An investigation into the use of a PTA Monitor in anaesthesia and analgesia

Background: The monitoring of nociception in dogs and cats under general anaesthesia can be challenging. Currently, haemodynamic reactivity alongside no change in anaesthetic depth is the most accurate way of detecting nociception in anaesthetised patients. Recent technologies, adapted from human medicine, use heart rate variability and respiratory patterns to calculate parasympathetic activity in the body, such as the Parasympathetic Tone Activity (PTA) Monitor. This numerical value can then be used to understand the patient's comfort level and titrate analgesics accordingly. Methods: Prospective, non-randomised controlled study with retrospective and questionnaire elements. A total of 36 canine and feline patients undergoing elective ovariohysterectomy procedures were recruited. The frequency of intra-operative rescue analgesia (RA) administration between the PTA Monitor (PTA) group and the retrospective group (no PTA Monitor (nPTA)) were analysed. An online questionnaire comprising Likert scales and open and closed questions were given to the Registered Veterinary Nurses monitoring general anaesthesia in the practice to comprehend their understanding of the machine and the possible value it adds to their monitoring. Results: Out of the 36 patients, 44.4% ( n =16) were in the PTA group and 55.5% ( n =20) were in the nPTA group. A total of 60% ( n =12) of patients in the nPTA group and 62% ( n =10) in the PTA group required the administration of RA during their surgical procedure. A statistically significant association was not observed between the frequency of RA administration and the use of the PTA monitor ( P =0.87), or between the use of the PTA monitor and drug classification ( P =0.96). The online questionnaire identified that of the participants, 80% ( n =4) found the machine to be valuable when monitoring nociception during general anaesthesia, alongside their usual monitoring techniques. Conclusion: Despite the absence of statistical significance of the impact of the PTA Monitor on RA administration, the clinical significance of the machine was highlighted by RVNs. Future research is required to further understand the value of this machine in clinical practice.