Machine Checks
Flowmeters
Pneumatics
Misc.
Scenarios
100
What are the three most important preoperative checks?
1. Calibration of the O2 analyzer (ensures correct FiO2 reading)
2. Low pressure circuit leak test
3. High pressure test
100
Which gas flow meter should be positioned last in the anesthesia manifold and why?
The oxygen flow meters should be positioned LAST in the sequence of flow meters in the manifold to reduce the likelihood that a leak in one of the flow meters would allow oxygen to escape in lower inspired O2 concentration. Could cause a hypoxic gas mixture.
O2 remains closest to the patient, "Fail-safe"
100
Which pressure system are these parts a part of?
Cylinder supply
Cylinder pressure gauges
Cylinder Pressure regulators
High-pressure system
100
Name 3 things your machine HAS to have on it.
1. Arterial O2 saturation of hemoglobin
2. Arterial BP
3. Continuous EKG
100
In the event your oxygen supply fails and you must switch indefinitely to your back up oxygen tanks, what are appropriate measures to reduce the amount of oxygen consumed and prolong the duration of your back up oxygen supply?
Some anesthesia machines utilize oxygen as the driving gas to power the ventilator. By reducing fresh O2 flow rates and eliminating the use of the ventilator by allowing the patient to breathe spontaneously or ventilating through the reservoir bag, you will prolong the back up oxygen supply.
200
Name the machine checks done in between each case
#2, 4, 7, 11-15
200
Does the arrangement of flow tubes always prevent hypoxia?
No, patient can still receive a hypoxic mixture if there is a break in the system.
200
What system are these parts a part of?
Pipeline supply
O2 low pressure alarm
Fail-safe device
O2 flush valve
Auxillary O2 flowmeter
etc.
Intermediate Pressure System
200
The N20 proportioning system will not let you turn N2o up above what %?
75%
200
Which change would you see if there's a leak in the bellows in an oxygen driven ventilator?
Oxygen driven ventilators use 50 psi pressure source to drive the ventilator. If a leak develops in the bellows and the patient is exposed to that higher pressure and peak inspiratory pressure would rise. The fraction of inspired oxygen would also rise.
300
Name the machine checks done daily.
300
If the digital screen stops working or if there is an electrical supply failure, what do we use to provide O2?
Auxillary O2 Flowmeter
300
What system are these parts a part of?
Flowmeters
Vaporizers
Check valve
Common Gas outlet
Low pressure system
300
What does a check valve do?
Ensures one-way flow/prevents backflow/retrograde flow
EX: Retrograde flow can occur from pt coughing
300
What would happen if an oxygen cylinder is left open in the pipeline pressure drops below 45 psi?
Normal pipeline pressure is 50 psi. If the pressure drops below 45 psi and the oxygen cylinders open, oxygen will begin to flow from the cylinder. There is no alarm to alert of this condition. The low oxygen supply alarm does not sound until the emergency supply is exhausted.
400
What 2 components does the high-pressure test test for?
That positive pressure can be maintained through the breathing circuit and that the unidirectional valves are functional.
400
Using the oxygen flush valve allows oxygen to bypass what components?
Using the O2 flush valve creates a direct communication between the high and low pressure circuits and allows oxygen to bypass the flow meters and manifold.
400
Name the pressures associated with each pressure system.
High--2000 to 45psi or 750 to 45psi
Intermediate--50 to 14.7psi
Low 14.7psi
400
What are some examples of what would set off the O2 low-pressure alarm?
-depleted O2 tank
-low pipeline pressure
-disconnected O2 hose from machine
400
During a general anesthetic you hear a loud sound of escaping gas from the machine, what might be the source?
something is leaking
Ambu bag + new machine
500
How do we conduct a negative pressure test?
Connect bulb to common gas outlet and squeeze bulb and see if it inflates (if it inflates there is a leak,).
Also test with each vaporizer on and make sure the bulb stays flat.
If there is a leak, the bulb will inflate, showing a leak in the flowmeter or vaporizer/vaporizer connection
500
What is the only machine safety device that detects problems downstream from the flow meters?
The O2 analyzer
500
What is the pressure and flow associated with the O2 flush valve?
50 psi and 35-75L
500
What is a risk of hitting the O2 flush valve other than barotrauma?
Patient awareness-hitting the O2 flush valve delivers a high volume of fresh gas to your patient and will dilute your volatile anesthetic which can cause patient awareness
500
You have pressure tested your breathing system by occluding the Y connector and flushing the circuit with O2, what can you conclude about the integrity of the system from the flowmeter assembly to the breathing circuit?
Nothing, This only tests the circle system