Anesthesia Machine Flashcards
What is the purpose of the anesthesia machine?
Provides delivery of medical gases and vapors of volatile anesthetics in known concentration to a common gas outlet.
- Gases enter breathing system
- Delivered to patient during either spontaneous or mechanical ventilation
- Exhaled gases are removed from the breathing system
Who oversees standards of the anesthesia machine prior to 2000 and since 2000?
Prior to 2000- American National Standards Institute (ANSI)
After 2000- American Society for Testing and Materials (ASTM)
What other groups have say in anesthesia machine?
International Electrochemical Commission (IEC)
Compressed Gas Association (CGA)
Institute of Electrical and Electronic Engineers (IEEE)
Food and Drug Administration (FDA)
What are some contemporary components of anesthesia machine?
- Electrical Supply
- Batter back up (30 min)
- Alarms
- high medium and low prioriry
- Required monitors
- Oxygen supply
- pipeline,
- cylinder
- Vaporizors
- Flowmeters
- Oxygen flush valve
- waste gas system
What are some required monitors on the anesthesia machine?
- inspired o2
- expired o2
- oxygen supply failure
- hypoxic guard system
- anesthetic vapor concentration
- vitas signs
What are the components of the high pressure system
- Auxiliary E-cylinder
- Yoke assembly
- Burdon gauge
- High pressure regulator
High pressure system includes segments exposed to high pressure of auxiliary gas cylinders
<2000 psi
What is the most common gas cylinder size?
E
What tank sizes are used as back up for hospital supplies or banks?
Size G-H
What can tanks be made out of?
Steel
Aluminum (MRI)
What is the purpose of the yoke assembly?
- Orient tanks
- Gas tight seal
- Unidirectional flow of gases
Components
- contains a filter
- Some have check valves
- stop leaking into atmosphere
- stop transfer between tanks
- Pin index safety system (PISS)
What are the common PISS numbers for air, nitrous and oxygen?
Air (1,5)
Oxygen (2,5)
Nitrous oxide (3,5)
What is the capacity and pressure of the E cylinder?
660 L capacity
Pressure 1900 psi
What is the color of oxygen, physical state at room temp, volume of full tank, pressure of full tank and critical temp of O2?
- Color- Green
- Physical state- Gas
- Volume full tank (L)- 660
- Pressure, full tank- 2200psi
- Critical temperature -118
What is the color of nitrou oxide, physical state at room temp, volume of full tank, pressure of full tank and critical temp of N2O?
- Color- blue
- Physical state- liquid and gas
- Volume, full tank- 1590 L
- Pressure- 750 psi
- Critical Temp 36.5
What is the color of air, physical state at room temp, volume of full tank, pressure of full tank and critical temp of air?
- Color-yellow
- State- gas
- Volume -625L
- Pressure- 1800 psi
What are 2 cylinder safety systems?
Frangible disk
- burst under extreme pressure
Fusible Plug
- metls at predetermined temperature
- made of bismuth, lead, tin, and cadmium
- BLT with cheese
What is the function of th ehigh pressure regulator?
Reduces the high and variable pressure delievered from cylinder to a lower and more constant pressure suitable for anesthesia machine
- Pressure regulators preset by factory for 40-45psig
- Ensures hospital pipeline gas is used preferentially to cylinder
What are the components of the intermediate pressure system?
- Hospital supply (pipeline inlet)
- Oxygen flush vlave
- Pneumatic safety systems/electrical system (on switch)
- Auxiliary oxygen flowmeter
- Second stage regulator
Receives gases from pressure regulator and pipeline inlet
What are 2 pneumatic safety systems?
Oxygen supply failure alarms
Oxygen Failure protection devices
How is the hospital supply of oxygen stored?
- Typically stored as liquid
- -184 celsius
- Supplied to hospital as a gas at 50psi
- Multpile shut off valves b/w supply and anesthesia machine
What do hospital supply connetions contain?
- Utilize Diameter Index Safety System (DISS)
- Ensures only correct anesthesia gas connected
- sized and threaded diff
- body, nipple, nut combination
- Contains
- filter
- check valve
- pressure gauge
What do older hospital supply connectors use?
Quick connections
gas specific
manufacture specific
What is purpose of the oxygen flush valve? What does it provide? Potential hazards?
Provides 100% oxygen to anesthesia circuit
Enters circuit downstream from vaporizer-directly to common gas outlet
Flow rate 35-75L/Min
Protected by rim to lessen chance of accidental activation
Hazards
- barotrauma
- stuck valve
- if used during inspiratory phase
- older- ventilator relief valve closed and apl out of circuit
- newer- fresh gas decoupling valve
- Awareness
- dilutes anesthesia gases
What is the oxygen supply failure alarm?
- On Older Ohmeda machines
- audible indication when pneumatic system turned on (oxygen filling whistle)
- When oxygen pressure drops <38 psig, whist valve opens
- whistle sounds until o2 pressure drops <6 psig
- At 30 psig, anesthetic gases are stopped
What are the fail safe devices used and how does it work?
- Designed to help prevent delivery of hypoxic gas mixture form the machine in event of failure of oxygen supply
- monitor pressure not flow
- protects agianst unrecognized exhaustion of oxygen delivery form either pipeline or oxygen tank
- Either proportionally decrease the flow or shuts off flow of all other gases except oxygen
What are the limits of the fail-safe device?
Does not prevent anesthesia gases from flowing
works even if wrong gas supplied
How does the fail safe device work in drager?
Needle valve in n2o pipeline that will be pushed open as long as 50 psig o2 flowing
If o2 decreases to 25psig, the n2o will also be decreased to 25 psig
If 0 psig in o2, then n2o flow stops