The word anesthesia was first introduced by O.W. Holmes in 1846, following the first demonstration of ether anesthesia at the Massachusetts General Hospital. In modern times, general anesthesia can be clinically defined by four criteria: amnesia (loss of recall for the event), analgesia (insensibility to pain), hypnosis (unconsciousness), and muscle relaxation.
Anesthetics is the collective term for preparations which temporarily restrains the functions of living cells. Temporarily consciousness, the pain feeling and the muscle tension are switched off by the paralysis of the central nervous system. The term "general narcotics" is in use as a synonyme.
Among the inhalation anesthetics rank ether, laughing gas and halothane. Injection anesthetics are ketamine and barbiturates. An involuntary oral admission takes place with so-called K.O. drops. The impact of the anesthetics is not clearly clarified until today. The inhibition of the cell respiration in the mitochondria is discussed.