Liposomal bupivacaine local analgesia reduces systemic inflammatory responses following equine laparoscopic surgery

Objective: Liposomal local anesthetics have been shown to extend analgesia duration and improve pain scores dose-dependently in horses. Our objective was to assess concurrent impact on systemic inflammatory markers. Methods: 18 mares (age, 2 to 20 years) with normal ovarian anatomy were enrolled. Laparoscopic bilateral ovariectomies were performed standing with sedation. Local analgesia was: 80 mL bupivacaine hydrochloride (BHCl; n = 6), 30 mL 0.75% BHCl + 20 mL (low-dose) liposomal bupivacaine (LB) expanded to 80 mL with saline (LB20, n = 6), or 30 mL 0.75% BHCl + 40 mL (high-dose) LB expanded to equal volume around incision sites and mesovarium prior to ovariectomy (LB40, n = 6). Whole blood samples were obtained (0, 0.5, 1, 2, 4, 8, 24, 48, and 72 hours), and plasma was separated. Serum amyloid A (SAA) and 23 cytokines were quantified via commercially available kits and multiplex immunoassay, respectively. Results: SAA increased postoperatively from 24 to 72 hours (548.11 ± 726.84, 957.76 ± 1,006.62, and 841.18 ± 953.4, respectively). Serum amyloid A was lower in the LB40 group versus the LB20 group at 48 hours (303 ± 347.74 vs 773.17 ± 733.19) and 72 hours (439.67 ± 461.53 vs 951.6 ± 1,052.4). Cytokine concentrations were quantifiable for 14 cytokines; differences between groups were seen for eotaxin, granulocyte colony-stimulating factor, and IL-8. No group had consistently higher or lower values. Conclusions: High-dose LB suppressed the systemic inflammatory response, resulting in lower SAA postoperatively following ovariectomy. Clinical Relevance: Infiltration of extended-duration local anesthetics decreased inflammatory responses postoperatively.