I always find this very confusing… can’t they just say it in normal language? Bleh. Knowing it is one thing, but being able to apply it is another. Fuyo… talking like a pro. Of course I’m not la… that’s what most lecturers like to say… It’s like a cliche or something.
So here, me, a dungu fella, will try to explain it in my own words.
Total Body Water (TBW) = 0.6 x Body Weight
Almost everywhere I get to see that 70kg is the most popular weight being used. So much so that after multiplying, you get 42L. As a result, everyone starts to think that we all have 42L of water in us.
Wrong concept la I tell you.. take me for example la. I’m just like 55kg. I’m lighter than most girls out there… heh. Please ah… this is not sexist. All I know is that I’m sexy.
So, 0.6 x 55kg = 33L of water. See? Difference of 9 litres. Is that significant?
Now, before we proceed, just to clarify these 2 terms first.
Intracellular fluid (ICF)
- In dungu terms, it means water inside cells la. As long as it’s liquid within anything that’s covered with a membrane it’s ICF la. ICF ICF… isn’t it easier just to say water inside cell? So easy to understand.
Extracellular fluid (ECF)
- “Extra” means outside ma… so it means water outside cells la..
Now, to sum things up. We all have 2/3 of water inside our cells and 1/3 of water outside our cells. Understooded ma? Don’t use litres yet coz’ it’s misleading, like I mentioned earlier.
Okay, there are now water outside cells. So where do they go? Lepak in your si fatt loong? They like to be in 2 places la… hence comes these 2 terms:
- It means water between cells la. All cells are sustained in some form of medium right… they don’t just float in thin air in our body.
- Water inside the blood vessels la.
So… the 4 stuff you need to know is:
- water inside cells (ICF)
- water outside cells (ECF) which consists of:
- water in between cells (ISF)
- water in blood vessels (plasma)
Finally, in the ECF, 3/4 of water goes in between cells and 1/4 goes into the blood vessels.
Okay… I know you couldn’t be bothered will all this crap. You just want to save lives and be the good doctor you’ve always dreamt to be.
Fine. Then just keep this in mind.
A 70 kg patient who comes in with an estimated blood loss of 2L is way different from a 55kg patient who has the same exact amount of blood loss. Why?
If you are to calculate, the 70kg fella has 3.5L of plasma and the poor 55kg fella only has 2.75L of plasma. Both lost 2L of blood. Who’s in a more severe state? Duh. So treat smartly and don’t treat everyone equally. Don’t be so kayu la…
Reorganize your priority and resuscitate immediately.