Oxygen & Mixed Gas Therapy
Therapeutic respiratory gases, medical gas storage and delivery, cylinder safety systems, regulators, flowmeters, air-oxygen blending, cylinder duration, Heliox delivery, and oxygen concentrators.
Cylinder Duration Calculation Practice
Calculate each duration in minutes. Round to the nearest whole minute.
Formula
[(PSI - 500) x tank factor] / L/min = minutes
The 500 psig safety factor leaves reserve time before the cylinder runs empty.
Heliox H: (PSI x 2.50) / L/min = minutes
Tank Factors
D
0.16 L/psig
E
0.28 L/psig
G
2.41 L/psig
H & K
3.14 L/psig
Heliox H
2.50 L/psig
Exercise 1
A patient is receiving oxygen by nasal cannula during transport.
Tank
E
Gas
Oxygen
PSI
2000
Flow
5
Exercise 2
A small cylinder is being used for low-flow oxygen delivery.
Tank
D
Gas
Oxygen
PSI
1800
Flow
2
Exercise 3
A large cylinder is powering a high-flow oxygen device.
Tank
H/K
Gas
Oxygen
PSI
2200
Flow
10
Exercise 4
A G cylinder is being used for a transport device at 15 L/min.
Tank
G
Gas
Oxygen
PSI
1600
Flow
15
Exercise 5
An E cylinder has reached 1000 psig and still needs reserve time.
Tank
E
Gas
Oxygen
PSI
1000
Flow
4
Exercise 6
An H cylinder of Heliox is running through a non-rebreather mask.
Tank
Heliox H
Gas
Heliox
PSI
2200
Flow
10
Exercise 7
An H cylinder of Heliox is being used with a ventilator setup.
Tank
Heliox H
Gas
Heliox
PSI
1800
Flow
12
Current score: 0 / 7
Answers within 1 minute of the rounded result count as correct.
Heliox Delivery with O2 Flowmeters
When Heliox is delivered with an oxygen flowmeter, actual flow is greater than the indicated flow.
80/20
O2 flow x 1.8
70/30
O2 flow x 1.6
60/40
O2 flow x 1.4
Flow Exercise 1
Heliox 80/20 is set on an oxygen flowmeter at 10 L/min. Calculate the actual delivered flow.
Mix
80/20
O2 Flow
10
Factor
1.8
Flow Exercise 2
Heliox 70/30 is set on an oxygen flowmeter at 8 L/min. Calculate the actual delivered flow.
Mix
70/30
O2 Flow
8
Factor
1.6
Flow Exercise 3
Heliox 60/40 is set on an oxygen flowmeter at 12 L/min. Calculate the actual delivered flow.
Mix
60/40
O2 Flow
12
Factor
1.4
Heliox flow score: 0 / 3
Answers within 0.5 L/min of the calculated flow count as correct.