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NON-INVASIVE CNON-INVASIVE CAAPNOGRAPHYPNOGRAPHY
ALS Blue In-Service
Part III
Oxygenation and VentilationOxygenation and Ventilation
What is the difference?What is the difference?
Oxygenation and VentilationOxygenation and Ventilation
OxygenationOxygenation(oximetry(oximetry))
CellularCellularMetabolismMetabolism
VentilationVentilation(capnography)(capnography)
COCO22
OO22
Oximetry and CapnographyOximetry and Capnography
• Pulse oximetry measures oxygenationPulse oximetry measures oxygenation
• Capnography measures ventilation and Capnography measures ventilation and provides a graphical waveform available provides a graphical waveform available for interpretationfor interpretation
OxygenationOxygenation
• Measured by pulse oximetry (SpOMeasured by pulse oximetry (SpO22) ) – Noninvasive measurementNoninvasive measurement– Percentage of oxygen in red blood cells Percentage of oxygen in red blood cells – Changes in ventilation take minutes Changes in ventilation take minutes
to be detected to be detected – Affected by motion artifact, poor perfusion Affected by motion artifact, poor perfusion
and some dysrhythmiasand some dysrhythmias
OxygenationOxygenation
Pulse OximetryPulse Oximetry SensorsSensors
Pulse Oximetry WaveformPulse Oximetry Waveform
VentilationVentilation
• Measured by the end-tidal COMeasured by the end-tidal CO22
– Partial pressure (mmHg) or volume (% vol) of Partial pressure (mmHg) or volume (% vol) of COCO22 in the airway at the end of exhalation in the airway at the end of exhalation
– Breath-to-breath measurement provides Breath-to-breath measurement provides information within secondsinformation within seconds
– Not affected by motion artifact, poor perfusion Not affected by motion artifact, poor perfusion or dysrhythmiasor dysrhythmias
VentilationVentilation
Capnography waveformCapnography waveform
Capnography Capnography LinesLines
Oxygenation and VentilationOxygenation and Ventilation
• OxygenationOxygenation– Oxygen for Oxygen for
metabolismmetabolism
– SpOSpO22 measures measures
% of O% of O22 in RBC in RBC
– Reflects change in Reflects change in oxygenation within oxygenation within 5 minutes5 minutes
• VentilationVentilation– Carbon dioxide Carbon dioxide
from metabolismfrom metabolism
– EtCOEtCO22 measures measures
exhaled COexhaled CO22 at at
point of exitpoint of exit– Reflects change in Reflects change in
ventilation within ventilation within 10 seconds10 seconds
Oxygenation versus VentilationOxygenation versus Ventilation
• Monitor your own Monitor your own SpOSpO22 and EtCO and EtCO22
• SpOSpO22 waveform is in waveform is in the second channelthe second channel
• EtCOEtCO22 waveform is waveform is in the third channelin the third channel
Capnography in EMSCapnography in EMS
Capnography in EMSCapnography in EMS
Low-flow sidestream technologyLow-flow sidestream technology
Using CapnographyUsing Capnography
• Immediate information via Immediate information via breath-to-breath monitoring breath-to-breath monitoring
• Information on the ABCsInformation on the ABCs– AirwayAirway– BreathingBreathing– CirculationCirculation
• DocumentationDocumentation
Using CapnographyUsing Capnography
• AirwayAirway– Verification of ET tube Verification of ET tube
placementplacement– Continuous monitoring of Continuous monitoring of
ET tube positionET tube position
• CirculationCirculation– Check effectiveness of Check effectiveness of
cardiac compressionscardiac compressions– First indicator of ROSCFirst indicator of ROSC– Monitor low perfusion statesMonitor low perfusion states
AirwayAirway
CirculationCirculation
Using CapnographyUsing Capnography
• BreathingBreathing–– HyperventilationHyperventilation
–– HypoventilationHypoventilation
–– AsthmaAsthma
–– COPD COPD
Using CapnographyUsing Capnography
• DocumentationDocumentation– WaveformsWaveforms
• Initial assessmentInitial assessment• Changes with treatmentChanges with treatment
– EtCOEtCO22 values values
• Trends over timeTrends over time
WaveformsWaveforms
TrendsTrends
Why Measure VentilationWhy Measure Ventilation——Intubated PatientsIntubated 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 Indicator of probability of successful
