Análise comparativa entre a utilização de Levobupivacaína e de Ropivacaína na anestesia epidural no espaço lombossacro em gatos (Felis catus domesticus - Linnaeus 1758)

Abstract

The aim of this study was to compare the effectiveness and quality of analgesia of Levobupivacaine and Ropivacaine. Six cats were used with weights varying from three kilos and two hundred grams to three kilos and six hundred grams, and ages ranging from one to three years old. After the cats were fasted for 12 hours for food and three hours for water, the animals underwent general anesthesia with isoflurane into an anesthesia chamber, in order to perform chemical restraint for epidural technique without causing distress and injuries. . The animals were randomly anesthetized into a blind study with three treatments groups. For each cat the prodedures occurred with intervals of one week amongst them. The groups were: Control Group (CG) with saline solution 0.9% in volume of 0.4 mL.Kg-1; Levobupivacaine Group (LG) 0.5% witch used a dose of 2 mg.Kg-1 in total of 0.4 mL.Kg-1; Ropivacaine Group(RG) at a dose of 2 mg.Kg-1diluted in saline with a final volume of 0.4 mL.Kg-1. After the epidural infusion of either solution nociceptive stimuli was initiated by clamping in three pre-defined locations: Base of tail, lateral right and left thighs and webbed feet of both legs at the times 5, 10, 15, 20, 30 minutes, 1, 2, 3, 4, 5, 6, 7, 8 and 9 hours. The degree of analgesia was determined with the aid of three scales for pain assessment and a Visual Analogue Scale (VAS) and two Simple Descriptive Scales (SDS). In addition to noxious stimuli was also evaluated and the patellar reflex and heart and respiratory rates were measured after the clampings. For quantitative variables we used analysis of variance test (ANOVA). For qualitative variables we used the Kruskal-Wallis test. There was no statistically significant difference (p> 0.05) for the variables heart rate and breathing. For the pain assessment scales significant difference (p< 0,05) occurred between drugs after 60 minutes. For the patellar reflex significant difference occurred after 30 minutes. Levobupivacaine was more effective than Ropivacaine for epidural anesthesia because it showed the best degree of analgesia with greater duration of effect and longer motor blockade.