okay guide to anesthetic drugs so again our drugs are so specialized and so the way i think of this
is you know if i want to buy between a laptop this is just a gazillion details right so what i try to
do is find the point of difference between each product um it's kind of like using the critical
issue in the other scenarios that we talked about but then tailoring it to what makes this agent
different or better or worse than another and so this is what i had to learn from my um part
one exam which just sounds incredibly annoying but really what you notice is there's a whole bunch of
patterns in this very very busy complex complex um table um so i won't even bore you with that
it's a lot of my niche the pharmaceutics connects some dynamics for each drug are important
but this is mostly useful to parts and past some really bad part one exam stuff but in
real life all of our decisions are made on just a few crucial facts and in the tables i've provided
i find that these are really my decision making facts um of each drug and you'll very you'll get
very comfortable with a few patterns uh as we go on so uh here are a few aspects of hypnotic agents
i'm just thinking i'm not going to go through them in too much detail because we'll we'll go
through the cases and i think that's a far better way of learning this uh than me just telling you
stuff that's on the slide rock uranium atrocitum and saturation sucks and methodium they have
certain particularities again and there's no ideal agent like in some situations you may just have
bad effects of any drug on that patient and you just have to decide and that that's quite common
as well and here your analgesics i'm just going through these three facets because the induction
agents hypnotics analgesics and relaxants are the three agents that you will are very anesthetically
relevant and the ones you'll have to decide on as you're presenting you know your case to your boss
and drawing out your medication so again the most practically relevant ones are these
these um small tables let's give you a bit of a practice with this so page 22 or near page 22
choose your induction meds so i want you to choose your hypnotic analgesic and muscle paralytic agent
for these cases you've got a 50 year old female for a laparoscopic cholecystectomy with renal
impairment so i just want you to make a a call a judgment about what you'd choose i guess i think
in terms of medications even though she's got renal impairment propofol fentanyl rocky rhodium
yeah absolutely and why did you choose rock uranium in spite of the renal impairment
um oh i guess because i think that sucks and ethonium would probably be the other uh
relaxing i'd be thinking but you know these side effects you know are probably worse to someone
with renal impairment like the high k um like high anaphylaxis rate as well so great now rock uranium
and such methane both have a high energy rate are there any medications relaxants you could
give that have no renal issue at all and you and you'll see this pattern time and time again your
answer is not wrong by the way so profile receiver maintenance completely the regular thing that most
people would do fentanyl correct because morphine has active metabolites that may accumulate that
said there's plenty of times you'd use morphine as well depending on how bad the renal failure is
just see that there's so many gray areas here again i just want you to come up with a reasonable
decision and know how you got that decision because that's what matters that you're making
these decisions um you know and you're actually acting like a senior person
at your current cesar cysticum are both non-organ dependent so they will
just be eliminated regardless of whatever renal or liver impairment there is but there's plenty
of people that would use rock uranium because it's also renal and liver excreted so i'm giving you a
whole lot a lot of ifs and buts uh but just to show you that there's sometimes multiple
things you can use but just to be able to you know there's no real right or wrong answer
if you you said exactly right with if you need such something it has a high in aphylaxis rate
and i'd also check the potassium uh in the patient with renal failure because such
medium can cause a rapid rise in potassium if they're already hyperkalemic that can be lethal
let's go to this one six-year-old female for umbilical hernia repair
they've got a strong history of post-operative nausea and vomiting and they look like a
difficult bag mask ventilation but let's say the intubation looks pretty easy to do this patient
with a difficult bag marks you don't really want to have a prolonged duration uh to wake with the
muscle relaxant so something like saxonythonium if it's not contraindicated or a high dose rock
could be chosen and then with the post-operative nausea vomiting you could choose a teva technique
or just add a few extra anemia medics fantastic that's exactly right so uh if it was that bad i'd
use tv so profound induction and maintenance so instead of running the gas i'd run you know proper
fall through the drip fentanyl but you could really use any any combination there multimodal
