WWI Medical Questions

Ooo I have just the thing! The Internet Book Archive (https://archive.org/details/texts) is just the most amazing resource--millions of digitized old publications from collections worldwide. I was recently discovered it is the best for answering questions on medical practice and procedures, with loads of period medical textbooks for doctors and nurses.
This one, called War nursing : a text-book for the auxiliary nurse, published in 1917, is one I had saved for my own future WWI project requiring medical-related research: https://archive.org/details/54420270R.nlm.nih.gov . It's not super long but it has so so many tiny details of hospital care, from bed-making to handling to feeding.

A bit more searching right now yields Surgical Nursing in War, also 1917, which has more information on treating specific kinds of injuries: https://archive.org/details/54630640R.nlm.nih.gov

A 1915 firsthand account of a nurse at a French military hospital: https://archive.org/details/infrenchmilitary00catorich

A 1915 published journal of a front line nurse: https://archive.org/details/diaryofnursingsi00nursuoft

A 1919 book with 589 case studies of shell shock victims: https://archive.org/details/shellshockothern00soutuoft

and more!: https://archive.org/details/texts?and[]=war+nursing&sort=date&page=1

So that should keep you busy for a while.

I think a big thing to remember is that penicillin wasn't discovered, so even flesh wounds were far more deadly than they were afterwards. So on surgery, the outcome was never very good for battlefield wounds. I would expect too, given the lack of penicillin, that nurses were more concerned with changing bandages than today - in the sense of doing it more regularly to check for and drain infectious fluids, e.g. pus.

Shellshock and trauma is a well-trodden topic, I think you'll find that in a lot of places.

and try and see if there are documentaries or university lectures on youtube

Definitely no references to PTSD (a term coined in the 80s).

Page 900 of that 1915 text that flapper referenced seems pertinent to your needs.