Important note: These pages were written in around 1997 as part of my Deep Background website that I maintained as a resource for X-Files fanfic writers. I handed over that website in 1998, but I still find the medical pages useful. The site is still online somewhere, maintained not by me, but I thought it might be useful to put up the medical pages here, since they might be useful to writers in my current fandom.
Please note that:
Critical Care: This contains information on temperature, blood pressure, pulse and respiration rate (how to measure them, what "normal" is, and the effects of them being too high/too low). It also has quite a lot of information on shock.
Tubes: A head-to-toe description of the tubes that a patient might possibly have.
Injuries: Descriptions of the effects of gunshots, head injuries, knife wounds, some specific poisons, and broken ribs.
Hospitals: Information about who does what in a hospital, and an account of what might happen when a fictional character is admitted to hospital. This was written for X-Files fanfic writers, so only covers American hospitals, but some information might be useful to writers in other fandoms.
Medicinal drugs: Information on drugs that may be used to treat certain conditions. Note: This was written in 1997, so might be out of date.
Toxicology: This was actually part of the Forensics section of Deep Background, and not part of the Medical section, but I've included it here since it might be useful to h/c writers. This is a list of common poisons and their symptoms. The emphasis is on fatal poisons, but you might be able to do some research and find out about the effects of non-fatal doses on your characters.