Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

2025 Anesthesia > Exam 4: Lecture 26 - Equine Anesthesia > Flashcards

Exam 4: Lecture 26 - Equine Anesthesia Flashcards

(69 cards)

Start Studying
1
Q

prior to modern day anesthesia, what did we use for horses

A

heavy physical restraint and herbal remedies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are some of the physical restraints used prior to modern day anesthesia in equines

A

hobbles, casting harness, ropes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

___1___ became widely used in vet med after 1845 and ____2___ after 1847

A
  1. chloroform
  2. ether
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

after ___1______, equine anesthesia really started to evolve into a more specific process which had the development of new drugs

A

1950

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what happened in 1955 for equine anesthesia

A

succinylcholine was used for short surgical procedures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is succinylcholine

A

a depolarizing neuromuscular blocking drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happened in 1957 for equine anesthesia

A

Halothane first used in horses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what happened in late 1960s for equine anesthesia

A

Guaifenesin used to reduce the dose of thiopental and subsequent cardiovascular depression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what happened in early 1970 for equine anesthesia

A

xylazine was introduced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the components of our preoperative eval for equine anesthesia

A
  1. history
  2. concurrent meds
  3. PE
  4. lab data
  5. ASA assigned
  6. fasting (withhold food for 3-6 hours)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what things factor into our patient prep

A
  1. IV access should always be in place prior to anesthesia
  2. flush food debris out of mouth
  3. clean feet and remove/tape over shoes
  4. perioperative abx, anti-inflammatories, and tetanus prophylaxis given 30 mins prior to sx
  5. clip hair over sx site
  6. fluid resuscitation prior to anesthesia if dehydrated or in shock
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the BIGGEST consideration for equine anesthesia

A

safety first

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Other than safety, what are some other considerations for equine anesthesia

A
  1. behavior
  2. adequate staff/facilities
  3. increased anesthetic risk in horses
  4. anatomy and physiology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the important things to remember about the anatomy and physiology in equine anesthesia

A
  1. obligate nose breathers
  2. prone to V/Q mismatch and hypoxemia
  3. GI tract considerations
  4. Large muscle mass and body weight can lead to development of myopathy and/or neuropathy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the 10 things that increase risk of anesthesia in equines

A
  1. fracture repair
  2. young (<1month) or old (>14 yrs)
  3. colic and/or emergency surgery
  4. surgery between midnight and 6am
  5. experience of surgeon
  6. duration of anesthesia
  7. trauma, dehydration, stress, poor condition, systemic disease
  8. pregnant
  9. drug choices
  10. breed predisposition (EX: HYPP, myelomalacia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is the newer tool called that is used for pre-anesthetic risk that accounts for additional factors unique to horses

A

CHARIOT (combined horse anesthetic risk ID and optimisation tool)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the respiratory considerations for equine anesthesia

A
  1. they are prone to compression atelectasis in dorsal recumbency
  2. all anesthetic drugs depress respiratory drive, muscle function, ventilatory rate/volume
  3. inhalant anesthetics alter the distribution of pulmonary blood flow
  4. upper airway obstruction from nasal edema is expected after prolonged sx
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

why does the fact that inhalant anesthetics alter the distribution of pulmonary blood flow matter in equine anesthsia

A

it abolishes hypoxic pulmonary vasoconstriction resulting in areas of the lung that are perfused but not ventilated which worsens the hypoxemia by contributing to a V/Q mismatch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the 3 cardiovascular considerations for equine anesthesia

A
  1. second degree AV block is generally normal and is due to high vagal tone
  2. horses have a large SA node so a wandering pacemaker is common
  3. atrial mass is large so biphasic P wave is normal but the large size makes atria predisposed to development of re-entrant rhythms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is being shown in these pictures

A

atrial fibrillation in a horse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what are the 4 main categories of drugs we use for premed in equine

A

acepromazine, alpha-2 agonists, opioids, benzodiazepines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe when we use ace as a premed and the potential complications

A

typically used as an adjunct to other sedatives in excitable horses

caution when used in breeding stallions due to potential for penile prolapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

describe what alpha-2 agonists we use as premeds in equine and why

A

xylazine, detomidine, dexmedetomidine, romifidine

most commonly used for sedation, muscle relaxation, and analgesic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what opioids are commonly used as premeds in equines and what is the benefit of them

A

butorphanol, morphine, hydromorphone, buprenorphine

less likely to cause excitement when co-administered with alpha-2 agonists or ace

