Monro-Kellie doctrine and venous ICP patho

[VentMonkey]

I wanted to share this abstract with everyone. I don't remember learning much about the Monro-Kellie doctrine in my initial paramedic training, so I figured it would be worth sharing here and paying it forward.

The article itself is pretty thorough in describing different types of brain-injured patients as well, therefore, this may help any paramedics-to-be understand some of the basic principles of ICP in the brain-injured patients that goes a bit more in depth, and beyond the average paramedic text:

http://journals.sagepub.com/doi/full/10.1177/0271678X16648711

 

[TXmed]

Good article, thank you

Given what is said about the importance of venous drainage. Why is nitro drips not used to lower BP in cerebral bleeds rather than cardene ?

 

[VentMonkey]

Good article, thank you

Given what is said about the importance of venous drainage. Why is nitro drips not used to lower BP in cerebral bleeds rather than cardene ?

I believe it has to do with it being a Ca++ channel blocker, but would have to pull up some notes. I do know Cardizem is also considered for a patient with an ICH.

Perhaps @E tank, @Remi , @Chase, or another well versed ICU poster will chime in with their experiences. It's kind of what I was aiming for as we've been chasing our tails quite a bit lately on the forum; figured it's time for some good medical topic(s).

 

[E tank]

I believe it has to do with it being a Ca++ channel blocker, but would have to pull up some notes. I do know Cardizem is also considered for a patient with an ICH.

Perhaps @E tank, @Remi , @Chase, or another well versed ICU poster will chime in with their experiences. It's kind of what I was aiming for as we've been chasing our tails quite a bit lately on the forum; figured it's time for some good medical topic(s).

I'll kick in first. Just to refine the idea, Cardene is used for control of the hypertension, not the ICP. It's an important distinction, because the way that the blood pressure is controlled can affect the ICP. Because of the way NTG works, the feeling has been that while the MAP does fall, the dilation of cerebral capacitance vessels (veins) can cause the ICP to actually rise. It's generally avoided for that reason.

Think of the h/a some patients get after a whack of nitro under the tongue. There is a similar concern with nipride.

We used to use nipride a lot for BP control in folks we were concerned about intracranial hemorrhage. But that wasn't always in the setting of increased ICP. Basically, titrating that drug was very difficult compared to nicardipine. Nicardipine is also very useful in treating/avoiding cerebral artery spasm that would result in ischemia.

Cut to the chase...nicardipine is infinitely more user friendly and predictable than anything else around and does not increase cerebral blood flow/ICP

 

[VentMonkey]

Thanks, tank. I learned something new. In hindsight it sounds practical, but thanks nonetheless. I hope others chime in as well.

 

[TrueNorthMedic]

Thanks for posting this, it was an interesting read. Didn't realize that c-collars had such an effect on ICP.

 

[Carlos Danger]

My reply was going to be pretty much word for word what E tank wrote. The cerebrodynamics of nitroglycerin are at least theoretically (I don't know if outcomes have ever seen shown to differ between the two drugs) not as favorable as the other drugs. Nitroprusside is actually a somewhat tricky drug to use. Nicardipine is effective at lowering ICP and very safe and easy to use. As someone who doesn't use either drug routinely, I would definitely choose cardene if I had to manage a patient with very high ICP.

 

[Eden]

Thanks! Definitely going to read it.

 

[TXmed]

Great stuff guys, thanks for the response.

We use cardene as our first line anti-hypertensive now so ive become familiar and comfortable with it. The one time i took nipride it was crazy sensitive and potent and just difficult to manage.

 

[VFlutter]

Agreed, Cardene is my preference and seems to be the most favored by ICU/Neuro. Especially in SAH patients when vasospasm is a concern. However antihypertensives mostly pertain to ICHs. The real fun is TBIs and clipped SAH when you get into Triple H therapy and multiple pressors and drips. Outside of the CTICU the NeuroSurg ICU is a great place to see hemodyamics at work.