Anesthesia - Small Animal ANx 2

drraythe's version from 2016-03-15 20:57

Cats are dumb

Question Answer
What is the unique look cats get w/ opioids?Their eyes DILATE instead of get pinpoint
What is a peculiarity of cat metabolism? What does this mean for them as a unique thing?They have a deficiency in glucuronidation → phenolic compounds are metabolized slowly, resulting in oxidative insult (eg acetylsalicylic acids, paracetamol, Propofol, Morphine) (so basically either dont use in cats or use lower dosages.)
How should you handle dosing a cat w/ Propofol?No glucuronidation → slower metabolism → just titrate to effect & do not use repeatedly over several days or it will build up & cz problems
Why is ET intubation difficult in cats?Laryngospasm (w/ cat neuter, prolly don't need to intubate)
What drug do we like to give/use w/ feral cats?Ketamine
Is Ketamine + Midazolam a good idea?No analgesia & will probably not sedate unless young or old or sick. Problem is when they recover they freak out...its not the Ketamine, the Ketamine wears off 1st, then paradoxical rxn of Midazolam in cat.
What premed combos might you wanna do in a feral cat? (2)Ketamine+Dexmedetomidine, Ketamine+ace
#1 thing you wanna do 1st if you get a blocked at?Rehydrate
What are 2° problems w/ blocked cats that you should expect?Electrolyte imbalances → HYPERKALEMIA (BRADYCARDIA)
Azotemia (can make them sensitive to drugs)
Metabolic ACIDOSIS
Post-obstructive diuresis (once stones are flushed back into bladder & urethra free-they pee a ton & then are more dehydrated)
How does HYPERK affect the ECG??BRADYCARDIA
Tented T (tall T)
Disappearing P
(also prolonged P-R interval, ↑ QRS duration)
If you can't measure the level of K in a blocked cat, what HR is an alarm bell?120 or under
*****Dont induce anesthesia is K is ____ (level)>6mmol/L (>9-10 can see ventricular fibrillation too)
(Said in class) Why can you still give LRS to a blocked/hyperkalemic cat (even tho there is K in it?)Some K, but lower than what's in plasma so you’re still diluting & has lactate, which is metabolized to bicarb to help Tx acidemia
Why do you want to give glucose to a hyper-K cat?Insulin czs K to shift from extracellular to intracellular, thus ↓ serum levels of K
Who do you wanna give Calcium-gluconate to & why?Blocked cats-provides myocardium stabilization (doesn't help w/ K tho-only an ER Tx)
If you must sedate a cat which is blocked, what do you prolly wanna use?Opioid + Benzo
What can you use to induce a blocked cat? Maintain?INDUCE: Ketamine-Midazolam, or Midazolam-Etomidate
MAINTAIN: Inhalant anesthetic, Fentanyl CRI (if need to Sx remove stones)
What is contraindicated drug in blocked cats?α-2s bc diuretic effect (dont wanna ↑ volume of bladder) & also severe CV impact
Which sedative has a diuretic effect?α-2s
What do you think about cats & Benzos?That cat better be sick or really young or old. They can flip out from Benzos. (They can stim appetite tho!)
Which do you usually combine w/ Ketamine for cats?Midazolam
When are α-2s (Medetomidine/Dexmedetomidine) usually indicated in cats?Combo w/ Ketamine & an opioid for minor procedures & for IM induction of anesthesia in feral cats, for sedation only in combo w/ Butorphanol
Antagonist for α-2s?Atipamezol (alpha atip)
When is Xylazine usually used in cats?Strong emetic effect...not really good for sedative. Just for making them puke
What do you think about Buprenorphine in cats?Awesome for cats - Good analgesia & sublingual route is useful
What do you think about Methadone in cats? Morphine?Meth = Only for SEVERE pain
Morph = Not opioid of choice-lots of dysphoria & excitement
What do you think about Thiopental in cats?Not drug of choice!
Resp depressionA
Small therapeutic window
What do you think about cats & Propofol?Heinz body anemia
Etomidate in cats?Only if theyre really sick
What is a popular reason Ketamine is desired in cats? Combine w/ what?IM injxn. Always combine w/ sedative/mm relaxant, like (dex) Medetomidine, Midazolam (not Diazepam if im!!!), or Acepromazine
Advantages of Ketamine + ace?Good mm relax, smooth recovery
Disadvantages of Ketamine + ace?No visceral analgesia
MM rigidity
Advantages of Ketamine + α-2s?Potent analgesia, good mm relax, can antagonize a-2s
Disadvantages of Ketamine + α-2?PRONOUNCED CV effects
Advantages of Ketamine + Midazolam?Minimal CV impact, good mm relax
Disadvantages of Ketamine + Midazolam?No visceral analgesia, ET intubation not always possible, top-up w/ Propofol possible

Babies (Neonate/Pediatrics)

