Search Results (17)

High-density polyethylene (HDPE) is a key material in modern engineering, highly valued for its versatility and wide range of applications. However, accurately assessing its mechanical performance under complex stress conditions has remained a challenge. This study developed an improved small specimen bulging test (SBT) combined with finite element simulation using ABAQUS 2017 software to more precisely evaluate the deformation resistance of HDPE. Both the experimental and simulation results showed that during the hydraulic bulging test, the maximum bulging pressure of the HDPE specimens reached approximately 22 MPa, with a maximum bulging height of about 2.6 mm. The material exhibited three distinct deformation stages: elastic deformation, plastic deformation, and large deformation near failure. Based on the experimental data and simulation results, we established a more accurate material response model for HDPE, which not only better reflects the material’s behavior under actual stress conditions but also provides a reliable basis for engineering design and material selection. Full article

Background and Objectives: Unassisted breathing through a T-piece was the most used spontaneous breathing trial (SBT) in endotracheal intubated prolonged mechanical ventilation (PMV) patients. However, the optimal duration of an SBT in PMV patients remains uncertain. In this study, we compared the extubation outcome between a 12 h T-piece SBT and a 24 h T-piece SBT in PMV patients. Materials and Methods: We reviewed the medical records of PMV patients who were extubated after passing a 12 h or 24 h T-piece SBT. The extubation, weaning, and hospital outcomes between the 12 h T-piece SBT group and the 24 h T-piece SBT group were compared. Kaplan–Meier survival plots and Cox proportional hazard models were used to evaluate the risk of extubation failure between groups. Results: In this study, 120 patients were extubated after passing the 12 h T-piece SBT and 234 patients were extubated after passing 24 h T-piece SBT. Patients in the 24 h T-piece SBT group had higher APACHE II score and lower Glasgow coma scale upon RCC arrival than patients in the 12 h T-piece SBT group. There was no difference in gender, age, or ventilator days before extubation between these two groups of patients. After extubation, patients in the 12 h T-piece SBT group and 24 h T-piece SBT group had similar extubation failure rates within 5 days (26.7% vs. 26.1%, p = 0.904). There was no difference in the RCC weaning rate (85% vs. 85.5%, p = 0.929) and hospital mortality rate (19.8% vs. 21.8%, p = 0.821) between the 12 h T-piece SBT group and the 24 h T-piece SBT group. Subgroup analysis showed that 24 h T-piece SBT was associated with a lower extubation failure rate in PMV patients with myocardial infarction or heart failure, but not in older PMV patients or those with cerebrovascular disease. Conclusions: The extubation and weaning outcomes were similar in PMV patients extubated after passing 12 h T-piece SBT or 24 h T-piece SBT. Full article

Background: This study analyzed weaning characteristics and assessed the association of clinical and ultrasonographic indices—maximum inspiratory pressure (MIP), rapid shallow breathing index (RSBI), peak flow expiratory (PFE), diaphragm-thickening fraction (DTF), diaphragm thickness (DT), diaphragm excursion (DE), diaphragm-RSBI (D-RSBI), and lung ultrasound (LUS) patterns—with weaning failure. Methods: This retrospective cohort study included critically ill COVID-19 patients aged 18 and older who had been on invasive mechanical ventilation for at least 48 h and undergoing weaning. Exclusion criteria included absence of ultrasound assessments, neuromuscular diseases, and chronic cardio-respiratory dysfunction. Results: Among 61 patients, 44.3% experienced weaning failure, 27.9% failed the spontaneous breathing trial (SBT), 16.4% were re-intubated within 48 h, and 28% required tracheostomy. Weaning failure was associated with prolonged ventilation (29 vs. 7 days, p < 0.001), extended oxygen therapy, longer ICU stays, and higher ICU mortality. These patients had higher pressure support, lower oxygenation levels, a higher RSBI, and a lower MIP. While PEF, DTF, DE, and D-RSBI showed no significant differences, both right and left diaphragm thicknesses and the inspiratory thickness of the left diaphragm were reduced in failure cases. LUS scores were significantly higher before and after SBT in the failure group. Bivariate analysis identified RSBI [OR = 1.04 (95% CI = 1.01–1.07), p = 0.010], MIP [OR = 0.92 (95% CI = 0.86–0.99), p = 0.018], and LUS [OR = 1.15 (95% CI = 0.98–1.35), p = 0.025] as predictors of weaning failure; however, these associations were not confirmed in multivariate analysis. Conclusions: Ultrasound provides supplementary information during weaning, but no definitive association between ultrasound indices and weaning failure was confirmed in this study. Full article

