Efficacy of locally infiltrated tramadol compared to bupivacaine during elective ovariohysterectomy procedures in canine patients: A double-blinded randomized parallel study

Effective acute pain management is an integral component of modern veterinary surgery, in particular for pain arising from surgical wounds. Peri-incisional local anaesthetics are indicated to manage both intra- and postoperative pain. The aim of the study was to evaluate the use of tramadol as a local anaesthetic agent and its effects on postoperative pain. Sixteen dogs undergoing elective ovariohysterectomies were randomly assigned to receive either tramadol or bupivacaine as local anaesthetics. Acute postoperative pain levels were assed at 2-, 4-, and 6-h postinfiltration using a Glasgow Composite Measure Pain Scale - Short Form. Local wound effects, including swelling and bruising were also evaluated at 6- and 20-h intervals. No significant differences were found in pain scores between the tramadol and bupivacaine groups at any time interval (2-h: 2.5/24 compared to 3.5/24, p = 0.31; 4-h: 1.5/24 compared to 3/24. p = 0.31; 6-h: 0.5/24 compared to 1.5/24, p = 0.83, respectively). However tramadol demonstrated significantly less swelling compared to bupivacaine at the 20-h interval (1/3 compared to 2/3, p = 0.04). No difference in swelling scores at the 6-h interval, or bruising scores at the 20-h interval were found. Locally infiltrated tramadol offered comparable analgesic and local wound effects to that of bupivacaine, although further studies with larger sample sizes are required. This study shows the importance of discussions surrounding alternative local analgesic agents within the veterinary industry, which may ultimately lead to better patient care and outcomes.