[tackem (OP)]

A friend had a stroke and the hospital struggled to reduce her blood pressure of 200+/100+.
As the body contains around 10 pints in a closed system would it not be logical to remove a pint to reduce the pressure by 10%?

[alancalverd]

Sadly, no. Blood pressure is the pressure required to maintain the required volume flow through a system of elastic vessels which can expand and contract in response to chemical and physical triggers. When substantial quantities of blood are lost, some (mostly peripheral) vessels constrict in order to maintain sufficient oxygen to the "more vital" areas.  Chemical intervention is required to reduce blood pressure to prevent further damage in the case of stroke.

[neilep]

Wishing Tackem's friend better.

As a supplemental question, is it beneficial (to the doner) to donate a pint of blood  ? if so, what are the benefits ?

[Halc]

As a supplemental question, is it beneficial (to the doner) to donate a pint of blood  ?

There are definitely some benefits.

It appears that regular donation reduces thickness of blood, lowering the pressure needed to maintain an adequate flow. This lowers stress to the heart.

You can burn 600-some calories without doing a workout. This is reduced by the free sugary snacks they give you afterwards, which itself might be a benefit to some. Don't skip the snacks. I almost passed out once long ago from dropped blood sugar and was 'revived' via a small bottle of coke syrup and breathing into a small paper bag.

You get a free medical screening, including pressure, iron levels, etc.

I've heard that regular donation reduces chance of certain cancers (lung, throat, stomach). Don't know why.

Finally, on the thinking that nobody will come to your funeral if you don't go to theirs, the biggest benefit is that it sets an example for everybody, which benefits everybody when the need arises.

[evan_au]

For some conditions, blood donation can be a life-saver (for the donor).
https://en.wikipedia.org/wiki/Hereditary_haemochromatosis#Treatment

[vhfpmr]

Finally, on the thinking that nobody will come to your funeral if you don't go to theirs, the biggest benefit is that it sets an example for everybody, which benefits everybody when the need arises.

They don't want mine, it's full of drugs.