This study compared laboratory risk and turn-around time (TAT) between sequence-based typing (SBT) and next-generation sequencing (NGS) for human leukocyte antigen (HLA) typing. For risk assessment, we utilized the risk priority number (RPN) score based on failure mode and effect analysis (FMEA) and a risk acceptability matrix (RAM) according to the Clinical Laboratory Standards Institute (CLSI) guidelines (EP23-A). Total TAT was documented for the analytical phase, and hands-on time was defined as manual processes conducted by medical technicians. NGS showed a significantly higher total RPN score than SBT (1169 vs. 465). NGS indicated a higher mean RPN score, indicating elevated severity and detectability scores in comparison to SBT (RPN 23 vs. 12, p = 0.001; severity 5 vs. 3, p = 0.005; detectability 5 vs. 4, p < 0.001, respectively). NGS required a greater number of steps than SBT (44 vs. 25 steps), all of which were acceptable for the RAM. NGS showed a longer total TAT, total hands-on time, and hands-on time per step than SBT (26:47:20 vs. 12:32:06, 03:59:35 vs. 00:47:39, 00:05:13 vs. 00:01:54 hh:mm:ss, respectively). Transitioning from SBT to NGS for HLA typing involves increased risk and an extended TAT. This study underscored the importance of evaluating these factors to optimize laboratory efficiency in HLA typing. Full article

Background: It is unclear whether other cardiac biomarkers than NT-proBNP can be useful in the risk stratification of patients weaning from mechanical ventilation. The aim of this study is to summarize the role of ischemic cardiac biomarkers in predicting spontaneous breathing trial (SBT) or extubation failure. Methods: We systematically searched Embase, MEDLINE, Web of Science, and Cochrane Central for studies published before January 2024 that reported the association between ischemic cardiac biomarkers and SBT or extubation failure. Data were extracted using a standardized form and methodological assessment was performed using the QUIPS tool. Results: Seven observational studies investigating four ischemic cardiac biomarkers (Troponin-T, Troponin-I, CK-MB, Myoglobin) were included. One study reported a higher peak Troponin-I in patients with extubation failure compared to extubation success (50 ng/L [IQR, 20–215] versus 30 ng/L [IQR, 10–86], p = 0.01). A second study found that Troponin-I measured before the SBT was higher in patients with SBT failure in comparison to patients with SBT success (100 ± 80 ng/L versus 70 ± 130 ng/L, p = 0.03). A third study reported a higher CK-MB measured at the end of the SBT in patients with weaning failure (SBT or extubation failure) in comparison to weaning success (8.77 ± 20.5 ng/mL versus 1.52 ± 1.42 ng/mL, p = 0.047). Troponin-T and Myoglobin as well as Troponin-I and CK-MB measured at other time points were not found to be related to SBT or extubation failure. However, most studies were underpowered and with high risk of bias. Conclusions: The association with SBT or extubation failure is limited for Troponin-I and CK-MB and appears absent for Troponin-T and Myoglobin, but available studies are hampered by significant methodological drawbacks. To more definitively determine the role of ischemic cardiac biomarkers, future studies should prioritize larger sample sizes, including patients at risk of cardiac disease, using stringent SBTs and structured timing of laboratory measurements before and after SBT. Full article

A positive fluid balance may evolve to fluid overload and associate with organ dysfunctions, weaning difficulties, and increased mortality in ICU patients. We explored whether individualized fluid management, assessing fluid responsiveness via a passive leg-raising maneuver (PLR) before a spontaneous breathing trial (SBT), is associated with less extubation failure in ventilated patients with a high fluid balance admitted to the ICU after liver transplantation (LT). We recruited 15 LT patients in 2023. Their postoperative fluid balance was +4476 {3697, 5722} mL. PLR maneuvers were conducted upon ICU admission (T1) and pre SBT (T2). Cardiac index (CI) changes were recorded before and after each SBT (T3). Seven patients were fluid-responsive at T1, and twelve were responsive at T2. No significant differences occurred in hemodynamic, respiratory, and perfusion parameters between the fluid-responsive and fluid-unresponsive patients at any time. Fluid-responsive patients at T1 and T2 increased their CI during SBT from 3.1 {2.8, 3.7} to 3.7 {3.4, 4.1} mL/min/m² (p = 0.045). All fluid-responsive patients at T2 were extubated after the SBTs and consolidated extubation. Two out of three of the fluid-unresponsive patients experienced weaning difficulties. We concluded that fluid-responsive patients post LT may start weaning earlier and achieve successful extubation despite a high postoperative fluid balance. This highlights the profound impact of personalized assessments of cardiovascular state on critical surgical patients. Full article

In the past decade, automotive companies have invested significantly in autonomous vehicles (AV), but achieving widespread deployment remains a challenge in part due to the complexities of safety evaluation. Traditional distance-based testing has been shown to be expensive and time-consuming. To address this, experts have proposed scenario-based testing (SBT), which simulates detailed real-world driving scenarios to assess vehicle responses efficiently. This paper introduces a method that builds a parametric representation of a driving scenario using collected driving data. By adopting a data-driven approach, we are then able to generate realistic, concrete scenarios that correspond to high-risk situations. A reinforcement learning technique is used to identify the combination of parameter values that result in the failure of a system under test (SUT). The proposed method generates novel, simulated high-risk scenarios, thereby offering a meaningful and focused assessment of AV systems. Full article

