1. End-Tidal CO2
(EtCO2)
The Wave Of The Future

2. EtCO2 Basics
EtCO2 measures ventilation
SAo2 measures oxygenation
Uses infra-red light to measure exhaled air
Vacuum in LP15 draws 50mL/min

3. EtCO2 Basics
Tachypnea - abnormally rapid breathing
Hyperventilation - Increased minute
ventilation that results in decreased EtCO2
levels (hypocapnea)
Hypoventilation - Decreased minute
ventilation that results in increased EtCO2
levels (hypercapnea)

4. Cellular Ventilation

5. Alveolar Ventilation

6. EtCO2 Basics
EtCO2 monitoring is continuous - changes
are immediately seen (CO2 diffuses across
membranes < 0.5 sec)
SAo2 monitoring relies on trending

7. EtCO2 Basics
Normal Values 35-45mmHg
<35 = hyperventilation
decreased metabolic state
>45 = hypoventilation
increased metabolic state

8. EtCO2 Basics
< 35mmHg (Hyperventilation)
Increased CO2 clearance (tachypnea)
Decreased CO2 production
(hypothermia, sedation, paralysis)
Decreased delivery to lungs
(decreased cardiac output)
V/Q mismatch (ventilating non-perfused
lungs - Pulmonary embolism)

9. EtCO2 Basics
> 45mmHg (Hypoventilation)
Decreased central drive, muscle
weakness, diffusion problems
Increased CO2 production
(Fever, burns, Hyperthyroidism, sz,
Bicarb, ROSC, reperfusion)

10. EtCO2 Basics
Normal Capnogram

11. EtCO2 Basics
Baseline - CO2-free air in dead spaces

12. EtCO2 Basics
Expiratory Upstroke (exhalation)

13. EtCO2 Basics
Expiratory plateau (exhalation of mostly
alveolar gases)

14. EtCO2 Basics
Inspiration (inhalation of CO2-free gases)

15. Bronchospasm
Normal Bronchospasm
(Uneven alveolar emptying)

17. Emphysema

18. Pulmonary Edema

19. Poor Plateau

20. Differential Lung
Emptying

21. Curare Cleft

22. Carbonated Beverages

23. Esophageal Intubation

24. Ineffective Respirations

25. Pain Management/
Sedation

26. Hypothermia/
Low Metabolic Demand

27. Malignant Hyperthermia

28. Metabolic States
Diabetes/Dehydration
EtCO2 tracks serum HCO3 & degree of acidosis
↓EtCO2 = metabolic acidosis

29. Metabolic States
Sepsis
EtCO2 inversely related to Lactate
The lower the EtCO2, the higher the
lactate levels
Lactate levels >4 = sepsis
EtCO2 levels <25 = sepsis alert

30. Cardiac Output

31. Cardiac
CHF/Heart Failure

32. Cardiac Arrest