SAFETY INDEX OF ULTRA-SHORT ACTING INTRAVENOUS ANAESTHETICS

[摘要] References(9)The selection of a potent anaesthetic agent is mainly guided by its margin of safety. “Safety index” or therapeutic coefficient of intravenously administered barbiturates has been determined in the past by employing various methods in different laboratory animals. Consequently results obtained are neither uniform nor comparable. The ratio of minimal lethal dose/minimal head drop dose in 50% of rabbits has been considered as the therapeutic coefficient by Werner, Pratt and Tatum (1). Swanson and Chen (2) determined the median anaesthetic dose (AD50) and median lethal dose (LD50) in rabbits, rats, cats and dogs for predicting safety of intravenous barbiturates. While some believe that toxicity of these agents runs parallel to their hypnotic potency others feel that doses of the various barbiturates required to produce sedative, hypnotic and anaesthetic grades of depression bear a rather fixed relationship to the median fatal dose. This is believed to be because of lack of a suitable method for accurate measurement of various grades of central depression in laboratory animals [Goodman and Gilman (3)]. Recently Ghosh, Srivastava and Ghosh (4, 5) and Srivastava and Ghosh (6) described a method for determining the margin of safety of volatile anaesthetics. Herein individual anaesthetic and fatal doses have been measured accurately in mice, rats and guinea-pigs. In the present study margin of safety of seven ultra-short acting intravenous barbiturates has been determined in rabbits by a method which permits accurate measurement of different stages of central depression in individual animals.

[学科分类] 药理学