resuscitationresuscitation• Optimally adjust manual ventilations in patients Optimally adjust manual ventilations in patients
sensitive to changes in COsensitive to changes in CO22
Why Measure VentilationWhy Measure Ventilation——Non-Intubated PatientsNon-Intubated Patients
• Objectively assess acute Objectively assess acute respiratory disorders respiratory disorders – Asthma Asthma – COPDCOPD
• Possibly gauge response to treatmentPossibly gauge response to treatment
Why Measure Ventilation—Why Measure Ventilation—Non-intubated PatientsNon-intubated Patients
• Gauge severity of hypoventilation statesGauge severity of hypoventilation states– Drug and ETOH intoxicationDrug and ETOH intoxication– Congestive heart failureCongestive heart failure– Sedation and analgesiaSedation and analgesia– Stroke Stroke – Head injury Head injury
• Assess perfusion statusAssess perfusion status• Noninvasive monitoring of patients in DKANoninvasive monitoring of patients in DKA
End-tidal COEnd-tidal CO2 2 (EtCO(EtCO22))
r r Oxygen
O2
CO2O
2
VeinA te y
VentilationVentilation
PerfusionPerfusion
Pulmonary Blood Flow
Right Ventricle
LeftAtrium
a-A Gradienta-A Gradient
r r Alveolus
PaCO2
VeinA te y
VentilationVentilation
PerfusionPerfusion
arterial to Alveolar Difference for CO2
Right Ventricle
LeftAtrium
EtCO2
End-tidal COEnd-tidal CO22 (EtCO (EtCO22))
• Normal a-A gradientNormal a-A gradient– 2-5mmHg difference between the EtCO2-5mmHg difference between the EtCO22
and PaCOand PaCO22 in a patient with healthy lungs in a patient with healthy lungs
– Wider differences found Wider differences found • In abnormal perfusion and ventilation In abnormal perfusion and ventilation • Incomplete alveolar emptyingIncomplete alveolar emptying• Poor samplingPoor sampling
End-tidal COEnd-tidal CO2 2 (EtCO(EtCO22))
• Reflects changes inReflects changes in – VentilationVentilation - movement of air in and - movement of air in and
out of the lungsout of the lungs– DiffusionDiffusion - exchange of gases between - exchange of gases between
the air-filled alveoli and the pulmonary the air-filled alveoli and the pulmonary circulationcirculation
– Perfusion Perfusion - circulation of blood- circulation of blood
End-tidal COEnd-tidal CO2 2 (EtCO(EtCO22))
• Monitors changes in Monitors changes in – VentilationVentilation - asthma, COPD, airway - asthma, COPD, airway
edema, foreign body, strokeedema, foreign body, stroke– Diffusion Diffusion - pulmonary edema, - pulmonary edema,
alveolar damage, CO poisoning, alveolar damage, CO poisoning, smoke inhalationsmoke inhalation
– PerfusionPerfusion - shock, pulmonary - shock, pulmonary embolus, cardiac arrest, embolus, cardiac arrest, severe dysrhythmiassevere dysrhythmias
Physiological Factors Affecting ETCOPhysiological Factors Affecting ETCO2 2
LevelsLevels
Interpreting EtCOInterpreting EtCO22 and the and the Capnography WaveformCapnography Waveform
• Interpreting EtCOInterpreting EtCO22 – MeasuringMeasuring– PhysiologyPhysiology
• Capnography waveformCapnography waveform
Capnographic WaveformCapnographic Waveform
• Normal waveform of one respiratory cycleNormal waveform of one respiratory cycle• Similar to ECGSimilar to ECG
– Height shows amount of COHeight shows amount of CO22
– Length depicts timeLength depicts time
Phase 1Phase 1
• First Upstroke of the capnogram First Upstroke of the capnogram waveformwaveform
• Represents of gas exhaled from upper Represents of gas exhaled from upper airways (I.e. anatomical dead space)airways (I.e. anatomical dead space)
Phase 2Phase 2
• Transitional Phase from upper to lower Transitional Phase from upper to lower airway ventilation, and tends to depict airway ventilation, and tends to depict changes in perfusionchanges in perfusion
Phase 3Phase 3
• Represents alveolar gas exchange, which Represents alveolar gas exchange, which indicates changes in gas distributionindicates changes in gas distribution
• All increases of the slope of Phase 3 All increases of the slope of Phase 3 indicates increased maldistribution of gas indicates increased maldistribution of gas deliverydelivery
Capnographic WaveformCapnographic Waveform
• Waveforms on screen and printout Waveforms on screen and printout may differ in durationmay differ in duration– On-screen capnography waveform is On-screen capnography waveform is
condensed to provide adequate information condensed to provide adequate information the in 4-second viewthe in 4-second view
– Printouts are in real-timePrintouts are in real-time– Observe RR on deviceObserve RR on device
Capnographic WaveformCapnographic Waveform
• Capnograph detects only COCapnograph detects only CO22 from ventilationfrom ventilation
• No CONo CO22 present during inspiration present during inspiration– Baseline is normally zeroBaseline is normally zero
A B
C D
E
BaselineBaseline
Capnogram Phase ICapnogram Phase IDead Space VentilationDead Space Ventilation
• Beginning of exhalationBeginning of exhalation
• No CONo CO22 present present
• Air from trachea, Air from trachea, posterior pharynx, posterior pharynx, mouth and nosemouth and nose– No gas exchange No gas exchange
occurs thereoccurs there– Called “dead space”Called “dead space”
DeadspaceDeadspace
Capnogram Phase I Capnogram Phase I BaselineBaseline
Beginning of exhalationBeginning of exhalation
A B
I BaselineBaseline
Capnogram Phase IICapnogram Phase IIAscending PhaseAscending Phase
• COCO22 from the alveoli from the alveoli
begins to reach the upper begins to reach the upper airway and mix with the airway and mix with the dead space air dead space air – Causes a rapid rise in the Causes a rapid rise in the
amount of COamount of CO22
• COCO22 now present and now present and
detected in exhaled airdetected in exhaled air
Alveoli
Capnogram Phase IICapnogram Phase IIAscending PhaseAscending Phase
COCO22 present and increasing in exhaled air present and increasing in exhaled air
II
A B
C
Ascending PhaseAscending PhaseEarly ExhalationEarly Exhalation
Capnogram Phase IIICapnogram Phase IIIAlveolar PlateauAlveolar Plateau
• COCO22 rich alveolar gas rich alveolar gas now constitutes the now constitutes the majority of the majority of the exhaled air exhaled air
• Uniform concentration Uniform concentration of COof CO22 from alveoli to from alveoli to
nose/mouthnose/mouth
Capnogram Phase IIICapnogram Phase IIIAlveolar PlateauAlveolar Plateau
COCO22 exhalation wave plateaus exhalation wave plateaus
A B
C D
III
Alveolar PlateauAlveolar Plateau
Capnogram Phase IIICapnogram Phase IIIEnd-TidalEnd-Tidal
• End of exhalation contains the highest End of exhalation contains the highest concentration of COconcentration of CO22 – The “end-tidal COThe “end-tidal CO22””
– The number seen on your monitorThe number seen on your monitor
• Normal EtCONormal EtCO2 2 is 35-45mmHgis 35-45mmHg
Capnogram Phase IIICapnogram Phase IIIEnd-TidalEnd-Tidal
End of the the wave of exhalationEnd of the the wave of exhalation
A B
C D End-tidal
Capnogram Phase IVCapnogram Phase IVDescending PhaseDescending Phase
• Inhalation beginsInhalation begins• Oxygen fills airwayOxygen fills airway
• COCO22 level quickly level quickly
drops to zerodrops to zero
Alveoli
Capnogram Phase IVCapnogram Phase IVDescending PhaseDescending Phase
Inspiratory downstroke returns to baselineInspiratory downstroke returns to baseline
A B
C D
EIV
Descending Phase Descending Phase InhalationInhalation
Capnography WaveformCapnography Waveform
Normal range is 35-45mm Hg (5% vol)Normal range is 35-45mm Hg (5% vol)
Normal WaveformNormal Waveform
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0
Capnography Waveform QuestionCapnography Waveform Question
• How would your capnogram change How would your capnogram change if you intentionally started to breathe if you intentionally started to breathe at a rate of 30?at a rate of 30?– FrequencyFrequency– DurationDuration– HeightHeight– ShapeShape
45
0
HyperventilationHyperventilation
RR : EtCORR : EtCO22
45
0
NormalNormal
HyperventilationHyperventilation
Waveform: Waveform: Regular Shape, Plateau Regular Shape, Plateau BelowBelow Normal Normal
• Indicates COIndicates CO22 deficiency deficiency HyperventilationHyperventilation
Decreased pulmonary perfusionDecreased pulmonary perfusion
HypothermiaHypothermia
Decreased metabolismDecreased metabolism
• InterventionsInterventions Adjust ventilation rateAdjust ventilation rate
Evaluate for adequate sedationEvaluate for adequate sedation
Evaluate anxietyEvaluate anxiety
ConserveConserve body heat body heat
Capnography Waveform QuestionCapnography Waveform Question
• How would your capnogram change How would your capnogram change if you intentionally decreased your if you intentionally decreased your respiratory rate to 8?respiratory rate to 8?– FrequencyFrequency– DurationDuration– HeightHeight– ShapeShape
HypoventilationHypoventilation
45
0
45
0
RR : EtCORR : EtCO22
NormalNormal
HypoventilationHypoventilation
Waveform: Waveform: Regular Shape, PlateauRegular Shape, Plateau AboveAbove NormalNormal
• Indicates increase in ETCOIndicates increase in ETCO22 HypoventilationHypoventilation
Respiratory depressant drugsRespiratory depressant drugs
Increased metabolismIncreased metabolism
• InterventionsInterventions Adjust ventilation rateAdjust ventilation rate
Decrease respiratory depressant drug dosagesDecrease respiratory depressant drug dosages
Maintain normal body temperatureMaintain normal body temperature
Capnography Waveform PatternsCapnography Waveform Patterns
0
45
HypoventilationHypoventilation
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0
HyperventilationHyperventilation
45
0
NormalNormal
Capnography Waveform QuestionCapnography Waveform Question
How would the waveform How would the waveform shape change during an shape change during an asthma attack?asthma attack?
Bronchospasm Waveform PatternBronchospasm Waveform Pattern
• Bronchospasm hampers ventilationBronchospasm hampers ventilation– Alveoli unevenly filled on inspiration Alveoli unevenly filled on inspiration – Empty asynchronously during expirationEmpty asynchronously during expiration– Asynchronous air flow on exhalation dilutes exhaled Asynchronous air flow on exhalation dilutes exhaled
COCO22
• AltersAlters the ascending phase and plateauthe ascending phase and plateau– Slower rise inSlower rise in COCO2 2 concentration concentration
– Characteristic pattern for bronchospasmCharacteristic pattern for bronchospasm– ““Shark Fin” shape to waveformShark Fin” shape to waveform
Capnography Waveform Patterns Capnography Waveform Patterns
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NormaNormall
BronchospasmBronchospasm45
0
Capnography Waveform PatternsCapnography Waveform Patterns
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0
HypoventilationHypoventilation
NormalNormal
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0
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0
BronchospasmBronchospasm
HyperventilationHyperventilation
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0
The Intubated PatientThe Intubated Patient
Confirm ET Tube PlacementConfirm ET Tube Placement
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0
Detect ET Tube DisplacementDetect ET Tube Displacement
• CapnographyCapnography– Immediately detects Immediately detects
ET tube displacementET tube displacement
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0Hypopharyngeal Dislodgement
Source: Murray I. P. et. al. 1983. Early detection of endotracheal tube accidents by monitoring CO2 concentration in respiratory gas. Anesthesiology 344-346
Detect ET Tube DisplacementDetect ET Tube Displacement
• Only capnography provides Only capnography provides – Continuous numerical value of EtCOContinuous numerical value of EtCO22 with with
apnea alarm after 30 secondsapnea alarm after 30 seconds– Continuous graphic waveform for immediate Continuous graphic waveform for immediate
visual recognitionvisual recognition
45
0
Esophageal Dislodgement
Source: Linko K. et. al. 1983. Capnography for detection of accidental oesophageal intubation. Acta Anesthesiol Scand 27: 199-202
Confirm ET Tube PlacementConfirm ET Tube Placement
• Capnography providesCapnography provides– Documentation of Documentation of
correct placementcorrect placement– Ongoing documentation Ongoing documentation
over time through the over time through the trending printouttrending printout
– Documentation of Documentation of correct position at correct position at ED arrivalED arrival
Capnography in Capnography in Cardiopulmonary ResuscitationCardiopulmonary Resuscitation
• Assess chest compressionsAssess chest compressions• Early detection Early detection
