anesthesia- stages

common reflexes monitored under anesthesia

• corneal

• ear flick

• palpebral

• pedal

commonly monitored vital signs under anesthesia

• BP

• ETCO2

• SpO2

• ECG

other commonly monitored parameters

• jaw tone

• eye position

• pupil size

• swallowing

corneal relfex

• touch corenea with sterile swab or use sterile water

• animal should blink and withdraw eye into orbit

• should be present during safe/surgical planes of anesthesia

palpebral reflex

• gently tap media; canthus of the eye and observe blinking reflex

• present early (ie. intubation) but usually dissapears during safe/surgical planes of anesthesia

pedal reflex

• pinch or squeeze digit or pad

• should be absent during safe/surgical planes of anestheisa

jaw tone

• open jaw and observe muscle tone

• should have some jaw tone during safe/surgical planes of anesthesia

  • relaxed but still present

  • puppies/kittens have weak jaw tone

eye position

• eyes should rotate ventromedial during safe/surgical planes of anestheisa

• sometimes may be central to slightly medial

  • can indicate too light/too deep

  • be influenced by drugs used or breed

pupil size

• slight mydriasis under safe/surgical planes of anesthesia

swallowing

• absent under anesthesia

stage 1- voluntary excitement

• Immediately after admin of injectable or inhalant anesthetic

• Animals are conscious but disoriented

• Behavior depends on drugs/method of induction

• All reflexes present

stage 2- involuntary excitement

• Begins with loss of consciousness

• Look like they are “fighting” anesthesia but these are not conscious actions

• All reflexes present

stage 3- plane 1

• Light plane of anesthesia

• Can be intubated

• Not able to withstand surgery

stage 3- plane 2

• Medium plane of anesthesia

• Suitable for most surgical procedures

stage 3- plane 3

• Deep plane of anesthesia

• Excessively deep for most surgical procedures

stage 3- plane 4

• Anesthetic overdose

• Too deeply anesthetized, in danger of resp and cardiac arrest

stage 4

• Cessation of respirations

• Death

• Cpr is necessary