Comparison of intra and postoperative analgesia efficacy of intraperitoneal levobupivacaine alone or in combination with dexmedetomidine in cats undergoing ovariohysterectomy; a randomized, prospective, blinded, clinical trial

This study aimed to compare the analgesic and cardiopulmonary effects of levobupivacaine with or without dexmedetomidine, in cats undergoing ovariohysterectomy. In this prospective, randomized, and blinded clinical trial, 24 healthy cats were recruited. Animals received either saline (S group; 2 mL NaCl), levobupivacaine alone (Lev; 0.35 mg/kg), or levobupivacaine with dexmedetomidine (LevDex group; 0.004 mg/kg), which was infiltrated intraoperatively into the subcutaneous tissue at various incision sites, including the right and left ovarian pedicles and the caudal aspect of the uterine body. Intraoperative analgesia was evaluated using a cumulative pain scale, while postoperative analgesia was assessed at various time points: before surgery (T_b), and at 0 (T₀), 1 (T_1h), 2 (T_2h), 4 (T_4h), 8 (T_8h), 12 (T_12h), and 24 (T_24h) hours after the procedure, using the UNESP-Botucatu multidimensional composite pain scale (MCPS). Significant decreases in heart rate, respiratory rate, and mean arterial pressure were observed in LevDex group as compared to S and Lev groups (p < 0.05). The S group required significantly more rescue morphine doses than the LevDex group (p = 0.029), but the difference was not significant when compared to the Lev group (p = 0.123). At T_1h and T_2h, the S group had significantly higher MCPS scores than both the Lev and LevDex groups (p = 0.029). However, at T_8h, no significant difference was found between the S and LevDex groups (p = 0.741). While adding dexmedetomidine to levobupivacaine may slightly prolong postoperative analgesia, this combination does not provide significant additional benefit over levobupivacaine alone in terms of response to surgical stimulation.