Surgical site infiltration with comfort-in device and traditional syringe in dogs undergoing regional mastectomy: evaluation of intra- and postoperative pain and oxidative stress

The surgical site infiltration of a local anesthetic is defined as the direct injection of a drug. This study aimed to compare the effects of surgical site infiltration with 4 mg kg⁻¹ lidocaine using a Comfort-in device and traditional syringe on oxidative status and intra- and postoperative pain in dogs undergoing regional mastectomy. Sixty adult female dogs divided into C (Comfort-in device), S (traditional syringe), and CTR (control) groups received 2 µg kg⁻¹ dexmedetomidine and 4 mg kg⁻¹ tramadol IM, 5 mg kg⁻¹ tiletamine/zolazepam IV, and isoflurane. The physiological and anesthesiological parameters were measured. The assessment of intra- and postoperative responses to the surgical stimulus was performed using a cumulative pain scale (CPS score of 0–4) and the Colorado Pain Scale (CSU-CAPS score of 0–4). The hematological and biochemical parameters and inflammatory oxidative status were measured. The CPS scores showed no significant differences between the C and S groups (p = 0.236), while the comparison between the CTR, C, and S groups, respectively, showed a significant difference (p < 0.001). The postoperative analgesia scores were significantly lower in the C group compared to those of the S and CTR groups (p < 0.001). In the C group, no subject received rescue analgesia during the intra- and postoperative periods. The level of oxidative inflammatory stress was lower in group C than those in S and CTR groups, and no side effects were observed in all the groups.