Anesthesiology Quiz 1 Part 4

kelseyfmeyer's version from 2015-09-08 16:57

Anticholinergic (antimuscarinic) (parasympatholytic) agents (***this is premeds but I had to move it for it to all fit on the previous set)

Question Answer
what are the three anticholinergics?atropine, Glycopyrrolate, Scopolamine (Hyoscine)
what is the MOA of anticholinergics?block acetylcholine receptors of the parasympathic system (parasympatholytic)
how do anticholinergics affect heart rate? how might this be useful?INC heart rate, which is useful as it prevents or treats drug (opioid) induced bradycardia
how do anticholinergics affect salivation?reduce salivation(useful for ketamine where you salivate too much)--> saliva becomes more viscous. (this is crappy tho)
how do anticholinergics affect GI motility? what should you know about this?REDUCE gut motility, which can cause impacted colic in horses :(
how do anticholinergics affect pupils, and what clinical relevance does this have?dilates pupils, which spoils focus--> cats and horses can panic
how do anticholinergics affect the bronchioles?relax bronchiole smooth mm--> counteract constriction.
WHAT IS THE SUPER DUPER AWESOME THING WE WANNA USE ANTICHOLINERGICS THE MOST FOR?For treatment of bradycardia caused by vagal stimulation
what is the pk like for atropine?can cross BBB and placenta!!!
how does atropine affect the HR?although anticholinergics inc heartrate, atropine might have an initial decrease in HR
explain the major species differences in doses with atropinehorses/cats/dogs are similar. you need HIGH doses for effect in rumis, and rabbits have atropine esterase so it will be VERY short acting
is glycopyrrolate synthetic or natural? how does its pk differ from atropines? what is it usually used for?synthetic, doesnt cross BBB. DRUG OF CHOICE FOR RABBITS
check out the atropine vs glycopyrrolate HR chart on second last slideatropine is steeper inc and higher resulting HR. glyco is slower and lower


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 soyabean oil and purified egg phosphatide--> promotes bacterial growth) SO, discard within 24hr after opening.
what is the apprx pH of propofol?7ish (nice and neutral)
does propofol cause tissue irritation?no! apprx pH of 7
what is propoflo 28? how is it different from propofol?new formula which contains benzyl alcohol, discard 28d (not 24hr) after opening. NOT FOR USE IN CATS!! AHHHH!!
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 60sec (ppt said 30sec). Usually lasts about 10 minutes. It is sUPER PROTEIN BOUND (97%)
what is the metabolism and accumulation like for propofol? excretion?there is rapid metabolism in the liver, and MINIMAL accumulation which means it is suitable for CRI and TIVA. Excreted from the kidneys.
how well do cats and propofol get along?propofol is glucoronidated in the liver to be metabolized...and cats can't glucoronidate. this means they have prolonged recoveries. ALSO, feline hemoglobin is prone to oxidative damage from phenolic compounds--> this leads to a heinz body anemia and decrease in PCV
what are some signs you'd see in a cat after PROLONGED/REPEATED propofol anesthesia?(since it causes a heinz body anemia)... anorexia, depression, diarrhea, facial edema, and delayed recovery
how does propofol affect the CV system? resp system?causes HYPOTENSION (nobody's quite sure why), and can cause RESP DEPRESSION and APNEA!!
how does propofol affect the CNS?anticonvulsant properties and a neuroprotective.... they might also show EXCITATORY SIGNS (mostly during induction)
while inducing anesthesia with propofol, many animals might show excitatory signs, such as...myoclonus, paddling, nystagmus, "propofol shakes"
does propofol provide analgesia?NO!
when using propofol as an anesthetic induction agent, what two 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 with propofol, what must you do?supplement O2!! (resp depression and apnea)
how useful is propofol in... cats/dogs? horses? rumis?C/Ds: widely used. Horses: rough induction phase. RUMI: useful but not approved
what must you be ready to do once you induce with propofol?be ready to intubate and ventilate!
what are the 4 major contraindications for using propofol?(1) hypovolemic pts (causes more hypovolemia) (2) pts in heart failure (causes hypovolemia) (3) dont use in hyperlipidemia and pancreatitis patients(disorders of lipid metabolism could be aggrevated by the lipid emulsion) (4) AVOID REPEATED PROPOFOL ANESTHESIAS IN CATS!
what are the three huge reasons propofol quickly became preferred over thiopental?rapid awakening, non-cumulative effect (fast liver metabolism), and no legal restriction

Injectables: Etomidate

Question Answer
what are the two 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: about 7
how long does etomidate last once opened?the LIPID EMULSION promotes bacterial growth, so you must discard ampule in 24hr. (this isnt an issue in the classic preparation)
major caution with the classical preparation?~perivascular injection results in necrosis and phlebitis
what is the MOA of etomidate?works on 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 AND bile!
does etomidate accumulate in the body?there is MINIMAL accumulation
when is etomidate the anesthetic of choice?in pts with CV dz, OR in critically ill pts where CV derangement is undesirable!!!
what is onset of action and duration of etomidate?onset with IV injection is 60sec, duration from bolus is about 10 minutes (and is dose dependent!) --> so, FAST INDUCTION AND RECOVERY IN DOGS+CATS
what is the caution when using etomidate (about administration)if used without premed, there is a high incidence of myoclonus and pain on injection!
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 after single bolus. usually there is no detrimental effect after single bolus induction, but if prolonged, can kill pt, and is more concerning with single bolus if elderly or debilitated pt (either way, avoid as use of CRI bc of this)
would you want to use etomidate in a high-risk patient?yes! suitable for this
is it better to use etomidate alone, or in combination? (explain)best used with 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 with known adrenal insufficiency!! (etomidate inhibits adrenal steroid production). Also NOT USED in horses and cattle
5 reasons etomidate has not gained much popularity in vetmed..(1) most expensive (vs thiopental and propofol) (2) sneezing/retching/myoclonic twitching on induction (can dec with premed) (3) inhibits adrenocortical fxn (4) hemolysis and hematuria reported in cats and dogs (5) the classical preparation has propylene glycol which is painful on injection (the lipid emulsion doesnt have this problem)

