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NON INVASIVE MONITORS

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					NON INVASIVE MONITORS
Pulse oximetry
• An inexpensive and noninvasive
  method to measure arterial blood
  hemoglobin saturations
• Measures SpO2
  – Oxygenation in capillary blood
Pulse oximetry
• Indications
  – Monitor adequacy of arterial
    Oxyhemoglobin
  – Quantify response to therapeutic
    procedures
  – Comply with mandated regulations
• Contraindications
  – The need for ongoing actual
    measurement of Ph, PCO2, PaO2
  – Abnormal hemoglobin
   Pulse oximetry
• Precautions/complications
  – False readings
  – Tissue injury
• Assessment of need
  – Direct measurement not readily available
  – Continuous and prolonged measurements
  – When acid-base status not needed
• Assessment of outcome
  – SpO2 should reflect condition
  – Documentation of results and intervention
 Pulse oximetry
• Frequency
  – Determined by clinical status of patient
  Pulse oximetry
• Instrumentation
   – Uses photoplesmography
       • Light detects volume changes in pulsatile
         blood flow
   – Uses red and infrared light
   – Transmitter – two sided
       • LED’s transmit light through
         tissue
       • Intensity of light measured
         through photodetector on
         other side
Pulse oximetry
• Output signal is filtered and amplified
• Processed and displayed
Pulse ox
• Components of absorption
  – Baseline
  – Pulsatile
Pulse ox
• Accuracy
  – Falls within ± 3-5% of ABG’s
  – As SpO2 falls, the accuracy will also fall
  – Not accurate with saturations below
    70%
Pulse ox
• Procedure
  –   Follow manufactures protocol
  –   Never mix components
  –   Sensor must be right size, fit
  –   Confirm good signal, allow time
  –   Set low SpO2 88-92%
  –   Validate baseline with ABG
  –   Clean and disinfect between patients
  –   Inspect probe site frequently
  –   Never act on SpO2 readings alone
  –   Careful with readings
Pulse ox
• Documentation
  –   Date and time
  –   Patients position, location of probe, activity
  –   FiO2 or O2 flow at time of reading
  –   Model of pulse ox
  –   Comparison of SpO2 to ABG
  –   Stability of readings
  –   Patients clinical appearance
  –   Document HR on pulse ox to manual
      palpitation of HR
Pulse ox
• Factors effecting efficiency
   –   COHb
   –   MetHb
   –   Fetal Hb
   –   Anemia
   –   Vascular dyes
   –   Billirubin
   –   Dark skin pigmentation
   –   Poor perfusion
   –   Motion artifact
   –   Nail polish
   –   Ambient light
Pulse ox
• ALWAYS TREAT THE PATIENT.
  NOT THE NUMBER
End Tidal CO2
• Capnometry
  – The measurement of CO2 in respiratory
    gases
• Capnometer
  – Instrument that measures end tidal
    CO2
• Capnography
  – The graphic display of CO2
    concentrations versus time
  – Shows changes with every breath
ETCO2
• Indications
  – Evaluate CO2 in mechanically ventilated
    patients
  – Monitoring severity of pulmonary disease and
    response to treatment
  – Determine tracheal vs. esophageal intubation
  – Monitor integrity of vent circuit, artificial airway,
    and ventilator
  – Reflect CO2 elimination
  – Monitor inhaled CO2 during therapeutic CO2
    administration
ETCO2
• Contraindications
   – None, remember that your treating the patient, not the
     number
• Precautions
   – Misunderstanding the numbers
   – Weighing down the vent circuit
• Assessment of need
   – Standard of care in OR
• Assessment of outcome
   – Results should reflect patients appearance
• Monitoring
   – Vent params
   – Hemodynamics
ETCO2
• Instrumentation
  – Infrared absorption
    • Most common
  – Raman scattering
  – Mass spectroscopy
  – Photoacustic technology
ETCO2
• Sampling ports are either sidestream
  or mainstream
ETCO2
• Mainstream
  – In line analyzer chamber placed between the patients
    airway and the vent circuit
• Advantages
  – Sensor at airway
  – Fast response
  – No sample flow
• Disadvantages
  –   Secretions and humidity block sensor window
  –   Frequent calibration
  –   Bulky and heavy
  –   Non disposable
  –   Intubated patients only
ETCO2
• Sidestream
  – Sampling tube placed between patient
    and circuit, air pumped into measuring
    chamber
ETCO2
• Advantages
  –   No bulky sensor
  –   Measures N2O
  –   Disposable sample line
  –   Use with non intubated patients
• Disadvantages
  –   Secretions block sample tube
  –   Trap needed to remove excess water
  –   Frequent calibration
  –   Slow response
  –   Sample flow may decrease tidal volume
ETCO2
• Waveform interpretation
• I
   – CO2 zero. Origination of exhalation,
     deadspace
• II
   – Steep upward slope, mixed deadspace gas
     and alveolar gas
• III
   – Plateau, alveoli empty, end of plateau is
     PetCO2
• IV
   – Rapid decrease in CO2, patient inhalation
ETCO2




• In healthy individuals, the PetCO2
  averages 1-5mmHg lower than ABG’s
            (5-6%)
ETCO2 abnormal
waveforms
• Hypoventilation



• Hyperventilation



• Leak
ETCO2 abnormal
waveforms
• Disconnect
Transcutaneous monitors
• Provides continuous noninvasive
  estimated PO2 and PCO2
• Heats blood to arterialize it
• Dependant on age and perfusion
  status
• CO2 more reliable
• Used mostly in the NICU

				
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posted:12/12/2011
language:Latin
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