A drawer full of old valves; nothing you'd want to keep

How long had he been asleep? thought Caroon, slipping back into both unconsciousness and the third person.

But whatever he may claim in his weaker moments, one question must be answered: if unaccountable headaches are the root cause of this hospital stay, then why is there a metal tube inserted between two of his lower vertebrae? What is the tube connected to at the other end? And the fluid that can be heard gurgling inside it: is it going in or coming out?