Lab Test 1 - Anesthetic Machines Flashcards
Endotracheal tubes work by:
Transfering anesthetic gases directly from the machine into the patient’s lungs
List 4 advantages of using an ET tube for surgery
Less anatomical dead space, precision administration of anesthetic agent, prevents pulmonary aspiration, monitors respirations
What are 2 types of ET tubes and how do they differ?
Murphy - has a cuff/balloon at the end of the tube to better fit into patient
Cole - no cuff or side hole.
Describe the Patient End of an ET tube:
the end of the tube that is passed through the mouth and into the trachea
Describe the Machine End of an ET tube:
protrudes from the mouth and is connceted to the breathing circuit of the anesthetic machine
Describe the Cuff of the ET tube:
Located at the patient end and is inflated to create a seal between the tube and the trachea, preventing inhalation of room air
Describe the Pilot Balloon of an ET tube:
small tube connected to the cuff, which also includes a valve that is used to inflate the cuff. Also used by anesthetist to monitor cuff inflation visually or manually
What is a Laryngoscope?
A deviced used to increase visibility of the larynx to place an ET tube
What 3 parts make up a Laryngoscope?
Handle (contains batteries), Blade (depresses tongue and epiglottis) and Light source (illuminates the throat)
What are the 2 types of Laryngoscope blades?
McIntosh (curved) and Miller (straight)
What is an Anesthetic Mask?
Cone-shaped device used to administer oxygen and anesthetic gases to non-intubated patients by mouth
Why wouldnt we use an Anesthetic Mask on a Brachycephalic patient?
They do not maintain an open airway so airway blockage is possible
What is an Anesthetic Chamber? Why would we use it?
Clear, aquarium-like boxes used to induce general anesthesia in small patients or patients that cannot be handled without undue stress, or patients who would be a danger to themselves or the staff
What is the primary function of the Anesthetic Machine?
Deliver precise amounts of Oxygen and Volatile Anesthetic under controlled conditions to patients undergoing Anesthesia
What is the most basic principle of how an Anesthetic machine works?
A liquid anesthetic (Isoflurane) is vaporized in a carrier gas (Oxygen) which delivers the anesthetic to the patient via a breathing circuit
What are the 3 important functions that an Anesthetic machine and Breathing circuit MUST be able to perform?
- The carrier gases (Oxygen or Nitrous Oxide) must be delivered at a controlled flow rate.
- A precise concentration of liquid inhalant anesthetic (Isoflurane) must be vaporized, mixed with carrier gas and delivered to patient
- Exhaled gas containing Carbon Dioxide must be moved away from patient and either removed through a scavenging system or recirculated to the patient. If they are recirculated, the machine must remove the Carbon Dioxide before returning them to the patient
Components of an anesthetic machine: Compressed Gas Supply
Supplies carrier gases (Oxygen and Nitrous Oxide)
Components of an anesthetic machine: Anesthetic Vaporizer
Vaporizes liquid inhalant (Isoflurane) and mixes it with carrier gases. Vaporizers are classified as precision or non-precision, and vaporizer-out-of-circuit (VOC) or vaporizer-in-circuit (VIC)
Components of an anesthetic machine: Breathing Circuit
conveys the carrier gases and inhalant anesthetic to the patient and removes exhaled carbon dioxide. CLassified as rebreathing or non-rebreathing
Components of an anesthetic machine: Scavenging System
Disposes of excess and waste anesthetic gases
What are the 2 main functions of Oxygen from the Compressed Gas Supply on an Anesthetic Machine
- Increase inspired oxygen to at least 30% to maintain cellular metabolism
- Used to carry vaporized anesthetic to patient
What is the purpose of the Cylinder tank? What 2 main types are there?
Contain large volume of gas under high pressure (as much as 2200psi) E tanks are small and attach directly to the anesthetic machine. H tanks are large and are remotely attached for supply
Green or White hoses indicate _______
Oxygen supply
Purple hoses indicate _____
Scavenge system
Blue hoses indicate ________
Nitrous Oxide
Yellow or Black&White hoses indicate _________
Medical air
Grey hoses indicate ______________
Carbon Dioxide
Tank Pressure Gauge measures:
The pressure of gas remaining in the compressed gas cylinder
The purpose of the Pressure Reducing Valve is:
Immediately after exiting the tank, gas flows through the pressure reducing valve and then into the intermediate gas line
The purpose of the Line Pressure Gauge is to:
Indicate pressure in the gas line between the pressure-reducing valve and the flowmeter
The purpose of the Flowmeter is to:
a vertical gas cylinder of graduated diameter with a valve attached to the bottom, an indicator within the cylinder rises to indicate the gas flow, expressed in Liters of gas per min (L/min)
What does the Oxygen flush valve do?
