AGM Flashcards
Check valves
Prevent backflow of gas
Gas can only flow in one direction
Found all over AGM
Pressure regulator
Drops pressure
Drops pressure from tanks (2000psi) to intermediate pressure (50psi)
2nd stage pressure regulator drops pressure from intermediate to low pressure (16psi)
High pressure system
750-2200psi
Cylinders
Cylinder pressure gauge
Cylinder pressure regulator
Hanger yoke
Yoke block with check valve
Intermediate pressure
40-50psi
Ventilator power inlet
Check valves
Pressure gauges
Flow meter valves
Oxygen pressure failure devices
Oxygen second stage regulator
Flush valve
Low pressure system
16psi
Flow meter tube
Vaporizers
Check valves
Common gas outlet
Low pressure leak test
Fail if suction bulb inflates within 10 seconds
Needs to be done everyday before 1st case
Should be repeated with vaporizers off and on
High pressure leak test
Fail if circuit does not remain pressurized at 30cm h2o
Close APL valve to pressurize circuit
Should be done between every patient and when circuit is changed
SPDD
Supply
Processing
Delivery
Disposal
Supply (SPDD)
Gases from cylinders and wall
Electricity from power cord
Processing (SPDD)
How AGM prepares gases before delivery
Delivery (SPDD)
Circuit brings gases to the patient
Disposal (SPDD)
Scavenger system removes gases from the breathing circuit
Can only remove an amount equal to FGF minus volume lost to 02 consumption
Too much removal - negative pressure in circuit
Too little removal- risk of barotrauma
APL (spontaneous breathing) and ventilator spill valve control gas going to scavenger
Parts of the scavenger
Gas collection assembly
Gas disposal tubing
Gas disposal system (gets gas from scavenger to earths atmosphere, active uses suction, passive relies on positive pressure and no suction)
Transfer tube
Interface (open vs closed)
Convenience receptacles
Found on back of AGM
Protected by circuit breakers or fuses
In theory, blowing a fuse should not affect operating of the AGM
Devices not requiring electricity
Spontaneous ventilation
Mechanical flow meters
Scavenging
Laryngoscope
IV bolus or infusion
Peripheral nerve stimulators
Five senses
Bypass vaporizers
Devices requiring electricity
Ventilators
Monitors
Lights
Digital flow meters
Bypass pumps and oxygenators
Warming blankets
Gas vapor blenders (Tec-6) or vaporizers with electronic controls (Aladin, Aisys)
Open interface
No mask on face
Open to atmosphere
Only used with active systems (suction)
Risk of healthcare team exposure
Contains reservoir
Too much suction- room air entrained
Too little suction- waste gas goes to healthcare team
No positive or negative pressure valves
No risk of barotrauma
Closed interface
Mask on face
Uses pressure valves
Doesn’t remove fresh gas from circuit
If passive- needs positive pressure relief
If active- needs both positive and negative pressure relief
Contains reservoir
5 tasks of oxygen in AGM
O2 flush valve (25-75 LPM)
O2 supply failure (less than 30 psi)
O2 pressure failure (fail safe, prevents hypoxic mixture)
Ventilator drive gas (to bellow, jet devices, auxiliary flow meter)
Flow meters (circle system-> patient)
PISS
Pin index safety system
Prevents cylinder from misconnection to AGM
Defeated if more than one washer used, or pins are removed or missing
PISS for air, O2, and Nitrous oxide
1,5
2,5
3,5
DISS
Diameter index safety system
Prevents gas hose from misconnection
Cylinder sizes
E- 2x4 (travel size, what we mostly see)
H- 4x9 (bedside when no pipeline available, in OR as N2 compressed gas)
Capacity and PSI of O2
660L, 1900-2200psi
Capacity and psi of air
600L, 1800psi
Capacity and psi for N2O
1600L, 745psi
How to determine what is left in N2O?
Weigh cylinder
Tank will read 745psi until all liquid is gone
Once liquid is gone, tank has 1/4 left
Change tank if psi drops below 745psi
Most fragile part of cylinder?
Cylinder valve
Cylinder valve parts
Body
Gas exit port
PISS
Safety relief
Conical depression for securing screw
What is the safety relief device of the cylinder valve?
Releases contents in a controlled fashion in the case of a fire (rather than exploding)
Hanger yoke
Orients cylinder
Provides gas tight seal
Ensure unidirectional flow
Contain a filter
Check babe to minimize transfilling
What is the safety release device made of?
Fusible plug made of woods metal
Frangible disc that bursts under pressure
Valve that opens under extreme pressure
Cylinder safety
No oils
Keep closed when not using
Don’t interchange regulators or gauges
Open slowly
Don’t stand up in their own
Temperature under 130 F
New washer for every tank
How is oxygen produced?
How is it delivered to hospital?
How does hospital deliver it?
Fractional distillation of liquid air
Delivered to hospital and stored as liquid at 184c
Hospital converts to gas and supplies pipeline at 50psi
Shut off valves in OR suite
To isolate leaks and interrupt supply in case of fire
Possible problems with pipeline supply
Pressure loss
Cross contamination
Cross connection
Leaks
Theft
How will you know of loss of pipeline supply?
What alarms will sound?
Indicated by pipeline pressure gauge
If pressure loss is profound, oxygen low pressure alarm sounds, and fail safe valves halt delivery of other gases
Guideline for oxygen pipeline supply failure
Trust that there is failure
Turn in back up oxygen cylinder
Call for help
Use low flow oxygen
Turn off vent and bag
Calculate time on cylinder
Do not reconnect patient until pipeline is tested
Ventilate with oxygen or room air via bag valve mask
Oxygen pressure failure device
“Failsafe”
Alarms when oxygen pressure is below 30psi (depleted tank, drop in pipeline pressure, disconnected oxygen hose)
Monitors for low oxygen pressure
Does NOT alarm for pipeline crossover and won’t detect a crack in flow meter
When this alarms, flow of N2O will stop
Hypoxia prevention safety device
Does not allow a hypoxic mixture
Flow meters are mechanically linked
Flows are pneumatically connected
Maintains O2:N2O at 1:3, or 25% oxygen minimum
When will a hypoxic mixture not be detected with hypoxia prevention safety device?
Pipeline crossover
Leaks distal to flow meter valves
Administration of 3rd gas
Defective mechanic or pneumatic components
Flow meters
Delivers gas to patient circuit
Receives low pressure
Needle valve
Thorpe tube is gas specific and tapered with largest diameter at top
Float ball - read in the middle (all other read at top)