NON INVASIVE MONITORS

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NON INVASIVE MONITORS

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Pulse oximetry

• An inexpensive and noninvasive method to measure
  arterial blood hemoglobin saturations
• Measures SpO2
• Oxygenation in capillary blood

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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

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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

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Pulse oximetry

• Frequency
• Determined by clinical status of patient

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Pulse oximetry

• Instrumentation
• Uses photoplesmography
• Light detects volume changes in pulsatile blood
  flow
• Uses red and infrared light
• Transmitter two sided
• LEDs transmit light through
  tissue
• Intensity of light measured
  through photodetector on
  other side

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Pulse oximetry

• Output signal is filtered and amplified
• Processed and displayed

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Pulse ox

• Components of absorption
• Baseline
• Pulsatile

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Pulse ox

• Accuracy
• Falls within 3-5 of ABGs
• As SpO2 falls, the accuracy will also fall
• Not accurate with saturations below 70

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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

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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

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Pulse ox

• Factors effecting efficiency
• COHb
• MetHb
• Fetal Hb
• Anemia
• Vascular dyes
• Billirubin
• Dark skin pigmentation
• Poor perfusion
• Motion artifact
• Nail polish
• Ambient light

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Pulse ox

• ALWAYS TREAT THE PATIENT. NOT THE NUMBER

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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

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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

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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

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ETCO2

• Instrumentation
• Infrared absorption
• Most common
• Raman scattering
• Mass spectroscopy
• Photoacustic technology

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ETCO2

• Sampling ports are either sidestream or
  mainstream

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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

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ETCO2

• Sidestream
• Sampling tube placed between patient and circuit,
  air pumped into measuring chamber

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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

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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

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ETCO2

• In healthy individuals, the PetCO2 averages
  1-5mmHg lower than ABGs
• (5-6)

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ETCO2 abnormal waveforms

• Hypoventilation
• Hyperventilation
• Leak

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ETCO2 abnormal waveforms

• Disconnect

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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