Rapidly delivers a large volume of pure oxygen at a flow rate of 35-75L/min directly into the common gas outlet or rebreathing circuit, bypassing the vaporizer and flowmeter.
After exiting the vaporizer through the outlet port, oxygen and anesthetic mixture (fresh gas) enters the breathing circuit through the connection known as the:
fresh gas inlet
What are the 2 different types of Anesthetic Vaporizers and how do they differ?
Non-precision vaporizer delivers low vapor pressure anesthetics (rarely used)
Precision Vaporizers deliver a precise amount of anesthetic (high-vapor pressure anesthetics)
Based on the location of the vaporizer in relation to the breathing circuit, Vaporizers can be separated into what 2 categories:
Vaporizer-Out-Of-Circuit: vaporizer is NOT located within the breathing circuit, oxygen from the flowmeter flows into vaporizer before entering breathing circuit
Vaporizer-In-Circuit: Carrier gases enter the breathing circuit directly from the flowmeter without first entering the vaporizer
Which type of Vaporizer (VOC/VIC) do we use? Why?
VOC - it has a high resistance gas flow
Factors that affect vaporizer output (4)
- Temperature
- Carrier Gas Flow Rate
- Respiration Rate and Depth
- Back pressure
Induction flow for Isoflurane is _____%
3-5
Maintenance flow for Isoflurane is _____%
1.5-2.5
What is the Vaporizer Outlet Port?
The point where Oxygen, inhalant anesthetic and Nitrous Oxide exit the vaporizer on the way to the breathing circuit
What is the Common (Fresh) Gas outlet?
Where waste gasses exit through the Scavenge
A breathing circuit may be incorporated into the anesthetic machine (_____ system) or it may be a separate unit (______ system)
Rebreathing, Non-rebreathing
Rebreathing systems are also called _______ systems because exhaled gas (minus carbon dioxide) are recirculated and re-breathed along with fresh gas
Circle
Rebreathing systems are suitable for all patients except those who weigh less than _____kg
7
Rebreathing systems are further divided into _____ and ______ systems
Closed and Semi-closed
Describe a closed re-breathing system
The pop-off valve can be kept nearly or totally closed and the flow of oxygen is low, providing only necessary volume to meet patients metabolic needs
Describe a semi-closed re-breathing system
The pop-off valve is positioned partially open and more oxygen is added than the patient requires. A portion of gases are recirculated, but any excess exits through the pop-off valve and into Scavenging system
A rebreathing circuit consists of what 8 parts?
- fresh gas inlet
- unidirectional valves
- pop-off valve
- carbon dioxide absorber
- pressure manometer
- air take in-valve
- Breathing tubes
- Y-piece
The unidirectional valves are responsible for _______
controlling the direction of gas flow through the rebreathing circuit
A reservoir bag should hold a volume of at least ________
50mL per kg of patient weight
What is found within the Carbon Dioxide Absorbent canister? How does it work?
Soda Lime granules that react with CO2 to form Calcium Carbonate
Replace the granules after 6-8 hours of use or when 1/3 of the granules have _______
changed colour (usually purple or yellow)
Name 2 types of Non-rebreathing circuit configurations and 2 types of rebreathing configurations?
Non rebreathing: Bain Coaxial Circuit or Arye’s T-Piece
Rebreathing: Y or F Circuits
Induction flow rate in a semi-closed rebreathing system is:
50-100 ml/kg/min
Maintenance flow rate in a semi-closed rebreathing system is:
20-40ml/kg/min
A Doppler is used to measure _______ in small animals
systolic blood pressure
The Cardell is a multi-function monitoring device we use. What 4 important things does it do?
- Electrocardiogram
- Capnograph
- Pulse oximeter
- Blood pressure monitor
An electrocardiogram is used to:
Monitor patient’s heart rate and rhythm with a graphic representation of the electrical activity of the heart
A Capnograph monitors patient’s _____ levels by measuring the _____ level in the air inhaled and exhaled by the patient
SPO2, CO2
The Pulse Oximeter measures the patient’s ______ levels and indicates ______
Pulse and Oxygen Saturation levels, indicating oxygen availability
______ on the ear or web may help connect the Pulse Oximeter in pigmented animals
Alcohol
