During World War I, the scale of the fighting as well as the kinds of injuries sustained meant that doctors and scientists had to develop new ways of treating patients. World War One was the first conflict where the number of deaths from wounds outstripped those from disease. Shrapnel and machine gun fire destroyed men’s flesh and left behind some of the worst injuries ever seen. New weapons caused complex wounds that needed new surgical techniques, in areas such as orthopaedics and plastic surgery. Wound care developed further with antiseptic treatments, such as the Carrel-Dakin technique, which consisted of regular irrigation through rubber tubes placed in the wounded area. There were also psychological wounds¹.
The heat of the Middle East brought with it its own complications, as did the extreme cold in Salonika, where frostbite became common. Diseases such as malaria (which had major epidemics in Macedonia, Palestine and Mesopotamia, in particular), typhoid (in the Mediterranean) and dysentery (on the warmer fronts, in particular) raged amongst those stationed on these fronts. Venereal disease was another problem for forces on both sides – as well as for civilians – and a matter of great concern among government and military powers¹.
The Thomas splint was introduced to the Western Front in 1916, and between then and 1918 it reduced the rate of mortality from fractures, and from fractures of the femur in particular, from 80% to 20%. The splint was originally designed in the 1870s by Hugh Owen Thomas, who is considered the father of orthopaedic surgery in Britain, with the intention that it would stabilise a fracture and prevent infection. However, it was not widely used until his nephew, Robert Jones, introduced it for use in the war. Essentially, the splint keeps the leg immobile which prevents further bleeding (caused by the movement of broken bones) and helps to align the fractured pieces. By keeping the leg secure, it furthermore made the men more comfortable during transportation¹.
The war also saw advances in plastic surgery techniques which were used to reconstruct faces damaged by shrapnel or burns⁴. The war also saw advances in anesthesia techniques which helped reduce pain during surgeries². The war also saw advances in triage practices which helped medical officers prioritize patients based on their injuries².
At the end of World War I medicine had made significant progress. The war had led to new advances in medicine and modern medical practices such as reformed cleanliness standards, new medicines, updated triage practices or anesthetic². The war had also led to fundamental advancements such as the use of ambulances which helped transport wounded soldiers quickly to hospitals⁴.
I hope this helps..