Question Answer
Neonate is till what age? Pediatric?Neonate: Till 4 weeks
Peds: 12 weeks
NEONATE → CO is dependent on what?HR dependent (so don't ↓ HR too much w/ drugs!)
Which dominates in the neonate: symp or parasymp?PARASYMP (so bradycardic effect of some drugs might induce SEVERE hypotension) (really? you think a neonate is gonna fight or flight? no.)
What is a neonate's PCV like?LOWER, so less able to tolerate blood loss
What is FRC, what is it like in neonates, what does this mean for you as a vet?Fxnal reserve capacity (the amount of air left in lungs after exhale) & it is↓in neonates (also ↓ in fatties & preggos). It means they don't really have an O2 reserve so they con't tolerate 2-3min of not breathing if inducing anesthesia, so PREOXYGENATE THEM
Why do you wanna pre-oxygenate neonates?They have↓FRC (fxnal reserve capacity)
Neonates → their lung/chest wall compliance is low, which means there are major risks ofAirway closure & hypoventilation
What is the O2 demand of a neonate like?2-3xs Higher (↑ metabolic rate)
What is the RR of a neonate like?HIGHer
The neonate's ↑ RR, ↑ O2 demand, ↓ FRC (fxnal reserve capacity) & ↓ lung/chest wall compliance all lead to what risk factors?Hypoxemia & re-breathing (cant breathe against resistance)
What is temp regulation like in the neonate? Why? What can you do?↓ SC fat reserves, ↑ surface area:body area ratio, poor thermoregulatory ability & less ability to shiver means → MAJOR RISK OF DEVELOPING HYPOTHERMIA DURING ANESTHESIA~! So use warming devices & do everything you can to minimize duration of Sx & anesthesia
What should you keep in mind if giving fluids to a neonate?↓ GFR ability during 1st 6-8wk → so don't overload w/ fluids!
What unique attributes of the neonate must you keep in mind when giving drugs?Immature hepatic metabolism of neonate up to 12wk & Hypoalbuminemia (so greater free/active portion of drug) & ↑ permeability of BBB → MORE SENSITIVE TO DRUGS
How do you approach fasting w/ neonates/pediatrics? (Keep age in mind)<6 weeks NO FASTING. >6wk only 2-3 hrs
Blood work → glucose → how does this usually run in neonates?W/ glucose they often run low, so do LRS infusion combined w/ glucose to make sure dont get hypoglycemia
If there is an abdominal emergency what must you closely monitor?Electrolytes
Which premeds should be AVOIDED in babies?NO A-2s & NO ACE (contraindicated! due to CV effects of dex (need HR maintained, dont wanna induce bradycardia) & ace is just too long Acting-need them up as soon as possible so they can eat/drink soon)
Which premeds are preferred in babies?Benzos (good for v young PTx)
Should you use opioids in babies?Risk of resp depression & bradycardia, but SHOULD be used for PAINFUL conditions
Which anesthetic gas is preferred in mask induction of babies?SEVO (less irritating to airways)
What is a pro & con of IV induction?IV placement often challenging but very rapid (good for abd Sx or dyspnea)
Most common IV anesthetic induction combo for babies?Propofol or Ketamine/Midazolam
Advantage & disadvantage of Ketamine in a baby?Always combine w/ sedative! Good: lack of CV depression. Bad: extensive hepatic metabolism & salivation
What drugs should you AVOID in animals <8-10wk?Barbiturates
Is Alfaxalone good in babies?Works well
Should you intubate a baby? (Pro vs con)PRO: Recc due to narrow upper airways & big tongue
CON: Delicate tissue, laryngeal edema, spasm easily produced. DONT CUFF
Which breathing system?Non-rebreathing
If you need to move an intubated baby, ALWAYSDISCONNECT THEM FIRST. (You can tear their trachea)
When (age) should you use NSAIDS?ONLY ABOVE 12 WK
How should you do opioids, which opioid is preferred?Reduced dosage
↑ intervals. Buprenorphine
Butorphanol > pure mu agonists
What kinda LA might you wanna do?EMLA (calc max dose very careful w/ babies)
*Lidocaine dose?2 mg/kg
How much glucose do you want to provide in fluids?2.5% glucose in LRS*
Which premed combo is usually desired for babies?IF NECESSARY, Midazolam+Butorphanol (both can be antagonized)

Old Farts (Geriatric)

Question Answer
How do you define geriatric?Reached 75-80% of breed - specific expected lifespan (dogs >8y, Great Danes >6y, toy >12y, cats >12y)
How does age affect the CV system?Reduced cardiac reserve capacity
Cardiac dz common
Likelihood of arrhythmia ↑
Circ time ↑
Clinical implications of CV changes in old animals?Avoid extreme HR changes
Avoid sudden changes in ABP
Avoid ↑ vascular resistance
Avoid arrythmogenic drugs
How is the resp system affected clinically?↓ fxn reserve, ↓ PaO2