one of the main focuses of my prepping has be medical needs.
i'm a nurse who has worked a few roles that support my prepping well.
some of my areas of knowledge are:
medical nursing (which is pretty much everything from 18 years and older that is mostly stable)
wound and skin management. i can tell you that wounds (even not infected) can take a massive amount of supplies. i did this role both in hospital and in community. i've been lucky to have some great education from would speciallists (ET, and MD that only do wounds)
infection control, this was a big roll on the medical unit, because everyone is sick and many of them carry nasty bugs. 1/4 of our patients were immunocompomised so when some others carried C-Diff, MRSA or VRE, it became very important to have propety isolation techique and set up.
emergency nursing. this was the first time i worked with kids and i'm very glad i took the courses before had that i did. kids are a unique group, with some challenges with assessment and treatments, but when they are sick sick, you can see them turn the corner fast too. it works the other way as well, when they are only starting to get sick, they can go down hard and fast, and that's a shit thing to see happen.

when i say 'one of my main focuses" that's because there is nothing worse then having a problem and not the tools to fix it. so many problems are fixed with easy things (tylenol, or ibuprofen, a litre of fluid can make a huge difference) when pressure doesn't stop bleeding, would closure skill help, when to treat infections topically (skin) vs systemically (with pills). when will an illness benefit from antibiotics vs just supportive care. this is something some doctors would have a hard time judging without lab tests and xrays, i see it all the time. i'm not saying i'm a better judge, hell, i sometime look at all the same info, and i antispate their orders . . . "it's going to be this antibiotic" and bam they pick something we rarely use. (there are best practice guidelines and i'm lucky enough to work with an ER/ICU doc that is part of the infectionous disease/antibiotic stewardship program, i bug him often with questions) i'm also friends with the pharmacist in this program, and friends with another. while i have a good handle on medications and uses, it's great to have "buddies" that are more in the know.

saying all that, what i stock for medical needs wouldn't benefit most people, there are skills, knowledge and judgment took years of school and many more years or experience. but the amount of stuff needed is really never ending. i had a dog that post op and complications that required a lot of attention, it was a very experense dressing change twice a day. i've seen wounds that were upwards of $60/day.

while you may not want to go to university for medical training there are a handful of courses to take. first aid, and cpr are a good start. the US has more, and it's too bad because i'd love to get into a few of them. there are also a ton of books that are helpful.

The Sanford guide to anti-microbial therapy 2011 by David N Gilbert MD
Bugs and drugs 2012
anti-infective guidelines for community acquired infections (Orange book) this is the book any good doctor checks before Rx antibiotics
Nursing drug handbook (updated yearly, buy last years book to save a lot)
CPS (harder to find as most places have gone electronic, but use to be free from pharmacies when the new book came out)
Neonate and paediatrics dosing handbook by Taketome (not likely to benefit most)
Nursing Herbal medicine handbook (this is a great source for OTC "natural" things, talks about side effects which you don't get in most sources)
St. John’s ambulance Can. Military 1st Aid hand book
The US army Special Forces medical handbook
Where there is no Dentist by Murray Dickson
Where there is no Doctor by David Werner
When there is no Doctor By Gerard Doyle MD
Survival medicine Dr bones and nurse Amy (a good book for the non medical person, written for preppers)
Improvised medicine: providing care in extreme environments
Emergency War surgery NATO manual
Ditch Medicine: Advanced Field Procedures for Emergencies
Official wilderness first aid guide by Wayne merry (SAS)
Medical dictionary
Medical handbook (gives an over view of illess, symptoms and maybe treatments, i don't have it at my finger tips right now)
Herb book (with great illustrations)
Essential oils for dogs by Stacy Moore (kindle)
Essential oils for beginners Jeannie lambert (kindle)
Essential oils everything you need to know Kathryn browning (kindle) (yes oils have there place. . . and no i'm not a hippy lol)

(school text books follow)
Pathology textbook
Maternal child nursing text
Physical assessment
==============================
The Coming Plague: newly emerging diseases in a world out of balance by Laurie Garrett (haven't read yet, so can't comment on)

(books i bought when i changed jobs)
Emergency nursing procedures by Proehl
Emergency in General adult nursing by Philip Downing
Sheeley’s Manual of Emergency care by EMA Belinda B
HSC handbook paediatrics by Adam Cheng
HSC handbook of pediatric emergencies by Suzan Schneeweiss (HSC hospital for sick children, these books are meant for paeditrians, but a good reference . . . that's why i have them)
============================
clinical guide to skin and wound care (good book for problems, product picker (what dressing to use) and treatment)

if you have any questions i'll check back when i can. i hope this discussion helps, and i always benefit from thinking about things i haven't for a while.