The Impact of Nociception Monitor-Guided Multimodal General Anesthesia on Postoperative Outcomes in Patients Undergoing Laparoscopic Bowel Surgery: A Randomized Controlled Trial.

BACKGROUND: Excess surgical stress responses, caused by heightened nociception, can lead to elevated levels of postoperative inflammation, resulting in an increased incidence of complications after surgery. We hypothesized that utilizing nociception monitor-guided multimodal general anesthesia would exert effects on postoperative outcomes (e.g., serum concentrations of C-reactive protein (CRP) after surgery, postoperative complications). METHODS: This single-center, double-blinded, randomized trial enrolled ASA class I/II adult patients with normal preoperative CRP levels, scheduled for laparoscopic bowel surgery. Patients were randomized to receive either standard care (control group) or nociception monitor-guided multimodal general anesthesia using the nociceptive response (NR) index (NR group), where NR index was kept below 0.85 as possible. The co-primary endpoint was serum concentrations of CRP after surgery or rates of 30-day postoperative complications (defined as Clavien-Dindo grades ≥ II). MAIN RESULTS: One hundred and four patients (control group, n = 52; NR group, n = 52) were enrolled for analysis. The serum CRP level on postoperative day (POD) 1 was significantly lower in the NR group (2.70 mg·dL-1 [95% confidence interval (CI), 2.19-3.20]) than in the control group (3.66 mg·dL-1 [95% CI, 2.98-4.34], p = 0.024). The postoperative complication rate was also significantly lower in the NR group (11.5% [95% CI, 5.4-23.0]) than in the control group (38.5% [95% CI, 26.5-52.0], p = 0.002). CONCLUSIONS: Nociception monitor-guided multimodal general anesthesia, which suppressed intraoperative nociception, mitigated serum concentrations of CRP level, and decreased postoperative complications after laparoscopic bowel surgery.

Association between averaged intraoperative nociceptive response index and postoperative complications after lung resection surgery.

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 the 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 2 groups with Clavien-Dindo grade

Association between thoracic epidural block and major complications after pleurectomy/decortication for malignant pleural mesothelioma under general anesthesia.

INTRODUCTION: A 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. METHODS: In 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. RESULTS: In 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 without epidural block (n=65). In sensitivity analysis in patients with ASA physical status II alone, the same results were obtained. CONCLUSION: Epidural block is likely associated with reduction of the incidence of major complications after pleurectomy/decortication for malignant pleural mesothelioma under general anesthesia.

Quantitative evaluation of the effects of interscalene block on physiological responses to the balance between nociception and anti-nociception among inpatients undergoing total shoulder arthroplasty under general anesthesia.

Although the suppression of physiological responses to the balance between nociception caused by surgical trauma and anti-nociception due to anesthesia during total shoulder arthroplasty (TSA) is relevant for better perioperative managements, quantitative evaluations of the effects of ultrasound-guided interscalene brachial plexus block (ISB) on physiological responses have not been performed. Physiological responses were assessed using the nociceptive response (NR) index. In this multi-institutional observational study, associations between ISB and NR values were examined among inpatients undergoing TSA under general anesthesia between March 2019 and January 2021. The effects of ISB on acute postoperative pain and major complications within 30 days after surgery were also examined. NR values after skin incision clearly showed significant suppressions of physiological responses in patients undergoing TSA with ISB (n = 60), compared to those without ISB (n = 24). Acute postoperative pain on the day of surgery was also significantly less in patients with ISB than in those without ISB. Postoperative complications, classified by Clavien-Dindo grades, showed no significant differences between patients with and without ISB. A propensity score-matched sensitivity analysis confirmed the same results in patients with (n = 21) and without ISB (n = 21). In conclusion, suppression of physiological responses to the balance between nociception and anti-nociception by ISB can be quantitatively evaluated by NR index during TSA.

Intra-operative nociceptive responses and postoperative major complications after gastrointestinal surgery under general anaesthesia: A prospective cohort study.

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.

Association between intraoperative nociception and surgical invasiveness in patients undergoing non-cardiac surgery under general anesthesia: a retrospective cohort study.