Discontinuing mechanical ventilation remains challenging. We developed a machine learning model to predict weaning outcomes using only continuous monitoring parameters obtained from ventilators during spontaneous breathing trials (SBTs). Patients who received mechanical ventilation in the medical intensive care unit at a tertiary university hospital from 2019–2021 were included in this study. During the SBTs, three waveforms and 25 numerical data were collected as input variables. The proposed convolutional neural network (CNN)-based weaning prediction model extracts features from input data with diverse lengths. Among 138 enrolled patients, 35 (25.4%) experienced weaning failure. The dataset was randomly divided into training and test sets (8:2 ratio). The area under the receiver operating characteristic curve for weaning success by the prediction model was 0.912 (95% confidence interval [CI], 0.795–1.000), with an area under the precision-recall curve of 0.767 (95% CI, 0.434–0.983). Furthermore, we used gradient-weighted class activation mapping technology to provide visual explanations of the model’s prediction, highlighting influential features. This tool can assist medical staff by providing intuitive information regarding readiness for extubation without requiring any additional data collection other than SBT data. The proposed predictive model can assist clinicians in making ventilator weaning decisions in real time, thereby improving patient outcomes. Full article

It has now been proven that many pathogens that cause infections and inflammation gradually mutate and become resistant to antibiotics. Chemically synthesized drugs treating inflammation most often only affect symptoms, but side effects could lead to the failure of human organs’ functionality. On the other hand, plant-derived natural compounds have a long-term healing effect. It was shown that sea buckthorn (SBT) twigs are a rich source of biologically active compounds, including oligomeric proanthocyanidins (PACs). This study aimed to assess the anti-pathogenic and anti-inflammatory activity of water/ethanol extracts and PACs obtained from the lignocellulosic biomass of eight SBT cultivars. The anti-pathogenic activity of extracts and PACs was studied against pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus cereus and fungus Candida albicans in 96-well plates by the two-fold serial broth microdilution method. The anti-bacterial activity of purified PACs was 4 and 10 times higher than for water and water/ethanol extracts, respectively, but the extracts had higher anti-fungal activity. Purified PACs showed the ability to reduce IL-8 and IL-6 secretion from poly-I:C-stimulated peripheral blood mononuclear cells. For the extracts and PACs of SBT cultivar ‘Maria Bruvele’ in the concentration range 0.0313–4.0 mg/mL, no toxic effect was observed. Full article

Predicting the correct timing for extubation is pivotal for critically ill patients with mechanical ventilation support. Evidence suggests that extubation failure occurs in approximately 15–20% of patients, despite their passing of the extubation evaluation, necessitating reintubation. For critically ill patients, reintubation invariably increases mortality risk and medical costs. The numerous parameters that have been proposed for extubation decision-making, which constitute the key predictors of successful extubation, remains unclear. In this study, an extended classifier system capable of processing real-value inputs was proposed to select features of successful extubation. In total, 40 features linked to clinical information and variables acquired during spontaneous breathing trial (SBT) were used as the environmental inputs. According to the number of “don’t care” rules in a population set, Prob_usage, the probability of the feature not being classified as above rules, can be calculated. A total of 228 subjects’ results showed that Prob_usage was higher than 90% for minute ventilation at the 1st, 30th, 60th, and 90th minutes; respiratory rate at the 90th minute; and body weight, indicating that the variance in respiratory parameters during an SBT are critical predictors of successful extubation. The present XCSR model is useful to evaluate critical factors of extubation outcomes. Additionally, the current findings suggest that SBT duration should exceed 90 min, and that clinicians should consider the variance in respiratory variables during an SBT before making extubation decisions. Full article

Liberation from mechanical ventilation is of great importance owing to related complications from extended ventilation time. In this prospective multicenter study, we aimed to construct a versatile model for predicting extubation outcomes in critical care settings using obtainable physiological predictors. The study included patients who had been extubated after a successful 30 min spontaneous breathing trial (SBT). A multivariable logistic regression model was constructed to predict extubation outcomes (successful extubation without reintubation and uneventful extubation without reintubation or noninvasive respiratory support) using eight parameters: age, heart failure, respiratory disease, rapid shallow breathing index (RSBI), PaO₂/FIO₂, Glasgow Coma Scale score, fluid balance, and endotracheal suctioning episodes. Of 499 patients, 453 (90.8%) and 328 (65.7%) achieved successful and uneventful extubation, respectively. The areas under the curve for successful and uneventful extubation in the novel prediction model were 0.69 (95% confidence interval (CI), 0.62–0.77) and 0.70 (95% CI, 0.65–0.74), respectively, which were significantly higher than those in the conventional model solely using RSBI (0.58 (95% CI, 0.50–0.66) and 0.54 (95% CI, 0.49–0.60), p = 0.004 and <0.001, respectively). The model was validated using a bootstrap method, and an online application was developed for automatic calculation. Our model, which is based on a combination of generally obtainable parameters, established an accessible method for predicting extubation outcomes after a successful SBT. Full article

