Where does “hypovolemia” come from?

I need to work through this chain carefully, but I notice there's a problem with the data provided. The chain shows: - English volume - Ancient Greek ὑπό (hypo-, meaning "under") - Ancient Greek ὑπό (repeated) - Latin -men (a suffix forming nouns) - Proto-Indo-European wel- (to turn, roll) - Proto-Indo-European -mn̥ (nominalizing suffix) However, "hypovolemia" should derive from "hypo-" (under) + "volume" (quantity of space). The chain provided doesn't clearly support a coherent path to "hypovolemia" — it seems to conflate the etymology of "volume" with a prefix, and the meaning of "volume" (from Latin *volūmen*, related to volvere "to roll") isn't properly captured here. Given the

hypovolemia (English): A state of decreased blood volume