Had this as a reply from a former paramedic on another forum. Wise advice, and echoes what @BigMike posted earlier. Note: he just carries a standard first aid kit in his vehicle. Also, his wife is an RN. "In all my years, I never saved anyone with significant trauma, other than by replacing fluids and preventing further blood loss. Given that in a 'non-professional' scenario, you cannot provide IV fluids since they have significantly short shelf life, then direct pressure by means of bandages (or substitutes such as towels) or tourniquets is the only realistic option. All the rest is just extra weight to carry around. The only place trauma victims get saved is in the OR. The trick is to get them there alive. Thus: Keep air going in and out, and blood from running out. YMMV"