Exam 1: Lecture 5: Monitoring Anesthetic Depth Flashcards
What is general anesthesia
- both loss of consciousness and sensation
- include muscle relaxation, analgesia, suppression of stress response and hypnosis
- Reversible process
- May be produced by 1 drug or many
Which anesthesia level is described? If there is a plane also indicate that.
+ reaction to surgical stimulation
+ palpebral reflex
Normal to dilated eye and pupil reflex
Stage I
Which anesthesia level is described? If there is a plane also indicate that.
normal to decreased jaw tone
normal to increased HR
normal to increased RR
Stage I
Which anesthesia level is described? If there is a plane also indicate that.
+ reaction to surgical stimulation
+ reaction to palpebral relfex
Decreased pupil size
Stage II
Which anesthesia level is described? If there is a plane also indicate that.
tense jaw tone
increased HR
increased RR
Stage II
Which anesthesia level is described? If there is a plane also indicate that.
+- reaction to surgical stimulation
+ palpebral reflex
third eyelid elevated
Stage III
Plane I
Which anesthesia level is described? If there is a plane also indicate that.
Slight decrease in jaw tone
normal to increased HR
normal to increased RR
Stage III
Plane I
Which anesthesia level is described? If there is a plane also indicate that.
- reaction to surgical stimulation
- palpebral reflex
third eyelid elevated
Stage III
Plane 2, 3 and 4
Which anesthesia level is described? If there is a plane also indicate that.
Mild decrease in jaw tone
normal to decreased HR
normal to decreased RR
Stage III
Plane 2 and 3
Which anesthesia level is described? If there is a plane also indicate that.
large decrease in jaw tone
decrease in HR
Abdominal slow / shallow
Stage III
Plane 4
Which anesthesia level is described? If there is a plane also indicate that.
Dilated / large pupils
Apnea
Cardiac arrest
Stage IV
Which anesthesia level is described? If there is a plane also indicate that.
- defined as the time from the start of administration of induction drugs until loss of consciousness
- stage of voluntary movement
- able to initially turn or lift head without support
Stage 1
Which anesthesia level is described? If there is a plane also indicate that.
- Some analegesia present
- Progressive ataxia = lateral recumbancy
- If patient is excited (little premed effect) = struggle , breath holding, increased heart rate, and pupil dilation due to epinephrine release, defecation, urination and salvation
- Most variable stage
Stage 1
Which anesthesia level is described? If there is a plane also indicate that.
- Struggling or exaggerated reaction to stimuli
- vomiting or regurgation can occur / salivation
- Laryngospasm
- Dilated pupils / nystagmus (common in horses)
- increased ororregular respiratory pattern . breath holding
Stage II
Which anesthesia level is described? If there is a plane also indicate that.
- Increased heart rate / arrhythmias due to catecholamine release
- Active palpebral reflex
- tight anal sphincter
- jaw tone present
- may vocalize
Stage 2
Which anesthesia level is described? If there is a plane also indicate that.
- can be characterized as stage of delirium and involuntary movement and lasts from loss of consciousness to onset or regular breathing pattern
Stage 2
Which anesthesia level is described? If there is a plane also indicate that.
- Stage of surgical anesthesia
Stage 3
Which anesthesia level is described? If there is a plane also indicate that.
- Stage of surgical anesthesia due to level of unconsciousness with progressive depression of reflexes, muscle relaxation and slow, regular breathing patterns
- Vomiting (by plane I) and Swallowing (by plane 2) reflexes abloshed
- Loss of Jaw tone
Stage 3
Which anesthesia level is described? If there is a plane also indicate that.
- May also be called a light plane of anesthesia
- persists until eyeballs movement stops
- Minimally invasive / painful procedure (ex: biopsy, would closure)
Stage 3
Plane 1
Which anesthesia level is described? If there is a plane also indicate that.
- May also be called a medium plane of anesthesia
- characterized by progressive intercostal paralysis
- respiration and heart rate stabilized
- Sluggish palpebral reflex
Stage III
Plane 2
Which anesthesia level is described? If there is a plane also indicate that.
