in the previous video we have discussed cyanide poisoning today let's talk about
how to diagnose and how to treat this evil poison remember the most common
cause in the United States are fires so firefighters any person who was involved
in the fire and don't forget they tried poisoning Rasputin by giving him cyanide.
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As you know from the previous lectures, Cyanide could be gas, liquid or solid.
Cyanide poisoning could be due to inhalation, ingestion or skin absorption.
Causes of cyanide poisoning; smoke inhalation is the most common cause in
United states by far. suicide ingestion so, pharmacists, doctors,
nurses. Medication such as: sodium nitroprusside. Industrial exposure and
the polyurethane in the famous foam bubble wrap, just the one that you keep like
picking with your fingers. I love it, that's why I'm crazy, because of the cyanide.
Cyanide loves binding to ferric therefore cyanide will either bind to
ferric in the Met hemoglobin, or will bind to the ferric in the cytochrome C
oxidase in your mitochondria. In the absence of met hemoglobin, cyanide have
no choice, but to bind to the ferric in the cytochrome C oxidase. Now this enzyme
is gone: irreversible binding. This is an enzyme inhibition. This complex 4 is
now gone.
Oxygen cannot act as an electron acceptor therefore we will go
to an aerobic glycolysis as a source for our energy because ATP from the electron
transport chain is no longer viable and as you know this pathway is not gonna
work when you have no met hemoglobin but when you are relatively lucky and you
have met hemoglobin it will bind cyanide forming cyano met hemoglobin by the
liver Rhodanase, thanks to sodium thiosulfate, we end up with thiocyanate,
which contains cyanide, and it's gonna be excreted in the urine.
Go to hell, cyanide. Go multiply by yourself. Some people will never get this
joke. Cyanide binds ferric in the cytochrome oxidase which will lead to
inhibition of complex 4... what is complex 4 ?! -Cytochrome a/a3 ...Now, no ATP
formation, mitochondria cannot utilize oxygen, we will shift to
anaerobic glycolysis which will lead to lactic acid, lactic acidosis, metabolic
acidosis. What type? - High anion gap metabolic
acidosis. What's the normal anion gap? -It's less than 12 ...Now when your tissue
cannot use oxygen, the concentration gradient between hemoglobin and tissue
is different... So, here is the red blood cell which contains the famous
hemoglobin and here is your tissue normally your tissue is using lots of
oxygen lots of oxygen lots of oxygen which makes the concentration of oxygen
on the hemoglobin greater than the concentration of oxygen in the tissue
which will lead to a diffusion concentration gradient down the
concentration gradient down this concentration gradient but now your
tissue is not using oxygen so there is no concentration gradient for oxygen to
flow from hemoglobin to the tissue oxygen is gonna stay on the hemoglobin
from passing it to the artery then to the vein because there is no oxygen
going to the tissue because your mitochondria cannot utilize oxygen which
destroys the concentration gradient there is no gradient there is no flow to
the tissue the venous oxygen content is high as high as the artery that's why in
cyanide poisoning pao2 which is the partial pressure of oxygen in the artery
equals the P vo2 which is the partial pressure of oxygen and vein some words
of wisdom in cyanide poisoning despite the abundance of oxygen it cannot be
utilized by the mitochondria that's how it ends up in the vein
eating lots of apricots and almonds is bad for you why they contain amygdalin
which is hydrolyzed into hydrogen cyanide one apple a day keep the doctor
away lots of almonds a day mitochondria has
gone astray eating lots of almond will lead to cyanide poisoning however in
cyanide poisoning the patient's breath smells like bitter almond just
fascinating so here is our nice firefighter who serves his community I
serve and protect and smelt like almond now if your doctor is going to test your
ability to answer the question about cyanide poisoning correctly they will
use one of these scenarios the firefighter in coma with almond like
breaths after a fire patient who was prescribed sodium nitroprusside suddenly
collapses he has metabolic acidosis why because of
the lactic acidosis the factory worker in the middle industry who comes to the
ER comatose after an explosion in the mill a pharmacist who suffer from major
depressive disorder presents with confusion seizure and loss of
consciousness hatred cyanide clinically we have symptoms and we have signs what
is the difference between symptom and sign symptom is what you as a patient
complain of signs are what I as a great doctor discover or observe so symptoms
weakness why there is no ATP the electron transport chain is gone tissue
hypoxia yes the tissue is not getting enough oxygen the mitochondria is not
