I'M EMT and cardiac tech so I have access to more than some. My truck tech kit contains:
gloves
stethoscope
BP Cuff
n95 masks
gowns
Trauma dressings
kerlex
coban wrap
cavi wipes
ace bandages
SAMs splints, soft splints
triangular bandages(sling)
sterile saline-bottles, syringes
Ratcheting tourniquet
OB kit
O2 cylinder
Bag valve mask
O2 delivery ( NRB,simple mask, nasal cannula)
Combi tubes
Oral airways, Nasal airways
2 Bags of normal Saline
IV sets
AED
At home in my SHTF supplies I have all of the above in greater quantities plus:
Suture kits
AED/12 lead EKG moniter, with pad supply
Dermabond(medical super glue)
OTC meds, epi pens, other meds…..
needles, syringes etc
of course the items that expire will eventually be useless if I can’t rotate them out but better than nothing.
As far as getting going with a kit you can go a few ways. There are numerous places on line (galls, firestore.com etc) where you can buy prestocked bags at various levels and prices. You can restock most of your supplies after use at CVS, Walgreens or Wal-Mart. Or if you want look at the list of supplies included in these, then buy the supplies at above stores and buy a duffel bag or backpack. Also if you have to use supplies on a scene ask the responding EMS personnel if they would mind replacing the supplies you used. Some may not but I am always happy to oblige a citizen who took the effort to help another in need.
Is this truck kit merely a OMG SHTF TEOTWAWKI kit or a just in case you come upon an emergency kit?
I ask because assuming you are an EMT basic, IV's are way out of your scope of practice, and combitubes are most certainly outside of your scope of practice without medical direction, and is pushing the limits of good samaritan law. Even if your certification level is higher than basic, IV's would still be out of your scope without medical direction.
This all of course assuming you arent also a volunteer.
Also, as a cardiac tech I wont question your ability to interpret a 12 lead, but what purpose does it serve to have other than the cool factor?
I mean, sure if grandma has chest pain you could run a 12 lead, but in SHTF I dont think a cath lab will be nearby.