- Strong corneal reflex
- Adequate muscle relaxation and analgesia
- Abolished laryngeal reflexes
Stage III
Plane 2
Which anesthesia level is described? If there is a plane also indicate that.
- Most surgical procedures performed at this plane (light plane of surgical anesthesia)
Stage III
Plane 2
Which anesthesia level is described? If there is a plane also indicate that.
- May also be called deep plane of anesthesia or deep plane of surgical anesthesia
Stage III
Plane 3
Which anesthesia level is described? If there is a plane also indicate that.
- Decreased HR
- Slow, shallow abdominal breathing pattern (Diaphragmatic Respiration)
- No jaw tone
- No reaction to surgical stimulation, profound muscle relaxation
- Pupil progressively dilated and central
Stage 3
Plane 3
Which anesthesia level is described? If there is a plane also indicate that.
- Gone way too far and need to lighten up quickly
- Pupils dilated
- Hypotension processing to shock
- Slow CRT
- Slow and irregular respirations
- Lack of muscle tone
- NO anal sphincter tone
Stage 3
Plane 4
Which anesthesia level is described? If there is a plane also indicate that.
- Gone way too far
- Extreme CNS depression = anesthetic overdose
- Pale to white mucous membrane (equal to or greater than 3 seconds)
- Respiratory arrest followed by cardiac arrest
- Central, widely dilated pupils
- Absent ocular reflexes
- Flaccid Muscle tone
- Death unless swift intervention
Plane 3
Stage 4
What should be checked during surgery to monitor depth of anesthesia?
- Ocular signs
- Jaw tone
- Anal reflex
- Pedal reflex: tail / ear pinch or ear flick
- Overall muscle tone or degree of patient relaxation
When following ocular signs during anesthesia what should be checked
- palpebral relfex
- eye position
- lacrimation
- nystagmus
- Corneal reflex
Why should you place lubrication ointment in the eyes during surgery?
To keep the eyes lubricated if they stay open
- this will prevent corneal ulcers
- may need to reapply during surgery if they keep drying out
What is the goal for a surgical anesthesia plane
- relaxed jaw tone
- mild to no palpebral reflex
- ventral medial eye rotation
- relaxed anal tone
- smooth and regular respiratory pattern
- normal heart rate
- no swalloing, coughing, vomiting or laryngospasm
What species will lacrimate in light stages of anesthesia?
- eyes stay central instead of ventral medual eye rotation
- Nystagmus in Stage II
- corneal refelx persists into deeper anesthesia plane
Horses
What species may go into laryngospasm and / or may cough, swallow and vomiting relfex until they reach a deeper plane of anesthesia?
Cats
What species have a consistent and reliable eyeball rotation during anesthesia?
cattle
What species can you observe the feet, ears, muzzle for pallor or cyanosis?
- pedal reflex
Rodents
What species can you examine the comb and or wattle for pallor
- vent reflex
Poultry
What species can you use the color of light reflected from the eyes to determine circulation status?
Rabbits
What are some factors that make monitoring depth of anesthesia difficult?
Drugs
oxygenation adequacy
CO2 retention
Physical status
What drug may cause typical eye signs not to be produced during anesthesia?
Ketamine
What drug may cause no analgesia or apnea during anesthesia?
Propofol
What is the role of an Anesthetic gas analyzer during anesthesia?
- Measure the depth of anesthesia
- used to perform minimum alveolar concentration (MAC) studies in may species
As the Bispectral index (BIS) what does it mean as the BIS level goes closer to 90?
the patient is in the process of waking up
How long should a patient be closely monitored in recovery
Making sure until animal has close to normal body temperature, able to set up, and aware of surroundings
What stage of recovery may be difficult due to delirium/dysphoria, especially in equine patients during recovery from surgery?
Stage II
What can be given to horses that is used to sedate that is an inhalant anesthesia recovery and stimulation is minimized (quite, dark room)
Alpha 2 agonist
