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Ischemic Stroke 04: Treatment with tPA

now let's continue with the treatment of

ischemic stroke and as we talked about

in the previous video our treatment is

one of the treatments actually is TPA a

clot busting drug and the road to

getting here was not an easy one it was

filled with lots of studies in which

busting drugs were given to patients and

they didn't do so well and it wasn't

until the 90s through the nihms trial ni

NDS showed that there was benefit in

giving TPA to nations with stroke within

three hours now there's a lot of

controversy still to this day

surrounding the use of this drug and

even this trial I'm not going to go over

any of that this has made it to the a

subclinical policy and some even call it

a standard of care and so we're just

going to talk about the

non-controversial stuff that's written

even though a lot of people disagree

with it so TPA was a drug that was

dangerous right because it would cause

people to bleed in their heads and so

the nihms trial showed that if you gave

it within three hours then it could

safely be given in the benefits

outweighed the risks and so we're really

under time pressure here we were under

we're working against the clock actually

we're working against two clocks the

first clock here is that we want to give

TPA within three hours of onset of

symptoms and the second clock here is

that we want to give the TPA

within one hour of the patient arriving

to our emergency department and so let's

look in more detail at this one-hour

time line which we call the door to

needle time and so we want to door to

needle time to be less than 60 minutes

and to make that happen a lot about

things a lot of pieces have to fall into

place and there are actually guidelines

that say that certain things have to

happen within a certain amount of time

and so we'll go through each one of

these very quickly

so at time zero the patient pulls into

your door the emergency department and

that's when the clock starts within ten

minutes this you the patient needs to be

assessed by a doctor and and labs need

to be drawn and the doctor is going to

ask when were your last normal and do a

stroke scale and then within 15 minutes

the you want to make a call to the

stroke team the stroke team is going to

involve a it's a multidisciplinary team

it involves pharmacists neurologists

radiologists everybody that's going to

be involved to get this to happen

quickly within 60 minutes and so

additionally with you know you also got

to get the patient to CT and so you got

to get them there within 25 minutes to

get that patient's head CT done and then

you need to get those results back

within 45 minutes so that's the results

of the CT as well as the results of the

labs and you depend on the neurologist

would be there and preferably this is

read by a neuroradiologist you discuss

neurologist in a decision that is made

to give the TPA the pharmacists then has

15 minutes to mix up this drug and

administer the bolus to start the bolus

and that's how we get the door leave in

less than 60 minutes now I set a bolus

the dose for this drug is 0.9 milligrams

per kilogram and there is a limit for

our heftier patients now this drug is

given in two phases the first 10% of the

dose is given as the bolus and the next

90 percent is given over the next hour

and so this drug is given in eligible

patients so who is eligible to get this

well guess what dr. Lin has a process

verbis card for the contraindications

for thrombolytics and so you want to go

through this and and they're not really

that outrageous right anything that

would put someone at risk for bleeding

on would be a contradiction so if they

vent head trauma

if you think they have a subarachnoid if

they've had an arterial punctures

you can't compress previous head bleed

cancer in their head or aneurysms if

they've had some spinal surgery if their

blood pressure is too high and look at

this number here so if their blood

pressure is greater than 185 systolic or

greater than 110 diastolic and then you

can't give it we're going to come back

to that if they have any bleeding or if

their platelets are low if they had

heparin if their INR is too high if they

have any other sort of clotting drugs

that were given to them if their blood

glucose is too low or they have a multi

lowbar infarct so greater than third of

the cerebral hemispheres so if any of

these things are present then you cannot

give the TPA now I said we're going to

come back to that blood pressure the

first thing that you're going to

remember seriously is that the brain

auto regulates and and raises the blood

pressure up high and so you know that we

don't want to lower this blood pressure

too much but if we want to give TPA you

have the opportunity you can give a drug

to bring this down just below these

numbers and some drugs that you might

consider using include these easily

titratable drugs like labetalol or night

karna pain if you got to give one or two

doses and it brings the pressure down

great if it takes many doses or it's

just tough bringing it down then talk to

your knowledge is because maybe they are

not a good candidate for TPA in that

case because if their blood pressure

rises again with the TPA on board they

are at risk for getting a head bleed so

you can see over here that this is for

zero to three hours from symptom onset

now there was a subsequent trial in

Europe called the eks3 which looked at a

longer time frame it looked at three to

four point five hours and they found

that it was safe and there is benefit

well let me just say the benefit

outweighed the risks for patients if

they met these exclusion criteria

Stubbins above so if they're greater

than 80 you don't want to do it if they

have a bad stroke scale so stroke scale

greater than 25 if they are just taking

oral anticoagulants it doesn't matter

what their inr if their INR is 1 if

they're on coolant still you don't want

to do it and if they have history of

diabetes and they've got a prior stroke

in the past so if they have any of these

contraindications then they're not going

to get TPA in the three to four point

five hour window and here is another

plug for academic life in emergency

medicine great site go visit it and

download this process verbis card from

there for the contraindications to

thrombolytics now if you give

thrombolytics

you cannot give any kind of

anticoagulants or antiplatelet agents

for the next two four hours also keep

the blood sugar under control don't let

them get any fevers because that has a

bad outcome they're going to need to go

to a neuro floor or neuro ICU where they

have experience taking care of these

patients patients with strokes should

get aspirin within 48 hours so if they

are not getting TPA you could give them

an aspirin in the emergency department

but if they are getting TP remember no

antiplatelet agents for the next 24

hours after getting TPA so giving today

or recombinant tissue plasminogen

activator is a complicated process right

look at all these things that you have

to do the dose is even complicated all

the things you have to do afterwards are

complicated and there's a gigantic list

of contraindications as well that makes

sense because this is a potentially

dangerous drug if you used in the wrong

patient you only want to use it in

patients in whom the benefit outweigh

the risks and so that covers our

treatment of ischemic strokes with the

drug tissue

plasminogen activator and we really

stressed these time constraints there

okay thank you for watching