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Flashcards in Depth of Anesthesia Deck (42)
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1

Signs used to monitor anesthetic depth

1. Physical signs (subjective)
2. Physiologic parameters of the autonomic system

2

How do you monitor neurologic depression?

EEG- Bi-spectral analysis

3

Bispectral analysis

Processed EEG that monitors cortical activity

The lower the number, the more depressed (0-100)

4

Is BIS always accurate and useful?

No, depends on the person, but not a practical modality in vet med

5

Physical signs of anesthetic depths

1. Prescence/absence of purposeful movement in response to stimuli
2. Muscle relaxation
3. Lack of reflexes
4. Autonomic signs

6

Which muscles are checked for tones?

Eyeball rotation, jaw tone, anal tone, abdominal muscle tone

7

Which reflexes are checked?

Palpebral, corneal, anal, pupillary light (not terribly useful

8

Four stages of gas anesthetic depth

I- Analgesia
II- Delirium
III- Surgical Anesthesia
IV- Medullary paralysis

9

Are there clear demarcations between stages?

No

10

What order do the reflexes dissapear in?

Palpebral--Pharyngeal--corneal--light

11

Can these signs/stages be disrupted by the use of other drugs?

Yes, they are only based on gas anesthesia so using any injectable with disrupt the signs

12

T/F:If there is no response to a particular stimulation, there will be no response to any stimulation.

False

Eg, lack of movement to a toe pinch does not mean that there will be lack of movement to a surgical stimulus

13

What reflex should always be present in an anesthetized patient?

Corneal

Gag/swallow and palpebral reflexes present indicate they are too light

14

What is assessed for a baseline idea of anesthesia depth?

Jaw tone- should be easily moved by two fingers and tested throughout anesthesia

15

What position of the eye suggests that an animal is too deep?

Central

Eyes should be rolled ventrally with no palpebral reflex

16

What is indicated with the size of the palpebral fissure

Small- light anesthesia, may/may not have palpebral reflex

Large- deeper plane

Always assess with jaw tone

17

What is an ocular sign of light anesthesia in a horse?

Tearing

18

Which way do eyes tend to roll in large animals?

Forward

19

Which animals are eye signs not helpful in?

Swine

20

Is pupil size a good indication of anesthetic depth?

No, typically appears as pin point to mid size depending on drugs used

21

What pupil sign is bad?

Fixed and dilated- medullary paralysis

22

Should both eyes be assessed?

Yes

23

Equine eye sign

Brisk nystagmus- reliable sign of very light anesthesia, movement risk

24

Signs of Light anesthesia

Toe pinch +/-
Palpebral + esp horses
Corneal +
Lacrimation +/-
Eye position Central
Jaw tone +
Abdominal breathing +/-

25

Signs of Moderate anesthesia

Palpebral
Corneal - (may be +/- in horses)
Eye position Deviated

26

Signs of Deep anesthesia

Corneal - when too deep
Eye position central
Abdominal breathing +/-

27

Gradual decrease in HR/RR is an indication of?

Adequate depth

28

Autonomic response is responsible for...

Increase in HR/RR at induction

Avoid excessive excitation at induction

29

Common causes of Increased RR

1. Too light (pain/stimulation)
2. Hypercapnia
3. Hypoxemia
4. Hyperthermia

30

Common causes of Increased BP

1. Pain/stimulation
2. Renal dz/ catecholamine releasing tumors