OBJECTIVES

Sevoflurane is an inhalant volatile anaesthetic that has been recently introduced in veterinary medicine. The advantages of sevoflurane in domestic animals have been reported in several experimental studies. The aim of this study was determine clinical effectiveness of sevoflurane in dogs with different anaesthetic risk.

MATERIALS

A total of 307 dogs (144 males and 163 females, age 3.5±3.2 years and weighing 19.3±9.7 Kg) were included in this study. 157 dogs (107 ASAI, 32 ASAII, 12 ASAIII and 5 ASAIV) were anaesthetized with sevoflurane, and 150 patients (87 ASAI, 40 ASAII, 17 ASAIII and 6 ASAIV) with isoflurane. Alfa-2 adrenoceptor agonist sedatives (medetomidine at 5-10 mg/kg IV, or romifidine at 20-40 mg/kg IV) were used as preanesthetic in all cases to exception ASAIV patients. Anaesthesia was induced with propofol (2 mg/kg IV). After tracheal intubation anaesthesia was maintenance with sevoflurane or isoflurane in oxygen via a semiclosed circuit. The following variables were registered: Heart rate (HR), respiratory rate (RR), mean arterial pressure (MAP), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), hemoglobin oxygen saturation (SpO2), end-tidal carbon dioxide (EtCO2), tidal volume (VT), end-tidal sevoflurane and isoflurane concentrations (EtSEV, EtISO). RR, VT, EtCO2, EtSEV and EtISO were recorded with a respiratory gases monitor (RGM-5250, Ohmeda-Boc). HR, MAP, SAP, DAP and SpO2 were registered with a cardiovascular monitor (Dinamap Plus 8720, Critikon Inc). Recovery times also were registered. Statistical analysis was performed using an ANOVA and a post hoc test (Tukey HSD for unequal N). Values were considered significant when p<0.05.

RESULTS

HR, RR, SpO2 and recovery times no showed differences between sevoflurane and isoflurane. MAP, SAP and DAP were higher during sevoflurane anaesthesia. EtCO2 and VT were lower during isoflurane anaesthesia. These differences were also registered for each anaesthetic risk. The mean EtSEV and EtISO values were 2.1±0.5% and 1.4±.0.4% respectively.

CONCLUSION

Results suggest that sevoflurane anesthesia provide a better cardiovascular and respiratory stability.