Retrospective assessment of the relationship between intraoperative nociception and postoperative analgesia requirements in dogs undergoing thoracic surgery.

Abstract

BACKGROUND: The analgesia management of thoracic surgery can be challenging and debate exists regarding the efficacy of pre-emptive analgesia and its relationship with postoperative pain. The aim of this study was to assess the relationship between intraoperative nociception and postoperative pain in dogs undergoing thoracic surgery. If proven, effective prevention of intraoperative nociception could imply prospective lower postoperative analgesia requirements. METHODS: The study was retrospective and observational. Clinical records from dogs undergoing thoracic surgery (2015-2019) were reviewed and cases were allocated to one of two groups: NOCI-FREE - dogs with no evidence of intraoperative nociception; NOCI - dogs that required intraoperative rescue analgesia to address a nociceptive response. Pre-anaesthetic medication, locoregional analgesia, intraoperative infusions and rescue analgesia were used. Additionally, postoperative pain scores and analgesia plans were registered and compared between groups. RESULTS: Our study failed to identify a difference in the postoperative pain scores and analgesia requirements between dogs having signs of intraoperative nociception and those without. Additionally, the use of postoperative analgesic preventive infusions and rescue analgesia was similar for both NOCI and NOCI-FREE. Being on an intraoperative infusion of opioids, dexmedetomidine or lidocaine was identified as a protective factor for nociception [OR = 11; (4.15-29.7)]. CONCLUSIONS: In the population studied, it appears that dogs showing signs of nociception intraoperatively do not necessarily show higher pain scores nor do they need additionally pain relief in the postoperative period.