Anesthesia Machine Flashcards
Who decides what is needed for an anesthesia work station
the American Society for Testing and Materials
What are the required conponents of an Anesthesia work station
- battery backup (30min minimun)
- alarms:high, medium, or low priority
- pO2, BP, EKG monitors
- PIN-indexed hanger yoke system
- flowmeters
- at least one oxygen cylinder attached
- electricle cord that is non-detachable
High Priority alarms may not be silenced for more than….
2 mins
When should a High-priority pressure alarm must sound?
- if user adjustable limits are exceeded
- if continuing high pressure is sensed
- for negative pressure
What are the required monitors
- exhaled volume
- inspired oxygen with a high priority alarm that will alarm within 30sec of O2 falling below 18%(or user adjustable limit)
- O2 supply failure alarm
- hypoxic guard mixture if nitrogen is used(O2 less than 21%)
- anesthetic vapor conentration
- disconnect alarm
What are Flowmeters
- uniquely shaped oxygen flow control knobs
- with a valve stop to prevent access rotation
- O2 must enter common manifold downstream of other gases
- O2 flush capable of 35-75L/min flow which does not proceed through any vaporizers
A Hanger Yoke Assembly must use what type of connecting system
Pin-Index Safety System (PISS)
What are the functions of a Hanger Yoke Assembly
- connects E-cylinders to machine
- ensure gas tight seal
- orients cylinders (PISS)
- prevents misconnections
Gases from a central suppy source ( wall source) enter the machine at a PSI of…
45-55
Where are check valves located and what are their funtions
located downstream to prevent backflow of gases from machine to wall supply
What is the PSI of an O2 E-cylinder
-2000 psi which is reduced to 40-50 psi when it passes through the hanger yoke valve and pressure regulator
what is a Hanger Yoke Check Valve
- a free floating valve (opens and closes with pressure)
- prevents retrograde gas flow
- allows change of cylinders during use
- minimizes transfilling of gases
Air Index Pin
1, & 5
Oxygen Index Pin
2, & 5
Nitrous Index Pin
3, & 5
How to convert cylinder PSI to Liters
- multiply PSI by 0.3
- O2: 2000-2200 PSI-660L
- N2: 750 PSIG-1590L
- Air: 1900 PSI-625L
what is the function of a Cylinder Pressure Regulator
- converts cylinder pressure to a constant pressure of about 45psi dowmstream of the regulator
- this is to allow the machine to use the pipeline gas source with the higher pressure
- helps prevent cylinder depletion if left open
How is TIME to O2 cylinder exhaustion calculated
dividing the the remaining O2 volume in the cylinder by the rate of O2 consumption
How it the volume of N2O in a cylinder dertermined
- the volume of N2O cannot be determined by PSIG
- N2O reads 745 PSIG until all the liquid in the cylinder is vaporized
- it can be assumed that 75% (or 3/4) of N2O has been exhausted when the pressure reads less than 745 PSIG
what is Critical Temperature
the temperature above at which a gas CANNOT be liquidfied
What is the Critical temperature of oxygen and N2O
Oxygen= -119 degrees C N2O= 39.5 degrees C
F= (C x 1.8) + 32
C=(F-32) x 5/9
what is Woods Metal
a safety device in a E-cylinder that melts under excessive heat (>200 F) to allow gas to escape preventing an explosion
what is the Joules Thomas Effect
the cooling effect of a cylinder once compressed gas is allowed to escape in open space
what is Adiabatic Heat of Compression
the generation of heat by compression of cylinder contents into a small space that may cause combustion
