Some years ago, coagulating agents came on the scene. The first I'm aware of was Celox, which did the job but had some downsides, the biggest one being that it could get very hot when used, leading to some nasty burns on patients. However, when the choice was bleeding to death or a nasty burn, well...self-cauterizing, anyone?
Later, a new generation of agents came on the scene, with the most well known probably being QuikClot. First available to the military, it quickly showed up in civilian medical venues, and can now be purchased in a variety of packagings.
No trauma kit is complete without a supply of coagulating agents. Most commonly available as pre-impregnated folded gauze and sponges, anyone with some basic training and the ability to keep their wits when the heat is on can use these to save a life. Speaking of minimal training, a couple of videos. For the faint of stomach, there is plenty of blood and gore. Consider yourself on notice.