Stages of Anaesthesia Flashcards
How many stages of Anaesthesia are there?
4
What does stage 1 run from and to
Voluntary excitment
from induction to loss of consciousness
What does stage 1 cause (name 4 most common and 1 potential sign)
- increased pulse
- Increased resp
- Dilated pupils
- Skeletal muscle tone increased (hyper reflexia)
Potential: vocalising, salivation, urination/defecation
What does stage 2 run from and to
Involuntary excitement Unconsciousness to rhythmic breathing
What does stage 2 commonly cause (name 4)
- cranial reflexes present
- eyes wide open
- pupils dilated
- eyes rotate ventromedial
- withdrawl reflex brisk
- breathing irregular, becoming regular
What in stage 2 can ensure smooth induction and rapid passing into stage 3?
Good premedication regime
Appropriate dose and use of induction agent
How many planes are in stage 3?
3
What is stage 3 ?
Surgical anaesthesia
What does plan 1 of stage 3 cause (name 5)
- 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
What can you perform during plane 1 of stage 3?
- Stitch ups
- Lance abscess
- Skin mass removal
What does plane 2 or stage 3 cause? (name 5)
- 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
What does plane 3 of stage 3 cause? (name 5)
- 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
What is stage 4?
Overdose!
Name 4 things stage for causes?
- 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
How do you avoid stage 4 Overdose? (name 3 things)
- 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
Why should an anaesthetic under-dose be avoided?
- 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
What is the purpose of monitoring?
To check what the animals physiological state is
What do you check during monitoring? (name 5)
- HR
- RR
- CRT
- BP
- CVP
- MM colour
- Body temp.
- Urine output
- Perfusion (bleeding)
- Oxygen saturation
Name 3 reflexes to check how deeply anaesthetised an animal is?
- Palpebral (blink) reflex
- Swallowing reflex
- Pedal reflex
- Ear flick reflex
- Corneal reflex
- Laryngeal reflex
- Muscle tone / eye position / pupil size
