Sutures are for closing wounds, not stopping massive bleeding. If you are all ready lightheaded from bloodloss, it's a little late to be thinking about preforming minor surgery on yourself. Sealing up the wounds won't help, the bleeding will continue. So anyone that carries a knife or firearm, needs to carry FAK stuff to deal with any potential wound. But it does happen, a few years ago my buddies came upon a lone hunter. He'd shot his foot with a 7mm rifle and laid down to die. They managed to save him, and it took a LOT of gauze to get the bleeding stopped. He was flown out and lost half of his foot, but lived.

Dave