Blood pH dropping - how low can we go?

neongrey

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So, I'm mostly looking for ballparking here (since the character isn't human, but for my purposes we can assume the same body chemistry), but say someone's afflicted by a curse that will gradually lower the pH of their blood, to wit, magically turning it acidic. The intention is that this will eventually be fatal.

How much more acidic than normal would it need to be for this to, in fact, kill the person? My operating supposition here is 'not much', but I figure I might as well check. I don't have any concerns about it being traceable or not, the only thing I'm wondering is just how acid it needs to get.
 

neongrey

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What you're looking for is "acidosis".

Sweet, I should have known this would be an actual thing. Thanks!


Not hard to find the figure incompatible with life. Blood pH has a very narrow range. Either side of it and the neuroelectrical activity ceases to function. The heart stops.

It occurs with alkalosis as well as acidosis.

Yeah, I figured it wouldn't take much, but I didn't have what I needed to be looking for to know how much 'not much' it'd be. Thanks.

Have a look at the oxygen-haemoglobin dissociation graphs for the Bohr effect.

Ooh, graphs. I love graphs! (e: not sarcastic) Thanks!
 
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Roxxsmom

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Here's a link to a fairly straightforward article about acidosis (and its various causes and the body's compensatory mechanisms) from the Merck Manual. Normal blood pH ranges from around 7.35 to 7.45 (venous blood tends to be a bit more acidic than arterial blood). A person with acidosis has an average blood pH below 7.35, and symptoms will start to appear at this level, though acidosis can be compensated in various ways, so a person with problems that would cause acidosis can have a more normal blood pH (the issue can still be detected via medical tests) and milder symptoms.

http://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/acid-base-balance/acidosis

Blood pH of less that 6.8 is generally thought to be incompatible with life in mammals (leading to coma and heart failure and irreversible cellular damage), though in humans without medical intervention it can be fatal before it reaches this point. There is a record of at least one person surviving when their blood pH was lower, however, though they received a lot of supportive care.
 
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neongrey

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Beautiful, thank you.