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what are the benzodiazepines we use as premeds in equine and are they commonly used
diazepam or midazolam rarely used by itself except in foals
26
what are the drugs we use for IV induction in equine
1. ketamine + benzodiazepines 2. ketamine + guaifensin 3. ketamine alone following heavy alpha-2 agonist sedation 4. propofol 5. telazol 6. alfaxalone
27
T/F: We commonly use propofol in equine anesthesia
false, not commonly used because of cost, large volume needed, and poor quality induction
28
T/F: Telazol is excellent for induction following alpha-2 agonist sedation but the recovery is rough
true!
29
T/F: Alfaxalone is commonly used in equine anesthesia
false, has been studied in horses but is very expensive!
30
what drugs are used for maintenance of anesthesia in equine
isoflurane and sevoflurane
31
what do we use a lidocaine CRI for in equine anesthesia
improves analgesia and GI motility, reduces MAC by ~ 25%
32
what is the benefit of a morphine-lidocaine-ketamine CRI in equine anesthesia
can reduce MAC by 50%
33
when is a dexmedetomidine CRI used in equine anesthesia
for prolonged standing sedation
34
what is the rate we should use crystalloids for in equine anesthesia
replacement fluids (isotonic): 5-10 ml/kg/hr hypertonic saline 2-4 ml/kg over 15 mins for emergency resuscitation of hypovolemia
35
what is the problem when using fluids in foals
foals are not able to compensate for increased fluid load and may retain fluids leading to edema
36
T/F: scavenging can be active or passive for equine anesthesia
true! charcoal canisters become ineffective at high fresh gas flow rates that are used for adult horses
37
what type of equipment should we have for equine anesthesia
hydraulic lift on a sx table, soft ropes to tie limbs, oxygen demand valve, padded recovery stall/sling
38
what are things we should keep in mind for the induction period
1. designated space for induction 2. owner kept at a safe distance and explain what is going to happen with their horse 3. keep noise level down 4. BE SURE YOUR PATIENT IS ADEQUATELY SEDATED
39
what person during induction has the MOST responsibility
person on the head
40
how do we do an induction using an induction stall with swing gate
keep the head steady until patient begins to buckle at the knees and then push head up to make the horse "dog sit" before coming down on the front legs
41
how do we do an induction using a free-fall induction
once the horse begins to buckle and relax before falling, turn the head the OPPOSITE direction of how you want the horse to lay
42
what position do we have the horse in for a blind intubation
lateral or in sternal recumbency
43
what size ET tube do we use for the average adult
26mm
44
what size ET tube do we use for larger horses
30mm
45
what size ET tube do we use for the newborn foal
10-11mm
46
what size ET tube do we use for a donkey
14-16mm
47
what size syringe should we use to inflate the cuff for equine ET tubes
60cc
48
what should we ALWAYS be prepared for with equine anesthesia
always be prepared for them to become light and start to move!!!
49
what do we do if the equine patient becomes light and starts to move
1. communicate to surgeon to stop stimulation and all available hands to safety hold patient on table 2. give a rapidly acting injectable anesthetic like propofol or ketamine 3. increase vaporizer and O2 flow rate, give IPPV 4. consider adding in a local anesthetic block if possible
50
what are the physical signs of anesthetic depth in equines
1. eye signs such as palpebral and corneal reflexes, lacrimation, nystagmus, position of eyeball 2. muscle tone, movement of limb 3. swallowing 4. ear movement 5. anal sphincter tone 6. response to surgical stimulation 7. shivering or stretching 8. respiratory rate, HR, BP are less reliable
51
T/F: We should physically or visually monitor our patient during equine anesthesia
true!!
52
where do we place the leads for a base-apex electrocardiogram
negative electrode on the right jugular furrow, positive electrode on left thoracic wall in area of left ventricular apex
53
what did the study done in 1987 show a direct link between
arterial hypotension and post-anesthetic myopathy
54
what is the treatment of hypotension for equines
lighten anesthetic depth, administer a positive inotrope to effect or ephedrine, correct volume deficits, change anesthetic regimen to PIVA
55
what is the normal HR for equines under anesthesia
30-45 bpm
56
what is the normal RR for equines under anesthesia
6-20 bpm
57
what is the normal CRT for equines under anesthesia
<2.5 secs
58
what is the normal temp for equines under anesthesia
>98 and <101
59
what is the normal arterial pH for equines under anesthesia
7.35-7.45
60
what is the normal PaCO2 for equines under anesthesia
40-60mmHg
61
what is the normal PaO2 for equines under anesthesia
100-500mmHg
62
what is the normal ETCO2 for equines under anesthesia
30-50mmHg
63
what is the normal MAP for equines under anesthesia
70-80mmHg
64
what is the normal CO for equines under anesthesia
30-50 ml/kg/min
65
what are the 3 things we need to consider during recovery of GA in equines
1. communicate with the sx team so you can coordinate movement to the recovery area 2. this is still a potentially life-threatening time period for the horse 3. administer a dose of alpha-2 agonist as the inhalant is discontinued
66
how long does recovery take for equines that underwent general anesthesia
it varies by the patient, duration of procedure, drugs used, body temp, etc but generally about 30 mins
67
what type of recovery is being shown here
pool recovery
68
what type of recovery is being shown here
rope assisted recovery
69
what are the 9 "keys" to equine anesthesia success
1. understand its risky 2. have/develop horse sense 3. know your pharmacology and physio! 4. keep MAP > 70-80 mmHg 5. adequate padding and positioning 6. maintain patent airway 7. keep sx less than 3 hours 8. safety is IMPORTANT 9. be prepared for the worst case scenario

2025 Anesthesia (29 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions