NON-INVASIVE CAPNOGRAPHY - PowerPoint PPT Presentation

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NON-INVASIVE CAPNOGRAPHY

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Title: NON-INVASIVE CAPNOGRAPHY


1
NON-INVASIVE CAPNOGRAPHY
ALS Blue In-Service Part III
2
Oxygenation and Ventilation
  • What is the difference?

3
Oxygenation and Ventilation
Ventilation (capnography)
Oxygenation (oximetry)
O2
Cellular Metabolism
CO2
4
Oximetry and Capnography
  • Pulse oximetry measures oxygenation
  • Capnography measures ventilation and provides a
    graphical waveform available for interpretation

5
Oxygenation
  • Measured by pulse oximetry (SpO2)
  • 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

6
Oxygenation
Pulse Oximetry Sensors
Pulse Oximetry Waveform
7
Ventilation
  • Measured by the end-tidal CO2
  • Partial pressure (mmHg) or volume ( vol) of CO2
    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

8
Ventilation
Capnography Lines
Capnography waveform
9
Oxygenation and Ventilation
  • Oxygenation
  • Oxygen for metabolism
  • SpO2 measures of O2 in RBC
  • Reflects change in oxygenation within 5 minutes
  • Ventilation
  • Carbon dioxide from metabolism
  • EtCO2 measures exhaled CO2 at point of exit
  • Reflects change in ventilation within 10 seconds

10
Oxygenation versus Ventilation
  • Monitor your own SpO2 and EtCO2
  • SpO2 waveform is in the second channel
  • EtCO2 waveform is in the third channel

11
Oxygenation versus Ventilation
  • Now hold your breath
  • Note what happens to
    the two
    waveforms

SpO2
EtCO2
How long did it take the EtCO2 waveform to go
flat line?
How long did it take the SpO2 to drop below 90?
12
  • Numeric reading HR 100
  • Waveform

13
  • Numeric reading HR 100
  • Waveform

14
Capnography in EMS
15
Capnography in EMS
  • Low-flow sidestream technology

16
Using Capnography
  • Immediate information via breath-to-breath
    monitoring
  • Information on the ABCs
  • Airway
  • Breathing
  • Circulation
  • Documentation

17
Using Capnography
  • Airway
  • Verification of ET tube placement
  • Continuous monitoring of ET tube position
  • Circulation
  • Check effectiveness of cardiac compressions
  • First indicator of ROSC
  • Monitor low perfusion states

Airway
Circulation
18
Using Capnography
  • Breathing
  • Hyperventilation
  • Hypoventilation
  • Asthma
  • COPD

19
Using Capnography
  • Documentation
  • Waveforms
  • Initial assessment
  • Changes with treatment
  • EtCO2 values
  • Trends over time

Waveforms
Trends
20
Why Measure VentilationIntubated Patients
  • Verify and document ET tube placement
  • Immediately detect changes in ET tube position
  • Assess effectiveness of chest compressions
  • Earliest indication of ROSC
  • Indicator of probability of successful
    resuscitation
  • Optimally adjust manual ventilations in patients
    sensitive to changes in CO2

21
  • A 2005 study comparing field intubations that
    used capnography to confirm ETT placement vs.
    non-capnography use showed a 0 unrecognized
    misplaced ETT and 23 in the non-EtCO2 monitored
    group
  • Confirm ETI with waveform capnography!!

22
Why Measure VentilationNon-Intubated Patients
  • Objectively assess acute respiratory disorders
  • Asthma
  • COPD
  • Possibly gauge response to treatment

23
Why Measure VentilationNon-intubated Patients
  • Gauge severity of hypoventilation states
  • Drug and ETOH intoxication
  • Congestive heart failure
  • Sedation and analgesia
  • Stroke
  • Head injury
  • Assess perfusion status
  • Noninvasive monitoring of patients in DKA

24
End-tidal CO2 (EtCO2)
Pulmonary Blood Flow
Ventilation
Left Atrium
Right Ventricle
Perfusion
25
a-A Gradient
arterial to Alveolar Difference for CO2
Ventilation
Left Atrium
Right Ventricle
Alveolus
r
r
V
e
i
n
A
t
e
y
EtCO2
PaCO2
Perfusion
26
End-tidal CO2 (EtCO2)
  • Normal a-A gradient
  • 2-5mmHg difference between the EtCO2 and PaCO2
    in a patient with healthy lungs
  • Wider differences found
  • In abnormal perfusion and ventilation
  • Incomplete alveolar emptying
  • Poor sampling

