Chapter 37 Medical Gases

Question 1

How pure is oxygen made from fractional distillation? What else is left over?

Answer 1

99.5%
.5% nitrogen
And trace argon

NO WATER IS LEFT OVER

Question 2

What are the steps in fractional distillation?

Answer 2

• air is filtered to remove pollutants, water, and CO2
• purified air is liquified by compression and cooled by RAPID EXPANSION
• mixture is heated slowly in distillation tower
• liquid is transferred to cryogenic storage

Question 3

What are the 2 methods for physical separation of oxygen?

Answer 3

• use of sieves composed of aluminum silicate pellets that bind to N2
• pull it from ambient air through oxygen concentrators

Question 4

What is the percent concentration of oxygen from using sieves during physical separation?

Answer 4

90%

Question 5

What is the percent concentration of oxygen from using oxygen concentrator during physical separation?

Answer 5

40%

Question 6

How is medical air usually produced?

Answer 6

By filtering and compressing atmospheric air

Question 7

What must medical air be free of before use?

Answer 7

It must be free of oil, particulate contamination, and DRY.

Question 8

What is the most common method used for drying medical air?

Answer 8

Cooling, which produces condensation to separate water.

Question 9

What is the most common use of CO2?

Answer 9

To calibrate blood gas analyzers

Question 10

How do we use helium?

Answer 10

Helium at 100% is not used

• it’s mixed with oxygen to produce heliox.
• it’s used to manage airway obstruction.

Question 11

What is nitric oxide(NO) used for?

Answer 11

Near term infants with hypoxic respiratory failure when mechanical vent is failing.

Question 12

What is nitrous oxide (N2O) used for?

Answer 12

Anesthesia

CNS depressant

Question 13

What is the common way for hospitals to produce oxygen?

Answer 13

Fractional distillation

Question 14

What is the color for oxygen?

Answer 14

Green

Question 15

What is the color for CO2?

Answer 15

Gray

Question 16

What is the color for N20?

Answer 16

Blue

Question 17

What is the color for helium?

Answer 17

Brown

Question 18

What is the color for N?

Answer 18

Black

Question 19

What is the color for air?

Answer 19

Yellow

Question 20

What are the markings on the side of a gas cylinder?

Answer 20

• DOT
• cylinder class (3A or 3AA)
• the normal filling pressure
• EE for elastic expansion
• results of testing the tank

Question 21

How often are safety tests conducted on tanks?

Answer 21

Every 5 to 10 years

Question 22

What does a + sign mean on a tank?

Answer 22

DOT approval for filling of 10% over service pressure. 2015 psi to 2200 psi

Question 23

What are placed on hospital floors equipped with gas piping systems in case of an emergency?

Answer 23

Zone valves

Question 24

What are the 3 basic indexed safety systems for medical gas?

Answer 24

• ASSS
• PISS
• DISS

Question 25

What tanks is ASSS used for?

Answer 25

H/K or large tanks

Question 26

What tanks is PISS used for?

Answer 26

Smaller tanks like E

Question 27

Where would you find DISS outlets?

Answer 27

- pressure reducing valves - at station outlets - flowmeters and equipment

Question 28

What are 3 basic designs of safety relief valves?

Answer 28

- frangible disk - fusible plug - spring loaded valve

Question 29

How does a frangible disk work?

Answer 29

The disk ruptures at a specific pressure

Question 30

How does a fusible plug work?

Answer 30

The plug melts at a specific temp

Question 31

How does a spring loaded valve work?

Answer 31

The valve opens at a set high temp

Question 32

How do you know how much oxygen is left in a liquid oxygen tank?

Answer 32

By its weight, not pressure

Question 33

How do you calculate how much oxygen is left in the liquid oxygen tank?

Answer 33

``` 1L is 2.5 lbs and 860L of oxygen So, Weight X 860 ----------------- = amount of gas (L) 2.5lbs/L ``` Then you can calculate duration with prescribed flow

Question 34

What makes thorpe tubes not recommended for patient transport?

Answer 34

They are gravity dependent because readings are dependent on the floating steel ball inside

Question 35

What is a reducing valve?

Answer 35

Device used to fix pressure to desired working pressure. | It can be either set (like 50psi) or adjustable

Question 36

What is the difference between a single stage and a multistage regulator?

Answer 36

- A single stage breaks down pressure from tank directly to 50 psi - multistage regulator uses multiple chambers to get to working pressure, allowing for more precise pressure outputs