Clinical Use of The Parasympathetic Tone Activity Index As a Measurement of Postoperative Analgaesia in Dogs Undergoing Ovariohysterectomy

Ismael Hernández-Avalos; Alex Valverde; José Antonio Ibancovichi-Camarillo; Pedro Sánchez-Aparicio; Sergio Recillas-Morales; Desiderio Rodríguez-Velázquez; Jorge Osorio-Avalos; Luis Armando Magdaleno-Torres; Julio Chavez-Monteagudo; Carlos Manuel Acevedo-Arcique

doi:10.2478/jvetres-2021-0004

Clinical Use of The Parasympathetic Tone Activity Index As a Measurement of Postoperative Analgaesia in Dogs Undergoing Ovariohysterectomy

J Vet Res. 2021 Jan 26;65(1):117-123. doi: 10.2478/jvetres-2021-0004. eCollection 2021 Mar.

Affiliations

¹ Department of Biological Sciences, Clinical Pharmacology and Veterinary Anaesthesia, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Cuautitlán Izcalli, Estado de México, 54740 Estado Mexico.
² Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1 Canada.
³ Department of Veterinary Anesthesia and Analgesia, Ontario, Canada.
⁴ Department of Pharmacology, Ontario, Canada.
⁵ Department of Surgery Education, Ontario, Canada.
⁶ Department of Biostatistics, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México, El Cerrillo, Piedras Blancas, Toluca, Estado de México, Estado 50295 Mexico.
⁷ Veterinary Hospital for Small Animals, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatan, 97315 Mexico.

Abstract

Introduction: While the current tools to assess canine postoperative pain using physiological and behavioural parameters are reliable, an objective method such as the parasympathetic tone activity (PTA) index could improve postoperative care. The aim of the study was to determine the utility of the PTA index in assessing postoperative analgaesia.

Material and methods: Thirty healthy bitches of different breeds were randomly allocated into three groups for analgaesic treatment: the paracetamol group (G_PARAC, n = 10) received 15 mg/kg b.w., the carprofen group (G_CARP, n = 10) 4 mg/kg b.w., and the meloxicam group (G_MELOX, n = 10) 0.2 mg/kg b.w. for 48 h after surgery. G_PARAC was medicated orally every 8 h, while G_CARP and G_MELOX were medicated intravenously every 24 h. The PTA index was used to measure the analgaesia-nociception balance 1 h before surgery (baseline), and at 1, 2, 4, 6, 8, 12, 16, 20, 24, 36, and 48 h after, at which times evaluation on the University of Melbourne Pain Scale (UMPS) was made.

Results: The baseline PTA index was 65 ± 8 for G_PARAC, 65 ± 7 for G_CARP, and 62 ± 5 for G_MELOX. Postoperatively, it was 65 ± 9 for G_PARAC, 63 ± 8 for G_CARP, and 65 ± 8 for G_MELOX. No statistically significant difference existed between baseline values or between values directly after treatments (P = 0.99 and P = 0.97, respectively). The PTA index showed a sensitivity of 40%, specificity of 98.46% and a negative predictive value of 99.07%.

Conclusion: Our findings suggest that the PTA index measures comfort and postoperative analgaesia objectively, since it showed a clinical relationship with the UMPS.

Keywords: PTA index; analgaesia; dogs; ovariohysterectomy.