Comparison between emulsified isoflurane and propofol/isoflurane combination on plasma thyroid hormones, insulin, glucose, and glucagon in dogs

It is important to determine the varying effects of anaesthesia agents on the endocrine function. In this study, the effects of emulsified isofiurane and propofol-isoflurane on the endocrine function were compared in dogs. Sixteen dogs were randomly divided into two groups: one group (G1) of dogs were induced with intravenous 5 mg/kg propofol and maintained with inhaled 2-2.5% inspiratory isoflurane in 100% oxygen; second group (G2) of dogs were induced with intravenous 1 ml/kg emulsified isoflurane and maintained with intravenous 8 ml/kg/h emulsified isoflurane. Blood samples to determine the endocrine function were collected prior to induction of anaesthesia and at 15 min, 30 min, 60 min, 2 h, 6 h, and 24 h after drug administration. Serum triiodothyronine and tetraiodothyronine concentrations in G1 increased significantly (P < 0.05) at 15 min and were higher than in G2. Serum insulin at 15 min and 30 min were significantly (P < 0.05) higher in both G1 and G2. Serum insulin in G1 was higher after anaesthesia than in G2. Serum glucagon decreased at 15 min, 30 min, and 60 min, without significant changes (P > 0.05). Serum glucose increased at 15 min and 30 min after anesthesia, and was significantly higher in G1 than in G2 (P < 0.05) at 60 min. In conclusion, both emulsified isoflurane and propofol-isoflurane anaesthesia affected triiodothyronine, tetraiodothyronine, and insulin in dogs, but emulsified isoflurane anaesthesia had a minimal effect on triiodothyronine and tetraiodothyronine. With its less deleterious effect on the endocrine function, emulsified isoflurane may be more suitable for canine anaesthesia.