Pocket Pets Anesthesia Flashcards
Why is it important to support the rump of pocket pets (especially rabbits)?
Rabbits can kick out if rump isn’t supported and fracture their T-L spine or tibia
When restraining pocket pets, why is it especially important to pay attention to hand placement, specifically around their thorax?
You don’t want to compress their thoracic cavity & cause mechanical obstruction of airway
Why should you be extremely careful with rounding when calculating drug dosages for pocket pets?
Because they are so small, even the slightest difference in numbers will significantly affect the dosage for them
Why do pocket pets have a higher fluid requirement than small animals and require more frequent drug dosing?
They have a high metabolic rate, so metabolize drugs faster
Pocket pets have a high surface area to volume ratio. What does this put them at greater risk for?
Hypothermia
Why should you try to use minimal handling for pocket pets undergoing anesthesia?
Stresses them out -> release catecholamines -> tachyarrhythmias
Why is tympany problematic in pocket pets undergoing anesthesia?
Distended abdomen puts pressure on the diaphragm (already have smaller respiratory reserve) & may occlude abdominal great vessels, leading to decreased venous return to the heart
T/F: Rabbits, ferrets, and rodents are primary/obligate nasal breathers.
T
Obese pocket pets are more prone to hypoventilation or hyperventilation when placed in dorsal recumbency?
Hypoventilation
Why is fasting not recommended in pocket pets?
- Can lead to perioperative ileus
- Known to cause hepatic lipidosis in rabbits & pregnancy toxemia in guinea pigs
- Hypoglycemia due to high metabolic rate
In rats, where is the best location to collect blood for pre-anesthetic prep?
Lateral coccygeal vein (tail vein)
Why is it okay to not have pocket pets fast prior to anesthesia?
They do not regurgitate or vomit unlike other small animals
Why do we give rabbits a local anesthetic as part of the pre-anesthetic prep?
To prevent vasospasm
In rabbits, you can place catheters in the marginal ear vein, but what is a potential complication if you accidentally injure the auricular artery in the process?
Can cause thrombosis & ischemic necrosis
Pocket pets have a higher metabolic rate. What effect does this have on the size of our dosages?
Will need larger doses because they will metabolize the drug fast
Why do you need to use multiple sites for IM injections in pocket pets?
Excessive volumes in one location can lead to muscle necrosis & volume overload
List the pros and cons associated with using induction chambers for anesthetic induction in pocket pets.
Pros - requires minimal physical restraint (minimal stress), reduces injury to animal & handler
Cons - environmental contamination & difficult monitoring
T/F: It is okay to use mask induction un-premedicated pocket pets as long as proper restraint is used
F, you will stress them out (release of catecholamines -> tachyarrhythmias); they NEED to be pre-medicated
What should the oxygen flow rate be set to for pocket pets?
At least 200mL/kg/min - they have high oxygenation rates!
What reflex can you use to determine when a pocket pet should be removed from the induction chamber?
Loss of righting reflex
What is the righting reflex?
Animal responds to their innate instinct to avoid the vulnerability of dorsal recumbency
With mask induction, why should the head and neck be kept in extension?
To prevent obstruction to breathing
Like cats & pigs, pocket pets also have laryngospasm which can make intubation difficult. What can you do to stop the spasms?
Lidocaine splash
What can you use to visualize the airway in rabbits?
Laryngoscope (if it’ll fit), otoscope, or rigid endoscope
What is the most reliable way to confirm proper ET tube placement?
Detection of exhaled carbon dioxide on capnograph (looking for sharp waveform)
V-gel is a supraglottic device to intubate that can be used in ONLY what species?
Rabbits
List some reasons why guinea pigs are rarely intubated.
- Cheek pouches contain stored food
- Readily regurgitate
- Profuse salivary secretions
- Soft tissue at base of tongue readily traumatized
When guinea pigs are intubated, it should be done with a rigid endoscope and entry into the glottis is through what anatomical structure?
Palatal ostium
Describe airway management in rats, hamsters using the following:
Tool used for direct visualization:
Dorsal or sternal recumbency:
Need local anesthetic?
Size catheter:
- Rigid endoscope or otoscope
- Dorsal recumbency
- Local anesthetic for laryngospasm
- 14-16G over the needle catheters
Ferrets have sharp teeth, so what can you do to prevent them from lacerating the ET tube?
Place something between their teeth and the ET tube
Face masks used for pre-oxygenation should be snug around the muzzle. What happens if you use a mask that is too big?
