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Anesthesiology - Quiz 1-4

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pufexaxe's version from 2016-09-19 01:20

Injectables: Propofol

Question Answer
What kinda drug is Propofol? What form does it come in? (Notes about this)A hypnotic alkyl phenol. It comes as a white oil-in-water emulsion (1 or 2% solution) *(contains soybean oil & purified egg phosphatide → promotes bacterial growth) SO, discard w/in 24hr after opening.
What is the apprx pH of Propofol?7ish (nice & neutral)
Does Propofol cz tissue irritation?No! Apprx pH of 7 (any of you who have worked in a clinic know that it actually does cz mild irritation, it feels like sand paper & is uncomfortable)
What is Propoflo 28? How is it different from Propofol?New formula which contains benzyl alcohol, discard 28 DAYS (not 24 hr) after opening. NOT FOR USE IN CATS!!
Where does the MOA for Propofol take place?Interaction at the GABA-A receptor
What is the onset of action for Propofol? How long is its effect usually? What is the protein binding like?Onset of action is ~30sec (in long notes 60sec). Usually lasts about 10 minutes. It is SUPER PROTEIN BOUND (97-98%)
What is the metabolism & accumulation like for Propofol? Excretion?There is rapid metabolism in the liver & MINIMAL accumulation which means it is suitable for CRI & TIVA. Excreted from the kidneys.
How well do cats & Propofol get along?Propofol is metabolized via glucoronidation in the liver...cats can't glucoronidate well. This means they have prolonged recoveries. ALSO, feline Hb is prone to oxidative damage from phenolic compounds → this leads to a Heinz body anemia & ↓ in PCV
What are some signs you'd see in a cat after PROLONGED/REPEATED Propofol anesthesia?(Since it czs a Heinz Body Anemia)
Anorexia
Depression
Diarrhea
Facial edema
Delayed recovery
How does Propofol affect the CV system? Resp system?Czs HYPOTENSION (nobody's quite sure why) & can cz RESP DEPRESSION & APNEA!!
How does Propofol affect the CNS?Anticonvulsant properties & a neuroprotective.... they might also show EXCITATORY SIGNS (mostly during induction)
While inducing anesthesia w/ Propofol, many animals might show excitatory signs, such as...Myoclonus (spasmodic jerky contraction of groups of muscles)
Paddling
Nystagmus
"Propofol shakes/shivers"
Does Propofol provide analgesia?NO!
When using Propofol as an anesthetic induction agent, what 2 things must you do/keep in mind?(1) Dose needed dependent on premedication
(2) Slowly titrate to effect
If you are doing repeated doses or TIVA w/ Propofol, what must you do?Supplement O2!! (Resp depression & apnea)
How useful is Propofol in... Cats/dogs? Horses? Rumis?Cats/Dogs: Widely used
Horses: Rough induction phase
RUMI: Useful but not approved
What must you be ready to do once you induce w/ Propofol?Be ready to intubate & ventilate! (don't pull a Michael Jackson!)
What are the 4 major contraindications for using Propofol?(1) Hypovolemic PTxs (czs more hypovolemia)
(2) PTxs in heart failure (czs hypovolemia)
(3) Dont use in hyperlipidemia & pancreatitis PTx (disorders of lipid metabolism could be aggravated by the lipid emulsion)
(4) AVOID REPEATED PROPOFOL ANESTHESIAS IN CATS!
What are the 3 huge reasons Propofol quickly became preferred over Thiopental?Rapid awakening
Non-cumulative effect (fast liver metabolism)
No legal restriction
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Injectables: Etomidate

