For those who are trained... assorted oral airways, a CPR mask...makes CPR easier by stopping the wet nasties like vomit from going into the rescuers mouth, a bag mask type resuscitator, a traction splint...basic half ring metal splint might be found in government/ military surplus stores.. your triangle bandages can be used to make a traction device, inflatable splints.. easy to carry and use, small O2 bottles with a regulator and assorted masks, portable oral suction device..I have seen foot powered devices as surplus from cold war era packaged disaster hospitals..might be available in surplus stores, flea markets etc.
While not medical, I would want some of the following items if I had to contend with disaster situations: GI type entrenching tool, a multipurpose rescue tool..available from EMT/FD supply stores or a couple of good old crow bars, lengths of stout rope, a bottle type hydraulic jack, leather gloves, safety goggles, government surplus type folding stretchers and a supply of blankets.
IV fluids are a good idea, but you need training and lots of practice to be good at doing IV sticks.
I have found some excellent first aid kits and first responder kits and supplies from www.galls.com. I am looking in my area for Red Cross first aid courses and then later, wilderness first aid courses.
Excellent point. Having done wound care recently (over the past six weeks!), I can attest to the fact that a single slow-healing wound can use up an enormous amount of gauze. What I thought was enough for a year or two of SHTF injuries turned out not to be enough for even two weeks of care for one wound - and it wasn't even infected. The amount of gauze actually needed if something goes wrong is quite impressive.