Term
| Quantifying Remaining Gas* |
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Definition
With a liquefied gas such as N2O pressure remains constant until all liquid is evaporated, then pressure begins to drop
With a non-liquefied gas such as O2 pressure will decrease proportionally as gas is depleted
A gauge can be used to quantify remaining gas in a cylinder of non-liquefied gas
The cylinder must be weighed to quantify remaining gas in a cylinder of liquefied gas |
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Term
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Definition
Delivered to the machine from hospital’s plumbed in gas supply
Used if hospital gas supply fails or if pipeline supply is unavailable |
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Term
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Definition
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Term
| Normal pipeline pressure is |
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Definition
| ~ 50-55 psi (345-380 kPa) |
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Term
| Normal tank pressure is reduced to |
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Definition
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Term
| AGM preferentially draws from the higher pressure pipeline supply at |
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Definition
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Term
| If pressure drops or supply fails AGM will draw from tank supply at |
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Definition
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Term
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Definition
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Term
| Cylinder valves are closed |
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Definition
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Term
| Avoids unrecognized cylinder depletion due to |
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Definition
| pipeline pressure variations |
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Term
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Definition
D, E, & H are most common medical sizes
Protective cap should be used over valve
Cylinders should not be stored upright without safety chains or other security devices
Keep cylinders away from heat sources
Steel cylinders cannot be used near MRI suites
Store unused cylinders in designated areas |
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Term
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Definition
The T° above which a substance cannot be liquefied by addition of pressure
Critical T° of O2 is -118°C
Critical T° of N2O is 36.5°C
O2 is a gas at room T°, N2O is a mixture of gas and liquid
Liquid O2 is stored in a pressurized vacuum-insulated container |
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Term
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Definition
Cheaper and less bulky method of storing large quantities of O2
Liquid O2 must be stored below its boiling point to avoid evaporation (-297°F/-183°C)
Stored in pressurized vacuum-insulated tanks
Heat of vaporization helps keep tank cold
Temperature drops when gas is used
If no gas is used tank slowly warms, pressure rises due to evaporation, and O2 is vented out |
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Term
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Definition
Diameter Indexed Safety System
Color coded tubing
Inlet filters
Check valves
Hose pressure is 50-55 psig (345-380 kPa)
Gases usually include O2, N2O, Air, N2
Vacuum (for waste gas evacuation & suction) |
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Term
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Definition
Crossovers between O2 and other gases are possible
Incorrect outlets can be installed on gas plumbing or hoses
Pipelines may be filled with the wrong gas after repair or construction
O2 concentration monitor on the AGM is essential for detection of crossovers |
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Term
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Definition
Devices actuated by gas pressure will function with the wrong gas
Cylinders can also be filled with the incorrect gas or a mixture of gases
Cylinders can contain contaminants
PIS system can be defeated |
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Term
| Suspected Crossover Actions |
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Definition
Disconnect the 02 supply hose
Open a fresh 02 cylinder for gas supply to the AGM and patient
If this does not correct poor oxygenation in the absence of a patient condition
Ventilate the patient using room air and an Ambu Bag |
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Term
| Diameter Indexed Safety System |
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Definition
Designed to prevent incorrect gas connections
Body, nipple, and nut
Body has 2 concentric bores
Nipple has 2 shoulder diameters
They must match to allow connection |
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Term
| Diameter Indexed Safety System |
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Definition
As the Compressed Gas Association # (CGA) of the nipple increases, the small shoulder diameter increases (diagram page 36 D & D)
The large shoulder diameter decreases |
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Term
Gas Cylinders
Color coded: US/International |
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Definition
Air: Yellow/White and Black
Carbon Dioxide: Gray/Gray
Helium: Brown/Brown
Nitrogen: Black/Black
Nitrous Oxide: Blue/Blue
Oxygen: Green/White |
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Term
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Definition
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Term
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Definition
| pounds per square inch gauge (Difference between measured pressure and atmospheric pressure) |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| 14.7 psi or 1030 cm H2O or 760 mmHg |
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Term
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Definition
Size OD Length Weight/lbs.
E 4-1/4 26 14
H 9-1/4 51 119 |
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Term
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Definition
Air/625L
Carbon Dioxide/1,590L
Helium/500L
Oxygen/660L
Nitrogen/610L
Nitrous Oxide/1,590L |
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Term
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Definition
Air/6,550
Carbon Dioxide/N/A
Helium/6,000
Oxygen/6,900
Nitrogen/6,400
Nitrous Oxide/15,800 |
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Term
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Definition
Air/1,900 psi
Carbon Dioxide/838 psi
Helium/1,600 psi
Oxygen/1,900 psi
Nitrogen/1,900 psi
Nitrous Oxide/745 psi |
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Term
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Definition
Air/2,200 psi
Carbon Dioxide/N/A
Helium/2,200 psi
Oxygen/2,200 psi
Nitrogen/2,200 psi
Nitrous Oxide/745 psi |
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Term
| E Cylinder Physical State* |
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Definition
Air/Gas
Carbon Dioxide/Gas + Liquid (<88°F)
Helium/Gas
Nitrogen/Gas
Nitrous Oxide/Gas + Liquid (<98°F)
Oxygen/Gas |
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Term
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Definition
Cylinder body with an integral valve
Body is constructed of steel
Aluminum version available (MRI safe)*
E size is most frequently used in the OR
Should be stored in designated areas and racks
Nitrous Oxide cylinders should be stored in secure area due to diversion potential
Do not use oil or grease on valves (explosion risk) |
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Term
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Definition
Allows for gas egress and ingress
Valve is considered an integral part of the cylinder and is not end user serviceable
Has PIS system and gas outlet with washer
Right hand thread stem closure
Valves are most fragile part of tank
Protect with a cover during transport |
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Term
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Definition
Stem
Body
Safety relief valve
Gas port
Conical depression
PISS pin holes
Threaded valve outlet |
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Term
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Definition
Frangible disc (ruptures under pressure excess)
Pressure relief valve (opens when pressure exceeds safety setting)
Fusible plug (melts and releases pressure in extreme heat situations)
Often called Wood’s metal plug
Combination device (frangible disc/fusible plug) |
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Term
| Pin Indexed Safety System |
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Definition
Holes on the cylinder valve
Pins on the yoke or pressure regulator
Designed to prevent wrong cylinder attachment
Wrong gas in cylinder still possible
Yoke without pins could take any cylinder
Can be defeated by using multiple washers or due to missing pins |
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Term
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Definition
Supports and attaches cylinder to machine
Has check valve to prevent back flow
Provides unidirectional gas flow
Pin indexed safety system
Has a clamping device that resists leaks
Contains a filter
Cylinder pressure gauge and cylinder pressure regulators
Do not use oil or grease due to explosion risk |
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Term
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Definition
Body
Retaining device
Nipple
Index pins
Sealing washer
Filter
Check valve |
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Term
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Definition
Store cylinders in designated racks
Do not stand upright unsecured
Do not use oil or grease on valves
Use only the proper gas regulator
Keep away from heat sources and flames
Don’t carry cylinders in your car like this guy! |
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Term
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Definition
Patented in France in 1849 by Eugene Bourdon
Utilizes a curved hollow flexible flattened tube with a closed end
The tube straightens as pressure increases and drives the indicator needle via a sector and pinion gear
Good sensitivity, linearity, and accuracy |
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