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Did you notice I love talking about strokes?  I wanted to expand a little more on my previous post about them.

Cerebral collateral circulation

Do you remember in your cardiac unit when they talked about collateral circulation?  When a blockage is slowly formed, your body forms little blood vessels over time to get around it.  It’s your body’s way of making up for the lack of blood flow being caused by the blockage.  That’s why younger people who have heart attacks have a higher mortality rate because their hearts haven’t had years to build up that collateral circulation.

Interesting, right?

The same is true for your brain, but there’s more than in the heart.  It’s called cerebral collateral circulation.  So you’re pushing up the blood pressure to force blood flow through those smaller vessels to perfuse the brain tissue past that clot.  Then the penumbra, which is an area of ischemia (but the cells are still viable) still has a chance!

This site has a good picture of it.

(The picture is good but they use unnecessarily large words which kind of annoys me so I stopped reading it after two paragraphs.)

This is why you may see neuro changes in your ischemic stroke patient whose blood pressure drops.  It may be a normal 120/80 pressure, but it’s not high enough to perfuse all those area of the brain now so they start acting crazy.  Typically, it’s a change in their mood/behavior/level of consciousness.  They’re more difficult to wake up, they’re really upset and agitated for no reason but have been super nice all night, and they’re saying some things that just don’t make sense… That should be a red flag to you.

Remember, neuro changes are subtle, if you’re waiting for pupillary changes or for them to become obtunded, you’re going to be way late and they will be far gone.

So, yes, this is a call the doctor right now because they need Neosynephrine or some medicine in the ICU that keeps their blood pressure up for a little while.  It’s not an OMG THEY’RE DYING moment, but you need to drop everything else you’re doing and address it now.

Does that make sense?  Yes, no?  Enough to make it look like you know what you’re talking about to your patient and their families?  Ok good.  That’s enough.

Something to worry about:  hemorrhagic conversion of an ischemic stroke

Let’s say you just got report on your ischemic stroke patient that is coming up and you actually had time to pull up their CT scan.  So you pull up the scan and there’s the big blob in their brain.

That’s their stroke.  That’s the area of ischemia.  So naturally, you think, “we need to prevent them from having another stroke so let’s thin their blood NOW!” Cue internal freak out because you’re not sure what you need to freak out about..


Uummmm… time out there.  Hold up!  I appreciate the enthusiasm but there’s a reason why we don’t necessarily jump on that Coumadin train right away.

If you do that too soon to a large ischemic stroke, you risk that area turning into a hemorrhage.  So that big spot on their CT scan would get a whole lot bigger.  Annnndd that’s terrible.  So, we have to wait until the neurologist says it’s okay to thin their blood to do so.  I don’t know how they determine when it’s okay, I just wait until I’m told and make sure no one orders anything that would contradict that.

So if your normal stroke order set comes with 5,000 units subcutaneous heparin injections q8hrs and a daily aspirin (as most do), you want to double check that they still want those medications given in a large ischemic stroke patient.  This can be overlooked because they both are part of a typical post-stroke order set.  Chances are that they do, but you’ll look like a rock star to that neurologist if you double check it with them.