Feasibility of an electric current stimulator device to assess the sensory response after transversus abdominis plane block in Guinea pigs (Cavia porcellus)

Samanta Waxman; Santiago Fuensalida; Nicolás Giansanti; Pablo Regner; Casilda Rodríguez; Pablo Otero

doi:10.1016/j.vaa.2024.10.142

Feasibility of an electric current stimulator device to assess the sensory response after transversus abdominis plane block in Guinea pigs (Cavia porcellus)

Vet Anaesth Analg. 2024 Oct 30:S1467-2987(24)00335-0. doi: 10.1016/j.vaa.2024.10.142. Online ahead of print.

Authors

Samanta Waxman¹, Santiago Fuensalida², Nicolás Giansanti², Pablo Regner³, Casilda Rodríguez⁴, Pablo Otero²

Affiliations

¹ Department of Anesthesiology, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Buenos Aires, Argentina; National Scientific and Technical Research Council (Consejo Nacional de Investigaciones Científicas y Técnicas; CONICET), Buenos Aires, Argentina. Electronic address: maribarbola_2000@yahoo.com.
² Department of Anesthesiology, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Buenos Aires, Argentina.
³ Deparment of Medicine, Production and Technology of Aquatic and Terrestrial Fauna, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Buenos Aires, Argentina.
⁴ Deparment of Toxicology and Pharmacology, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid, Spain.

PMID: 39581777
DOI: 10.1016/j.vaa.2024.10.142

Abstract

Objective: To assess the feasibility of using an adjustable intensity nerve stimulator for evaluating the sensory response after a transversus abdominis plane (TAP) block in guinea pigs (Cavia porcellus).

Study design: Prospective, randomized, blinded, experimental crossover study.

Animals: A total of six adult guinea pigs (Cavia porcellus).

Methods: Trial A involved a unilateral TAP block with 0.5% bupivacaine (1 mL kg^-1), and trial B involved a unilateral sham block with an equivalent volume of 0.9% saline. In both trials, the noninjected side served as the control. An electrical stimulus was bilaterally applied at 10, 20, 30, 60, 90 and 120 minutes post-injection. Stimulus intensity was gradually increased and the current intensity (mA) at which a response (body movements and/or voluntary limb withdrawal and/or vocalization) occurred on each side was registered. Measurements over time (Friedman test) and between sides at each time point (Wilcoxon test) were compared.

Results: In trial B, nonsignificant differences were observed between sides at each time point. In trial A, when comparing responses at each time point, nonsignificant differences were observed at 60 (p = 0.104), 90 (p = 0.598) and 120 minutes (p = 0.891); however, at 10 (p = 0.043), 20 (p = 0.027) and 30 minutes (p = 0.026), significant differences were observed. The stimulus intensity necessary to evoke a response in the bupivacaine-injected side was at least 23.8% higher than the current intensity required to elicit a response in the control side.

Conclusions and clinical relevance: The electrical stimulus method appears effective in distinguishing the presence or absence of sensory block in guinea pigs that were administered a TAP block. This approach may also serve to assess the onset time and duration of the block.

Keywords: interfascial plane block; laboratory animals; local block; pain; regional anesthesia.