Equine Anesthesia

Question 1

Horses are _ nasal breathers

Answer 1

obligate

Question 2

What can produce atelectasis in equine

Answer 2

large, heavy GI tract pressing on lungs

Question 3

How long should food and water be withheld prior to anesthesia

Answer 3

food 8-12hrs ; water 0-2hrs

Question 4

NO _ is to fed 24 hours before anesthesia

Answer 4

grain

Question 5

No _ is to be fed 12hrs before anesthesia

Answer 5

hay

Question 6

Foals scheduled for general anesthesia are usually allowed to nurse up to _hr before scheduled induction time

Answer 6

1

Question 7

Horses >_kg will be placed on LA machine

Answer 7

150

Question 8

_ drugs reduce GI motility which may result in colic

Answer 8

Anticholinergic

Question 9

Premedication or sedation drugs given IM or IV

Answer 9

Tranquilizers, alpha2-agonists, and opioids

Question 10

Preanesthetic procedure to prep horse for sx

Answer 10

-Place IVC in jugular vein
-Wash mouth to remove feed
-Feet cleaned and shoes removed or wrapped
-Place P in induction area or adjacent to tilt table

Question 11

What type of fluids are preferred

Answer 11

a polyionic solution with an alkalinizing effect

Question 12

Lactated Ringer’s or Normosol-R are most commonly used and are administer rapidly at _-_ml/kg/hr during the early phases of anesthesia since horses are commonly hypotensive then

Answer 12

10-25ml/kg/hr

Question 13

After hypotension is corrected, fluid admin may be slowed to

Answer 13

5-6ml/kg/hr

Question 14

What does horse look like with standing chemical restraint

Answer 14

-drooping lower lip
-reluctance to move
-wide based stance
-lack of interest in surrounding activity

Question 15

Goal of anesthetic induction

Answer 15

render the horse unconscious as quickly as possible so that the transition from standing (sedated) to lateral recumbency (unconscious) occurs with minimal risk of injury

Question 16

How are induction drugs administered rather than “to effect”

Answer 16

rapid bolus injection (except guaifenesin)

Question 17

What is the most common anesthetic drug combination for equine induction

Answer 17

xylazine and ketamine (+/- diazepam)

Question 18

Ketamine admin alone without sedative premed causes

Answer 18

excitement

Question 19

ketamine is injected _-_min after apparent xylazine induced sedation

Answer 19

3-5

Question 20

Why is ketamine not used IM in the conscious horse

Answer 20

because the horse may be injured during the period of incoordination occurring while the drug is taking effect

Question 21

Xylazine-ketamine anesthesia is accompanied by _ _ _ for the first 5 minutes, and usually nystagmus, a strong palpebral reflex, and pupillary dilation

Answer 21

strong muscle tone

Question 22

Guaifenesin is admin at _-_mg/kg IV to effect to produce sedation/muscle relaxation

Answer 22

50-100

Question 23

What position is the horse in for anesthesia

Answer 23

on table and pad superficial nerves and muscle groups, forelimb closest to table is pulled forward; separate hindlimb with padding

Question 24

How is the ET tube placed in a horse

Answer 24

from nostril into ventral nasal meatus and emerges in nasopharynx

Question 25

Foals should not be intubated with ET tubes smaller than _mm in diameter

Answer 25

10

Question 26

Adult ET tube sizes

Answer 26

22mm, 26mm, 30mm

Question 27

Orotracheal intubation is performed _

Answer 27

blindly

Question 28

Nasotracheal intubation is done for surgeries of the

Answer 28

head and neck

Question 29

Where is a nasotracheal tube placed

Answer 29

into the ventral nasal meatus and through the trachea

Question 30

Complications of intubation is similar to those of small animals but an additional concern would be

Answer 30

epistaxis from nasal intubation

Question 31

Changes in inhalant anesthetic and O2 flow rate occur _

Answer 31

slowly

Question 32

Horses are more likely to develop _,_,and _ with in inhalant agent

Answer 32

-Hypoventilation (seen w/ dorsal recumbency) -Hypotension (contributes to myopathy) -Hypoxemia (more common in obese, pregnant, have twisted intestines, and are in dorsal recumb.)

Question 33

Hypotension in a horse is an arterial blood pressure less than

Answer 33

<70 mmHg

Question 34

Hypoxemia is a PaO2 less than

Answer 34

<80mmHg

Question 35

Horses that will be under general anesthesia for longer periods of time are often placed on a

Answer 35

mechanical ventilator

Question 36

The ventilator replaces the _ _ and scavenger is hooked to the ventilator

Answer 36

reservoir bag

Question 37

Induction O2 flow rate

Answer 37

8-10L/min

Question 38

Maintenance O2 flow rate

Answer 38

3-5L/min

Question 39

Only _ systems are used in LA

Answer 39

rebreathing

Question 40

Problems occur more frequently and in greater magnitude than during canine anesthesia, more pronounced:

Answer 40

hypotension, hypoventilation, reduction of cardiac output

Question 41

Monitor of the cardiovascular system include

Answer 41

-Digital pulse palpation -CRT, MM -ECG -Arterial blood pressure (strongly recommended when using inhalant)

Question 42

How should hypotension be treated

Answer 42

fluids, inotropes, dobutamine used via syringe pump

Question 43

Monitoring the respiratory system includes

Answer 43

-Observation of rate and rhythm -Pulse ox -Capnometry -Artial blood gas analysis q30-60min

Question 44

How is hypoventilation treated

Answer 44

either with assisted or controlled ventilation

Question 45

Normal HR under anesthesia

Answer 45

28-40bpm

Question 46

Normal heart rhythm during anesthesia

Answer 46

NSR, SA, or 1st or 2nd degree AV block

Question 47

Normal RR under anesthesia

Answer 47

6-12 brpm

Question 48

Normal body temp under anesthesia

Answer 48

97-100F

Question 49

Using TIVA for procedures lasting <1hr produces

Answer 49

-higher blood pressure, less respiratory depression, and more active palpebral reflexes -good quality recovery

Question 50

_ _ infused at a very slow rate and inhalant anesthesia reduces amount of inhalant needed, provides muscle relaxation, provides analgesia

Answer 50

triple drip

Question 51

What drugs are included in the triple drip

Answer 51

guaifenesin, ketamine, and xylazine

Question 52

What are the benefits of using lidocaine or detomidine infusions and inhalant anesthesia

Answer 52

decrease inhalant agent requirement and provides analgesia

Question 53

Why should eyes be protected during induction

Answer 53

horses are prone to corneal scrapes

Question 54

Padding and positioning on sx table prevent

Answer 54

neuropathies and myopathies

Question 55

What can indicate horse will attempt to get up too soon

Answer 55

nystagmus (rapid) with paddling of limbs

Question 56

When should horse be extubated

Answer 56

chewing, swallowing, purposeful ear, or limb or tail movement

Question 57

What may be used for controlled recovery

Answer 57

head and tail ropes

Question 58

When can horse be returned to stall

Answer 58

when able to walk steadily

Question 59

Signs of neuropathy

Answer 59

-facial nerve paralysis (drooping eyelid and lip on affected side -radial nerve paralysis (inability to fully extend affected forelimb)

Question 60

Signs of myopathy

Answer 60

hard, swollen muscles, stiff and painful gait

Question 61

Signs of colic

Answer 61

rolling, kicking at the abdomen