Pocket Pet Anesthesia I and II

Question 1

When physically restraining pocket pets, you should be careful and concerned about inducing stress which will release ____________ in the body.

Answer 1

catecholamines

This can cause arrhythmias and excess stress can lead to hyperthermia.

Question 2

What is the best way to reduce stress in regards to restraint?

Answer 2

using chemical immobilization or inhalant anesthesia whenever it is possible.

Question 3

What challenges does small size of pocket pets present?

Answer 3

1. difficult vascular access
2. risk for mechanical obstruction of airway due to positioning
3. risk for compression of thoracic cavity during handling
4. lack of appropriate sizes/types of equipment and intra-operative monitoring
5. drug dosing (must be exact or can be detrimental)

Question 4

T/F: drug dosing in pocket pets is similar to that of dogs and cats where it is acceptable to round up because there is enough body surface area to compensate.

Answer 4

false – Need to be exact with doses.

Question 5

Pocket pets have a high metabolic rate. How does this affect performing anesthesia on them? (3 reasons)

Answer 5

1. if they are fasted for prolonged periods (>2 hours), they will become hypoglycemic
2. They metabolize drugs rapidly which will require you to redose frequently
3. they have higher fluid requirements

Question 5

What is the anatomical reason that pocket pets are prone to hypothermia during anesthetic procedures?

Answer 5

they have high surface area:volume ratio

The smaller the animal, the higher the risk. Hypothermia will lead to decreased anesthetic requirements, prolonged recovery, and possibly bradycardia or arrhythmias.

Question 6

The pre-anesthetic evaluation is vital in pocket pets. Why would underlying cardiovascular or respiratory disease be an issue in pocket pets prior to surgery?

Answer 6

they have small thoraxes and limited tidal volumes. If respiratory or cardiovascular disease was present, they do not have the reserve to compensate.

Question 7

Why is GI ileus and tympany (which can result from pain, starvation/fasting, stress, or diet alterations) concerning in pocket pets?
(2 big reasons)

Answer 7

it can put pressure on the diaphragm and cause difficulty or inability to breathe. it can also cause occlusion of abdominal great vessels.

Question 8

Pocket pets have high oxygen consumption rates. how will this affect your anesthesia procedures?

Answer 8

This means that they will have a LOW tolerance for hypoxemia. They will also rapidly uptake and eliminate inhalant anesthetics (recovery is faster, so be prepared).

Question 8

Why is intubation so difficult in pocket pets?

Answer 8

Visualization of the airway is poor.

They have a dorsal laryn and small tracheal diameter. Always study each species airway anatomy and practice on cadavers prior to attempting intubation to avoid increasing their risk for hypoxemia, hypercapnia, and respiratory arrest.

Question 10

Why is blood loss arguably more concerning in pocket pets than it is in other animals?

Answer 10

pocket pets have really low blood volumes. Blood loss should typically be <10% of the animal’s blood volume. This would be approx. 0.3 mL in the average mouse.

Question 11

Why is it important to check the upper airway of rabbits, ferrets, and rodents prior to anesthesia?

Answer 11

they are primary/obligate nasal breathers.

Question 12

why is obesity of concern in pocket pets undergoing anesthesia?

Answer 12

can lead to hypoventilation when placed in certain positions.

Question 13

T/F: we should recommend that our clients fast their pocket pets for 4 hours prior to undergoing anesthesia

Answer 13

false – fasting is not recommended. pocket pets do not regurgitate or vomit. fasting can lead to perioperative ileus, hepatic lipidosis, pregnancy toxemia, high metabolic rate, and hypoglycemia.

Question 14

Although a rabbits ear is an appropriate location for blood collection, what are the risks of using this site?

Answer 14

Skin in this area is easily burnt by clippers
Irritation to the skin can be caused by alcohol or iodine solutions (so dont use)
If the auricular artery gets injured, this can lead to thrombosis and ischemic necrosis.

Question 15

what is the best location for blood collection in rats?

Answer 15

tail vein

Question 16

T/F: maximum injection volumes in pocket pets are not different based on species

Answer 16

false they differ based on size of the animal and are much smaller in smaller pocket pets. this is important to consider to avoid volume overload and muscle necrosis.

Question 17

T/F: you should pre-medicate all pocket pets prior to using inhalant anesthesia

Answer 17

true – this helps with minimal restraint and reduces chance of injury to the animal and to you. You should not attempt to perform mask induction in a non-premedicated animal.

Question 18

For inducing anesthesia in pocket pets, we can utilize induction chambers. How will you determine if the animal has been successfully induced and can be removed from the chamber?

Answer 18

when the animal losing its righting reflex (the point at which the animal no longer responds to their innate instinct to avoid the vulnerability of dorsal recumbency).

Question 19

Why must you keep a pocket pets head/neck in extension during mask induction?

Answer 19

prevents airway obstruction and allows them to breathe.

