Anesthesiology Anesthesia In Horses Final

Front 1

Is regurgitation common in horses?

Back 1

No, only GI obstruction cases at risk

Front 2

Equines are susceptible to ______ related complications during anesthesia.

Back 2

Recumbency related

Front 3

True or false. Phenothiazine derivatives are rarely used for sedation in horses.

Back 3

False, commonly used - acepromazine

Front 4

What are 2 classes of drugs commonly used for sedation in horses? Give examples of each.

Back 4

1) Phenothiazine derivatives
-Acepromazine
2) Alpha-2 agents very common
-Xylazine, detomidine, romifidine

Front 5

What are 4 signs of sedation in horses?

Back 5

1) Head droop
2) Third eyelid ptosis
3) Ataxia
4) Penis prolapsed from sheath

Front 6

The most pronounced effect of phenothiazine derivatives is in ____ horses, so use lower doses.

Back 6

Older

Front 7

Do phenothiazine derivatives or alpha-2 agents have a slower onset of action?

Back 7

Phenothiazine derivatives

Front 8

Do phenothiazine derivatives or alpha-2 agents cause more profound sedation?

Back 8

alpha-2 agents

Front 9

Do phenothiazine derivatives or alpha-2 agents cause more ataxia?

Back 9

Alpha-2 agents

Front 10

Is sedation from phenothiazine derivatives or alpha-2 agents more easily overridden?

Back 10

Phenothiazine derivatives

Front 11

**What horses should you not use phenothiazine derivatives in?

Back 11

When shock or severe anemia is present because causes vasodilatation & some hypotension
-If cachexia is present use caution if at all

Front 12

What are 5 possible complications of phenothiazine derivatives in horses?

Back 12

1) Excitement
2) Severe hypotension
3) Collapse
4) Seizures
-due to route of administration, if inject ACE into carotid artery then drugs go straight to brain
5) Penile paralysis

Front 13

In what horses do you need to use a lower dose of alpha-2 agents?

Back 13

Older horses & draft horses

Front 14

What are the vascular effects of alpha-2 agents?

Back 14

Causes vasoconstriction & hypertension, then vasodilatation and some hypotension

Front 15

What are the cardiac effects of alpha-2 agents?

Back 15

Bradycardia & second degree heart block

Front 16

You should be careful when administering alpha-2 agents to patients if _____, _______ or ______ is present.

Back 16

Shock
Anemia
Cachexia

Front 17

What are 3 reversal agents used for alpha-2 agents?

Back 17

1) Tolazoline
2) Yohimbine
3) Atipamezole

Front 18

What is a possible complication of alpha-2 agents in horses?

Back 18

Seizures

Front 19

What are 4 drugs used for sedation in horses?

Back 19

1) Acepromazine
2) Xylazine
3) Romifidine
4) Detomidine
-can use combinations

Front 20

What neuroleptanalgesics are used in horses?

Back 20

Alpha-2 & opioid
-Xylazine or detomidine, or romifidine & butorphanol
-given simultaneously for premed

Front 21

What are the 4 components of preanesthetic preparation of horses?

Back 21

1) Fast 8-12 hours
2) water ad lib
3) Clinical path exams as needed
4) Venous catheterization

Front 22

Are sedatives usually required for recovery in horses? Chronotropes?

Back 22

Sedatives are usually used for induction & recovery
-chronotropes not usually required

Front 23

What are 3 other procedures done to horses to protect them during anesthesia?

Back 23

1) Wash mouth out
2) Leg wraps
3) Tail rope

Front 24

What are 4 different drug protocols used for induction of horses?

Back 24

1) Thiopental
2) Thiopental- guaifenesin
3) Ketamine-guaifenesin
-administered separately
-Guaifenesin given until horse ataxic followed by ketamine
4) Alpha-2 agonist & ketamine
-can add diazepam to improve muscle relaxation
-Xylazine or romifidine or detomidine followed by ketamine

Front 25

What are 2 different injectable anesthestic combinations used for anesthetic maintenance in horses?

Back 25

1) Xylazine, ketamine, and guaifenesin infused IV
2) Xylazine, ketamine & midazolam, infused IV

Front 26

What inhalant anesthetics can be used for induction/maintenance in horses?

Back 26

Isoflurane, sevoflurane, desflurane, halothane
-+ NO to hasten mask induction

Front 27

How are orotracheal and nasotracheal tubes put into a horse?

Back 27

Blindly

Front 28

What are 5 ways to confirm intubation of a horse?

Back 28

1) Absence of stertorus breath sounds
2) Steaming/ clearing of tube
3) Exchange of gas
4) Synchronous movement of chest & rebreathing bag
5) Presence of CO2 in expired gas

Front 29

What are the 6 ways the cardiovascular system is monitored during anesthesia?

Back 29

1) Heart rate
2) Pulse strength
3) Membrane color/ perfusion time
4) ECG
5) Blood pressure
6) Pulse oximetry

Front 30

What is the normal mean blood pressure for horses?

Back 30

75-100 mmHg

Front 31

Prolonged hypotension is associated with ________ in horses.

Back 31

Myopathy

Front 32

What is the normal respiratory rate of adult and juvenile horses?

Back 32

Adults: 4-10 breaths/ min
Juveniles: 6-20 breaths/ min

Front 33

Horses sometimes display Biot's breathing, what is this?

Back 33

Pattern where have alternating cycles of tachypnea and apnea, sometimes breath 10-20 /min then slow way down or stop, just make sure pauses don't get too long

Front 34

What are 2 ways to monitor the CNS of horses under anesthesia?

Back 34

Ocular reflexes
-palpebral, nystagmus, corneal
Response to pain

Front 35

What are 4 components of supportive therapy in horses?

Back 35

1) Positioning
2) Fluid administration
3) Mechanical ventilation
4) Cardiovascular support

Front 36

What are 3 things used for positioning horses (very important bc of myopathies!!)?

Back 36

Flat padded surface
-vinyl covered foam pads
-water beds
-dunnage bags

Front 37

What are 3 things to consider when putting a horse in lateral recumbency?

Back 37

1) Down forelimb extended, with inner tube for heavier horses
2) Elevate upper legs when in lateral recumbency
3) Protect dependent eye

Front 38

What are 4 things to consider when placing a horse in dorsal recumbency?

Back 38

1) Evenly balanced
2) Forelegs flexed & relaxed
3) Hindlegs flexed & relaxed
4) Nose roll

Front 39

What are 4 types of fluids that can be administered to horses during anesthesia?

Back 39

1) LRS
2) Normosol $
3) Saline
4) Sodium bicarbonate

Front 40

Is mechanical ventilation commonly used in horses?

Back 40

yes, horses ventilate poorly
-use human or vet ventilators for foals, LA ventilator for heavier horses

Front 41

What is the usual setting for the frequency of a mechanical ventilator when anesthetizing a horse?

Back 41

6-8 breaths/ minute

Front 42

When should you begin weaning a horse off the mechanical ventilator?

Back 42

10 minutes prior to end of surgery

Front 43

What's a possible complication in horses on a mechanical ventilator?

Back 43

Hypotension

Front 44

What are 2 ways to assess mechanical ventilation in a horse?

Back 44

1) Capnography
PETCO2 35-40mm Hg
2) Blood gas analysis
PaCO2 40 mmHg; PaO2>200 mmHg

Front 45

**What is very important to prevent myopathies in horses under anesthesia?

Back 45

Maintaining perfusion pressure!!

Front 46

What are 3 drugs used for cardiovascular support in horses?

Back 46

1) Dobutamine (1st choice)
2) Calcium gluconate
3) Ephedrine (last choice)

Front 47

What are 3 analgesics used for horses undergoing anesthesia?

Back 47

1) Flunixin
2) Butorphanol
3) Lidocaine
-loading dose w/ infusion

Front 48

What are 3 components of equine recovery from anesthesia?

Back 48

1) Confirm gas exchange after extubation
2) Oxygen administration recommended
3) Alpha-2 agonists, based on temperament

Front 49

Where should horses be recovered from anesthesia?

Back 49

In a stall w/ padded walls and non-slip surface
-assistants need to be available
-horse can be returned to its stall after ataxia dissipates