CAPNOGRAPHY-CAPNOGRAPHY-and PULSE OXIMETRYand PULSE OXIMETRY

: The Standard of : The Standard of RESPIRATORY CareRESPIRATORY Care

Dr.Gehan A Tarrabih , MD ,

Ass. Prof .Anesthesia and SICU ,

Mansoura Faculty Of Medicine.

CAPNOGRAPHY-OXIMETRYCAPNOGRAPHY-OXIMETRY

Why use them?

Capnography & Capnography & Pulse OximetryPulse Oximetry

CO2:

Relects ventilationDetects apnea and

hypoventilation immediately

Should be used with pulse oximetry

O2 Saturation:

Reflects oxygenation30 to 60 second lag

in detecting apnea or hypoventilation

Should be used with capnography

Indications for Use -End-Tidal CO2 Monitoring

Validation of proper endotracheal tube placement

Detection and Monitoring of Respiratory depression

Hypoventilation Obstructive sleep apnea Procedural sedation Adjustment of parameter settings in

mechanically ventilated patients

ETCOETCO22 & Cardiac Resuscitation & Cardiac Resuscitation

Non-survivorsAverage ETCO2: 4-10 mmHg

Survivors (to discharge)Average ETCO2: >30 mmHg

ETCOETCO22 & Cardiac Resuscitation & Cardiac Resuscitation

If patient is intubated and pulmonary ventilation is consistent with bagging, ETCO2 will directly reflect cardiac output

Flat waveform can establish PEA Increasing ETCO2 can alert to return of

spontaneous circulation

Configuration of waveform will change with obstruction

CapnographyCapnography

What are we measuring?

Respiration–The BIG PictureRespiration–The BIG Picture

Capnography Depicts Capnography Depicts RespirationRespiration

Physiological Factors Physiological Factors Affecting ETCOAffecting ETCO2 2 LevelsLevels

Normal Arterial & Normal Arterial & ETCOETCO2 2 ValuesValues

DeadspaceDeadspace

CAPNOGRAPHYCAPNOGRAPHY

Theory of Operation

Infrared AbsorptionInfrared Absorption

A beam of infrared light energy is passed through a gas sample containing CO2

CO2 molecules absorb specific wavelengths of infrared light energy.

Light emerging from sample is analyzed. A ration of the CO2 affected wavelengths to

the non-affected wavelengths is re[ported as ETCO2

Capnography vs. Capnography vs. CapnometryCapnometry

Capnography: Measurement and

display of both ETCO2 value and capnogram (CO2 waveform)

Measured by a capnograph

Capnometry: Measurment and

display of ETCO2 value

(no waveform) Measured by a

capnometer

Mainstream vs. SidestreamMainstream vs. Sidestream

Quantitative vs. Qualitative Quantitative vs. Qualitative ETCOETCO22

Quantitative ETCO2:

Provides an actual numeric value

Found in capnographs and capnometers

Qualitative ETCO2:

Only provides a range of valuesTermed “CO2 Detectors”

Colorimetric COColorimetric CO22 Detectors Detectors

A “detector” – not a monitor

Uses chemically treated paper that changes color when exposed to CO2

Must match color to a range of values

Requires six breaths before determination can be made

CAPNOGRAPHYCAPNOGRAPHY

The Capnogram

Elements of a WaveformElements of a Waveform

Dead Space

Beginning ofexhalation

Alveolar gas mixes with dead

space

Alveolar Gas

End of exhalation

Inspiration

Value of the COValue of the CO22 Waveform Waveform

The Capnogram:Provides validation of the ETCO2 value

Visual assessment of patient airway integrityVerification of proper ETT placementAssessment of ventilator/breathing circuit integrity

The Normal COThe Normal CO22 Waveform Waveform

A – B Baseline

B – C Expiratory Upstroke

C – D Expiratory Plateau

D ETCO2 value

D – E Inspiration begins

Esophageal TubeEsophageal Tube

A normal capnogram is the best evidence that the ETT is correctly positioned

With an esophageal tube little or no CO2 is present

Inadequate Seal Around ETTInadequate Seal Around ETT

Possible causes:Leaky or deflated endotracheal or

tracheostomy cuffArtificial airway too small for the patient

HypoventilationHypoventilation(increase in ETCO(increase in ETCO22))

Possible causes:Decrease in respiratory rateDecrease in tidal volume Increase in metabolic rateRapid rise in body temperature (hypothermia)

HyperventilationHyperventilation(decrease in ETCO(decrease in ETCO22))

Possible causes: Increase in respiratory rate Increase in tidal volumeDecrease in metabolic rateFall in body temperature (hyperthermia)

RebreathingRebreathing

Possible causes:Faulty expiratory valve Inadequate inspiratory flow Insufficient expiratory flowMalfunction of CO2 absorber system

ObstructionObstruction

Possible causes:Partially kinked or occluded artificial airwayPresence of foreign body in the airwayObstruction in expiratory limb of the breathing circuitBronchospasm

Muscle RelaxantsMuscle Relaxants

“Curare Cleft”:Appears when muscle relaxants begin to subsideDepth of cleft is inversely proportional to degree of

drug activity

Faulty VentilatorFaulty VentilatorCircuit ValveCircuit Valve

Baseline elevated Abnormal descending limb of capnogram Allows patient to rebreath exhaled gas

Sudden Loss of WaveformSudden Loss of Waveform

Apnea

Airway Obstruction

Dislodged airway (esophageal)

Airway disconnection

Ventilator malfunction

Cardiac Arrest

QUIZ TIMEQUIZ TIME

#1#1

• Normal capnogram

controlled ventilations

spontaneous respirations

#2#2

Muscle relaxants General anesthesia

The cleft on the alveolar plateau is due to spontaneous respiratory effort

#3#3

Normal capnogramSpontaneous ventilation in childrenSampling from nasal cannula or O2 mask in adults

#4#4

Esophageal intubation following a mask ventilation

#5#5

Bronchospasm

#6#6

Hyperventilation

#7#7

Esophageal intubation

#8#8

Contamination of CO2 sensor

#9#9

Rebreathing

#10#10

Flat line

Waveform: Waveform: Regular Shape, Plateau Regular Shape, Plateau BelowBelow Normal Normal

• Indicates CO2 deficiency Hyperventilation

Decreased pulmonary perfusion

Hypothermia

Decreased metabolism

• Interventions Adjust ventilation rate

Evaluate for adequate sedation

Evaluate anxiety

Conserve body heat

Waveform: Waveform: Regular Shape, PlateauRegular Shape, Plateau AboveAbove NormalNormal

• Indicates increase in ETCO2 Hypoventilation

Respiratory depressant drugs

Increased metabolism

Fever, pain, shivering

• Interventions Adjust ventilation rate

Decrease respiratory depressant drug dosages

Assess pain management

Conserve body heat

QuestionsQuestions

ReferencesReferences

Capnography, Bhavani Shankar Kodali, MD Capnography in ‘Out of Hospital’ Settings, Venkatesh

Srinivasa, MD, Bhavani Shankar Kodali, MD Capnography, Novametrix Systems, Inc. Clinical Physiology of Capnography, Oridion

Emergency Medical Services Evolutions/Revolutions: Respiratory Monitoring,

RN/MCPHU Home Study Program CE Center End-Tidal Carbon Dioxide, M-Series, Zoll Medical

Corporation