utilizing oxygen so the oxygen is not gonna flow from the hemoglobin to the
tissue epidermal pain chest pain neurological problems such as headache
very important vertigo dizziness seizure in coma all of them are the same as in
carbon monoxide poisoning now signs dilated pupils diaphoresis which is
excessive sweating because we don't say sweating like the normal public we are
sophisticated we say diaphoresis which just means sweating arrhythmia yep
cardiovascular collapse possible decrease heart rate decrease blood
pressure increased respiratory rate yep shorts of breath and the important
cherry cherry red skin why because the partial pressure of oxygen in the vein
is high and what gives your blood the bright color at least the arterial blood
is the oxyhemoglobin when you have lots of oxyhemoglobin in the vein the vein is
gonna look like the artery bright red that's why your skin will look cherry
red in color because your veins are more superficial than your arteries don't
waste your time on crap and let's go to the lab arterial blood gases venous
blood gases what we're gonna find how about the
partial pressure of oxygen in the artery normal partial pressure of vein on the
oxygen higher than normal why because oxygen is not going to the
tissue because we have destroyed the concentration gradient pao2
now roughly equals P vo2 partial pressure of oxygen the artery partial
pressure of oxygen in the vein and partial pressure is not the oxygen
that's on the hemoglobin it's the oxygen in the bloodstream AV oxygen difference
is decreased it's less than 10% what is AV oxygen difference it's the
difference between oxygen concentration in the artery and the vein they are now
relatively equalizing high anion gap metabolic acidosis due to the lactic
acidosis in high anion gap metabolic acidosis it's a freaking acidosis so pH
is low what's the normal pH from 735 to 745 so the pH and patients with cyanide
is going to be less than 735 important decrease bicarbonate because it's a
freaking metabolic acidosis increased anion gap more than 12
okay what's the anion gap it's the positive ions on one end and the
negative ions on the other end and the difference between them is called the
anion gap there is no actual gap it's a gap in our knowledge it's a gap in our
measurement blood lamps we have increased blood lactate level greater
than 10 increased plasma cyanide concentration the EKG nonspecific
findings sinus tachycardia being the most common carboxy hemoglobin
concentration to rule out CO poisoning because both of them are abundant in
fires met hemoglobin level why to monitor therapy because we don't want to
give the patient too much methemoglobinemia global is also bad you
remember methemoglobinemia pros it can treat cyanide poisoning but we can't go
too far because met hemoglobin can kill you
please let me remind you of normal physiology then we'll discuss the effect
of cyanide on each one those you breathe an air the air has
oxygen the percentage of oxygen as compared to the atmospheric air is
called fio2 normally 21% oxygen goes to the lungs in the alveoli it's called P
big AO - that goes to the arterial blood it's called P small a o2 then jumps on
the hemoglobin called si O 2 jumps the tissue the tissue needs oxygen for the
electron transport chain and it produces carbon dioxide goes to the hemoglobin
this is called oxy hemoglobin this is called carb amino hemoglobin not carboxy
carb amino that goes to the venous blood it's P vo2 then back to the lungs you
exhale carbon dioxide so what's the effect of cyanide on each one of those
how about the fio2 it's perfectly normal okay so I nod has no say on that how
about P big a o2 in the alveoli again it's normal how about P small a o2
normal sao to normal but how about the partial pressure of oxygen in the vein
it's high oxygen content a called hemoglobin concentration plus PA o2 plus
si o - what's the effect of cyanide on hemoglobin concentration normal anemia
decreases your hemoglobin concentration but not cyanide poisoning about pao2
same thing normal sao to normal so the oxygen content in cyanide poisoning
normal believe it or not and here I'm talking about the arterial oxygen
content but how about the venous oxygen content it's increased in cyanide
poisoning if io2 is normal P big a o2 is normal P small a o2 is normal it's a Oh
- is normal P vo2 is increase don't ever forget that is the cell affected yes
indeed it's affected the mitochondria cannot utilize oxygen so oxygen is
released from hemoglobin to tissue but it cannot utilize it but didn't you say
that oxygen is not released in the beginning it is released but then the
mitochondria doesn't use it so the oxygen doesn't flow anymore but the
problem is not from oxygen being able to leave the hemoglobin and going to the
tissue that's why generally speaking the cyanide poisoning
does not shift the oxygen binding curve some words of wisdom from the father of
Medicine Hippocrates I will use my power to help the sick to the best of my
