Some special operations medics in Afghanistan now have a new device that helps save soldiers with the most common cause of preventable death in combat: a traumatic pelvic wound. Unlike a hemorrhage in the arm or leg where a tourniquet can be used to shut off bleeding, there was no way until recently to do the same for wounds in the lower torso, which can kill a person in a matter of minutes. It was “a noted capability gap on the battlefield: How do we treat bleeding where we can’t use tourniquets?” said John Croushorn, a former Army doctor. After...