27
End-tidal CO2 (EtCO2)
  • Reflects 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

28
End-tidal CO2 (EtCO2)
  • Monitors 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

29
Physiological Factors Affecting ETCO2 Levels
30
Interpreting EtCO2 and the Capnography Waveform
  • Interpreting EtCO2
  • Measuring
  • Physiology
  • Capnography waveform


31
Capnographic Waveform
  • Normal waveform of one respiratory cycle
  • Similar to ECG
  • Height shows amount of CO2
  • Length depicts time

32
Phase 1
  • First Upstroke of the capnogram waveform
  • Represents of gas exhaled from upper airways
    (I.e. anatomical dead space)

33
Phase 2
  • Transitional Phase from upper to lower airway
    ventilation, and tends to depict changes in
    perfusion

34
Phase 3
  • Represents alveolar gas exchange, which indicates
    changes in gas distribution
  • All increases of the slope of Phase 3 indicates
    increased maldistribution of gas delivery

35
Capnographic Waveform
  • Waveforms 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

36
Capnographic Waveform
  • Capnograph detects only CO2 from ventilation
  • No CO2 present during inspiration
  • Baseline is normally zero

Baseline
37
Capnogram Phase IDead Space Ventilation
  • Beginning of exhalation
  • No CO2 present
  • Air from trachea, posterior pharynx, mouth and
    nose
  • No gas exchange occurs there
  • Called dead space

38
Deadspace
39
Capnogram Phase I Baseline
B
A
I
Baseline
Beginning of exhalation
40
Capnogram Phase IIAscending Phase
  • CO2 from the alveoli begins to reach the upper
    airway and mix with the dead space air
  • Causes a rapid rise in the amount of CO2
  • CO2 now present and detected in exhaled air


41
Capnogram Phase IIAscending Phase
C
Ascending Phase Early Exhalation
II
B
A
CO2 present and increasing in exhaled air
42
Capnogram Phase IIIAlveolar Plateau
  • CO2 rich alveolar gas now constitutes the
    majority of the exhaled air
  • Uniform concentration of CO2 from alveoli to
    nose/mouth

43
Capnogram Phase IIIAlveolar Plateau
Alveolar Plateau
  • CO2 exhalation wave plateaus


44
Capnogram Phase IIIEnd-Tidal
  • End of exhalation contains the highest
    concentration of CO2
  • The end-tidal CO2
  • The number seen on your monitor
  • Normal EtCO2 is 35-45mmHg


45
Capnogram Phase IIIEnd-Tidal
D
C
End-tidal
A
B
  • End of the the wave of exhalation


46
Capnogram Phase IVDescending Phase
  • Inhalation begins
  • Oxygen fills airway
  • CO2 level quickly drops to zero

47
Capnogram Phase IVDescending Phase
C
D
Descending Phase Inhalation
I
V
A
B
E
  • Inspiratory downstroke returns to baseline


48
Capnography Waveform
Normal Waveform
  • Normal range is 35-45mm Hg (5 vol)

49
Capnography Waveform Question
  • How would your capnogram change if you
    intentionally started to breathe at a rate of 30?
  • Frequency
  • Duration
  • Height
  • Shape


50
Hyperventilation
  • RR EtCO2

Normal
Hyperventilation
4
5
0
51
Waveform Regular Shape, Plateau Below Normal
  • Indicates CO2 deficiency
  • Hyperventilation
  • Decreased pulmonary perfusion
  • Hypothermia
  • Decreased metabolism
  • Interventions
  • Adjust ventilation rate
  • Evaluate for adequate sedation
  • Evaluate anxiety
  • Conserve body heat

52
Capnography Waveform Question
  • How would your capnogram change if you
    intentionally decreased your respiratory rate to
    8?
  • Frequency
  • Duration
  • Height
  • Shape

53
Hypoventilation
RR EtCO2

Normal
Hypoventilation

54
Waveform Regular Shape, Plateau Above Normal
  • Indicates increase in ETCO2
  • Hypoventilation
  • Respiratory depressant drugs
  • Increased metabolism
  • Interventions
  • Adjust ventilation rate
  • Decrease respiratory depressant drug dosages
  • Maintain normal body temperature

55
Capnography Waveform Patterns
56
Capnography Waveform Question
  • How would the waveform shape change during an
    asthma attack?

