Performance of the Parasympathetic Tone Activity (PTA) index to assess the intraoperative nociception using different premedication drugs in anaesthetised dogs

Abstract

The dynamic variations of the Parasympathetic Tone Activity (PTA) index were evaluated to assess nociception in dogs undergoing anaesthetic protocols with different premedication drugs. Sixty-six dogs, divided into three groups of 22 dogs each, were given different premedication drugs "morphine" (0.2 mg/kg), "morphine + medetomidine (5 μg/kg)", "morphine + acepromazine (0.03 mg/kg)", then similarly induced and maintained under general anaesthesia. The PTA, HR (heart rate) and MAP (mean arterial pressure) were assessed at S (steady-state), Cut (cutaneous incision), PTA E (PTA Event, assessed 1 min before a significant PTA decrease), HDR (Haemodynamic reaction, assessed 5 min before an increase of ≥ 20% in HR and/or MAP). For each group, the dynamic variation of PTA (ΔPTA) was calculated and a Receiver Operating Characteristics (ROC) curve was performed to detect if any of the premedication drugs may alter the performance of PTA index to predict intraoperative haemodynamic reactions. In all groups, a haemodynamic reaction was detected after Cut, PTA E and HDR and was preceded with a significant decrease of PTA, except for "morphine + medetomidine" group which showed a significant drop of PTA only at PTA E and HDR. The ΔPTA showed a fair performance in all groups (a mean [95%

Neurobiology of anesthetic-surgical stress and induced behavioral changes in dogs and cats: A review

“…Both indices analyze HRV and reflect the sympathovagal balance [106]. Although they can be altered by premedication during surgery, they can predict hemodynamic reactivity [107] and indicate the analgesia/nociception balance [108,109]. A high value would indicate a high parasympathetic tone and the absence of nociception, and a low value would reflect a low parasympathetic tone and potential nociception Available at www.veterinaryworld.org/Vol.14/February-2021/10.pdf (Figure -3) [98].…”

Performance of the Parasympathetic Tone Activity (PTA) index to predict changes in mean arterial pressure in anaesthetized horses with different health conditions

“…ANI index was validated to detect nociception during anaesthesia in human patients [8]. PTA index was evaluated to assess the analgesia/nociception balance and predict a haemodynamic reactivity in anaesthetized dogs [9]. The autonomic nervous system (ANS) is a major regulator of the cardiovascular system: it maintains internal physiologic homeostasis, but can be altered by a variety of perioperative factors, including anaesthetic drugs and clinical condition, with resulting haemodynamic changes [10] [11].…”

Opioid‐free anaesthesia for surgical attenuation of a congenital extrahepatic portosystemic shunt in a dog

“…The PTA monitor is used to detect intraoperative nociception in dogs earlier and with greater sensitivity than non-specific haemodynamic reactivity parameters, such as tachycardia, increases in blood pressure or changes in respiratory pattern. 27,28 High values of the parasympathetic tone suggest absence of nociception, whereas lower values reflect possible pain stimuli. Due to the absence of additional analgesia requirements and PTA changes during surgery, it was possible to infer that the QL technique was adequately performed.…”

“…The patient maintained stable index values at around 80, which indicate prominent parasympathetic tone throughout surgery and suggest absence of nociception. [27][28][29] A suitable analgesia due to the locoregional technique may be therefore presumed.…”