985

15. ” with/without prolonged
expiration =
–
–
epinephrine)

16. ROSC:
–
– Check for pulse; contact BIOTEL for drip
authorization

17. Return of Spontaneous Circulation (ROSC)
ETCO2 can be the first sign of return of spontaneous circulation
(ROSC). During a cardiac arrest, if you see the CO2 number shoot
up, stop CPR and check for pulses.
End-tidal CO2 will often overshoot baseline values when circulation
is restored due to carbon dioxide washout from the tissues.
A recent study found the ETCO2 shot up on average 13.5 mmHg
with sudden ROSC before settling into a normal range.-Grmec S,
Krizmaric M, Mally S, Kozelj A, Spindler M, Lesnik B.,Resuscitation.
2006 Dec 8

18. RISING BASELINE =
– Patient is rebreathing CO2:
Check equipment for adequate oxygen inflow
Allow intubated patient more time to exhale

19. HYPOVENTILATION:
– ? RR; Prolonged waveform; baseline CO2 = 0;
ETCO2 > 45 mm Hg
–

20. HYPERVENTILATION:
– ? RR; shortened waveform; baseline ETCO2
= 0; ETCO2 < 35 mm Hg
Management:
– Biofeedback if conscious, decrease assisted
ventilation rate if unconscious/intubated
– **Important exceptions: Severe metabolic acidosis (DKA,
sepsis, salicylate poisoning, acute renal failure, methanol
ingestion, tricyclic overdose) will cause tachypnea (??
RR), but ETCO2 will be HIGH.
**In other words, if RR is high, but ETCO2 is also high,
consider the above diagnoses. This is NOT normal!

21. PATIENT BREATHING AROUND ET TUBE:
Adult: Broken cuff or tube is too small
Pediatric: tube is too small
reintubate

22. Assisting Intubation
Continuous end-tidal CO2 monitoring can
confirm a tracheal intubation.
A good wave form indicating the presence
of CO2 ensures the ET tube is in the
trachea.

23. 2005 study comparing field intubations that used
continuous capnography to confirm intubations versus
non-use showed zero unrecognized misplaced
intubations in the monitoring group versus 23%
misplaced tubes in the unmonitored group. -Silverstir,
Annals of Emergency Medicine, May 2005
“When exhaled CO2 is detected (positive reading for
CO2) in cardiac arrest, it is usually a reliable indicator of
tube position in the trachea.” - The American Heart
Association 2005 CPR and ECG Guidelines

24. THE END!!!

25. Oxygenation:
– What is oxygenation?
Ventilation:
– What is ventilation?

26. Relationship between CO2 & respiratory
rate (RR):
HYPERventilation =
– What is relationship of RR?
– What is relationship of CO2?
– ETCO2 < _____?
HYPOventilation
– What is relationship of RR?
– What is relationship of CO2?
– ETCO2 > _____?

27. CAPNOGRAPHY =
“THE VENTILATION VITAL SIGN”:
”
INTUBATED APPLICATIONS:
1.
2.
3.
4.

28. CAPNOGRAPHY =
“THE VENTILATION VITAL SIGN”:
”
INTUBATED APPLICATIONS:
Verification of ETT placement

29. Capnography Applications in CCT
NON-INTUBATED APPLICATIONS:
1.
2.
3.
4.

30. Capnography in CCT
NON-INTUBATED APPLICATIONS:
anaphylaxis
post-ictal
biofeedback monitor

31. CAPNOGRAPHY IS USED:
1. IS THE ____________________?
2. WHAT IS THE _________________?
3. WHAT IS THE ________________?

32. 3 QUESTION TO ASK EVERY
TIME CAPNOGRAPHY IS USED:
1. IS THE ET TUBE IN THE TRACHEA
(rise and fall of detectable CO2)?
2. WHAT IS THE ETCO2 VALUE
(height of the waveform)?

33. 35 – 45 mm/hg
1. What is the normal range of ETCO2?
2. ETCO2 <_____ ? = _____________?
3. ETCO2 >_____ ? = _____________?

34. 35 – 45 mm/hg
ETCO2 Less Than 35 mmHg =
– "Hyperventilation/Hypocapnia"
ETC02 Greater Than 45 mmHg =
– "Hypoventilation/Hypercapnia"

35. CAPNOGRAPHY WAVEFORM
ANALYSIS:
Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

36. CAPNOGRAPHY WAVEFORM
ANALYSIS:
“Square box” waveform;
”
baseline CO2 = 0;
ETCO2 = 35-45 mm Hg

37. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

38. DISLODGED ETT:
–
– Replace ETT

39. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

40. ESOPHAGEAL INTUBATION:
–
ETCO2.
– Re-intubate

41. Pt is pulseless
Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

42. CPR:
– “Square box” waveform; baseline CO2 = 0;
ETCO2 = 10-15 mm Hg (possibly higher) with
adequate CPR
– Change rescuers if ETCO2 drops < 10

43. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

44. ROSC:
–
– Check for pulse; contact BIOTEL for drip
authorization

45. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

46. ” with/without prolonged
expiration =
–
–
epinephrine)

47. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

48. RISING BASELINE =
– Patient is rebreathing CO2:
Check equipment for adequate oxygen inflow
Allow intubated patient more time to exhale

49. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

50. HYPOVENTILATION:
– ? RR; Prolonged waveform; baseline CO2 = 0;
ETCO2 > 45 mm Hg
–

51. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

52. HYPERVENTILATION:
– ? RR; shortened waveform; baseline ETCO2
= 0; ETCO2 < 35 mm Hg
Management:
– Biofeedback if conscious, decrease assisted
ventilation rate if unconscious/intubated
– **Important exceptions: Severe metabolic acidosis (DKA,
sepsis, salicylate poisoning, acute renal failure, methanol
ingestion, tricyclic overdose) will cause tachypnea (??
RR), but ETCO2 will be HIGH.
**In other words, if RR is high, but ETCO2 is also high,
consider the above diagnoses. This is NOT normal!

53. Is ETT in Trachea?
What is ETCO2 value?
What is the shape?
What is management?

54. PATIENT BREATHING AROUND ET TUBE:
Adult: Broken cuff or tube is too small
Pediatric: tube is too small
reintubate

55. THE END!!!