That's pretty young to have all his vitals be way off, as Bones says just before he starts arguing with Scotty about the torpedoes.
You're reading too much into it. When McCoy is referring to Kirk's vitals, he's doing it in the same vein as today's doctors do: Blood pressure, heart rate, pulse ox. The whole point of the line is to convey that Kirk isn't in his right mind, he isn't thinking clearly, and that something is very wrong -- same as the brilliant inversion of the Trek theme a minute earlier, during the sequence where the shuttlecraft heads to the Enterprise. It's text and subtext all saying, essentially, "shit ain't right."