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ObjectiveWe determined whether regional haemodynamics and perfusion index (PI) could be reliable indicators of a successful sciatic nerve block (SNB).DesignProspective observational trial.SettingA tertiary teaching hospital in China from April 2020 to August 2020.ParticipantsWe assessed 79 patients for eligibility to participate in this study. Nine patients were excluded for not meeting our inclusion criteria, and three patients were excluded due to missing measurements at all time points.InterventionsThe patients underwent SNB. Pulsed-wave Doppler and PI measurements were performed.Primary and secondary outcome measuresThe primary outcome measure was the diagnostic power of regional haemodynamic change and PI to predict successful SNB. The secondary outcome measure was the effect of SNB on the regional haemodynamics and PI in the lower extremity.ResultsWe assessed 79 patients in this study and 67 patients available for the final analysis. The SNB was successful in 59 patients and failed in eight patients. There were no significant differences in demographic characteristics between the patients with successful and failed SNB. Starting from 10 min after SNB, the peak systolic velocity (PSV), end-diastolic velocity, time-averaged maximum velocity and time-averaged mean velocity of the anterior tibial artery and posterior tibial artery of patients in the successful SNB group were significantly higher than those in the failed SNB group (p<0.05). The PSV percentage increase at 10 min after SNB has great potential to predict the block success. The area under the receiver operating characteristic curve (AUC) values were 0.893 (95% CI 0.7809 to 1.000) and 0.880 (95% CI 0.7901 to 0.9699). The corresponding cut-off values were 19.22 and 35.88, respectively. The PI increased during 5–45 min intervals in patients with successful SNB. The AUC for the PI percentage increases at 10 min after SNB was 0.853 (95% CI 0.7035 to 1.000), with a cut-off value of 93.09.ConclusionThe regional haemodynamic variables, PSV and PI in particular, can be used as alternative indicators for clinicians to evaluate the success of SNB objectively and early.Trial registration numberChiCTR2000030772.

Neuroinflammation plays a dominant role in the progression of postoperative cognitive dysfunction (POCD). Vitamin D has been known to have important regulatory functions in inflammation and immune response. The NOD-like receptor protein 3 (NLRP3) is an essential inflammasome in the inflammatory response and could be activated by anesthesia and surgery. In this study, male C57BL/6 mice aged 14–16 months were given VD3 for 14 days straight before having an open tibial fracture surgery. The animals were either sacrificed to obtain the hippocampus or tested in a Morris water maze test. Western blot was employed to estimate the levels of NLRP3, ASC, and caspase-1, immunohistochemistry was used to identify microglial activation, and an enzyme-linked immunosorbent assay was used to measure the expression of IL-18 and IL-1β, while using the corresponding assay kits to assess ROS and MDA levels to reflect the oxidative stress status. We showed that VD3 pretreatment significantly improved surgery-induced memory and cognitive dysfunctions in aged mice, which was linked to the inactivation of the NLRP3 inflammasome and the inhibition of neuroinflammation. This finding provided a novel preventative strategy for clinically reducing postoperative cognitive impairment in elderly surgical patients. This study has some limitations. Gender differences in the effects of VD3 were not considered, and only male mice were used. Additionally, VD3 was given as a preventative measure; however, it is unknown whether it has any therapeutic benefits for POCD mice. This trial is registered with ChiCTR-ROC-17010610.

Endothelial dysfunction caused by high glucose is recognized as an important event in the pathogenesis of diabetes-related vascular complications. Ropivacaine is considered to have the best safety profile among the commonly used amide local anesthetics, but the extent of its actions remains incompletely understood. Here, we used human umbilical vein endothelial cells exposed to high glucose to explore the effects of ropivacaine on oxidative stress and markers of inflammation. Ropivacaine treatment exerted significant beneficial effects by rescuing oxidative stress and downregulating interleukin (IL)-1β and IL-18. We also found that ropivacaine could inhibit the secretion of the high-mobility group box 1 protein and improve cell viability. Importantly, sirtuin-1 (SIRT1) knockdown experiments show that the inhibitory effects of ropivacaine against NLRP3 inflammasome activation are dependent on SIRT1. Taken together, these results demonstrate the potential of ropivacaine as a promising therapy against diabetic endothelial dysfunction.