Anesthesia Machines (Exam III) Marcus's Cards Flashcards
What still works if master switch is off?
- Battery charger
- electrical outlets
- O2 flush valve
What is the biggest power draw in an anesthesia machine?
Ventilator
What are the electrical outlets on the anesthesia machine intended for?
Anesthesia monitors
What all is part of the high pressure system?
- Cylinders
- Hanger yoke
- Check valve assembly
- Cylinder pressure indicators
- Pressure regulators
What is the purpose of the high pressure system?
Reduce gas from cylinders to lower, more constant pressures suitable for the anesthesia machine
What are the functions of the hanger yoke?
- Orient & support cylinder
- Provide gas-tight seal
- Ensure unidirectional flow
What are the parts of the hanger yoke?
- Body
- Retaining screw: tightens cylinder
- Nipple: thru which gas enters machine
- Index pins
- Washer: forms seal between cylinder & yoke
- Check valve assembly: Ensures unidirectional flow
What are the purposes of the hanger yoke check valve assembly?
- Ensures unidirectional flow
- Prevents gas from exiting machine when no cylinder is in the yoke
Cylinder pressure gauges are required to be calibrated in what units?
kilopascals (kPa)
Increasing pressure on a Bourdon tube increases or decreases the curve?
decreases or straightens
What is the purpose of pressure regulators?
How many are there supposed to be?
- Reduce high variable pressure in cylinders to lower constant pressure for machines.
- One regulator for each gas supplied by a cylinder
What is part of the Intermediate pressure sytem?
- Pneumatic part of master switch
- Pipeline inlet connections & indicators
- Piping
- Oxygen pressure failure devices
- Oxygen flush valve
- Flow control valves
What is the pressure reading with the master switch turned off?
Zero
What are the pipeline & cylinder pressures in the intermediate pressure system?
- Pipeline: 50-55 psi
- Cylinder: 45 psi
What part of the intermediate pressure system relates to the DISS?
The pipeline inlet connections
Pipeline inlet connections must have what?
Unidirectional check valves to prevent gas returning to pipeline
Where are the pipeline pressure indicators located?
How many are there?
- Front of the anesthesia machine
- At least 1 for each gas
What pressure does the intermediate pressure system piping have to withstand?
What about leaks?
- Must withstand 4x intended pressure. Around 200-220 psi
- Leaks must not exceed 25 mL/min
What is happening if you hear an alarm about every 5 seconds?
The oxygen pressure is reduced to 30 psi
What is the purpose of the O2 failure safety device?
- Decreases or discontinues N₂O when in use
- Maintains 19% O₂ concentration at common gas outlet
- Continues until O₂ flow ceases
What is the flow when the O2 flush button is pressed?
35-75 L/min
Where does the O₂ flush button send oxygen?
To the common gas outlet
The oxygen flush must be what?
- Operable with 1 hand
- Single purpose
- self-closing
- designed to minimize accidental use
- have flow between 35-75 L/min
What are the hazards of the oxygen flush?
- May cause barotrauma
- May cause awareness d/t backwash
Flow adjustment controls must be?
- Only control one gas for each control knob/button
- Must be adjacent to its flowmeter
- O₂ flow knob must be larger & fluted compared to others
What are the parts of the low pressure system?
- Flowmeters
- Hypoxia prevention devices
- Unidirectional valves
- Pressure relief devices
- common gas outlet
The low pressure system starts where?
Downstream of flow control devices (Flowmeters)
What design do flowmeters have?
Thorpe tube design
Flowmeters empty into what?
Common manifold
What is the correct flowmeter sequence?
- Left: N₂O or Air
- Middle: Air or N₂O
- Right: ALWAYS O₂
What is the hypoxia prevention device?
- A minimum O₂ flow of 50-250 mL/min thru the machine
- Activated when master switch is turned on
What is the minimum O₂ ratio?
- It uses a mechanical linkage between O₂ & N₂O to keep O₂ concentration at at least 25% when N₂O is turned up
Where are the low pressure system unidirectional valves located?
- Between vaporizer & common gas outlet
- Upstream from O₂ flush valve
Where are pressure relief devices located?How do they work?
- Near common gas outlet
- Open to atmosphere if preset pressure is exceeded
What is a downside to pressure relief devices?
Limits the ability of the machine to provide adequate pressure for Jet ventilation
What characteristic must the common gas outlet have?
Difficult to disconnect
What should the common gas outlet not be used for?
Why?
- Supplemental O₂
- As it may deliver volatile anesthetics
What is the alternative O₂ control used for?
Why should one be careful with it?
- Delivers O₂ in case of loss of electricity
- If turned on it will turn off power to rest of the anesthesia machine
