Short answers, pulled from the story.
Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia, paralysis, amnesia, and unconsciousness.
On the 14th of November 1804, Hanaoka Seishu became the first person to successfully perform surgery using general anesthesia in Japan. He used a formula named tsusensan which combined Korean morning glory and other herbs.
Anesthesia-related deaths from all causes were reported at 1:75 in a first study from 1954 compared to 1:2680 attributed to anesthesia alone today. The rate of deaths totally attributed to anesthesia alone stands at 1:185,056 according to current data.
Incorrect pre-operative assessments are the root cause of 11% of all adverse anesthetic events. A well completed medical history arrives at the correct diagnosis 56% of the time which increases to 73% with a physical examination.
Horace Wells conducted the first public demonstration of inhalational anesthetic at Massachusetts General Hospital in Boston in 1845. On the 16th of October 1846, William Thomas Green Morton gave a successful demonstration using diethyl ether to medical students at the same venue.