The latest issue of Scientific American contains an article about the science of anesthesiology, noting that "the medical specialty of anesthesiology has evolved into a sophisticated art form."
The magazine reports that the scientific understanding of how anesthetic drugs actually work and how to make them better has lagged behind most other areas of drug development, a shortcoming that has resulted in safety concerns.
Episodes of awareness during operations while under general anesthesia, even when administered by trained professionals, are reported by one or two of every 1,000 patients. The article notes that today's general anesthesics have a "fairly narrow margin of safety, which is the difference between the therapeutic dose and a dose that is toxic, even lethal."(B. Orser, "Lifting the Fog Around Anesthesia," Scientific American, June 2007).
Although the above article does not mention the death penalty, concerns about the efficacy and application of the anesthetic drug used in lethal injections have resulted in constitutional challenges in many states recently. The anesthesia is generally applied by correctional officers and the level of consciousness of the inmate is monitored by non-medical personnel.