Stages of Anaesthesia

Question 1

How many stages of Anaesthesia are there?

Answer 1

4

Question 2

What does stage 1 run from and to

Answer 2

Voluntary excitment

from induction to loss of consciousness

Question 3

What does stage 1 cause (name 4 most common and 1 potential sign)

Answer 3

• increased pulse
• Increased resp
• Dilated pupils
• Skeletal muscle tone increased (hyper reflexia)
  Potential: vocalising, salivation, urination/defecation

Question 4

What does stage 2 run from and to

Answer 4

Involuntary excitement Unconsciousness to rhythmic breathing

Question 5

What does stage 2 commonly cause (name 4)

Answer 5

• cranial reflexes present
• eyes wide open
• pupils dilated
• eyes rotate ventromedial
• withdrawl reflex brisk
• breathing irregular, becoming regular

Question 6

What in stage 2 can ensure smooth induction and rapid passing into stage 3?

Answer 6

Good premedication regime

Appropriate dose and use of induction agent

Question 7

How many planes are in stage 3?

Answer 7

3

Question 8

What is stage 3 ?

Answer 8

Surgical anaesthesia

Question 9

What does plan 1 of stage 3 cause (name 5)

Answer 9

• breathing regular and deep
• limb movement absent
• pinch reflex brisk
• Nystagmus
• Eye ventromedial
• |Third eye partly across
• Slower palpebral reflex
• Brisk corneal reflex
• Slight cardiovascular depression

Question 10

What can you perform during plane 1 of stage 3?

Answer 10

• Stitch ups
• Lance abscess
• Skin mass removal

Question 11

What does plane 2 or stage 3 cause? (name 5)

Answer 11

• Eye is ventromedial
• Palpebral reflex is sluggish then stops
• Corneal reflex persists
• Pupils are constricted
• Muscles are relaxed
• Pedal reflex is sluggish then lost
• Tidal volume is reduced
• HR and BP reduced slightly
• Adequate for most procedures

Question 12

What does plane 3 of stage 3 cause? (name 5)

Answer 12

• Eye is central
• Eyelids are open
• Pupil size increases
• Resp rate is reduced
• Tidal volume is reduced
• Pedal reflex is lost
• HR and BP is reduced
• Adequate for all procedures

Question 13

What is stage 4?

Answer 13

Overdose!

Question 14

Name 4 things stage for causes?

Answer 14

• Progressive respiratory failure (diaphragmatic function only)
• Pulse either very high or low
• Eye central with eyelids open
• Pupil dilated
• Cornea dry (reflex absent)
• MM cyanosis to grey
• CRT increased

Question 15

How do you avoid stage 4 Overdose? (name 3 things)

Answer 15

• adequate pre-anaesthetic assessment
• Appropriate pre-med including dosage
• Appropriate use of induction and maintenance drugs
• Adequate and informed monitoring (use of monitoring equipment)
• Team effort

Question 16

Why should an anaesthetic under-dose be avoided?

Answer 16

• animal may become conscious (causing pain and stress)
• May move during surgery
• May extubate itself
• Release of adrenaline/nor-adrenaline may lead to cardiac arrhythmias and arrest
• Tachypnoea may cause impaired gas exchange and uptake of volatile agent

Question 17

What is the purpose of monitoring?

Answer 17

To check what the animals physiological state is

Question 18

What do you check during monitoring? (name 5)

Answer 18

• HR
• RR
• CRT
• BP
• CVP
• MM colour
• Body temp.
• Urine output
• Perfusion (bleeding)
• Oxygen saturation

Question 19

Name 3 reflexes to check how deeply anaesthetised an animal is?

Answer 19

• Palpebral (blink) reflex
• Swallowing reflex
• Pedal reflex
• Ear flick reflex
• Corneal reflex
• Laryngeal reflex
• Muscle tone / eye position / pupil size