1. CAPNOGRAPHY In Emergency Care EDUCATIONAL SERIES Part 2: Introduction

2. Part 2: Introduction to Capnography CAPNOGRAPHY In Emergency Care

3. Part 2: Introduction to Capnography Learning Objectives Differentiate between oxygenation and ventilationDifferentiate between oxygenation and ventilation Define end-tidal CO 2Define end-tidal CO 2 Identify phases of a normal capnogramIdentify phases of a normal capnogram Recognize patterns of hypoventilation, hyperventilation and bronchospasmRecognize patterns of hypoventilation, hyperventilation and bronchospasm

4. Oxygenation and Ventilation What is the difference?

5. Oxygenation and Ventilation Two completely different and separate functionsTwo completely different and separate functions –Oxygenation is the transport of O 2 via the bloodstream to the cells Oxygen is required for metabolismOxygen is required for metabolism –Ventilation is the exhaling of CO 2 via the respiratory tract Carbon dioxide is a byproduct of metabolismCarbon dioxide is a byproduct of metabolism

6. Oxygenation and Ventilation Oxygenation (oximetry ) CellularMetabolism Ventilation(capnography) CO 2 O2O2O2O2

7. Oxygenation Measured by pulse oximetry (SpO 2 )Measured by pulse oximetry (SpO 2 ) –Noninvasive measurement –Percentage of oxygen in red blood cells –Changes in ventilation take minutes to be detected –Affected by motion artifact, poor perfusion and some dysrhythmias

8. Oxygenation Pulse Oximetry Sensors Sensors Pulse Oximetry Waveform

9. Ventilation Measured by the end-tidal CO 2Measured by the end-tidal CO 2 –Partial pressure (mmHg) or volume (% vol) of CO 2 in the airway at the end of exhalation –Breath-to-breath measurement provides information within seconds –Not affected by motion artifact, poor perfusion or dysrhythmias

10. Ventilation Capnography waveform CapnographyLines

11. Oxygenation versus Ventilation Monitor your own SpO 2 and EtCO 2Monitor your own SpO 2 and EtCO 2 SpO 2 waveform is in the second channelSpO 2 waveform is in the second channel EtCO 2 waveform is in the third channelEtCO 2 waveform is in the third channel

12. Oxygenation versus Ventilation Now hold your breathNow hold your breath Note what happens to the two waveformsNote what happens to the two waveforms How long did it take the EtCO 2 waveform to go flat line? How long did it take the SpO 2 to drop below 90%? SpO 2 EtCO 2

13. Oxygenation and Ventilation OxygenationOxygenation –Oxygen for metabolism –SpO 2 measures % of O 2 in RBC –Reflects change in oxygenation within 5 minutes VentilationVentilation –Carbon dioxide from metabolism –EtCO 2 measures exhaled CO 2 at point of exit –Reflects change in ventilation within 10 seconds

14. Why Measure Ventilation— Intubated Patients Verify and document ET tube placementVerify and document ET tube placement Immediately detect changes in ET tube positionImmediately detect changes in ET tube position Assess effectiveness of chest compressionsAssess effectiveness of chest compressions Earliest indication of ROSCEarliest indication of ROSC Indicator of probability of successful resuscitationIndicator of probability of successful resuscitation Optimally adjust manual ventilations in patients sensitive to changes in CO 2Optimally adjust manual ventilations in patients sensitive to changes in CO 2

15. Why Measure Ventilation— Non-Intubated Patients Objectively assess acute respiratory disordersObjectively assess acute respiratory disorders –Asthma –COPD Possibly gauge response to treatmentPossibly gauge response to treatment

16. Why Measure Ventilation— Non-intubated Patients Gauge severity of hypoventilation statesGauge severity of hypoventilation states –Drug and ETOH intoxication –Congestive heart failure –Sedation and analgesia –Stroke –Head injury Assess perfusion statusAssess perfusion status Noninvasive monitoring of patients in DKANoninvasive monitoring of patients in DKA

17. Interpreting EtCO 2 and the Capnography Waveform Interpreting EtCO 2Interpreting EtCO 2 –Measuring –Physiology Capnography waveformCapnography waveform

18. End-tidal CO 2 (EtCO 2 ) Ventilation Perfusion Perfusion Pulmonary Blood Flow Right Ventricle Left Atrium

19. End-tidal CO 2 (EtCO 2 ) Carbon dioxide can be measuredCarbon dioxide can be measured Arterial blood gas is PaCO 2Arterial blood gas is PaCO 2 –Normal range: 35-45mmHg Mixed venous blood gas PeCO 2Mixed venous blood gas PeCO 2 –Normal range: 46-48mmHg Exhaled carbon dioxide is EtCO 2Exhaled carbon dioxide is EtCO 2 –Normal range: 35-45mmHg

20. a-A Gradient rr Alveolus PaCO 2 VeinAtey Ventilation Perfusion Perfusion Arterial to Alveolar Difference for CO 2 Right Ventricle Left Atrium EtCO 2

21. End-tidal CO 2 (EtCO 2 ) Normal a-A gradientNormal a-A gradient –2-5mmHg difference between the EtCO 2 and PaCO 2 in a patient with healthy lungs –Wider differences found In abnormal perfusion and ventilationIn abnormal perfusion and ventilation Incomplete alveolar emptyingIncomplete alveolar emptying Poor samplingPoor sampling

