ULTRASOUND-GUIDED FUNICULAR BLOCK: ROPIVACAINE INJECTION INTO THE SPERMATIC CORD TO IMPROVE ANALGESIA IN CATS UNDERGOING ORCHIECTOMY

BACKGROUND Cat orchiectomy is a common procedure carried out in general practice and requires general anaesthesia and effective analgesia. Surgical analgesia is very important because pain causes various negative effects that prevent patient recovery. The aim of this study was to compare intraoperative analgesia in two groups of cats undergoing orchiectomy. METHODS Forty healthy cats were randomly assigned in two groups (n=20) to receive pre surgery ropivacaine hydrochloride (0.2 mL/kg at 0.5% concentrate) into the spermatic cord (R Group), or an equal volume of NaCl 0.9% at the same sites (C group). All cats were operated on by the same team in general anaesthesia, with a scrotal approach for all animals. A fentanyl bolus (2 µg/kg) was administered intraoperatively in response to an increase in blood pressure, heart rate or respiratory rate during surgery (> 30% compared with the pre-incisional values). The intraoperative evaluation was carried out using the hemodynamic stability parameters and eventually administration of rescue analgesia. RESULTS Repeated-measures ANOVA showed significant differences in the comparison of intraoperative heart rate among different times (p < 0.0001), groups (p<0.0001) and interaction between time and group (p=0.025). ANOVA test showed significant differences in respiratory rate among various times (p = 0.001), between groups (p<0.0001), but not in the interaction between time and group (p=0.267). In addition, ANOVA test showed a significant difference also in blood pressure values among the various times (p < 0.0001), between groups (p<0.0001) and in the interaction between time and group (p<0.0001). Multivariate analysis showed a statistically significant association between rescue analgesia and group (aOR=0.18; 95%CI=0.05-0.64); no further associations were observed between outcomes and determinants (p>0.05). As result cats in R group showed better intraoperative hemodynamic stability and postoperative lower pain scores compared to the C group. CONCLUSIONS The ultrasound-guided funicular block used in this study, as already demonstrated in dogs, is a good method to protect the cats from surgical pain and ensure a good level of surgical analgesia.