Inhalational Anaesthetics Flashcards Preview

Veterinary Nursing Anaesthesia and Analgesia > Inhalational Anaesthetics > Flashcards

Flashcards in Inhalational Anaesthetics Deck (42)
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1

How are inhaled anaesthetics transported?

in carrier gasses

2

Name 3 types of inhaled anaesthetics

- Halothane
- Isoflurane (MUST KNOW)
- Sevoflurane (MUST KNOW)
- Desflurane
- Enflurane
-Methoxyflurane

3

What are these inhaled anaesthestics known as

Volatile anaesthetic agents

4

How is the level of agent determined

by dial up vaporiser

5

What do all inhaled anaesthetics cause some degree of

- respiratory depression
- cardiovascular depression

6

Do inhaled anaesthetics provide analgesia?

no

7

What are the two most commonly used inhaled anaesthetics

Isoflurane and Sevoflurane

8

Name the two carrier gasses?

Oxygen, Nitrous oxide, Carbon dioxide

9

What cylinder is oxygen kept in?

Black cylinders with white shoulders

10

What are 3 uses of oxygen

- 100% given to animals with anaemia, pulmonary pathology, hypoventilation, animals recovering from N2O anaesthesia/ supplied during recovery if needed
- Used operatively routinely
- Used pre-operatively if you think intubation will be difficult e.g. brachycephalics
- Post operatively

11

Name a benefit of oxygen?

- Does not depress ventilation
- Does not cause toxic nervous changes
- Does not cause toxic pulmonary changes
- Can be combined with nitrous oxide

12

How is nitrous oxide delivered?

from compressed air tanks

13

What is nitrous oxide combined with

oxygen

14

What % of concentration will provide analgesic effects?

20%

15

What % is nitrous oxide usually delivered at?

66% (33% oxygen)

16

What is the ratio of nitrous oxide to oxygen in non-rebreathing circuits?

2:1

17

What is the ratio of nitrous oxide to oxygen in rebreathing circuits?

1:1

18

Why can the use of nitrous oxide cause the anaesthetic sparing effect

if delivered at 66% then lowers need for high volatile agent levels

19

With what inhaled anaesthetic does nitrous oxide have a second gas effect?

Halothane

20

What cylinders do N2O come in?

Blue

21

What must you do once N20 is switched off?

oxygenate patient

22

Name 3 negatives with nitrous oxide?

- not to use more than 80% (will lower oxygen below normal levels and patient will go hypoxic)
- Hypoxia
- N20 diffuses into gas-filled spaces and accumulates
- Do not use in bowel obstruction
- Do not use in middle ear disease
- Delivering nitrous oxide with pneumothorax can double the size of the pneumothorax in 10 minutes

23

When might hypoxia occur? And how do you avoid it

if animal is breathing room air - as room air contains high levels of nitrogen
Avoid it by giving al patients 5-10 minutes of pure oxygen once N2O is switched off

24

What piece of equipment should you use if concerned about hypoxia?

Pulse oximeter

25

What cylinder is carbon dioxide in?

grey

26

When is co2 used?

if patient is hypo-capnic

27

At what level is co2 used?

4%

28

Name 3 advantages of inhalational anaesthetics over injectable anaesthetics?

- depth of anaesthesia readily altered
- Concentration of anaesthetic in blood or brain may be altered rapidly by changing vaporiser setting
- Elimination of inhaled agents occurs mainly via the lungs therefore advantage of liver/kidney patient
- Allows constant delivery of oxygen alongside agent
- Most patients are intubated therefore IPPV may be performed and anaesthetic is 'safe'
- Delivered to the lungs and then goes very quickly across the blood brain barrier to the brain and into the CNS

29

Name 3 disadvantages of using inhaled anaesthesia over injectable anaesthesia?

- need for anaesthetic machine and range of equipment (costly)
- Hazards, personnel risk, explosion risk
- Knowledge required of circuits and machine
- Induction and recover possibly delyaed due to lung pathology (not great induction agents)
- Only alternative is IV total anaesthesia

30

What is MAC

minimum alveolar concentration = measure of the anaesthetic potency