Figure 8-12 Pathway for the generation of the immune response after anesthetic exposure in susceptible patients. Halothane is metabolized to a trifluoroacetylated adduct that binds to liver proteins. The altered protein is seen as nonself, generating an immune response, which on subsequent exposure leads to toxicity and cell death. A similar process may occur after anesthetic exposure to other fluorinated drugs that generate a trifluoroacetylated or similar adduct. TFA, trifluoroacetyl (TFA-CI). (Adapted from Njoku D, Laster MJ, Gong DH, et al: Biotransformation of halothane, enflurane, isoflurane and desflurane to trifluoroacetylated liver proteins: Association between protein acylation and liver injury. Anesth Analg 84:173–178, 1997.