57
Bronchospasm Waveform Pattern
  • Bronchospasm hampers ventilation
  • Alveoli unevenly filled on inspiration
  • Empty asynchronously during expiration
  • Asynchronous air flow on exhalation dilutes
    exhaled CO2
  • Alters the ascending phase and plateau
  • Slower rise in CO2 concentration
  • Characteristic pattern for bronchospasm
  • Shark Fin shape to waveform

58
Capnography Waveform Patterns
Normal
Bronchospasm
59
Capnography Waveform Patterns
Normal
Hyperventilation
Hypoventilation
Bronchospasm
60
The Intubated Patient
61
Confirm ET Tube Placement
4
5
0
62
Detect ET Tube Displacement
  • Capnography
  • Immediately detects ET tube displacement

Source Murray I. P. et. al. 1983. Early
detection of endotracheal tube accidents by
monitoring CO2 concentration in respiratory gas.
Anesthesiology 344-346
63
Detect ET Tube Displacement
  • Only capnography provides
  • Continuous numerical value of EtCO2 with apnea
    alarm after 30 seconds
  • Continuous graphic waveform for immediate visual
    recognition

Source Linko K. et. al. 1983. Capnography for
detection of accidental oesophageal intubation.
Acta Anesthesiol Scand 27 199-202
64
Confirm ET Tube Placement
  • Capnography provides
  • Documentation of correct placement
  • Ongoing documentation over time through the
    trending printout
  • Documentation of correct position at ED arrival

65
Capnography in Cardiopulmonary Resuscitation
  • Assess chest compressions
  • Early detection of ROSC
  • Objective data for decision to cease resuscitation

66
CPR Assess Chest Compressions
  • Use feedback from EtCO2 to depth/rate/force of
    chest compressions during CPR

67
CPR Detect ROSC
  • Briefly stop CPR and check for organized rhythm
    on ECG monitor

68
ETCO2 Cardiac Resuscitation
  • Non-survivors
  • Average ETCO2 4-10 mmHg
  • Survivors (to discharge)
  • Average ETCO2 gt30 mmHg

69
Optimize Ventilation
  • Use capnography to titrate EtCO2 levels in
    patients sensitive to fluctuations
  • Patients with suspected increased intracranial
    pressure (ICP)
  • Head trauma
  • Stroke
  • Brain tumors
  • Brain infections

70
Optimize Ventilation
  • High CO2 levels induce cerebral vasodilatation
  • Positive Increases CBF to counter cerebral
    hypoxia
  • Negative Increased CBF, increases ICP and may
    increase brain edema
  • Hypoventilation retains CO2 which increases levels

CO2
71
Optimize Ventilation
  • Low CO2 levels lead to cerebral vasoconstriction
  • Positive EtCO2 of 25-30mmHG causes a mild
    cerebral vasoconstriction which may decrease ICP
  • Negative Decreased ICP but may cause or
    increase in cerebral hypoxia
  • Hyperventilation decreases CO2 levels

CO2
72
Optimize Ventilation
  • Treatment goals
  • Avoid cerebral hypoxia
  • Monitor blood oxygen levels with pulse oximetry
  • Maintain adequate CBF
  • Target EtCO2 of 35 mmHg

73
The Non-intubated Patient
CC trouble breathing
74
The Non-intubated Patient CC trouble
breathing
PE?
Asthma?
Emphysema?
Bronchitis?
Pneumonia?
Cardiac ischemia?
CHF?
75
The Non-intubated Patient Capnography
Applications
  • Identify and monitor bronchospasm
  • Asthma
  • COPD
  • Assess and monitor
  • Hypoventilation states
  • Hyperventilation
  • Low-perfusion states

76
Capnography in Bronchospastic Conditions
  • Air trapped due to irregularities in airways
  • Uneven emptying of alveolar gas
  • Dilutes exhaled CO2
  • Slower rise in CO2 concentration during
    exhalation

A
l
v
e
o
l
i
77
Capnography in Bronchospastic Diseases
  • Uneven emptying of alveolar gas alters emptying
    on exhalation
  • Produces changes in ascending phase (II) with
    loss of the sharp upslope
  • Alters alveolar plateau (III) producing a shark
    fin

78
Capnography in Bronchospastic ConditionsCapnogram
of Asthma
Changes in dCO2/dt seen with increasing
bronchospasm
Source Krauss B., et al. 2003. FEV1 in
Restrictive Lung Disease Does Not Predict the
Shape of the Capnogram. Oral presentation. Annual
Meeting, American Thoracic Society, May, Seattle,
WA
79
Capnography in Bronchospastic ConditionsAsthma
Case Scenario
Initial
After therapy
80
Capnography in Bronchospastic ConditionsPathology
of COPD
  • Progressive
  • Partially reversible
  • Airways obstructed
  • Hyperplasia of mucous glands
    and smooth muscle
  • Excess mucous production
  • Some hyper-responsiveness

81
Capnography in Bronchospastic ConditionsCapnograp
hy in COPD
  • Arterial CO2 in COPD
  • PaCO2 increases as disease progresses
  • Requires frequent arterial punctures for ABGs
  • Correlating capnograph to patient status
  • Ascending phase and plateau are altered by uneven
    emptying of gases

