[Effects of general anaesthesia with halothane and neuroleptic anaesthesia on free plasma amino acids (author's transl)].

Changes of plasma amino acids in animal studies were observed after administration of different narcotic drugs. In a randomised study the effects of neuroleptic anaesthesia and general anaesthesia with halothane on free plasma amino acids in respect to liver toxicity were investigated in patients during microsurgery of the middle ear. 24 hours postoperatively in both groups a significant increase of branched chain amino acids and of phenylalanine as metabolic sign of stress was found. Typical changes of amino acids as shown in hepatic failure could not be seen in both groups. The study showed that none of the narcotics used had a toxic effect on liver function as measured by the levels of free plasma amino acids and that for disagrees with the results of animal studies.