Medical Gas Systems

Question 1

What are two sources of gas for the anesthesia machine?

Answer 1

pipeline, ecylinder

Question 2

What is the DISS system? What’s it for?

Answer 2

Diameter Index Safety System, pipeline gases

Question 3

What are properties of the DISS system? (4)

Answer 3

non interchangeable connections for medical gas
connection is: body, nipple, nut
can only fit together w/ the right connections
every anesthesia machine uses it

Question 4

What is the PISS system? What’s it for?

Answer 4

Pin Index Safety System, gas cylinders

Question 5

What are the properties of the PISS system? (3)

Answer 5

series of pins to connect gas cylinders to matching yoke
each gas has unique pin combo
prevents wrong incorrect connections

Question 6

What are the pin indexes for the following gases?

air
O2
N2O 
CO2
Entonox

Answer 6

air 1,5
O2 2,5
N2O 3,5
CO2 1,6
Entonox 7

Question 7

What is the link proportioning system?

Answer 7

A safety system, a fail safe mechanism that prevents hypoxic mixture of gas. If you turn on N2O, the system will also turn on O2. The ratio can never drop below 3:1, or at least room air concentration of O2.

Question 8

What is a MAC of N2O?

Answer 8

105%

Question 9

What does MAC mean?

Answer 9

minimum alveolar concentration, end expiration concentration of anesthetic required to suppress movement to surgical stimuli in 50% of subjects

Question 10

Do electronic flow meters have a link proportioning system?

Answer 10

Yes, it is internalized

Question 11

What are the US system’s color codes for the following gases?

O2
N2O
Air
N2
He
Vacuum
Waste

Answer 11

O2 green
N2O blue
Air yellow
N2 black
He brown
Vacuum white
Waste purple

Question 12

How many L of O2 and at what pressure is a full e-cylinder?

Answer 12

660 L, 2000 psi

Question 13

How many L of N2O and at what pressure is a full e-cylinder?

Answer 13

1590 L, 745 psi

Question 14

True or false, pressure determines the fullness of a tank of N2O?

Answer 14

False (weighing the tank does, because as long as liquid remains in tank, pressure will read 745 psi)

Question 15

How much does a full ecylinder of N2O weigh?

Answer 15

20.7 lbs

Question 16

How much does an eyclinder with no liquid N2O weigh?

Answer 16

14.2 lbs

Question 17

How much does an eyclinder tank weigh empty?

Answer 17

12.9 lbs

Question 18

What formula is used to estimate how much time you have left in an ecylinder?

Answer 18

psi in tank/(200 x L/min flow of O2) = hours remaining of gas

Question 19

Who specifies the purity of medical gases?

Answer 19

US Pharmacopoeia

Question 20

Who establishes the requirements for manufacturing, filling, qualification etc.?

Answer 20

Department of Transportation

Question 21

What permanent markings are found on ecylinders? (8)

Answer 21

date, serial numbers, test markings, cylinder specification, type of material, service/working pressure, neck ring ID, retest markings (q5 years, q10 years if a star), + means over filled by 10%

Question 22

Whats a diamond label on ecylinder indicate?

Answer 22

denotes hazard class

Question 23

What is in charge of the labeling system for gas cylinders?

Answer 23

Compressed Gas Association (CGA)

Question 24

How do you properly use a cylinder tag?

Answer 24

When first opened, rip off portion of tag that says FULL, then when empty rip off portion that says IN SERVICE. Leaves EMPTY label behind signaling it needs to be refilled.

Question 25

What are 7 safe handling procedures for cylinders?

Answer 25

never stand upright without support
never leave empty on the machine
never leave plastic tape on port while installing cylinder
never rely on cylinder color for identification
never oil valves - fire risk
new cylinders should be cleared of dust/debris by briefly cracking the cylinder away from self and others
when cylinder is in use make sure it is fully open to ensure delivery of adequate gas