[Met-Hb formation and local anesthesia using bupivacaine, carticaine and etidocaine (author's transl)].

Hemoglobin-(= Met-Hb)formation by local anaesthesia and local anaesthetics is still a point for discussion. Until now met-hb-aemia only was proven to develop under local anaesthetics with relationship to aniline (Benzocaine, Citanest). Since aniline does not possess any oxidative properties, met-hb-formation only can occur after metabolism (phenylhydroxylamine or para-aminophenol), first of all amino- and nitro-groups [6, 14] will be made responsible for oxidation. Because of the fact that neither the relationship to aniline nor the benzol-structure is the pre-supposition for met-hb-formation, possibly other substances with amino- or nitro-groups may induce it. In consequence of incidental cyanosis under intra and extradural analgesia we studied the met-hb-behaviour after the use of different local anaesthetics. The aniline-related bupivacaine and etidocaine were opposed to the thiophene-related carticaine. In this examination we found neither an elevation of hemoglobin by the aniline-related nor by the thiophene-related substances.