Russian servicemen patrol the destroyed part of the Ilyich Iron and Steel Works in Ukraine's port city of Mariupol on May 18, 2022, amid the ongoing Russian military action in Ukraine.OLGA MALTSEVA/AFP via Getty Images Before invading Ukraine, Russia set up blood drives and field hospitals, The Economist reported. Surgeons in the field were even practicing on large animals that were under anesthetics. Ukraine's medical treatment has given them an advantage over Russia, The Wall Street Journal reported. An estimated 50,000 Russians have died fighting the war in Ukraine, according to a July Associated Press report, and for 17 months Russia averaged about 400 casualties per day — a bloody toll for which the Kremlin apparently tried to prepare.In the months before Russia invaded Ukraine in February 2022, there were several indications that Russia was preparing for mass casualties, and thus for war, Major-General Tim Hodgetts, the surgeon general of the British armed forces, told The Economist.First, Russia moved field hospitals close to the border.