anaesthesia - circuits

Question 1

what colour are oxygen cylinders?

Answer 1

black with white top or all white

Question 2

what colour are N2O cylinders?

Answer 2

blue

Question 3

what colour are air cylinders?

Answer 3

grey with black and white top

Question 4

what is the difference between oxygen and nitrous gauges?

Answer 4

-oxygen the gauge indicated the volume left -nitrous the gauge will read full if anything in it so weight it (due to vapour)

Question 5

what is the pin-index system?

Answer 5

so the wrong cylinder cant be connected to wrong yoke on the machine

Question 6

what is the bodek seal?

Answer 6

between cylinder and machine for gas tight seal

Question 7

what are schrader valaves?

Answer 7

at end of pipe supply so cant connect wrong cylinder to pipe -colour coded

Question 8

what does the pressure regulator (reducing valve) do?

Answer 8

reduces cylinder pressure so safer and constant -between the cylinder and flowmeter

Question 9

what do flowmeters and needle valves do?

Answer 9

mesure flow rate of a single gas, controlled mannually

Question 10

what is a vaporizer?

Answer 10

a chamber containing the volatile anaesthetic agent that a portion of the fresh gas passes through -keep upright -fill with key-index system

Question 11

what is the pressure release valve?

Answer 11

releases gases into room if builds up in system so doesnt go into animal

Question 12

what is scavenging?

Answer 12

all waste gases

Question 13

what is minute volume?

Answer 13

TV x RR

Question 14

what is normal Tidal volume?

Answer 14

10-15 ml/kg

10 for larger animals

Question 15

what is an approximation of minute volume?

Answer 15

200 ml/kg/min

Question 16

how is fresh gas flow calculated?

Answer 16

minute vol x circuit factor

= weight x 10-15 ml x rr x system factor

= or 200ml/kg x system factor

Question 17

what happens is FGF is too low?

Answer 17

will rebreathe

Question 18

advantages of non-rebreathing systems

Answer 18

cheap co2 absorber not needed what is inspired controlled by flowmeter and vaporiser low resistance to breathing rapid change in depth possible

Question 19

disadvantages of non-rebreathing systems

Answer 19

high FGF needed high consumption of volatile agent expired heat and moisture lost

Question 20

advantages of rebreathing systems

Answer 20

lower FGF more economical low volatile agent consumption rebreathed gas is already warm and humidified

Question 21

disadvantages of rebreathing systems

Answer 21

exact inspired composition unknown expensive slow to change depth

Question 22

What systems can you IPPV on?

Answer 22

Ayers Bain Circle

Question 23

what is a magill system?

Answer 23

non-rebreathing -animals over 10 kg -circuit factor 1-1.5 -valve close to drapes so not used much

Question 24

which system can be used on animals under 10 kg?

Answer 24

mini lack ayre’s t piece humphrey ADE

Question 25

what is a lack system?

Answer 25

non-rebreathing

• standard over 10 kg, mini 2- 10kg
• circuit factor 1-1.5

Question 26

what is an ayre’s T piece system?

Answer 26

non-rebreathing -can use under 10 kg -circuit factor 2.5-3

Question 27

what is a bain system?

Answer 27

non-rebreathing -over 10 kg but not too big(over 20) -circuit factor 2.5-3

Question 28

what is a humphrey ADE?

Answer 28

non-rebreathing -circuit factor alters with weight -valve up (A) - for spontaneous respiration -valve down (D/E) - for IPPV

Question 29

what is a circle system?

Answer 29

rebreathing -need a soda lime canister -only over 10 kg -when first connect use high FGF until animal stable

Question 30

what is a to- and -fro system?

Answer 30

rebreathing -horses in the field -cannister near ET tube and heavy so can pull out

Question 31

what is the komesaroff and stephen’s machines?

Answer 31

rebreathing -circle with a low resistance vaporiser in circuit

Question 32

What system is this?

Answer 32

Magill

non-rebreathing

Question 33

What system is this?

Answer 33

Lack (parallel)

coaxial would have one tube inside the other

Question 34

What system is this?

Answer 34

Ayre’s T piece

Question 35

What system is this?

Answer 35

Bain

Question 36

What system is this?

Answer 36

Humphrey ADE

Question 37

What system is this?

Answer 37

Circle

Question 38

What is the mapleson classification?

Answer 38

from A-F related to efficncy and how much FGF is needed

Question 39

Steps to checking an anaesthetic machine

Answer 39

1) switch on full reserve cylinder
2) pressure should be 150kPa
3) check o2 flush
4) check flowmeter - check bobbin rises and returns to zero and is spinning
5) turn off full reserve
6) turn on flowmeter to hear o2 alarm as o2 empties from machine
7) turn on in use cylinder and state pressure
8) check nitrous if fitted
9) check vaporiser - firmly attached, check fluid level, check dial on top moves freely
10) check for leaks in circuit - o2 on, attach circuit and close APL valve and occlude patient end and turn on flowmeter - resevoir bag should fill (listen for leaking) and the bag should stay inflated when squeezed. Open APL valve and squezee bag and gas should go out scavenging
11) if coaxial check inner tube by occluding it

Question 40

What system would you use for a small animal that may need ippv?

Answer 40

ayre’s t piece

Question 41

what system do ou use for a dog over 20 kg?

Answer 41

magill or lack

Question 42

what system would you use for a dog over 20 kg and need to IPPV?

Answer 42

circle

Question 43

what does APL stand for?

Answer 43

adjustable pressure limiting

Question 44

which non-rebreathing circuits are most economical?

Answer 44

magill and lack (ml)

low circuit factor

cant IPPV

*magill has APL valve at mouth end