Extra space traps exhaled gases high in CO2 -> rebreathing CO2 (will see higher end-tidal CO2)
What are benefits of using a concentric mask system?
- Delivery of anesthetic gases with removal of waste gas
- Prevent exposure of the operator
If you are using a 1.9mm fiberoptic scope to aid in visualization for intubation, what is the smallest ET tube you can use? What about for a 2.7mm rigid endoscope?
1.9mm -> smallest tube you can use is a 2.5mm
2.7mm -> smallest you can use is a 3.0mm
What gas(es) can you use for anesthetic chambers in pocket pets?
O2 alone or with nitrous oxide
How can you remove waste anesthetic gas from anesthetic chambesr?
Either ducted out of the room through scavenging system or adsorbed using activated charcoal
Should you use a rebreathing or non-rebreathing system for pocket pets?
Non-rebreathing
Non-rebreathing systems do not have soda lime canisters to remove CO2. So, how do we bypass this with non-rebreathers?
Use high O2 flow rates (200mL/kg/min) to get rid of CO2
What are some things we can use to monitor if the patient is moving into a light plane of anesthesia?
- Reflexes
- Muscle tone
- Movement
How can we monitor heart rate in pocket pets under anesthesia?
- ECG (best)
- Pulse rate
- Cardiac auscultation
How can we monitor blood pressure in pocket pets under anesthesia?
- Indirect BP measurement (best/easiest)
- Can do direct too but requires arterial catheterization
How can we monitor if a pocket pet is becoming hypoxemic under anesthesia?
- Pulse oximetry (SPO2; best), arterial blood gas sampling (requires arterial catheterization), mucous membranes
How can we monitor ventilation in pocket pets under anesthesia?
Capnography (ETCO2), blood gas sampling
T/F: Nothing detects cardiac arrest faster than ETCO2
T - will start to see decrease in number & waveform will get smaller
What reflexes can you check in pocket pets to see if they are in a good plane of anesthetic depth?
Pedal withdrawal - no response to toe/tail pinch indicates good plane
Pinna reflex - slight response to pinching ear in rabbits indicates light plane of anesthesia
Palpebral reflexes - should be absent or very slow in good plane of anesthesia
Corneal reflex - should NEVER lose this! If absent, then the P is in too deep of a plane
How do we assess anesthetic depth in pocket pets using muscle tone?
Can do jaw muscle or anal sphincter - should be relaxed
If HR, BP, & RR are all increased, what does that say about the patient’s anesthetic depth?
Too light
An esophageal stethoscope can be used to monitor cardiovascular function in which pocket pet species?
Rabbits
Where can you place the doppler flow probe for indirect BP measurement in pocket pets?
Tail base, carotid/femoral/auricular arteries, or directly over the heart
Give some locations where you can place pulse oximetry probes on pocket pets
Digits, paws, tongue, proximal tail, ear, rectum (& medial side of leg if you shave small area & place reflectance probe)
You can use either a main-stream or side-stream capnograph to monitor ventilation in pocket pets. However, side-stream capnographs may create more dead space, which we are trying to avoid. What can you do to overcome this?
Increase oxygen flow rates to compensate for dead space
In most cases, you are going to monitor temperature with a rectal thermometer/probe. What other method can you use in rabbits & big rodents?
Esophageal probe
What is one method you can use to ensure rats and other small pocket pets stay warm when undergoing anesthesia?
Gently wrap with bubble packing
What type of fluids should you use for pocket pets?
Isotonic fluids (LRS most common)
What should your fluid rate be for short procedures vs. long procedures in pocket pets?
Short procedures - 10ml/kg/hr
Long procedures - 5-8ml/kg/hr
List the routes you can administer fluids in the following species:
Small rodents:
Rabbits:
Small rodents: IP/SQ route
Rabbits: IV, SQ
List 5 things you should monitor for in recovery
- Ileus (& treat w/ pro-kinetics i.e. Metoclopramide)
- Vomiting/regurgitation
- Hypoglycemia (can give Dextrose)
- Hypothermia
- Dehydration
How can you assess a pocket pet for post-operative pain?
Touch incision & see how they react to it
If guinea pigs are anorexic or inappetent post-op, what should you do?
Give vitamin C supplement
Why might we consider adding a Fentanyl CRI to our anesthetic maintenance protocol for an invasive procedure?
Prevents pain & decreases the amount of inhalant (usually isoflurane) required