There are several indexes of intraoperative nociception during surgery under general anesthesia. Although a higher degree of surgical invasiveness increases intraoperative nociception, an association between the index of intraoperative nociception and severity of surgical invasiveness has not been reported. We hypothesized that there is associations between averaged values of nociceptive response (NR) throughout surgery (mean NR), as the index of intraoperative nociception, and surgical severity codes in the Surgical outcome risk tool (SORT) or procedure risk codes in the Surgical mortality probability model (S-MPM). The primary outcome was the association between mean NR and severity scores of surgical procedure. Hence, a single institutional retrospective cohort study was performed in consecutive patients undergoing non-cardiac surgery under general anesthesia from June 2018 to May 2019. There were significant increases in the three categories of procedure risk in the S-MPM corresponding to the increase in mean NR values in 5090 patients. In the SORT, the highest intensity in the four categories of surgical severity also significantly correlated with the increase in mean NR values. Increasing intensity of intraoperative nociception is likely associated with higher severity codes of surgical invasiveness in prediction models for postoperative morbidity and mortality.

Association between intraoperative nociception and postoperative complications in patients undergoing laparoscopic gastrointestinal surgery.

A higher degree of surgical invasiveness, which increases intraoperative nociception, might induce postoperative complications. Although several nociceptive indices for use during surgery are available in clinical practice, association between intraoperative nociception and postoperative complications has not been reported. An index representing intraoperative nociception, which is the averaged value of Nociceptive Response throughout the surgery (mean NR) was applied to examine the association in the present study. The retrospective study evaluated consecutive adult patients undergoing laparoscopic gastrointestinal surgery, American Society of Anesthesiologists-physical status (ASA-PS) I or II, whose preoperative C-reactive protein level was < 0.3 mg dL-1. We first used ordinal logistic analysis to examine the association between preoperative and intraoperative risk factors and complications graded by the Clavien-Dindo classification. Next, we performed propensity score matched analysis to evaluate the effects of mean NR throughout surgery on postoperative complications. Ordinal logistic analysis (n = 158) revealed that duration of surgery (P < 0.001), mean NR during surgery (P = 0.002), and ASA-PS (P = 0.016) were risk factors for postoperative complications. Then all patients were divided into two propensity score matched groups, based on a mean NR of < 0.85 and ≥ 0.85, with matching for age, ASA-PS, body mass index and duration of surgery. The severity of postoperative complications was significantly higher in the high NR group than in the low NR group (P = 0.005). In conclusion, there was likely an association between intraoperative nociception and postoperative complications in patients without serious preoperative conditions and comorbidities.

Effects of Thoracic Paravertebral Block on Nociceptive Levels After Skin Incision During Video-Assisted Thoracoscopic Surgery.

BACKGROUND Regional anesthesia provides excellent analgesic effects after surgery. However, the effects of regional anesthesia on nociceptive levels during surgery under general anesthesia have not been quantitatively evaluated. To reveal the effects of thoracic paravertebral block (PVB) on nociceptive levels after skin incision during general anesthesia, we performed a retrospective cohort study in patients without serious preoperative conditions or comorbidities undergoing elective video-assisted thoracoscopic surgery (VATS). Nociceptive levels during general anesthesia were calculated using our previously determined Nociceptive Response (NR) equation, which utilizes common hemodynamic parameters. MATERIAL AND METHODS Data on 77 adult patients who underwent VATS from May 2018 to August 2018 were retrospectively obtained from our institutional database. We then performed propensity score matching between patients who received thoracic PVB (PVB group: n=29) and those who did not (Control group: n=48). The averaged values of systolic blood pressure (SBP), heart rate (HR), perfusion index (PI), bispectral index (BIS), and NR from 10 to 5 minutes before skin incision (T0), 5 to 10 minutes (T1), 10 to 15 minutes (T2), 15 to 20 minutes (T3), and 20 to 25 minutes after skin incision (T4), were calculated. RESULTS Twenty-four propensity score-matched patients in each group were analyzed. Mean NR values at T1 and T2 in the PVB group were significantly lower than those in the Control group. SBP, HR, PI, and BIS, however, showed no significant differences between the 2 groups, except for SBP at T2. CONCLUSIONS Thoracic PVB prevented an increase in NR values, which quantitatively represent nociceptive levels under general anesthesia, in patients undergoing VATS.

Diffusion coefficients for nanoparticles under flow and stop-flow conditions.

Dynamic light scattering (DLS) is a well-known technique for measuring the size of nanoparticles from the diffusion coefficient. We developed a new DLS technique with high sensitivity and used it as a detection tool in microchemical applications. We found a step-like downward change in the diffusion coefficient of nanoparticles just by starting a slight flow in the fluid channel. Because the diffusion coefficient is defined by the ratio of the force due to the chemical potential gradient to the frictional coefficient for the particle by a solvent, we propose that the frictional coefficient increased significantly. This result suggests that nanoscale friction under liquid motion differs from that under a steady state.