Injectables: Alfaxalone

Question Answer
what kinda drug alfaxalone? is it soluable or insoluable in water?neuroactive steroid. INsoluable in water.
the new formula of alfaxalone (the old one was bad bc severe anaphylactic rxns) contains what solution? what does it look like, what is it's pH, and how irritating is it?cyclodextrin is the new solution, and it is a colorless and clear solution with a pH of around 7, which means that perivascular injection is NOT painful and it does NOT cause tissue necrosis at injection site
what is the MOA of alfaxalone? what are the two major effects it has?HYPNOSIS and MM RELAXANT via the GABA-A receptor!!!!
how fast is induction with alfaxalone? how has does it clear from the body? what is its accumulation like?rapid induction and rapid clearance (30-60sec, 6-10min). there is MINIMAL ACCUMULATION, which means you can use it as CRI.
what is protein binding like for alfaxalone? how is it metabolized and excreted?no sig protein binding (so PP levels wont change the dose or effectiveness), and is metabolized in the liver and excreted via BILE!!
how does alfaxalone affect the resp system?minimal resp. changes (dose and injection rate dependent)
how does alfaxalone affect the CNS?neuroprotective!
how does alfaxalone affect the resp system?HYPOTENSION--> mainly bc myocardial depression (she has ev. tachycardia, but im not sure what that means)
does alfaxalone provide analgesa?NO (she has a ? next to this.. there might be minor analgesia)
sp diff with alfaxalone during recovery with alfaxalone?myoclonus and opisthotonus (severe state of hyperextension) in CATS
what are the routes of admin you can use with alfaxalone? what is the speed at which you administer?IV, also IM (no tissue irritation, pH 7 with the cyclodextrin solution). slow injection and induction of dose over 60 seconds
which animals can you use alfaxalone in, and for what?DOGS AND CATS for anesthetic induction and TIVA (long notes say also horses, sm rumi and pigs)
what must you give concurrently with alfaxalone?premed, and analgesics!
how good is alfaxalone good for once it's opened?7 days

Injectables: Ketamine

Question Answer
what is the pH of ketamine like?3.5-5.5
what are the two forms of ketamine available?racemic mix OR as S(+) ketamine
how stable is ketamine as a solution?stable, but protected from light and heat
what is the type of anesthesia ketamine provides? explain it, and what it results inDissociative anaesthesia!! this causes a disassociation between the thalamic and limbic system. This leads to profound analgesia and amnesia with maintained reflexes
ketamine causes catalepsy-- what is this?muscular rigidity, open eyes and decreased sensitivity to pain
what is the MOA for ketamine?MAIN site: NMDA ANTAGONISM in brain and spinal cord. There is also some binding in opioid receptors, cholinergic receptors, adrenergic receptors, and GABA-A receptors
does ketamine cross the BBB fast or slow? how long is the onset of action?distributes and crosses BBB rapidly--> onset of action is then rapid. IV: 30-90 seconds. IM: 10-15 minutes.
what is metabolism of ketamine like? does it have active metabolites? excretion?hepatic metabolism to ACTIVE metabolies (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! inc in HR, BP, and CO! HOWEVER, it also has direct myocardial depression (weird...) Normally, the stimulatory effects predominate (except for in catecholamine-depleated patients)
how does ketamine affect the CNS?INC INTRACRANIAL PRESSURE! (not is ET-co2 is controlled-- END TIDAL) and MAY ELICIT SEIZURES!
what are the effects ketamine has on the eyes (notes about this)? what are reflexes like with ketamine?there is an inc in ocular pressure, and the eyes do NOT roll back, so use ointment to keep them moist. the swallow and cough reflexes are maintained :)
why do you want to be gentle with a pt on ketamine?they have hypersensitivity to noise, light, and handling...there is also hyperexcitability during recovery.
does ketamine provide analgesia?PROFOUND somatic analgesia
which barriers can ketamine cross?BBB and also CAN CROSS PLACENTAL BARRIER! which has a negative effect on the vigor of puppies
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 maintainance 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?can give IV, IM(**PAINFUL), SQ, oral, rectal, (epidural)
what are the drugs ketamine should always be combined with?benzodiazepines, acepromazine, or alpha-2 agonists
7 major contraindications for ketamine?(1) pts with CV disease (inc CV activity) (2) pts with hepatic insufficienty (metabolized by liver into active metabolites) (3) pts with renal insufficiency (Excreted via kidney) (4) Hyperthyerosis(hyperthyroid) pts, or OTHER dzs with high blood pressure. (5) PTS WITH HEAD TRAUMA/BRAIN TUMOR/EPILEPSY/MYELOGRAM (dye in CSF) (6) pts with inc intraocular pressure (7) c-section
what are the cons of using ketamine?mm rigidity, pain on injection, emergence of psychomimetic reactions
what are the pros of using ketamine?provides analgesia, amnesia, and hypnosis. It can be given through many routes of admin (including IM, which isnt possible with propofol or thiopental), there is sympathetic stimulation, minimal resp. depression, and bronchodilation!
what are the advantages of S(+) ketamine?same depth of anesthesia as the racemic mix, with longer and stronger analgesia! it is also more suggestive of myocardial and neuronal protection. It also has dec agitation, disorientation and anxiety, and a faster recovery.
whats a hellabrunner mix?ketamine and xylazine

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