Liver enzyme changes in dogs after 5-hour sevoflurane or isoflurane

Abstract

OBJECTIVE: To investigate the changes in serum enzymes considered as biochemical indicators of hepatobiliary function in dogs following 5 hours of anaesthesia with isoflurane (ISO) or sevoflurane (SEVO). STUDY DESIGN: Experimental randomized crossover study, with intervals of at least 15 days between successive treatments. ANIMALS: Eight healthy adult mongrel dogs, four male, four female, weight 13.6-21.6 kg. METHODS: Treatments consisted of anaesthesia with ISO or SEVO at 1 or 1.5 minimum alveolar concentration (MAC) delivered in oxygen. MAC was taken as 1.39% for ISO and 2.36% for SEVO. Anaesthesia was induced by mask then, after endotracheal intubation, maintained according to the treatment protocol using a small animal circle system. Cardiopulmonary monitoring was carried out. Venous blood samples, obtained by needle puncture, were taken at 24 hours and 2, 7 and 14 days post anaesthesia. Serum concentrations of total protein, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase, (LDH), alkaline phosphatase (ALP), gamma-glutamyltransferese and total bilirubin were measured. Changes with time and with treatment were compared by Friedman analysis, Wilcoxon Signed test and Kruskal-Wallis test as relevant. p- value < 0.05 was considered significant. RESULTS: Compared to base-line values, at 24 hours post-anaesthesia there were significant increases in AST, ALT, ALP and LDH following one or more of the treatments, but by 2 days residual changes were not significant. At 24 hours, AST for treatment 1.5 MAC ISO was higher than 1 MAC ISO (p < 0.002), and LDH higher for 1.5 MAC SEVO than 1 MAC SEVO. CONCLUSION AND CLINICAL RELEVANCE: Both ISO and SEVO, at concentrations used for clinical anaesthesia, produce transient moderate effects on some hepatobiliary enzyme concentrations in dogs.