Coconut water can't actually replace blood plasma

Coconut water is biologically pure and sterile, with a rich presence of amino acids, proteins, vitamins, and minerals. And interestingly emergency coconut IVs were reportedly used during the Pacific War, and they've been clinically tested on humans several times to see how well they'd be tolerated. Answer: overall, pretty well.

However, as you will often find stated, coconut is not similar to blood plasma. Chemical analysis shows that it is closer to intracellular fluid. The intracellular Fluid (ICF) is the cytoplams exclusive of organelles and membranes. It comprises 2/3 of the body's water. If your body has 60% water, ICF is about 40% of your weight. The ICF is primarily a solution of potassium and organic anions, proteins etc. Just a little lesson in Biology.

So when mixed with blood plasma it essentially acts like a saline solution.

Fresh coconut is sterile

Clinical studies and documented cases indicate that coconut water can be administered intravenously without frequent or serious evidence of toxicity. The notable feature is that fresh coconut water is sterile so treatment of the fluid with penicillin or by heat sterilisation prior to infusion is unnecessary. An interesting result of one research concluded that it was not useful in hydrating patients due to its diuretic properties. So in other words when when coconut water is used intravenously it has the effect of dehydration and not rehydration. This goes against all the marketing as natures isotonic in a clinical setting.

Conclusion

Coconut fluid has been shown to be an effective form of intravenous hydration solution in small volumes over short periods of time, and can be considered a temporary alternative to standard intravenous fluids in remote areas where supplies are scarce and coconuts, abundant and inexpensive. Additionally, it is a good source of potassium, chloride, and calcium and its use could be further indicated in situations in which these specific electrolytes need to be urgently increased.