It's good to think about what you carry would also be good for first aid...

Kelly Kettle: great for lots of boiling water for sanitizing stuff, delivering babies ???
Alcohol fuel: would be much better for first aid purposes if it was ethanol
Spare socks: 1 clean dry pair held in reserve as field dressing, or spare socks
Spare long underwear: if a skin layer is also held in reserve it might be worth sanitizing and sealing it for first aid purposes. Overkill perhaps, but mid-winter I do carry heavy wool underwear as insurance in case it goes subzero on me. Might as well clean them and seal them and use them as a pillow until needed for first aid, or emergency sleep wear or trudging clothes.

1. Broken/Sprained Limbs: blue foam pad, tarp cordage, webbing
2. Major Burns: gotta read up on my first aid, but the clean socks useful for many body parts
3. Major Cuts: gotta read up on my first aid, but ethanol and water, squirty fuel bottle, sewing kit, clean socks
4. A swolen foot/ankle can be a very tricky thing in winter if your boot no longer fits. Improvise a mukluk?
5. Critical gear failures are alot like first aid situations, and require similar solutions. i.e. Broken ski or ski binding?

Again you might need to improvise a mukluk and perhaps snow shoes from you gear and tree branches and thinking this out ahead of time and practicing it might be very helpful. Might be a fun thing to practice some of this stuff with my 9 year old daughter. I could be the victim and she could help me patch myself up, or make some snow shoes and mukluks, or whatever. I wonder if clean merino wool is as good as cotton as a field dressing, if sanitized? I should think so, as long as it doesn't knit into the wound and force you to tear open the wound later to change the dressing. I need to get better at drying stuff with a small fire, as it is often needed for first aid and emergencies in addition to just keeping socks and mitts dry. Need to review my first aid. My daughter is in Girl Guides now, so that should help, with merit badges and all.