Respiratory Monitoring? Flashcards
What are the Respiratory Monitoring Standards?
Continuously monitor oxygenation by observation and pulse oximetry
-When indicated use of ABG lab data
Continuously monitor ventilation
-Verify intubation
-Monitor airway pressures
-Monitor end-tidal carbon dioxide
-Mechanical/spontaneous ventilation with an airway
-Moderate/deep sedation with or without an airway
What is “the Ideal Alarm” to avoid alarm fatigue?
Easy to identify and recognize
Draws your attention despite other noises/distractions
Eliminates false alarms
Allows for continuation of effective communication
What is the best monitor?
You are the best monitor!
Continuous and systematic scanning patient/monitors
Respiratory events make up a large portion of the claims made in anesthesia
What is the Crisis Management Algorithm?
C- circulation and color
O- oxygen delivery
V- ventilation and vaporizer
E- endotracheal tube position and patency
R- review all monitors (alarms set and on)
A- airway patency
B- breathing pattern, review of ETCO2, and pulse oximetry
C- circulation- blood pressure and heart rate
D- review drugs given so far and what may need to be given soon?
How should one monitor the airway?
Using all of your senses…
Vision- chest rise and fall, condensation in mask or ETT, chest retractions, monitors and machine
Smell- gas leaks, smoke in the room
Touch- lung compliance on reservoir bag
Hearing- auscultation of breath sounds and heart sounds
Precordial stethoscope allows for continuous monitoring of heart and lung sounds
Listening for sounds of ventilator movement, air leaks, and scavenging system
How should Oxygenation be Monitored?
Patient color
-Skin
-Mucous membranes
-Lips
Pulse oximetry
Lab data
-Hemoglobin
-Hematocrit
-ABGHow should Ventilation be Monitored
Auscultation
-Precordial stethoscope
-Observation of chest movement
Spirometry data
-MV, TV, RR
-Flow-volume
-Pressure-volume
End-tidal Carbon Dioxide
-CapnometryWhat are the two types of Respiratory Gas Monitoring?
Non diverting (mainstream) Diverting (sidestream)
What is Nondiverting (mainstream) Respiratory Gas Monitoring?
Measures the gas concentration by using a sensor located directly in the gas stream near the patient’s airway
- Oxygen and CO2 are measured by nondiverting monitors - CO2 is measured by infrared technology with a sensor placed between the breathing circuit and the patient - A mainstream oxygen sensor uses electrochemical technology and is usually placed in the inspiratory limb of the breathing circuit - Are subject to interference by water vapor, secretions, and blood
What is Diverting (side stream) Respiratory Gas Monitoring?
Uses a pump to aspirate gas from the sampling site through a tube to the sensor that is located in the main unit
The sampled gas is continually drawn from the breathing circuit via an adapter placed between the circuit and the patient’s airway (y piece), it passes through a filter or water trap before entering the analyzer.
Sampling flow rate is usually about 200 mL/min
(range of 5—250 mL/min)
Leaks will result in erroneous readings and may not be obvious
What is Infrared Technology?
- IR technology allows for monitoring of carbon dioxide, nitrous oxide and volatile anesthesia agents
- IR analyzers are based on the principle that gasses have specific and unique IR spectra
- Advantages
- can discriminate between volatile agents and detect mixtures of agents
- Portable monitors and be used outside the OR
- Gas that is drawn into the monitor can be returned to the breathing circuit or sent to the scavenger
- Quick response time and short warm up time
- Disadvantages
- nitrogen cannot be measured
- If oxygen is at high concentrations it can interfere with accuracy
- Water vapor can absorb IR light
- Inaccurate in high respiratory rates
What is Paramagnetic Oxygen Analysis?
- When introduced into a magnetic field, substances locate themselves in the strongest portion of that field
- Oxygen is the only gas in anesthesia that is “paramagnetic”
- When a gas that contains oxygen is passed through a switched magnetic field, the gas will expand and contract, causing a pressure wave that is proportional to the oxygen partial pressure
What is Electrochemical Oxygen Analyzer?
- Galvanic or “fuel cell” analyzer
- Consists of a sensor, which is exposed to the gas being analyzed, and the analyzer box, which contains the electronic circuitry, display and alarms
- Sensor is placed in the inspiratory limb of the breathing circuit
- Respond slowly to changes in oxygen pressure, so they cannot be used to measure end-tidal concentrations
- The life of an electrochemical analyzer sensor s measured in percent hours
- The higher the oxygen concentration that it is exposed to, the shorter the sensor life
- The life of an electrochemical oxygen analyzer sensor can be prolonged by removing it from the breathing system and exposing it to air when not in use
- Calibration should be performed daily before use, and every 8 hrs afterward
What is Mass Spectrometry?
- Was the first multigas monitoring system
- Is no longer common in clinical use
- Ionizes gas molecules and passes them through a magnetic field
- Allows the identification and quantification on a breath by breath basis of up to 8 of the common anesthesia gases:
- Oxygen, nitrogen, nitrous oxide, halothane, enflurane, isoflurane
- Other agents (helium, sevoflurane, argon, and desflurane) could be added
- Single use analyzer units were too expensive for routine use
What is Raman Spectroscopy?
- Raman scattering passes a monochromatic laser beam through a gas mixture, causing an increased vibration frequency of the gas molecules
- The anesthetic gas molecules interact with the laser beam and may be absorbed, or scattered
- Each anesthetic gas scatters laser frequencies uniquely
- Can identify oxygen, CO2, nitrogen, nitrous oxide, and all volatile agents
- Helium cannot be analyzed
- Analyzers are small and portable
- Require calibration
- No longer in clinical use