plus opioids and then you're exactly right fast relaxant means you don't have to spend time trying
to bag mask someone who's difficult to bag mask so sucks or high dose rock uranium and if you haven't
done analytics you'll see this pattern um often enough uh seventeen-year-old male in the next
case laparoscopic nephrectomy cardiac renal and liver impairment and asthma so quite a few things
yeah wonderful uh so i would probably do a propofol induction with fentanyl despite the
uh renal impairment only using a sort of small amount and then considering um
some of the non-organ dependent okay infusion throughout the case if needed and then a
system for the paralysis given that it's uh often elimination that's great uh so profitable ketamine
midas induction let's say i've done that because of the cardiac patient and i'll go through that in
the induction section remy fentanyl and fentanyl so you know it's a long case and river liver and
renal impairment maybe i want to run remy sorry so at the end of the case there's no remy left
because it's such a fast offset and then i can give fentanyl which has less active metabolites
and there's no no real perfect option for relaxing you know cisatric cream has no histamine release
and non-organ dependent there's really slow onset and it can be quite frustrating bagging
the patient for five minutes before intubation rock uranium can be reversed so that's that's
often good but it is organ dependent and after curium has histamine released but again it's not
the biggest thing you can use atrocious patients and it's you know can be can be fine um but just
have a reason for why you use one or the other final case 30 year old female for ga cesarean
section with preeclampsia what are your induction meds the hero i just thought i'd check so why are
we avoiding histamine release for a patient is that to avoid iso tension like vasodilation
yeah and you could make an argument for that um histamine with bronchoconstriction
it's just the thing that people talk about again i don't know the the you know is this a real
high-yield thing or not prob probably not but it's something that people talk about and it's it's
good to know that it causes a histamine release and you might want to avoid it if you could
but yeah for bronchospasm for the asthma so i don't know much about pregnant people
that's right but i sort of the considerations would be possibly things that aren't going to
cross the placenta or impact the baby and also i guess the question is if it's an
emergency procedure probably induced with something fast-acting exactly
and what do you reckon uh it's the induction agent what do you reckon maybe rock uranium yeah that's
fast yeah absolutely so propofol is almost safe in very safe in pregnancy it would be the most
common drug we'd induce with these days and you're very right about al about worrying about placental
uh transmission of agents so we'd use al-fentanyl to void placental transfer
of a slightly longer acting opioid like fentanyl alphental is very quick as well and shorter acting
so you get this fast onset to prevent any blood pressure spike with intubation which is really
great in pre-eclampsia because you know that hypertension can cause intracranial hemorrhages
and it's emergency and in the aspiration risk patient which almost every patient is who's
pregnant by definition uh so fast relaxant either sucks or rock uranium so you're absolutely right
about that as well it's really good um again my aim for this is to be able to just give you give
you an insight into some of the decision making points sometimes there's really poor evidence for
one or the other and it's not the most important thing but it's very important that you would
you know talk about it in this kind of in this kind of way to show that you know the information
and there's one of this i think in one of the situations and you want to be seen to know stuff
even though some of the actual decisions don't have any good evidence or would even matter that
much and so take take this for what it is it's just a common talk and chat around the anesthesia
inductions that that we're talking about here this is in your workbook so common drugs and doses i
won't go into this um drawing up tricky meds um it's one of those things that no one ever went
through with me um so that's on the youtube channel as well for the difficult meds like
drawing up having tazers in and kefazolin and propofol quickly and again just practice enough
and you'll you'll get good at it uh good question can we emit the opioids until the baby is out
or is it expected in the pre-eclampsia uh that some ip is given yeah it's it's
almost because you've got to do it so rapidly and we always worry about a risk of awareness
almost always you'd give al fentanyl but i agree that if you gave enough propofol to this patient
chances are they'd feel the pain and become very tachycardic
so if they didn't have preeclampsia you could just give it without al fentanyl the fact is if
you had a severe tachycardia and had a blood pressure spike the intracranial hemorrhage
risk is this unknown factor that's why i would give al fentanyl for this preeclampsia patient
but that's a really good question most people would give our fentanyl in this