Anesthesia Machine

Question 1

In what order do we do the checks?

Answer 1

High pressure check, medium pressure check and then low pressure check.

Question 2

How is a high pressure check done?

Answer 2

Check cylinder tag to check if it’s full, in use or empty. Check bodock seal on the yoke, attach it to the cylinder. Turn on oxygen all the way, check the level of oxygen. Then turn off oxygen. Make sure the flow meter is off. Leave the machine for 20 minutes. Come back and check if the pressure gauge needle has dropped.

Question 3

How is a medium pressure check done?

Answer 3

Turn on oxygen then turn flow meter up to 8, leave for 30 seconds, then turn off. Turn on flowmeter onto 2 litres, leave for 30 seconds, then turn off. Make sure bobbin doesn’t drop for either. Turn flow meter to 1, and block off oxygen outlet with palm or thumb. There will be a drop but it shouldn’t drop significantly. Turn flow meter off. Turn vaporiser on up to 5, then back to 0, make sure there is no stiffness. Check how full vaporiser is and filling parts are closed.

Question 4

How is a low pressure check done?

Answer 4

Check if soda-lime needs to be changed or looks dusty. Connect breathing circuit, close off pop-off valve. Cover the patient end of the circuit with palm, cork or leg. Turn on the oxygen circuit to fill reservoir bag, once full turn off flow meter. Check the bag for holes by lightly squeezing, make sure no air is lost through the bag. If the bag stays full, open pop-off valve and make sure the circuit is emptied through scavenging unit only by continuing to cover the patient end of the circuit. Repeat with the next circuit. Turn off oxygen and turn flow meter up to 2 litres or more, empty the machine through scavenging system. Disconnect yoke.

Question 5

How long should the cylinder be left for when doing a high pressure check?

Answer 5

20 minutes.

Question 6

What does it mean if the pressure gauge drops during the 20 minute wait for the high pressure check? What should be done?

Answer 6

It indicates a leak in the high pressure system. Check the yoke and make sure it’s secure, if secure it may be issues with the valves on the cylinder or with various connections with the regulator. Request assistance from the oxygen supplier.

Question 7

How does the yoke attach to the cylinder?

Answer 7

Special pins that fit perfectly into the cylinder.

Question 8

Why can only an oxygen cylinder be used with the yoke?

Answer 8

The pins on the yoke won’t fit with any other cylinder except for oxygen cylinders.

Question 9

How often should a high pressure check be done?

Answer 9

Beginning of each surgical day.

Question 10

How should a flow meter dial or pop-off valve be turned?

Answer 10

Gently, with fingers.

Question 11

How often should a medium pressure check be done?

Answer 11

Beginning of each surgical day.

Question 12

How often should a low pressure check be done?

Answer 12

Prior to each case.

Question 13

What amount should we never let the anaesthetic agent in the vapouriser drop below? How much should it be filled with?

Answer 13

Never should drop below 1/3 full. It should be filled almost completely but with a small gap so people can see how much vaporiser is inside or never above the marker if there is one.

Question 14

What safety features do different vaporisers have?

Answer 14

Leaver, buttons or pushing in the dial to turn it.

Question 15

How full should a reservoir bag be during a low pressure check on either breathing circuit?

Answer 15

Full enough to get rid of wrinkles but doesn’t need to be completely full.

Question 16

What size reservoir bag is needed for a patient under 10kg?

Answer 16

1L

Question 17

What size reservoir bag is needed for an under 20kg patient?

Answer 17

2L

Question 18

What size reservoir bag is needed for an under 30kg patient?

Answer 18

3L

Question 19

When should soda-lime be changed?

Answer 19

When half is coloured, always check after surgery.

Question 20

What does it mean if the bobbin drops drastically during a medium pressure check?

Answer 20

May have a leak across one or more components of the machine.

Question 21

Where are reservoir bag holes most commonly found?

Answer 21

Around the top of the bag where it attaches to the machine.

Question 22

What can be used to help find leaks in the machine?

Answer 22

Soapy water. It will bubble where there are leaks.

Question 23

What makes soda-lime react? How does it react?

Answer 23

CO2 absorption. It changes colour.

Question 24

How can you tell the machine is emptied of oxygen when removing the yoke?

Answer 24

If there’s oxygen still inside, a hiss will be heard.

Question 25

Why is 100% oxygen used?

Answer 25

Air is only 21% oxygen. Gives time in emergencies and increases safety for the patient.

Question 26

What allows the anesthetic machine to function?

Answer 26

Pressure from the oxygen tank.

Question 27

What amount of pressure does an oxygen tank contain?

Answer 27

2,200 pounds per square inch.

Question 28

What weight should an animal need to be below to go onto a non-rebreathing circuit?

Answer 28

Below 8-10kg. Remember, it’s based on ideal body weight.

Question 29

What’s the difference between coloured and non-coloured tubes on the breathing circuit?

Answer 29

Coloured carries fresh gas, clear carries exhaled gas/carbon dioxide.

Question 30

What size reservoir bag is needed for an above 30kg patient?

Answer 30

4L