Getting Gas to Patient: Anesthetic Machine

Question 1

what composes the anesthetic machine

Answer 1

1. source of carrier gas
2. flowmeter
3. vaporizer
4. scavenging system

Question 2

what is the purpose of the anesthetic breathing system

Answer 2

deliver gases from machine to patient

Question 3

what are carrier gases

Answer 3

1. oxygen
2. nitrous oxide
3. medical air

Question 4

what are piped gases

Answer 4

cylinder manifold

liquid oxygen storage

but you still need O2 source on anesthetic machine

Question 5

what colour is the oxygen tank in UK

Answer 5

old: black
new: white body and white shoulder

USA: green

Question 6

what colour is the nitrous oxide tank in UK

Answer 6

old: bue
new: white body blue shoulder

USA: blue

Question 7

what colour is the medical air tank in UK

Answer 7

old: grey
new: white body and black/white shoulder
usa: yellow

Question 8

what determines how much gas is in the tank

Answer 8

pressure gauge

Question 9

what is the formula to determine how much gas is in the tank

Answer 9

P used/P full = V used/ V full

V used = P used/ P full x V full

Question 10

how do you determine how much nitrous oxide is in the tank

Answer 10

can’t use pressure gauge need to weigh it

Question 11

what are the safety features on the tanks

Answer 11

1. colour coding (cylinders, pipelines)
2. pin-indexing (cylinder yokes, wall sockets)

Question 12

what are flowmeters

Answer 12

needle valve

tapered tube

float/bobbin

Question 13

how do you read flowmeter

Answer 13

read from top of bobbin

read through centre of ball

Question 14

what are vaporizers

Answer 14

most inhaled gases are volatile –> a vaporizer adds anesthetic vapor to the carrier gas + provides a means of delivering a safe concentration to the patient

Question 15

what are waste anesthetic gases

Answer 15

chronic exposure to trace concentration so anesthetic vapors and gases can be detrimental

Question 16

how does the UK regulate exposure to anesthetic gases

Answer 16

badges

max exposure limits are set

Question 17

what are the 2 types of scavenging systems

Answer 17

1. passive
2. active

Question 18

what are passive scavenging systems

Answer 18

1. length of tubing that conducts waste gases out through an open window

or

2. length of tubing that conducts waste gases to a canister of activated charcoal

Question 19

what are active scavenging systems (2)

Answer 19

1. extractor fan generates negative pressure that draws waste gases from breathing system, venting it outside
2. air break receiver prevents transmission of negative pressure to breathing system (effective for all waste gases)

Question 20

what are ways to limit exposure (5)

Answer 20

1. good air conditioning
2. avoid using face masks to deliver gases & vaporizers
3. minimize equipment leaks
4. fill vaporizers at end of day and use key fillers
5. monitor exposure