BACKGROUND Surgical procedures stimulate nociception and induce physiological responses according to the balance between nociception and antinociception. The severity of surgical stimuli is associated with major postoperative complications. Although an intra-operative quantitative index representing surgical invasiveness would be useful for anaesthetic management to predict and prevent major complications, no such index is available. OBJECTIVES To identify associations between major complications after gastrointestinal surgery and intra-operative quantitative values from intra-operative nociception monitoring. DESIGN A multi-institutional observational study. SETTING Two university hospitals. PATIENTS Consecutive adult patients undergoing gastrointestinal surgery under general anaesthesia. MAIN OUTCOME MEASURES Averaged values of nociceptive response index from start to end of surgery (mean NR index) and risk scores of the Surgical Mortality Probability Model (S-MPM) were calculated. Pre and postoperative serum C-reactive protein (CRP) levels were obtained. After receiver-operating characteristic (ROC) curve analysis, all patients were divided into groups with high and low mean nociceptive response index. Associations between mean nociceptive response index and postoperative major complications, defined as Clavien-Dindo grade at least IIIa, were examined using logistic regression analysis. RESULTS ROC curve analysis showed a nociceptive response index cut-off value for major complications of 0.83, and we divided patients into two groups with mean nociceptive response index less than 0.83 and at least 0.83. The incidence of major complications was significantly higher in patients with mean nociceptive response index at least 0.83 (23.1%; n = 346) than in patients with mean nociceptive response index less than 0.83 (7.7%; n = 443; P < 0.001). Multivariate analysis revealed emergency surgery, S-MPM risk score, mean nociceptive response index and postoperative CRP levels as independent risk factors for major complications. CONCLUSION Mean nociceptive response index during surgery likely correlates with major complications after gastrointestinal surgery. TRIAL REGISTRATION The current observational study had no intervention, and was therefore, not registered.

IntroductionA curative-intent surgical procedure, pleurectomy/decortication, for malignant pleural mesothelioma is accompanied by a high incidence of major postoperative complications. Although epidural block, which suppresses nociception during and after surgery, reportedly has both benefits and disadvantages in terms of outcomes after thoracic surgery for other diseases, the effects of epidural block on major complications after pleurectomy/decortication have not been evaluated. The aim of this study was to evaluate the association between epidural block and major postoperative complications following pleurectomy/decortication.MethodsIn a single-institutional observational study, consecutive adult patients undergoing pleurectomy/decortication under general anesthesia were enrolled from March 2019 to December 2021. Multivariable logistic regression analysis was performed to determine the association between perioperative variables and major complications. Next, patients were divided into two groups: general anesthesia with and without epidural block. Incidences of major postoperative complications, defined as Clavien-Dindo grades≥III, were compared between groups.ResultsIn all patients enrolled with American Society of Anesthesiologists (ASA) physical status II or III (n=99), general anesthesia without epidural block was identified as a sole risk factor for major complications among perioperative variables. The incidence of major complications was 32.3% (95% CI 19.1% to 49.2%) in patients with epidural block (n=34), which was significantly lower than 63.1% (95% CI 50.9% to 73.8%) in patients with epidural block (n=65). In sensitivity analysis in patients with ASA physical status II alone, the same results were obtained.ConclusionEpidural block is likely associated with reduction of the incidence of major complications after pleurectomy/decortication for malignant pleural mesothelioma under general anesthesia.

OBJECTIVES Since postoperative complications, defined as Clavien-Dindo grade ≥ II, correlate with long-term survival after lung resection surgery in patients with primary lung cancer, identification of intraoperative risk factors for postoperative complications is crucial for better perioperative management. In the present study, we investigated possible association between intraoperative variables for use in anaesthetic management and Clavien-Dindo grade ≥ II. METHODS In this multi-institutional observational study, consecutive adult patients undergoing video-assisted thoracic surgery for primary lung cancer under general anaesthesia from March 2019 to April 2021 were enrolled. All patients were divided into two groups with Clavien-Dindo grade &lt; II and ≥ II. Uni- and multivariable analyses were performed to identify intraoperative risk factors. RESULTS After univariable analysis between patients with Clavien-Dindo grade &lt; II (n = 415) and ≥ II (n = 121), multivariable analysis revealed higher averaged nociceptive response (NR) index during surgery (mean NR), male sex, lower body mass index, longer duration of surgery, higher blood loss, and lower urine volume, as independent risk factors for postoperative complications. In sensitivity analysis, based on the cut-off value of mean NR for postoperative complications, all patients were divided into high and low mean NR groups. The incidence of postoperative complications was significantly higher in patients with high mean NR (n = 332) than in patients with low mean NR (n = 204; P &lt; 0.001). CONCLUSIONS Higher mean NR, as intraoperative variables for use in anaesthetic management, is associated with higher incidence of postoperative complications after primary lung cancer surgery.