Question Answer
What are the 2 formulations Etomidate is available in?(1) Classic preparation (in a clear solution)
(2) Lipid emulsion (white emulsion lipid)
What is the solution component in the Etomidate classic preparation? In the lipid emulsion?(1) Classic: Propylene glycol
(2) Lipid emulsion: Contains intralipid
What is the pH in the Etomidate class preparation? In the lipid emulsion?(1) Classic: pH 6.9 (HIGH OSMOLARITY)
(2) Lipid: ~7
How long does Etomidate last once opened?The LIPID EMULSION promotes bacterial growth, so you must discard ampule in 24hr (Not an issue in the classic preparation)
Major caution w/ the classical preparation?Perivascular injxn results in necrosis & phlebitis
What is the MOA of Etomidate?Agonism of the GABA-A receptor
What is protein binding like for Etomidate? How well does it penetrate the BBB? How long does it take to reach max CNS concentration?Protein binding at 75%, FAST penetration of the BBB → so MAX CNS conc in 1 minute!!
How is Etomidate metabolized? Are there active metabolites? How is it eliminated?Liver metabolism into INACTIVE metabolites (long notes said tissue esterases too). Elim via urine & bile!
Does Etomidate accumulate in the body?There is MINIMAL accumulation
When is Etomidate the anesthetic of choice?In PTxs w/ CV dz & in critically ill PTxs where CV derangement is undesirable!!!
What is onset of action & duration of Etomidate?Onset w/ IV injxn is 60 sec, duration from bolus is about 10 minutes (& is dose dependent!) → So, FAST INDUCTION & RECOVERY IN DOGS+CATS
What is the caution when using Etomidate (about administration)If used w/o premed, there is a high incidence of myoclonus & pain on injxn!
How does Etomidate affect the resp system?Dose-dependent resp depression
How does Etomidate affect the CNS system?NEUROPROTECTIVE!
Does Etomidate provide analgesia?NO!
What is something that Etomidate does which affects hormonal balance? Explain.INHIBITS ADRENAL STEROID PRODUCTION! For 2-6hr (3-6 in long notes) after single bolus. Usually there is no detrimental effect after single bolus induction, but if prolonged, can kill PTx & is more concerning w/ single bolus if elderly or debilitated PTx (either way, avoid as use of CRI bc of this)
Would you want to use Etomidate in a high-risk PTx?Yes! Suitable for this
Is it better to use Etomidate alone, or in combination? (Explain)Best used w/ PREMEDICATION! A useful protocol would be Fentanyl-Diazepam-Etomidate (pain-premed-induction agent)
Would it be better to quickly or slowly give Etomidate?SLOWLY titrate to effect
Contraindications of Etomidate?Avoid in animals w/ known adrenal insufficiency!! (Etomidate inhibits adrenal steroid production). Also NOT USED in horses & cattle
5 reasons Etomidate has not gained much popularity in vetmed...(1) Most expensive (vs Thiopental & Propofol)
(2) Sneezing/retching/myoclonic twitching on induction (can ↓ w/ premed)
(3) Inhibits adrenocortical fxn
(4) Hemolysis & hematuria reported in cats & dogs
(5) The classical preparation has propylene glycol which is painful on injxn (the lipid emulsion doesnt have this problem)
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Injectables: Alfaxalone

Question Answer
What kinda drug Alfaxalone? Is it soluble or insoluble in water?Neuroactive steroid. INsoluble in water.
The new formula of Alfaxalone (the old 1 was bad bc severe anaphylactic rxns) contains what solution? What does it look like, what is its pH & how irritating is it?Cyclodextrin is the new solution & it is a colorless & clear solution w/ a pH of around 7, which means that perivascular injxn is NOT painful & it does NOT cz tissue necrosis at injxn site
What is the MOA of Alfaxalone? What are the 2 major effects it has?HYPNOSIS & MM RELAXANT via the GABA-A receptor!!!!
How fast is induction w/ Alfaxalone? How has does it clear from the body? What is its accumulation like?Rapid induction & rapid clearance (30-60sec, 6-10min). excreted via bile.There is MINIMAL ACCUMULATION, which means you can use it as CRI.
What is protein binding like for Alfaxalone? How is it metabolized & excreted?No sig protein binding (so PP levels won’t change the dose or effectiveness) & is metabolized in the liver & excreted via BILE!!
How does Alfaxalone affect the resp system?Minimal resp. changes (dose & injxn rate dependent).
HYPOTENSION → mainly bc myocardial depression (she has reflex. tachycardia, but I’m not sure what that means)
How does Alfaxalone affect the CNS?Neuroprotective! Reduces intracranial pressure!
Does Alfaxalone provide analgesia?NO (she has a ? next to this... there might be minor analgesia?)
Sp diff w/ Alfaxalone during recovery w/ Alfaxalone?In CATS:
Myoclonus (spasmodic jerky contraction of groups of muscles)
Opisthotonus (severe state of hyperextension)
What are the routes of admin you can use w/ Alfaxalone? What is the speed at which you administer?IV, also IM (no tissue irritation, pH 7 w/ the Cyclodextrin solution). Slow injxn & induction of dose over 60 seconds
Which animals can you use Alfaxalone in & for what?DOGS & CATS for anesthetic induction & TIVA (long notes say also horses, sm rumi & pigs)
What must you give concurrently w/ Alfaxalone?Premed & analgesics!
How good is Alfaxalone good for once it's opened?7 days
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Injectables: Ketamine

