Coconut water can be used (in emergencies) as a substitute for blood plasma.

[RBCal]

From Listverse which posts interesting "facts".

The reason for this is that coconut water (the water found in coconuts - not to be confused with coconut milk, which comes from the flesh of the coconut) is sterile and has an ideal pH level. Coconut water is liquid endosperm - it surrounds the embryo and provides nutrition.

Coconut Plasma

[Dr. Dave]

This same list claims that The Fact: The largest food item on a menu is roast camel

which seems a lot like this UL

As for the fact in the fact in the OP, if someone needed red blood cells (for oxygen carrying capacity and intravascular volume), coconut water would do nothing. If one needed simply volume, such as in a case where saline would be used in an ER, then maybe. However, in a addition to pH, the fluid would need to be the correct osmolarity or you could kill the person. And in anycase, you would not be substituting for "blood plasma," you would be substituting for saline fluid. If they needed "plasma" which has clotting factors, etc, I do not know but doubt that coconut water would help.

In any case, if a person needs rapid rehydration (I'm assuming via IV since it is being touted as a blood replacement) due to say, hemmorhage on a desert island, a coconut could not possibly provide enough liquid for a normal sized adult. You would probably need several.

[Lainie]

Older versions of Jehovah's Witnesses' "No Blood Transfusion" cards listed some coconut byproduct as a possible alternative to blood.

They've since liberalized their stance on blood transfusions considerably (and completely inconsistently). I suspect they'll eventually eliminate it entirely if they can figure out a way to do it without courting lawsuits.

[Richard W]

Originally Posted by Dr. Dave

This same list claims that The Fact: The largest food item on a menu is roast camel

which seems a lot like this UL

... which appears to be true...

(eta) On the other hand, I was sure there was a page about the "allowable levels of insect parts in peanut butter" somewhere; I don't think that's true as stated.

[Mad Jay]

Originally Posted by Dr. Dave

in anycase, you would not be substituting for "blood plasma," you would be substituting for saline fluid. If they needed "plasma" which has clotting factors, etc, I do not know but doubt that coconut water would help.

I searched online for a bit, and all such claims go back to one Dr. D.P. Atukorale, a cardiologist from Sri Lanka. The claims are listed here

I think it is possible that he meant "saline fluid", but there was something lost in translation

[Lainie]

Let me add that I am shocked, shocked, to learn that the JWs were disseminating incorrect medical information.

[Dr. Dave]

Originally Posted by Dr. Dave

And in anycase, you would not be substituting for "blood plasma," you would be substituting for saline fluid.

Originally Posted by Mad Jay

I searched online for a bit, and all such claims go back to one Dr. D.P. Atukorale, a cardiologist from Sri Lanka. The claims are listed here

I think it is possible that he meant "saline fluid", but there was something lost in translation

I was actually mistaken- the coconut water may be a bit more than simple saline, as it has some protein as well. I should have said that it could be used as volume expander (an example of a non-blood product is Hetastarch) or albumin substitute, but not blood substitute. The way he writes it (translated in English at least) is reasonable.

My statement about the parcticalities- volume per coconut- stands.