Paramedics and rescue teams can't always afford to wait for blood supplies, especially when they're in remote locations where most vehicles would take too long (or can't visit at all). However, they might not have to worry for much longer. Johns Hopkins researchers have determined that it's safe to carry large bags of blood products (such as transfusions) using drones. In a study, they discovered that the robotic fliers didn't affect the chemical, hemotological or microbial traits of samples flown at an altitude of 328 feet, even when carrying it as far as 12 miles away. So long as the blood is kept in a temperature-monitored cooler, it's usable almost right away.