Question 20

What is the typical positioning used to induce and intubate rabbits?

Answer 20

Head and neck are hyperextended which aligns larynx and trachea with the oropharynx.

Question 21

T/F: rabbits, hamsters, ferrets, and rats have laryngospasms similar to cats and require lidocaine splashs during intubation

Answer 21

true

Question 22

T/F: intubating rabbits is typically done by direct visualization

Answer 22

true – using a laryngoscope, otoscope*, or endoscope

Question 23

How will you confirm ET tube placement in rabbits?

Answer 23

1. capnograph***
2. detect air movement with hair/cotton in front of tube
3. condensation on inside of tube
4. coughing in response to intubation

Question 24

What is a V-gel?

Answer 24

a supraglottic airway device that is species-specific. It can be passed blindly because it is fit to the animals specific airway anatomy. It is a sealing system, it does not go into the trachea.

Question 25

The entry to the guinea pig glottis is through the ____________, which is a structure that makes intubation extremely difficult in this species.

Answer 25

palatal ostium

Question 26

What do you use to intubate rats and hamsters?

Answer 26

rigid endoscope or otoscope and utilize direct visualization

then utilize a 14-16g catheter as the ET tube.

Question 27

T/F: due to size similarities, it is appropriate to use feline supraglottic airway devices in rabbits.

Answer 27

false

Question 28

When utilizing facemasks for anesthesia, it is required that they be snug around the muzzle. If they are too large, what is the consequence?

Answer 28

the extra space will trap exhaled gases that are high in CO2 and they will be essentially rebreathing. This will cause their ETCO2 to increase.

to prevent this, you should make sure they are snug around the face and use a concentric mask system (delivers gases and removes waste gases while preventing exposure to personnel)

Question 29

What is a “J-wire” used for?

Answer 29

it is a flexible intubation stylet that acts as a guide used when intubating.

Question 30

what size laryngoscope blade is used in pocket pets?

Answer 30

Miller # 0 or 1

Question 31

What are the 2 ways anesthetic gases are removed from anesthetic chambers?

Answer 31

1. active scavenging (ducted out of the room)
2. passive scavenging (absorbed by activated charcoal)

Question 32

what breathing circuit is used in pocket pets?

Answer 32

Bain non-rebreathing system

Question 33

T/F: fresh gas flow rates are higher in pocket pets.

Answer 33

true – this is to remove CO2.

Question 34

What monitoring should be done during pocket pet anesthesia?

Answer 34

1. assessing plane of anesthesia – reflexes, muscle tone, movement
2. ECG
3. indirect BP measurement
4. Pulse Ox (SpO2) or arterial blood gas to avoid hypoxemia
5. capnography (ETCO2) to avoid hypoventilation
6. rectal temp to avoid hypothermia

Question 35

What reflexes can you test to assess anesthetic depth in pocket pets?

Answer 35

1. Pedal withdrawal (should not respond)
2. Pinna reflex (if light, some movement)
3. Corneal (needs to be present)
4. Palpebral (should be gone or super slow)

Question 36

If your pocket pet patient displayed fixed dilated pupils that were unresponsive to light and there was no corneal reflex, how would you interpret this?

Answer 36

Deep anesthesia… not good. Need to reduce gas or reverse something.

Question 37

Which species can an esophageal stethoscope be used in to monitor CV function during anesthesia?

Answer 37

rabbits

others are likely too small so you can use a doppler and place it directly over the heart, tail base, or on the carotid/ femoral/ auricular arteries.

Question 38

T/F: pulse ox reflects ventilation and capnography reflects oxygenation

Answer 38

false – other way around.

Question 39

What are various ways that you can keep your pocket pet patients warm during anesthesia to prevent hypothermia?

Answer 39

Bubble wrap them
Place on heating pads
Fluid warmer
Decrease dead space in masks

Question 40

What is the isotonic fluid rate for pocket pets for short vs longer procedures?

Answer 40

short: 10 mL/kg/hr

longer: 5-8 mL/kg/hr

for smaller rodents do IP or SQ, in rabbits can do IV or SQ.

Question 41

what is the maintenance fluid rate in rabbits and rodents?

Answer 41

100 mL/kg/day

Question 42

What 5 things do you need to monitor for during post-operative care?

Answer 42

1. ileus (if present, give metocloprimide)
2. vomiting/regurg
3. hypoglycemia (if present, admin fluids + dextrose)
4. hypothermia
5. dehydration

Monitor: appetite, water intake, body weight, fecal/ urine output, hydration status, incision site, temp, and vitals for 72 hours. Assess pain as well and administer analgesics if necessary.

Question 43

If guinea pigs are anorexic or inappetant post-operatively, what can you give them?

Answer 43

Vitamin C

Question 44

T/F: all rabbits have high circulating levels of atropinases and thus break down atropine more readily.

Answer 44

false not all, but many.