of ROSCof ROSC• Objective data for decision Objective data for decision
to cease resuscitationto cease resuscitation
CPR: Assess Chest CompressionsCPR: Assess Chest Compressions
• Use feedback from Use feedback from EtCOEtCO22 to depth/rate/ to depth/rate/force of chest force of chest compressions compressions during CPRduring CPR
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0
CPR: Detect ROSCCPR: Detect ROSC
• Briefly stop CPR and Briefly stop CPR and check for organized check for organized rhythm on ECG monitorrhythm on ECG monitor
45
0
ETCOETCO22 & Cardiac Resuscitation & Cardiac Resuscitation
• Non-survivorsNon-survivors– Average ETCOAverage ETCO22: : 4-10 mmHg4-10 mmHg
• Survivors (to discharge)Survivors (to discharge)– Average ETCOAverage ETCO22: : >30 mmHg>30 mmHg
Optimize VentilationOptimize Ventilation
• Use capnography to titrate EtCOUse capnography to titrate EtCO22 levels levels in patients sensitive to fluctuationsin patients sensitive to fluctuations
• Patients with suspected increased Patients with suspected increased intracranial pressure (ICP)intracranial pressure (ICP)– Head traumaHead trauma– StrokeStroke– Brain tumorsBrain tumors– Brain infectionsBrain infections
Optimize Ventilation Optimize Ventilation
• High COHigh CO22 levels induce levels induce cerebral vasodilatationcerebral vasodilatation– Positive: Increases CBF to Positive: Increases CBF to
counter cerebral hypoxiacounter cerebral hypoxia– Negative: Increased CBF, Negative: Increased CBF,
increases ICP and may increase increases ICP and may increase brain edema brain edema
• Hypoventilation retains COHypoventilation retains CO22 which increases levelswhich increases levels
COCO22
Optimize Ventilation Optimize Ventilation
• Low COLow CO22 levels lead to cerebral levels lead to cerebral vasoconstrictionvasoconstriction– Positive: EtCOPositive: EtCO22 of 25-30mmHG of 25-30mmHG
causes a mild cerebral causes a mild cerebral vasoconstriction which may vasoconstriction which may decrease ICPdecrease ICP
– Negative: Decreased ICP but Negative: Decreased ICP but may cause or increase in may cause or increase in cerebral hypoxiacerebral hypoxia
• Hyperventilation decreases Hyperventilation decreases COCO22 levels levels
COCO22
Optimize VentilationOptimize Ventilation
• Treatment goalsTreatment goals• Avoid cerebral hypoxia Avoid cerebral hypoxia
– Monitor blood oxygen Monitor blood oxygen levels with pulse oximetry levels with pulse oximetry
– Maintain adequate CBF Maintain adequate CBF
• Target EtCOTarget EtCO22 of 35 mmHg of 35 mmHg
The Non-intubated PatientThe Non-intubated Patient
CC: CC: ““trouble breathing”trouble breathing”
The Non-intubated Patient The Non-intubated Patient CC: “trouble breathing”CC: “trouble breathing”
Asthma?
Asthma? Emphysema?
Emphysema?
Pneumonia?Pneumonia?Bronchitis?Bronchitis?
CHF?CHF?
PE?PE?
Cardiac ischemia?Cardiac ischemia?
The Non-intubated Patient The Non-intubated Patient Capnography ApplicationsCapnography Applications
• Identify and monitor bronchospasmIdentify and monitor bronchospasm– AsthmaAsthma– COPDCOPD
• Assess and monitor Assess and monitor – Hypoventilation statesHypoventilation states– HyperventilationHyperventilation– Low-perfusion statesLow-perfusion states
Capnography in Capnography in Bronchospastic ConditionsBronchospastic Conditions
• Air trapped due to Air trapped due to irregularities in airwaysirregularities in airways
• Uneven emptying of Uneven emptying of alveolar gas alveolar gas – Dilutes exhaled CODilutes exhaled CO22
– Slower rise inSlower rise in COCO2 2
concentration during concentration during exhalationexhalation
Alveoli
Capnography in Capnography in Bronchospastic DiseasesBronchospastic Diseases
• Uneven emptying of Uneven emptying of alveolar gas alters alveolar gas alters emptying on exhalationemptying on exhalation
• Produces changes in Produces changes in ascending phase (II) ascending phase (II) with loss of the sharp with loss of the sharp upslopeupslope
• Alters alveolar plateau Alters alveolar plateau (III) producing a “shark fin”(III) producing a “shark fin”
A B
C D
EII
III
Capnography in Bronchospastic ConditionsCapnography in Bronchospastic Conditions
Capnogram of AsthmaCapnogram of Asthma
