Comparative Anesthesia Resident University of Minnesota
This study determined the effect of pre-operative ultrasound-guided rectus sheath block (USRSB) on intra-operative hemodynamic responses to surgical stimulation and its effect on post-operative pain as compared to a standard treatment with robenacoxib.
Methods: Thirty-seven female intact cats presented for ovariohysterectomy (OHE) were anesthetized with a standardized anesthetic protocol and randomly assigned to receive bilateral USRSB with a volume of 0.8 mL kg-1 of 0.25% bupivacaine (RSB; n=17), or an equivalent volume of 0.9% saline (Control; n=20). An individual blinded to treatment identity recorded intraoperative systolic arterial pressure (SAP), heart rate (HR), and vaporizer setting before skin incision (baseline) and during several endpoints (celiotomy, ovarian pedicles excision, uterine body excision, abdominal wall closure). At the end of anesthesia, cats in the Control group received a subcutaneous injection of robenacoxib (2 mg kg-1) and RSB cats received an injection of 0.9% saline (0.1 mL kg-1). Post-operative pain was evaluated for 6 hours by two investigators blinded to treatment identity using the feline Glasgow Composite Measure Pain Scale. Intra-operative data were compared using a Mixed-effect model with Geisser-Greenhouse correction and Bonferroni post-hoc. Post-operative rescue analgesia was compared using survival curves and the Gehan-Breslow-Wilcoxon test, with 95% confidence intervals (CI) calculated using Mantel-Haenszel test. Data are mean ± SD or median (IQR), and statistical significance is set as p <0.05.
