Susceptibility of Rats to Corneal Lesions After Injectable Anesthesia

摘要

Cornealinjuryisnotacommonlyreportedsideeffectafterinjectableorinhalationanesthesiainrats,butanumberofsurgerystudiesatourfacilityresultedinahighincidenceoftheseinjuries.Toexplorethepotentialassociationofvariousanestheticprotocolswiththedevelopmentofcorneallesionsinrats,weretrospectivelyevaluatedclinicalrecordsandsectionsofeyesfrom215maleand187femaleWistarratsusedineightintravenousinfusiontoxicologystudies.Noneofthestudiedcompoundswasassociatedwitheyetoxicity.Forplacementofjugularveinvascularaccessports,ratswereanesthetizedwithenflurane,isoflurane,ketamine#8211;xylazine,orHypnorm#8211;midazolam.Histologically,cornealchangeswerescoredfrom0to4inlightofdegreeofmineralization,leukocyticinfiltrates,neovascularization,fibrosis,andulceration.Prestudy(postsurgical)ophthalmicexaminationfindingsofcornealopacitieswerecorrelatedwithmineralizationoftheanteriorlimitingmembraneandcornealulceration.Corneallesionsweremoresevereinanimalsanesthetizedwithketamine#8211;xylazine,andminimalchangesoccurredafteranesthesiawitheitherenfluraneorisoflurane.Theresultsoffurtheranalysissuggestthatcorneallesionscanbeobservedwithin24hafterinjectableanestheticadministrationandarenotreversible.Theseverityofcornealchangeswasreducedwhenketamine#8211;xylazineanesthesiawasreversedwithyohimbine.ComparedwithSprague-DawleyandLewisrats,Wistar,Long-Evans,andFischer344ratshadincreasedincidenceandseverityofcorneallesionsafteranesthesiawithketamine#8211;xylazine,suggestingthatthesethreestrainsareatincreasedriskfordevelopingpostanestheticcorneallesionswiththisregimen.