In August 1917, Dr Arthur Guedel arrived in France as part of the American Expeditionary Force. Of the 491 medical officers in the AEF, none had specialist anaesthetic training. Guedel was one of a team of only four doctors working continuously for 72 hours in theatre, due to the sheer number of casualties.

Clearly something needed to be done to assist the overstretched medical personnel.

To train lay staff and nurses to administer an anaesthetic safely, Dr Guedel devised a wall chart that illustrated four stages of anaesthesia. By the end of the war he was using his chart to supervise the delivery of anaesthesia at 40 sites, and he and his staff dealt with many of the over 250 000 American casualties of World War I.