The Performance of Using the Parasympathetic Tone Activity (PTA) Index to Assess Intraoperative Nociception in Cats
by
, and
Leonor Lima
1,†, 
José Diogo Dos-Santos
1,2,3,4,*,†,
Lénio Ribeiro
1,5,
Patrícia Cabral
1,
Bruno Colaço
3,4,6
and
João Martins
1,2,3,4,6 1
Faculty of Veterinary Medicine, Lusófona University, 1749-024 Lisbon, Portugal
2
Veterinary and Animal Science Research Centre (CECAV), Faculty of Veterinary Medicine, Lusófona University—Lisbon University Center, 1749-024 Lisbon, Portugal
3
Veterinary and Animal Science Research Centre (CECAV), UTAD, 5000-801 Vila Real, Portugal
4
Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisbon, Portugal
5
Research Center for Biosciences and Health Technologies (CBIOS), Universidade Lusófona de Humanidades e Tecnologias, 1749-024 Lisbon, Portugal
6
Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), UTAD, 5000-801 Vila Real, Portugal
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Vet. Sci. 2024, 11(3), 121; https://doi.org/10.3390/vetsci11030121
Submission received: 26 November 2023
/
Revised: 21 February 2024
/
Accepted: 4 March 2024
/
Published: 6 March 2024
(This article belongs to the Special Issue Anesthesia and Pain Management in Veterinary Surgery)
Simple Summary
The monitoring of nociception/antinociception poses a significant challenge during anesthesia in cats. Parasympathetic Tone Activity (PTA) monitoring could prove to be a useful tool for this purpose; however, there is no research on this species. This study aims to assess the effectiveness and speed of PTA monitoring in detecting nociception when compared to heart rate (HR) during the intraoperative period in female cats undergoing ovariectomy (OV). The monitoring included intraoperative instantaneous PTA (PTAi), heart rate (HR), respiratory rate (fR), non-invasive systolic and mean arterial pressure (SAP/MAP) (mmHg), and the time required for HR (HR time) and PTAi (PTAi time) to reach their minimum peak values after the application of five surgical stimuli (SS). Each surgical stimulus was categorized into three groups: no nociception detection with no HR reaction and a PTAi > 50 (Nhre), no HR reaction and a PTAi < 50 (Nhre < 50), and a HR reaction and a PTAi < 50 (Hre < 50). The findings of this study suggest that in a clinical setting, PTA monitoring may be more effective in detecting nociception compared to HR, and with more intense SS, both parameters present a similar speed in detecting nociception.
Abstract
Background: The monitoring of nociception/antinociception poses a significant challenge during anesthesia, making the incorporation of new tools like the Parasympathetic Tone Activity (PTA) monitor an added value in feline anesthesia. Objectives: To compare the effectiveness and speed of PTA monitoring when compared to heart rate (HR) in detecting surgical stimuli (SS) during the intraoperative period in 49 female cats undergoing ovariectomy (OV). Methods: Instantaneous Parasympathetic Tone Activity (PTAi) values, HR, fR, and non-invasive SAP and MAP were continuously monitored and systematically assessed. The time required for HR (HR time) and PTAi (PTAi time) to reach their minimum peak values following each surgical stimulus was collected at five points for each anaesthetized cat. Each collected surgical stimulus was categorized into 3 groups for statistical analysis: no nociception detection, no hemodynamic reaction and a PTAi > 50 (Nhre); no hemodynamic reaction and a PTAi < 50 (Nhre < 50); and hemodynamic reaction and PTAi < 50 (Hre < 50). Results: PTAi response demonstrated effectiveness in detecting nociception compared to HR. The SS were categorized as 36.1% in the Nhre group, 50% in the Nhre < 50 group, and only 13.9% in the Hre < 50 group. In the Hre < 50 group, PTAi time and HR time had similar speeds in detecting the SS (p = 0.821); however, PTA time was significantly slower in the Nhre < 50 group when compared to the Hre < 50 group (p = 0.001). Conclusions: PTA monitoring may be a useful tool to complement HR monitoring for detecting nociception. PTA monitoring demonstrated a superior diagnostic value compared to HR for detecting nociception in cats undergoing OV and a similar speed to HR in detecting SS when HR increases above 20%. Future studies are needed to understand in a clinical setting the meaning of sympathetic activation/nociception detected using the PTA monitor when the HR increase is not clinically relevant.
Keywords:
animal welfare; cat; heart rate; nociception; parasympathetic tone activity