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
Changes in dCOChanges in dCO22/dt seen with increasing bronchospasm/dt seen with increasing bronchospasm
Bronchospasm
Normal
Capnography in Bronchospastic ConditionsCapnography in Bronchospastic Conditions
AsthmaAsthma Case ScenarioCase Scenario
Initial Initial
After therapyAfter therapy
Capnography in Bronchospastic ConditionsCapnography in Bronchospastic Conditions
Pathology of COPDPathology of COPD
• Progressive Progressive • Partially reversiblePartially reversible• Airways obstructedAirways obstructed
– Hyperplasia of mucous glands Hyperplasia of mucous glands and smooth muscleand smooth muscle
– Excess mucous productionExcess mucous production– Some hyper-responsivenessSome hyper-responsiveness
Capnography in Bronchospastic ConditionsCapnography in Bronchospastic Conditions
Capnography in COPDCapnography in COPD
• Arterial COArterial CO22 in COPD in COPD– PaCOPaCO22 increases as disease progresses increases as disease progresses
– Requires frequent arterial punctures for ABGsRequires frequent arterial punctures for ABGs
• Correlating capnograph to patient statusCorrelating capnograph to patient status– Ascending phase and plateau are altered by Ascending phase and plateau are altered by
uneven emptying of gasesuneven emptying of gases
Capnography in Bronchospastic ConditionsCapnography in Bronchospastic Conditions
COPD Case ScenarioCOPD Case Scenario
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0
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0
Initial Capnogram AInitial Capnogram A
Initial Capnogram BInitial Capnogram B
Capnography in CHFCapnography in CHF
Case ScenarioCase Scenario
• 88 year old male 88 year old male • C/O: Short of breathC/O: Short of breath• H/O: MI X 2, on oxygen at 2 L/mH/O: MI X 2, on oxygen at 2 L/m• Pulse 66, BP 164/86, RR 36 labored and Pulse 66, BP 164/86, RR 36 labored and
shallow, skin cool and diaphoretic, shallow, skin cool and diaphoretic, 2+ pedal edema2+ pedal edema
• Initial SpOInitial SpO22 69%; EtCO 69%; EtCO22 17mmHG 17mmHG
Capnography in CHFCapnography in CHF
Case ScenarioCase Scenario
• Placed on non-rebreather mask with 100% Placed on non-rebreather mask with 100% oxygen at 15 L/m and aggressive SL nitroglycerin oxygen at 15 L/m and aggressive SL nitroglycerin as per protocolas per protocol
• Ten minutes after treatment:Ten minutes after treatment:
SpOSpO22 69% 99% 69% 99%
EtCOEtCO22 17mmHG 35 mmHG 17mmHG 35 mmHG
4 5
3 5
0
2 5
Time condensed Time condensed to show changesto show changes
Capnography in Capnography in Hypoventilation StatesHypoventilation States
• Altered mental statusAltered mental status– SedationSedation– Alcohol intoxicationAlcohol intoxication– Drug IngestionDrug Ingestion– StrokeStroke– CNS infectionsCNS infections– Head injuryHead injury
• Abnormal breathing Abnormal breathing
• COCO22 retention retention – EtCOEtCO22 >50mmHg >50mmHg
Capnography in Capnography in Hypoventilation StatesHypoventilation States
• EtCOEtCO22 is above 50mmHG is above 50mmHG
• Box-like waveform shape is unchangedBox-like waveform shape is unchanged
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0
Time condensed; actual rate is slowerTime condensed; actual rate is slower
Capnography in Hypoventilation StatesCapnography in Hypoventilation States HypoventilationHypoventilation
45
35
0
25
55
65
Time condensed; actual rate is slowerTime condensed; actual rate is slower
Capnography in Hypoventilation StatesCapnography in Hypoventilation States HypoventilationHypoventilation
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Hypoventilation in shallow Hypoventilation in shallow breathingbreathing
Capnography in Low PerfusionCapnography in Low Perfusion
• Capnography reflects changes in Capnography reflects changes in • PerfusionPerfusion
– Pulmonary blood flow Pulmonary blood flow – Systemic perfusionSystemic perfusion– Cardiac outputCardiac output
Capnography in Low PerfusionCapnography in Low Perfusion
Case ScenarioCase Scenario
• 57 year old male 57 year old male • Motor vehicle crash with injury to chestMotor vehicle crash with injury to chest• History of atrial fib, anticoagulantHistory of atrial fib, anticoagulant• UnresponsiveUnresponsive• Pulse 100 irregular, BP 88/pPulse 100 irregular, BP 88/p• Intubated on sceneIntubated on scene
