Safety and effectiveness of opioid-free anaesthesia in thoracoscopic surgery: a preliminary retrospective cohort study

Background This study aimed to observe the effect of opioid-free anaesthesia (OFA) on intraoperative haemodynamic,postoperative analgesia and postoperative nausea and vomiting (PONV) in thoracoscopic surgery in order to provide more evidence for evaluating the safety and effectiveness of OFA technology. Methods This was a single-centre retrospective observational study.Adult patients who underwent thoracoscopic surgery with the preoperative thoracic paravertebral block between January 2017 and June 2020 were included.A cohort of 101 thoracoscopic surgery patients who received the OFA technique were matched with 101 thoracoscopic surgery patients who received standard opioid-containing anaesthesia(SOA). Heart rate (HR) and mean arterial blood pressure (MAP) were measured before anaesthesia induction, immediately after endotracheal intubation, at the beginning of surgery, and 10, 20, and 30 min after surgery began.The total amount of intraoperative infusion, frequency of vasoactive drugs use, morphine ingested via the patient-controlled intravenous analgesia (PCIA) 24 h post-surgery,visual analogue scale (VAS) scores at rest and activity on the first day post-surgery, and frequency of nausea and vomiting within 24 h post-surgery were analysed. Results There was no significant difference in intraoperative HR between the two groups (F = 0.889, P = 0.347); however, there was significant difference in intraoperative MAP (F = 16.709, P < 0.001), which was lower in SOA patients than in OFA patients. The frequency of vasoactive drug use and amount of infusion was less in OFA patients ( P = 0.001). The consumption of morphine used by the PCIA 24 h post-surgery was significantly lower in OFA patients (OFA, 1.8 [0, 4.8] mg vs. SOA, 3.6 [0.6, 23] mg, P < 0.001). There was no significant difference in VAS scores at rest ( P = 0.745) or during activity ( P = 0.792) on the first day post-surgery. There was also no statistically significant difference in nausea and vomiting within 24 h post-surgery ( P = 0.651). Conclusions This case-control study demonstrated that compared with SOA, OFA can effectively maintain the stability of intraoperative MAP, reduce the incidence of hypotension. Although OFA reduced morphine consumption via the PCIA pump 24 h post-surgery, postoperative pain scores and nausea and vomiting within 24 h post-surgery were similar between the groups.But this study was only a preliminary study and needed to confirm in a larger, more robust trial.