82
Capnography in Bronchospastic ConditionsCOPD
Case Scenario
Initial Capnogram A
Initial Capnogram B
83
Capnography in CHFCase Scenario
  • 88 year old male
  • C/O Short of breath
  • H/O MI X 2, on oxygen at 2 L/m
  • Pulse 66, BP 164/86, RR 36 labored and shallow,
    skin cool and diaphoretic, 2 pedal edema
  • Initial SpO2 69 EtCO2 17mmHG

84
Capnography in CHFCase Scenario
  • Placed on non-rebreather mask with 100 oxygen at
    15 L/m and aggressive SL nitroglycerin as per
    protocol
  • Ten minutes after treatment
  • SpO2 69 99
  • EtCO2 17mmHG 35 mmHG

Time condensed to show changes
85
Capnography in Hypoventilation States
  • Altered mental status
  • Sedation
  • Alcohol intoxication
  • Drug Ingestion
  • Stroke
  • CNS infections
  • Head injury
  • Abnormal breathing
  • CO2 retention
  • EtCO2 gt50mmHg

86
Capnography in Hypoventilation States
Time condensed actual rate is slower
  • EtCO2 is above 50mmHG
  • Box-like waveform shape is unchanged

87
Capnography in Hypoventilation States
Hypoventilation
Time condensed actual rate is slower

88
Capnography in Hypoventilation States
Hypoventilation
  • Hypoventilation in shallow breathing

89
Capnography in Low Perfusion
  • Capnography reflects changes in
  • Perfusion
  • Pulmonary blood flow
  • Systemic perfusion
  • Cardiac output

90
Capnography in Low PerfusionCase Scenario
  • 57 year old male
  • Motor vehicle crash with injury to chest
  • History of atrial fib, anticoagulant
  • Unresponsive
  • Pulse 100 irregular, BP 88/p
  • Intubated on scene

91
Capnography in Low PerfusionCase Scenario
Low EtCO2 seen in low cardiac output
Ventilation controlled
92
Capnography in Pulmonary EmbolusCase Scenario
Strong radial pulse Low EtCO2 seen in decreased
alveolar perfusion
93
Capnography in Rebreathing Circumstances
Elevated Baseline
4
5
0
  • Baseline elevation
  • Oxygen mask
  • Poor head and neck alignment
  • Shallow breathing not clearing deadspace

94
Capnography in DKACase Scenario
Rapid rate, normal waveform and elevated EtCO2
seen in early respiratory compensation in DKA
Source Flanagan, J.F., et al. 1995. Noninvasive
monitoring of end-tidal carbon dioxide tension
via nasal cannulas in spontaneously breathing
children with profound hypocarbia. Critical Care
Medicine. June 23 (6) 1140-1142
95
Capnography Applicationson Non-intubated Patients
  • New applications now being reported
  • Pulmonary emboli
  • CHF
  • DKA
  • Bioterrorism
  • Others?

96
Quiz Time!
97
Sudden Loss of Waveform
  • Apnea
  • Airway Obstruction
  • Dislodged airway (esophageal)
  • Airway disconnection
  • Ventilator malfunction
  • Cardiac Arrest

98
Increase in ETCO2
  • Possible causes
  • Decrease in respiratory rate (Hypoventilation)
  • Decrease in tidal volume
  • Increase in metabolic rate
  • Rapid rise in body temperature (hyperthermia)

99
Esophageal Tube
  • A normal capnogram is the best evidence that the
    ETT is correctly positioned
  • With an esophageal tube little or no CO2 is
    present

100
Rebreathing
  • Possible causes
  • Faulty expiratory valve
  • Inadequate inspiratory flow
  • Insufficient expiratory flow

101
Inadequate Seal Around ETT
  • Possible causes
  • Leaky or deflated endotracheal or tracheostomy
    cuff
  • Artificial airway too small for the patient

102
Decrease in ETCO2
  • Possible causes
  • Increase in respiratory rate (Hyperventilation)
  • Increase in tidal volume
  • Decrease in metabolic rate
  • Fall in body temperature (hypothermia)

103
Obstruction
  • Possible causes
  • Partially kinked or occluded artificial airway
  • Presence of foreign body in the airway
  • Obstruction in expiratory limb of the breathing
    circuit
  • Bronchospasm

104
Muscle Relaxants
  • Curare Cleft
  • Appears when muscle relaxants begin to subside
  • Depth of cleft is inversely proportional to
    degree of drug activity

105
You Survived!
  • Thanks!
  • Questions to me via groupwise
  • jcushman_at_co.ho.md.us
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