22. End-tidal CO 2 (EtCO 2 ) Reflects changes inReflects changes in –Ventilation - movement of air in and out of the lungs –Diffusion - exchange of gases between the air-filled alveoli and the pulmonary circulation –Perfusion - circulation of blood

23. End-tidal CO 2 (EtCO 2 ) Monitors changes inMonitors changes in –Ventilation - asthma, COPD, airway edema, foreign body, stroke –Diffusion - pulmonary edema, alveolar damage, CO poisoning, smoke inhalation –Perfusion - shock, pulmonary embolus, cardiac arrest, severe dysrhythmias

24. Capnographic Waveform Normal waveform of one respiratory cycleNormal waveform of one respiratory cycle Similar to ECGSimilar to ECG –Height shows amount of CO 2 –Length depicts time

25. Capnographic Waveform Waveforms on screen and printout may differ in durationWaveforms on screen and printout may differ in duration –On-screen capnography waveform is condensed to provide adequate information the in 4-second view –Printouts are in real-time –Observe RR on device

26. Capnographic Waveform Capnograph detects only CO 2 from ventilationCapnograph detects only CO 2 from ventilation No CO 2 present during inspirationNo CO 2 present during inspiration –Baseline is normally zero Baseline

27. Capnogram Phase I Dead Space Ventilation Beginning of exhalationBeginning of exhalation No CO 2 presentNo CO 2 present Air from trachea, posterior pharynx, mouth and noseAir from trachea, posterior pharynx, mouth and nose –No gas exchange occurs there –Called “dead space”

28. Capnogram Phase I Baseline Beginning of exhalation A B I Baseline

29. Capnogram Phase II Ascending Phase CO 2 from the alveoli begins to reach the upper airway and mix with the dead space airCO 2 from the alveoli begins to reach the upper airway and mix with the dead space air –Causes a rapid rise in the amount of CO 2 CO 2 now present and detected in exhaled airCO 2 now present and detected in exhaled air

30. Capnogram Phase II Ascending Phase CO 2 present and increasing in exhaled air II A B C Ascending Phase Early Exhalation

31. Capnogram Phase III Alveolar Plateau CO 2 rich alveolar gas now constitutes the majority of the exhaled airCO 2 rich alveolar gas now constitutes the majority of the exhaled air Uniform concentration of CO 2 from alveoli to nose/mouthUniform concentration of CO 2 from alveoli to nose/mouth

32. Capnogram Phase III Alveolar Plateau CO 2 exhalation wave plateaus CO 2 exhalation wave plateaus AB CD III Alveolar Plateau

33. Capnogram Phase III End-Tidal End of exhalation contains the highest concentration of CO 2End of exhalation contains the highest concentration of CO 2 –The “end-tidal CO 2 ” –The number seen on your monitor Normal EtCO 2 is 35-45mmHgNormal EtCO 2 is 35-45mmHg

34. Capnogram Phase III End-Tidal End of the the wave of exhalation AB C D End-tidal

35. Capnogram Phase IV Descending Phase Inhalation beginsInhalation begins Oxygen fills airwayOxygen fills airway CO 2 level quickly drops to zeroCO 2 level quickly drops to zero

36. Capnogram Phase IV Descending Phase Inspiratory downstroke returns to baseline AB CD E IV Descending Phase Inhalation

37. Capnography Waveform Normal range is 35-45mm Hg (5% vol) Normal Waveform

38. Capnography Waveform Question How would your capnogram change if you intentionally started to breathe at a rate of 30?How would your capnogram change if you intentionally started to breathe at a rate of 30? – Frequency – Duration – Height – Shape

39. Hyperventilation RR : EtCO 2 45 0 Normal Hyperventilation

40. Capnography Waveform Question How would your capnogram change if you intentionally decreased your respiratory rate to 8?How would your capnogram change if you intentionally decreased your respiratory rate to 8? –Frequency –Duration –Height –Shape

41. Hypoventilation RR : EtCO 2 Normal Hypoventilation

42. Capnography Waveform Patterns Normal

43. Capnography Waveform Question How would the waveform shape change during an asthma attack?

44. Bronchospasm Waveform Pattern Bronchospasm hampers ventilationBronchospasm hampers ventilation –Alveoli unevenly filled on inspiration –Empty asynchronously during expiration –Asynchronous air flow on exhalation dilutes exhaled CO 2 Alters the ascending phase and plateauAlters the ascending phase and plateau –Slower rise in CO 2 concentration –Characteristic pattern for bronchospasm –“Shark Fin” shape to waveform

45. Capnography Waveform Patterns Normal Bronchospasm

46. Part 2: Introduction to Capnography Summary Oxygenation and ventilationOxygenation and ventilation Pulse oximetryPulse oximetry –Measures O 2 saturation in blood –Slow to indicate change in ventilation CapnographyCapnography –Measures CO 2 in the the airway –Provides a breath-to-breath status of ventilation

47. Part 2: Introduction to Capnography Summary Capnographic waveform has four phasesCapnographic waveform has four phases The highest CO 2 concentration is at the end of alveolar plateauThe highest CO 2 concentration is at the end of alveolar plateau –End-tidal CO 2 –Normal EtCO 2 range is 35-45mmHg Several conditions can be immediately detected with capnographySeveral conditions can be immediately detected with capnography

48. Capnography Waveform Patterns Hypoventilation Normal Bronchospasm Hyperventilation

49. Part 2: Introduction to Capnography We’re off to a running start!