Local anesthetic techniques for thoracic surgery in pigs.

Local anesthetic techniques for thoracic surgery in pigs Carlotta Lambertini1, Domenico Ventrella1, Maria Laura Bacci1, Alberto Elmi2, Francesca Spaccini1, Noemi Romagnoli1 1Department of Veterinary Medical Sciences, University of Bologna, Italy 2Department of Veterinary Sciences, University of Pisa, Italy Pigs are common models for testing medical devices requiring thoracic surgery, for which a multimodal analgesia is pivotal. We described three different local-anesthetic (LA) techniques applicable for these procedures, considering their feasibility, advantages and disadvantages. Twenty commercial hybrid pigs undergoing sternotomy as part of a study testing an extracorporeal circulation device were considered. In the isoflurane anaesthetized animals receiving fentanyl infusion, the following LA techniques were applied: none, blinded bilateral intercostal (IC) blocks and lumbar (L4-L5) spinal (SA) or epidural anesthesia (EA) anesthesia. Analgesia was considered inadequate if cardiovascular variables increased by 20% above the pre-operative values. The three LA techniques resulted in superior analgesia as compared with absence of LA techniques. The IC blocks were the easiest to perform, however, drawbacks consist in the larger volume of drug administered and in the longer time interval necessary to complete the procedure if compared with the other two techniques. The correct needle placement for the blinded IC blocks relied only on the anatomical landmarks. Both the SA and the EA required more training, but they were faster once the skill was acquired. In these cases, the correct needle placement was confirmed based on the anatomical landmarks and by the appearance of the liquor or with the hanging drop technique respectively for the SA and the EA. The LA techniques represent a refinement for analgesic management of pigs undergoing sternotomy; however, the identification of the anatomical landmarks cannot be overlooked, therefore their feasibility is limited by the body condition of the animals. References Guerra-Londono CE, Privorotskiy A, Cozowicz C, et al. Assessment of Intercostal Nerve Block Analgesia for Thoracic Surgery: A Systematic Review and Meta-analysis. JAMA Netw Open. 2021;4:e2133394. Lambertini C, Ventrella D, Barone F, et al. Transdermal spinal catheter placement in piglets: Description and validation of the technique. J Neurosci Methods. 2015;255:17-21.