Dr. Abbé Luvale Floribert was on duty when a desperate mother brought her wounded ten-year-old son to the hospital in Kayna, a village on the eastern edge of the Democratic Republic of the Congo.The region is the epicenter of conflict among multiple rebel groups, and the hospital often sees patients with gunshot wounds. That day, the boy and his mother had been running from the fighting but had gotten caught in the cross fire. By the time they arrived at the hospital, the boy had lost so much blood that he was unconscious and had gone into hemorrhagic shock.The young patient needed a transfusion, but the hospital didn’t have a blood bank. Instead, the doctors scrambled to find a donor with the matching blood type.…