Capnography in Low PerfusionCapnography in Low Perfusion
Case ScenarioCase Scenario
45
35
0
25
Low EtCOLow EtCO22 seen in seen in
low cardiac outputlow cardiac output
Ventilation controlledVentilation controlled
Capnography in Pulmonary EmbolusCapnography in Pulmonary Embolus
Case ScenarioCase Scenario
45
35
0
25
Strong radial pulseStrong radial pulse
Low EtCOLow EtCO22 seen in seen in
decreased alveolar perfusiondecreased alveolar perfusion
Capnography in Rebreathing CircumstancesCapnography in Rebreathing Circumstances Elevated Baseline Elevated Baseline
Baseline elevationBaseline elevation
• Oxygen maskOxygen mask
• Poor head and neck alignmentPoor head and neck alignment
• Shallow breathing – not clearing deadspaceShallow breathing – not clearing deadspace
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0
Capnography in DKACapnography in DKA
Case ScenarioCase Scenario
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0
Rapid rate, normal waveformRapid rate, normal waveformand elevated EtCOand elevated EtCO22 seen seen
in early respiratory in early respiratory compensation in DKAcompensation 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
Capnography ApplicationsCapnography Applicationson Non-intubated Patientson Non-intubated Patients
• New applications now being reportedNew applications now being reported– Pulmonary emboliPulmonary emboli– CHFCHF– DKADKA– BioterrorismBioterrorism– Others? Others?
r r O xy g e n
O 2
V e inA t e y
Quiz Time!Quiz Time!
Sudden Loss of WaveformSudden Loss of Waveform
ApneaApnea
Airway ObstructionAirway Obstruction
Dislodged airway (esophageal)Dislodged airway (esophageal)
Airway disconnectionAirway disconnection
Ventilator malfunctionVentilator malfunction
Cardiac ArrestCardiac Arrest
Increase in ETCOIncrease in ETCO22
• Possible causes:Possible causes: Decrease in respiratory rate (Hypoventilation)Decrease in respiratory rate (Hypoventilation) Decrease in tidal volumeDecrease in tidal volume Increase in metabolic rateIncrease in metabolic rate Rapid rise in body temperature (hyperthermia)Rapid rise in body temperature (hyperthermia)
Esophageal TubeEsophageal Tube
• A normal capnogram is the best evidence that the A normal capnogram is the best evidence that the ETT is correctly positionedETT is correctly positioned
• With an esophageal tube little or no COWith an esophageal tube little or no CO2 2 is is
presentpresent
RebreathingRebreathing
• Possible causes:Possible causes: Faulty expiratory valveFaulty expiratory valve Inadequate inspiratory flowInadequate inspiratory flow Insufficient expiratory flowInsufficient expiratory flow
Inadequate Seal Around ETTInadequate Seal Around ETT
• Possible causes:Possible causes:Leaky or deflated endotracheal or Leaky or deflated endotracheal or
tracheostomy cufftracheostomy cuffArtificial airway too small for the patientArtificial airway too small for the patient
Decrease in ETCODecrease in ETCO22
• Possible causes:Possible causes: Increase in respiratory rate (Hyperventilation)Increase in respiratory rate (Hyperventilation) Increase in tidal volumeIncrease in tidal volume Decrease in metabolic rateDecrease in metabolic rate Fall in body temperature (hypothermia)Fall in body temperature (hypothermia)
ObstructionObstruction
• Possible causes:Possible causes: Partially kinked or occluded artificial airwayPartially kinked or occluded artificial airway Presence of foreign body in the airwayPresence of foreign body in the airway Obstruction in expiratory limb of the breathing circuitObstruction in expiratory limb of the breathing circuit BronchospasmBronchospasm
Muscle RelaxantsMuscle Relaxants
• ““Curare Cleft”:Curare Cleft”: Appears when muscle relaxants begin to subsideAppears when muscle relaxants begin to subside Depth of cleft is inversely proportional to degree of drug Depth of cleft is inversely proportional to degree of drug
activityactivity
You Survived!You Survived!
Thanks!Thanks!
Questions to me via groupwise:Questions to me via groupwise:
jcushman@co.ho.md.usjcushman@co.ho.md.us
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