THE INFLUENCE OF ISOFLURANE ANAESTHESIA ON INTESTINAL PERMEABILITY IN HEALTHY DOGS

Abstract

This study investigated the most appropriate blood sampling time for determining the lactulose/mannitol (L/M) index, and whether isoflurane anaesthesia increases intestinal permeability in dogs, in terms of changes in the L/M index. Six dogs were given 100 ml of sugar solution (3.6 g lactulose and 3.4 g mannitol) with orogastric tube. Blood samples for determination of basal plasma L/M index were taken 90, 120, and 180 minutes later. The next day, the dogs were administered methadone, induced with midazolam mixed with ketamine, followed immediately by propofol, and anaesthesia maintained with isoflurane in oxygen for 200 minutes. The same sugar solution as the day before was administered at the end of anaesthesia and 12 and 24 hours post-anaesthesia. Blood samples were taken 90, 120 and 180 minutes after administration of sugar solution. HPLC-MS was used for plasma determination of lactulose and mannitol and the results expressed as L/M index. The highest concentrations of lactulose and mannitol were detected 120 minutes after administration of sugar solution. Lactulose/mannitol index significantly increased at the end of anaesthesia, regardless the sampling time, when compared to basal values from non-anaesthetized dogs. The increase of L/M index due to anaesthesia with isoflurane was short-lived as there was no significant difference between L/M index at 12 hours after the anaesthesia and basal values. The most appropriate blood sampling time for determining the L/M index is 120 minutes after oral administration of dual sugar solution. Key words: dog; isoflurane; intestinal permeability; L/M index VPLIV ANESTEZIJE Z IZOFLURANOM NA PREPUSTNOST ČREVESJA PRI ZDRAVIH PSIH Namen raziskave je bil ugotoviti najprimernejši čas odvzema krvi za določanje razmerja med laktulozo in manitolom (indeks L/M) in za ugotavljanje ali anestezija z izofluranom zveča indeks L/M in s tem prepustnost črevesne bariere pri psih. Šestim psom smo z orogastrično sondo dali 100 ml sladkorne raztopine, in sicer 3,6 g laktuloze in 3,4 g manitola. Za določitev bazalne vrednosti indeksa L/M smo psom odvzeli kri 90, 120 in 180 minut po dajanju sladkorne raztopine. Naslednji dan smo jih premedicirali z metadonom, v anestezijo pa uvedli z midazolamom s ketaminom in propofolom. Anestezijo smo vzdrževali z izofluranom v kisiku 200 minut. Enako sladkorno raztopino smo psom dali še trikrat, in sicer na koncu anestezije ter 12 in 24 ur po anesteziji. Po vsakem dajanju sladkorne raztopine smo po 90, 120 in 180 minutah odvzeli kri za določitev indeksa L/M. Laktulozo in manitol v plazmi smo določali z metodo HPLC-MS in rezultat izrazili kot indeks L/M. Najvišjo koncentracijo laktuloze in manitola smo zaznali 120 minut po dajanju sladkorne raztopine. Indeks L/M se je, v primerjavi z bazalnimi vrednostmi pri neanesteziranih psih, na koncu anestezije značilno zvišal ne glede na čas odvzema krvi. Anestezija z izofluranom kratkotrajno zveča indeks L/M, saj že 12 ur po anesteziji ni bilo značilne razlike v primerjavi z bazalno vrednostjo. Najprimernejši čas odvzema krvi za določitev indeksa L/M je 120 minut po dajanju sladkorne raztopine. Ključne besede: pes; izofluran; prepustnost črevesja; indeks L/M