Anaesthetic equipment

Question 1

What are the components to an aesthetic machine?

Answer 1

Oxygen supply
Flow meter
Vaporiser
Breathing circuit
Scavenging system

Question 2

The flow meter has an emergency bypass valve. What is this for?

Answer 2

Bypass anaesthia

Deliver just O2

Question 3

What does the vaporiser do?

Answer 3

Mix and vaporiser the correct ratio of O2:anaesthesia

Question 4

What is the scavenging system for?

Answer 4

Removing exhaled gases (anaesthetic and vapour)

from the environment

Question 5

Induction agents are usually IV. How long does this last? What does it give you time to do?

Answer 5

Short - 30 secs

Intubate and set up maintenance agent

Question 6

What is the maintenance agent?

Answer 6

Gas
Volatile liquid
Maintains anaesthesia

Question 7

Why are maintenance agents safer than IV agents?

Answer 7

IV require metabolism by liver to deactivate

Inhalation deactivate as soon as stop being delivered

Question 8

What are the advantages and disadvantages of a rebreathing system?

Answer 8

Large patients (>25kg) as high resistance
Economical as requires less gases

Question 9

What do you have attached to a rebreathing circuit? What does it do?

Answer 9

Soda lime canister
Removes CO2
Goes pink to white, or white to pink - need replacing

Question 10

What are the 5 main components to a breathing circuit?

Answer 10

Adapter 
Expiratory valve (adjusts pressure)
Expired gas tube (white)
Fresh gas tube (green)
Reservoir bag
(Soda lime canister)

Question 11

What does the adapter do?

Answer 11

Connect ET tube to breathing circuit

Question 12

What is the function of the reservoir bag?

Answer 12

Check patient is breathing

Do IPPV if needed

Question 13

The rebreathing system only requires a small top up of O2. How much gas is expired per minute? How many litres are requsaired per minute until anaesthesia is stable, and for maintenance?

Answer 13

10-50mls/kg/min of expired gas

2-3 litres/min until stable
0.5-1 litres maintenance

Question 14

Minute volume = volume of gas expired per minute. This is approximately…

Answer 14

200mls/kg/min

Question 15

Gas flow rate must exceed minute volume to prevent rebreathing of expired gas. How efficient, and therefore how much does minute volume need to be multiplied for per circuit?

Answer 15

Mapleson A = high efficiency 1x minute volume
Mapleson D = medium efficiency, 2-2.5x minute volume
Mapleson E = low efficiency, 2.5-3x minute volume

Question 16

What are the consequences of having a flow rate higher than needed?

Answer 16

Wasteful

Fresh gas expelled

Question 17

What are the consequences of having a flow rate slightly lower than needed? Is this accpetable?

Answer 17

Acceptable

Warmer than fresh gas

Question 18

What are the consequences of having a flow rate too low?

Answer 18

Dangerous!

Inhale CO2 –> hypercapnic

Question 19

What is Mapleson A and the modification of Mapleson A called?

Answer 19

A = Magill
Modification = parallel lack

Question 20

Mapleson D doesn’t have an alternative name. What is the name of the Mapleson D modification?

Answer 20

Coaxial Bain

Question 21

What is Mapleson E called? What does it lack? How does this affect E’s resistance?

Answer 21

Ayre’s T piece
No reservoir bag
Low resistance

Question 22

What is Mapleson F?

What is the difference between Mapleson E and F?

Answer 22

Jackson-Rees

Same as E but with reservoir bag

Question 23

The Magill breathing circuit only has what parts to the breathing circuit?

Answer 23

Expiratory valve
Reservoir bag
Fresh gas tube
Adapter
No expired tube

Question 24

If wanting to do IPPV, what do you need to do first?

Answer 24

Shut off expiratory valve and turn anaesthetic off

Difficult if far away