Question Answer
What is the pH of Ketamine like?3.5 - 5.5 (acidic)
What are the 2 forms of Ketamine available?Racemic mix OR as S(+) Ketamine
How stable is Ketamine as a solution?Stable, but should be protected from light & heat
What is the type of anesthesia Ketamine provides? Explain it & what it results inDissociative anesthesia!! This czs a disassociation btwn the thalamic & limbic system. This leads to profound analgesia & amnesia w/ maintained reflexes
Ketamine czs catalepsy. What is catalepsy?Muscular rigidity
Open eyes
↓ sensitivity to pain
What is the MOA for Ketamine?MAIN site: NMDA ANTAGONISM in brain & spinal cord. There is also some binding in opioid receptors, cholinergic receptors, adrenergic receptors & GABA-A receptors
Does Ketamine cross the BBB fast or slow? How long is the onset of action?Distributes & crosses BBB rapidly → onset of action is then rapid.
IV: 30-90 sec
IM: 10-15 min
What is metabolism of Ketamine like? Does it have active metabolites? Excretion?Hepatic metabolism to ACTIVE metabolites (Norketamine). Excreted via kidneys
Does Ketamine tend to accumulate?Accumulation after repeated admin or TIVA (active metabolites play a role in this)
What are the effects Ketamine has on the CV system?UNIQUE EFFECTS: ↑ HR, ↑ BP & ↑ CO
HOWEVER, it also has direct myocardial depression (weird...) normally, the stimulatory effects predominate (except for in catecholamine-depleted PTx)
How does Ketamine affect the CNS?↑ INTRACRANIAL PRESSURE! (not if ET-CO2 is controlled) & MAY ELICIT SEIZURES!
What are the effects Ketamine has on the eyes (notes about this)? What are reflexes like w/ Ketamine?There is an ↑ in ocular pressure & the eyes do NOT roll back, so use ointment to keep them moist. The swallow & cough reflexes are maintained :)
Why do you want to be gentle w/ a PTx on Ketamine?They have hypersensitivity to noise, light & handling...there is also hyperexcitability during recovery
Does Ketamine provide analgesia?PROFOUND somatic analgesia
Which barriers can Ketamine cross?BBB & also CAN CROSS PLACENTAL BARRIER! Which has a negative effect on the vigor of puppies (can cz failure to thrive)
What are the clinical uses for Ketamine? What must you always do when using Ketamine? Any downsides?Can use as induction agent in many species. Can also use as maintenance in short procedures (will be accumulation if used too much). Can use as CRI in subanesthetic doses as an analgesic. MOST IMPORTANTLY: NEVER USE ALONE (Downside: anesthetic depth difficult to assess)
What are the different routes of admin for Ketamine? Notes about particular admins?IV
IM (**PAINFUL)
SC
Oral
Rectal
(Epidural)
What are the drugs Ketamine should always be combined w/?Benzodiazepines
Acepromazine
α-2 agonists
7 major contraindications for Ketamine?(1) PTx w/ CV dz (↑ CV activity)
(2) PTx w/ hepatic insufficiency (metabolized by liver into active metabolites)
(3) PTx w/ renal insufficiency (excreted via kidney)
(4) Hyperthyerosis(hyperthyroid) PTx, or OTHER dzs w/ ↑ blood pressure
(5) PTx w/ HEAD TRAUMA/BRAIN TUMOR/EPILEPSY/MYELOGRAM (dye in CSF)
(6) PTx w/ ↑ intraocular pressure
(7) C-section
What are the cons of using Ketamine?Mm rigidity
Pain on injxn
Emergence of psychomimetic rxns
What are the pros of using Ketamine?Provides analgesia, amnesia & hypnosis.
It can be given through many routes of admin (including IM, which isnt possible w/ Propofol or Thiopental), there is sympathetic stimulation, minimal resp. depression & bronchodilation!
What are the advantages of S(+) Ketamine?Same depth of anesthesia as the racemic mix, w/ longer & stronger analgesia! It is also more suggestive of myocardial & neuronal protection. It also has ↓ agitation, disorientation & anxiety & a faster recovery
Whats a Hellabrunner mix?Ketamine
Xylazine
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