Different methods of anaesthesia Flashcards

(37 cards)

1
Q

What is anaesthesia?

A

Means loss of sensation which is achieved with drugs called anaesthetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is anaesthesia performed?

A

For medical reasons so that surgery/specific procedures can be carried out on patients and their pain can be controlled3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why is sedation performed?

A

A premedication prior to induction of general anaesthesia or used in a combination with local anaesthetic to negate the need for general

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a sedative drug?

A

One that produces drowsiness and calmness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is general anaesthesia?

A

An induced, reversible state of unconsciousness & provides analgesia and muscle relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the “triad of anaesthesia”?

A

Unconsciousness
Relaxation
Analgesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does general anaesthesia cause?

A

Depression of normal physiological functions

Dose-dependant depression of the CNS to reduce motor responses to noxious stimuli but also affects important functions such as breathing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How can general anaesthesia be administered?

A

IV or inhalation - or a combination of both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is dissociative anaesthesia?

A

A state where the patient is less aware of what is happening around them, however they are not rousable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When is dissociative anaesthesia used?

A

As part of a sedation plan for minor procedures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do dissociative drugs do to patients?

A

Produce a feeling of detachment from the environment and themselves by altering the conscious perception of sight, sound & touch from the other part of the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is dissociative anaesthesia characterised into?

A

Catalepsy
Catatonia
Analgesia
Amnesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What reflexes are maintained during dissociative anaesthesia?

A

Pharyngeal
Laryngeal
Corneal
Palpebral
Swallowing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the most common dissociative drug used?

A

Ketamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is Ketamine used in combination with?

A

An alpha-2 agonist (e.g. medetomidine) or a benzodiazepine (e.g. midazolam)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does ketamine not provide?

A

Muscle relaxation

17
Q

What is local anaesthesia?

A

When local anaesthesia drugs are administered to interrupt the signal from a specific nerve to the brain

18
Q

How do local anaesthetics work?

A

Reversibly bind to the sodium channels on the nerve cell
The sodium channels open along the axon like a mexican-wave which allows sodium to rush into the cell and carry on the impulse (action potential)
Once the local anaesthesia binds to the sodium channel, it interrupts the transmission of the impulse it is trying to send (sensory to motor)

19
Q

What is local anaesthesia considered as?

A

The only “true” analgesic as it is used to prevent the pains signal from reaching the brain

20
Q

How can local anaesthesia be provided?

A

Topical
Intradermal
Local infiltration
Intra-articular
Perineural
Intravenous regional anaesthesia
Epidural

21
Q

How is topical local anaesthesia used?

A

Has limited use and is usually confined to the eye & mucous membranes of the nasopharynx, larynx, penis, vagina, rectum & urethra

Applied as gel or a solution or by aerosol depending on the area

22
Q

What are examples of topical local anaesthesia?

A

Lignocaine spray (cats)
Amethiocaine drops (eyes)
EMLA cream (rabbit ears, cannulation)

23
Q

What is an intra-articular block?

A

Local anaesthetic instilled into the affect joint cavity
Commonly use post-surgery

24
Q

What is infiltration local anaesthesia?

A

Involves the injection of local anaesthetic intradermally/subdermally

25
When is infiltration local anaesthesia used?
Small or minor procedures where the volume of local anaesthetic solution is small because local toxicity of the agent may impair healing
26
What is regional anaesthesia?
Same as infiltration but involves the injection of local anaesthetic around a nerve or into a major nerve plexus to produce temporary sensation and motor blockage to a large area of the body e.g. femoral/radial nerve
27
What is perineural infiltration?
Local anaesthetic injected directly around a nerve e.g. intercostal nerve block, brachial nerve
28
What does a perineural infiltration do?
Stops the nerves conducting impulses and deadens the area of the body which that nerve supplies
29
When is perineural infiltration used?
Dental surgeries
30
What is epidural anaesthesia?
Involves the injection (using a large spinal needle) of drugs into the spinal canal at the lumbosacral space (usually between the 7th lumbar and 1st sacral)
31
When is epidural anaesthesia normally used?
In dogs but can be used in cats to relax the muscle in the hind limbs and deaden pain in that area
32
What is intravenous regional anaesthesia (IVRA)?
Involves the injection of a local anaesthetic solution distal to the site of a tourniquet (Eshmarch Bandage) on a limb
33
How long does intravenous regional anaesthesia last?
Occurs in a few minutes and lasts while the tourniquet occludes the arterial blood supply to the limb
34
Advantages of local anaesthesia
Easy to administer (no special equipment, monitoring required) Safe (animal doesn't lose consciousness) Wears off rapidly (leaving no side effects)
35
Disadvantages of local anaesthesia
Unsuitable for most procedures No muscle relaxation Unsuitable for uncooperative patients Post operative pain is higher than that of a GA
36
Advantages of general anaesthesia
Causes unconsciousness/still for procedure Pain free surger Muscle relaxation - easier to perform surgery (except ketamine)
37
Disadvantages of general anaesthesia
Requires special equipment Requires specialist monitoring Risk associated Breed, species, temperament, age of animal Complexity of procedure Experience of the surgeon Duration of effect & recovery Calibre of the nurse