03 capnography

NON-INVASIVE CNON-INVASIVE CAAPNOGRAPHYPNOGRAPHY

ALS Blue In-Service

Part III

Oxygenation and VentilationOxygenation and Ventilation

What is the difference?What is the difference?


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


Capnography waveformCapnography waveform

Capnography Capnography LinesLines


• 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


• 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


• BreathingBreathing–– HyperventilationHyperventilation

–– HypoventilationHypoventilation

–– AsthmaAsthma

–– COPD COPD


• 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


PerfusionPerfusion

Pulmonary Blood Flow

Right Ventricle

LeftAtrium

a-A Gradienta-A Gradient

r r Alveolus

PaCO2

VeinA te y


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


• 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


• 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


• 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


• 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

45

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


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


• 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


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


45

0


45

0

NormalNormal


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

45

0

NormaNormall

BronchospasmBronchospasm45

0

Capnography Waveform PatternsCapnography Waveform Patterns

45

0


NormalNormal

45

0

45

0

BronchospasmBronchospasm


45

0

The Intubated PatientThe Intubated Patient

Confirm ET Tube PlacementConfirm ET Tube Placement

45

0

Detect ET Tube DisplacementDetect ET Tube Displacement

• CapnographyCapnography– Immediately detects Immediately detects

ET tube displacementET tube displacement

45

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

45

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


AsthmaAsthma Case ScenarioCase Scenario

Initial Initial

After therapyAfter therapy


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 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


COPD Case ScenarioCOPD Case Scenario

45

0

45

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


• 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

45

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

45

0

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



• 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



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


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

45

0

Capnography in DKACapnography in DKA


45

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:

[email protected]@co.ho.md.us

03 capnography

Documents