capnography- and pulse oximetry : the standard of respiratory care dr.gehan a tarrabih, md, ass....
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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