Death rate 300%

Robert Liston
The nineteenth century AD

Amputated the leg in under 2​ 1⁄2 minutes (the patient died afterwards in the ward from hospital gangrene; they usually did in those pre-Listerian days). He amputated in addition the fingers of his young assistant (who died afterwards in the ward from hospital gangrene). He also slashed through the coat tails of a distinguished surgical spectator, who was so terrified that the knife had pierced his vitals he dropped dead from fright. That was the only operation in history with a 300 percent mortality.

Resources : https://en.m.wikipedia.org/wiki/Robert_Liston