ability I will abstain from harming or wronging any man by it I have a terrible
British accent plus Hippocrates was Greek he was not British what am I doing
with my life so let's use our power to help the sick and let's learn how to
manage cyanide poisoning first remove the clothes
why because cyanide poisoning can occur by absorption through the skin and don't
waste your time unbuttoning each button with care
because the shirt of the patient was expensive just get them off
don't be an SS s what I call a super sophisticatedly stupid then wash the
body with soap and water do not wait for the stupid labs
if you suspect cyanide treat it how to treat saina 100% oxygen then we try the
hyperbaric oxygen then the hyperbaric chamber remember your ABCs first airway
breathing circulation establish an IV line and continuous EKG monitoring give
the cyanide antidote what is the sign of antidote the famous triad
hydroxocobalamin sodium nitride sodium thiosulfate let's talk about sodium
thiosulfate sodium thiosulfate helps the Sanomat hemoglobin goes to thiocyanate
then become excreted in the urine go to hell cyanide go multiply by
yourself sodium nitrite converts the normal hemoglobin into meth hemoglobin
so the methemoglobinemia with cyanide forming cyano met hemoglobin then the
sodium thiosulfate will kick in converting them to thiocyanate which
will be excreted in the urine so here is the
famous giant hydroxocobalamin sodium thiosulfate and sodium nitrite sodium
nitrite converts the hemoglobin into met hemoglobin the Farrah's into ferric then
the methemoglobinemia forming cyano met hemoglobin level rhodanese sodium
thiosulfate they'll form thiocyanate excreted in the urine go-to-hell
hydroxocobalamin on the other hand combines directly with cyanide forming
cyano cobalamin again they are excrete is excreted in the urine and that's how
the evil cyanide ends up in the urine magnificent repetition is the mother of
pedagogy here we have the hemoglobin phorus thanks to sodium nitrite now we
have the met hemoglobin which contains furyk cyanides loves ferric without the
met hemoglobin cyanide will be able to bind the complex for the cytochrome a a3
in the electron transport chain destroying your mitochondria destroying
your cellular respiration but now net hemoglobin has gone distract cyanide and
take it away forming Cyanamid hemoglobin sparing the mitochondria from the grief
then cyan homuth hemoglobin thanks to sodium thiosulfate is gonna be converted
into FeO cyanide thio cyanide how about the
methemoglobinemia hemoglobin we can use methylene blue to return it back to
hemoglobin later but now let's get rid of the sanno matimak globin use sodium
thiosulfate now we have thiocyanate go to hell so we have mentioned two of the
triad sodium nitrite and sodium thiosulfate how about the third one
hydroxocobalamin vitamin b12 guys hydroxocobalamin will bind cyanide
forming cyano cobalamin go to hell without this amazing triad your cellular
respiration will be inhibited you will end up smelling like bitter almond with
cherry red skin until you die for a plus students while treating acute cyanide
poisoning do not give methylene blue why because methylene blue will confer
the methemoglobinemia back into regular hemoglobin okay so don't do this wait
until we clear all the sign out from the system then you can give methylene blue
to convert the methemoglobinemia great normal hemoglobin do not let me t
mclogan level rise too much we don't want to go too far yes Matt hemoglobin
is beneficial in treating cyanide poisoning by using too much
methemoglobinemia hemoglobin amine which is also a disease so everything has to
be balanced sodium nitroprusside leads to cyanide poisoning whereas sodium
nitrite and sodium thiosulfate treats this poisoning this is very important
and most students confuse these sodium nitroprusside is evil it leads to
cyanide poisoning sodium nitrite and sodium thiosulfate they treat the
cyanide poison sodium nitroprusside and cyanide and sodium nitrate and sodium
nitrite all lead to hypotension that's why men die on viagra when they are
using sodium nitrate both viagra and sodium nitrate will drop the blood
pressure leading to either death or reflex tachycardia which will also lead
to death in cyanide poisoning it's difficult to distinguish between
original arteries and retinal veins under Fonda's copic exam which is a
brilliant point why because the partial pressure of oxygen in the artery calls
the partial pressure of oxygen in the vein and oxygen is what gives the vessel
its bright color that's why normally arteries have bright
red blood all veins have dark but now we can't differentiate between arteries and
veins both of them are bright guys it can't get better than that so please
join me on patreon com4 / meta kosis and thank you so much for watching my videos
until next time be safe stay happy and study hard I'll see you in the next
video we have a crazy mnemonic about cyanide poisoning until next time