The anesthetic effects due to the association of medetomidine and epidural lidocaine in cats pretreated with acepromazine and midazolam were evaluated. Ten adult cats were used, male and female, healthy and weighing 2.5±0.6kg. They were divided into two groups (GM and GL) of equal numbers (n=5). Premedication with acepromazine, 0.2mg/kg, and midazolam, 0.5mg/kg, intramuscular was administered. Twenty minutes later, GM animals were given epidural lidocaine, 4.4mg/kg, associated with medetomidine, 0.02mg/kg. GL cats received lidocaine, 4.4mg/kg, associated with NaCl 0.9%. Assessments occurred before the pre-anesthesia (MPA), 20 minutes after premedication and before the epidural block, and 10, 20, 30 and 40 minutes after epidural anesthesia, respectively, T-20, T0, T10, T20, T30 and T40. Heart rate, respiratory rate, body temperature, oxyhemoglobin saturation, analgesia, muscle relaxation and recovery period were evaluated. In GM cats the heart rate decreased at T20, T30 and T40 as compared to T-20 and T10 and was lower than the heart rate in the GL cats at T20, T30 and T40, values being, respectively, 86, 91 and 88 beats/min and 194, 205 and 177 beats/min. The respiratory rate ranged from T-20 and the other time points in GL animals. Concerning electrocardiographic variables, in GM cats significant differences between T20, T30 and T40 and T0 and T-20, were observed, values being 235, 238 and 156 and 161ms and 240ms, respectively. GM animals differed from GL in T20, T30 and T40, values being 147, 132 and 150ms for GL cats. Eighty percent of the cats had severe pain and in all animals there was a relaxation of the jaw and tongue. The recovery time was 40 and 15 min at GM and GL, respectively. It was concluded that the association promoted lidocaine with medetomidine anesthesia with a stable level of anesthesia and anesthetic recovery of good quality.
anesthesia; electrocardiography
