Effects of isoflurane in an intoxication model: experimental study

Isoflurane is a volatile anaesthetic that has been commonly used since 1980. The major metabolites of isoflurane are fluoride ion and trifluoroacetate, both excreted in the urine.

This study manage to show the histopathological findings of ingested isoflurane on liver, kidney and lugs in an animal model. Twenty-one rabbits were selected and divided into three groups: Group Isoflurane-5 (I-5); Group Isoflurane-10 (I-10); and Group Control (C). Each group consisted of seven rabbits. I-5 and I-10 received 5 ml/kg and 10 ml/kg of liquid isoflurane, respectively, via nasogastric tube, while C received 5 ml/kg saline (0.9% NaCI). All animals in I-5 and I-10 were sacrificed without anesthetic drug administration. Tissue samples from livers, kidneys and lungs were collected, preserving tissue unity and avoiding infliction of any trauma. Samples were fixed in 10% formalin solution, embedded in paraffin blocks and sliced into 5 μm sections. To investigate the effects of isoflurane, sections were examined under light microscope and histopathological changes were scored.

Mean injury scores and the appearance of portal lymphocyte infiltration in liver samples showed significant increases in I-5 and I-10 compared to C (p = 0.005, p = 0.001 and p = 0.001, respectively). Mean lung injury scores revealed significant increases after isoflurane treatment in I-5 and I-10 compared to C (p = 0.026 and p = 0.017, respectively).

Ingested isoflurane led to mild liver and lung injuries in rabbits.