Surgical anaesthesia, conceptual artwork. Three vials of the benzodiazepine drug Midazolam are at lower left, with a syringe at right and a cannula at centre left. Midazolam is a benzodiazepine sedative drug used to produce unconsciousness before and during surgery. It is injected to initiate anaesthesia and a solution of it can be continually supplied through a cannula if required. Superimposed on the cannula are blood test results detailing levels of blood cells.