Comparison of incisional, transverse abdominis plane, and rectus sheath blocks in dogs undergoing ovariohysterectomy.

Objective: To compare the analgesia provided by incisional (Incisional), transverse abdominis plane (TAP), and rectus sheath (RS) blocks in dogs submitted for ovariohysterectomy (OHE).

Animals: 22 female mixed-breed dogs were allocated into 3 treatments of Incisional (n = 7), TAP (n = 7), and RS (n = 8) and underwent OHE from April 4 to December 6, 2022.

Procedures: After premedication with acepromazine (0.05 mg/kg) and morphine (0.5 mg/kg), anesthesia was induced (6 mg/kg) and maintained (0.4 mg/kg/min) with propofol. Each dog randomly received either an incisional (blind technique), TAP, or RS (ultrasound-guided) block. Intraoperative analgesia was assessed using cardiorespiratory variables. Postoperative analgesia was evaluated up to 6 hours after the operation with a Short Form of Glasgow Pain Scale (SF-GCPS) and Visual Analog Scale (VAS). Fentanyl was administered as a rescue analgesic when needed.

Result: During surgery, all data remained within normal limits without any significant differences. Fentanyl was administered to 1 dog in the Incisional and 1 in the TAP. Post-operatively, a single dose of fentanyl was given to 1 dog in the TAP and 1 in the RS. Four dogs in the Incisional and 3 in the RS received both doses of fentanyl. There was no significant difference regarding postoperative rescue analgesia among treatments.

Clinical Relevance: All 3 techniques demonstrated acceptable intra- and post-operative analgesia efficacy in dogs undergoing OHE. Further studies are warranted to confirm these findings.