Bloqueio infiltrativo com ropivacaína isolada e associada ao meloxicam em gatas submetidas à ovariosalpingohisterectomia: repercussões intra e pós-operatórias

Abstract

The aim of this study was to investigate the clinical effects of the local infiltration of ropivacaine and its combination with meloxicam in cats undergoing elective ovariohysterectomy. Forty-five cats were sedated with acepromazine (0.05 mg/kg) and pethidine (6 mg/kg). Anesthesia was induced with intravenous propofol (dose effect) and maintained with isoflurane/O2. The cats were randomly distributed into three treatments (n = 15), which consisted of the local infiltration of saline solution (group S), ropivacaine 0.25% alone (1 mg/kg, group R), and combined with meloxicam (0.2 mg/kg, group RM). The treatments were infiltrated in the midline incision, and into the ovarian pedicles and caudal uterine body. Heart rate (HR), systolic arterial blood pressure (SABP), end- tidal isoflurane concentration (FE´ISO) were recorded at T1 = baseline, skin incision, T2/T3/T4 = after the clamping of first, second ovarian pedicles and the uterine cervix, respectively, and T5 = skin suture. In the first 24 hours post-extubation, the degree of analgesia was assessed using an Interactive Visual Analog Scale (IVAS), UNESP-Botucatu Multidimensional Composite Pain Scale (MCPS) and von Frey filaments. Rescue analgesia was provided with intramuscular morphine (0.1 mg/kg). Data were analyzed using the chi-square test, Tukey test, Kruskal-Wallis test, and Friedman test (P < 0.05). FE´ISO was significantly lower in the RM compared to the S and R groups (P = 0.0002). Compared with S and R groups, mean isoflurane requirement in the RM group were decreased by a mean of 21.9% and 15.6%, respectively. Significantly lower values of HR were recorded at T2 (P = 0.001), T3 (0.0006), and T4 (P = 0.002) and of SABP at T2 (P = 0.001) and T3 (P = 0.006) in the RM compared to R and S groups. The IVAS pain scores were lower at one hour postoperatively in the RM compared to the R and S groups (P = 0.034). Rescue analgesia was required in 4/15 cats in the S group and in 1/15 cat in each of the R and RM groups. In conclusion, as part of a multimodal analgesic protocol, the treatment RM decreased isoflurane requirements and cardiovascular responses intraoperatively, and also decreased the postoperative pain scores (IVAS) at one hour after ovariohysterectomy in cats.