Venom immunotherapy (VIT) is the only efficient therapy for the Hymenoptera insect venom allergy. Immunotherapy with bee venom is encumbered with a higher risk of systemic side effects and/or therapeutic failures. The objective of the study was to assess if specific profiles of molecular IgE (Immunoglobulin E) responses are associated with an increased risk of systemic side effects and/or the treatment’s inefficacy. The study group numbered 64 bee venom allergic patients (BVA) who received venom immunotherapy modo ultra-rush (VIT-UR), (f/m: 32/32, mean age 43.4 ± 17.2). In total, 54.84% of them manifested allergic reactions of grades I-III (acc. to Mueller’s scale), while 48.66% manifested reactions of grade IV. In all the patients, IgE against bee venom extract, rApi m 1 and tryptase (sBT) were assessed. In 46 patients, assessments of IgE against rApi m 2, 3, 5, 10 were also performed. BVA patients manifesting cardiovascular symptoms (SYS IV⁰) showed higher levels of both sIgE-rApi m 5 (p = 0.03) and tryptase (p = 0.07) than patients with SYS I–III. Systemic adverse events during VIT with bee venom were more frequent in the induction phase than in the maintenance phase: 15.22% vs. 8.7%. In BVA patients who experienced systemic adverse events during VIT, higher concentrations of sIgE-rApi m 5 (p < 0.05), rApi m 1 (p = 0.009), and sBT (p = 0.019) were demonstrated. We conclude that higher levels of sIgE against rApi m 1, rApi m 5, and tryptase many constitute a potential marker of the severity of allergic reactions and therapeutic complications that can occur during VIT with bee venom. Full article

To fill the blank in the research on the dynamic performance of track structure under long-term service, the dynamic response study of China Railway Track System Ⅲ type slab ballastless track (CRTSIII SBT) under the action of fatigue for 30 million times and the parting between track slab and self-compacting concrete (SCC) was carried out. By establishing the finite element model of the CRTSIII SBT structure and taking the stiffness change of isolation layer and fastener under fatigue state and the parting during service as the research objects, combined with the full-scale model test, the dynamic response amplitude and vibration law of track structure was analyzed based on the finite element model of axle falling test method. The results show the following: (1) Under the fatigue load, the acceleration of rail and base increases obviously, the longitudinal tensile stress of SCC surface decreases, the longitudinal tensile stress of base surface increases, and the vertical stress of each layer of track structure increases as well. (2) Under the action of the parting, the dynamic response of each structural layer increases, and the change of acceleration and stress of each layer under the action point of axle falling is the most obvious. (3) The fatigue load will weaken the vibration damping performance of the track, and the parting will continue to develop under the action of the falling axle, resulting in partial or total failure of the SCC layer. Both of them will aggravate the dynamic response of the track structure and affect driving safety, which should be paid attention to during maintenance. Full article

Background and Objectives: Traditional assessment of the readiness for the weaning from the mechanical ventilator (MV) needs respiratory parameters in a spontaneous breath. Exempted from the MV disconnecting and manual measurements of weaning parameters, a prediction model based on parameters from MV and electronic medical records (EMRs) may help the assessment before spontaneous breath trials. The study aimed to develop prediction models using machine learning techniques with parameters from the ventilator and EMRs for predicting successful ventilator mode shifting in the medical intensive care unit. Materials and Methods: A retrospective analysis of 1483 adult patients with mechanical ventilators for acute respiratory failure in three medical intensive care units between April 2015 and October 2017 was conducted by machine learning techniques to establish the predicting models. The input candidate parameters included ventilator setting and measurements, patients’ demographics, arterial blood gas, laboratory results, and vital signs. Several classification algorithms were evaluated to fit the models, including Lasso Regression, Ridge Regression, Elastic Net, Random Forest, Extreme Gradient Boosting (XGBoost), Support Vector Machine, and Artificial Neural Network according to the area under the Receiver Operating Characteristic curves (AUROC). Results: Two models were built to predict the success shifting from full to partial support ventilation (WPMV model) or from partial support to the T-piece trial (sSBT model). In total, 3 MV and 13 nonpulmonary features were selected for the WPMV model with the XGBoost algorithm. The sSBT model was built with 8 MV and 4 nonpulmonary features with the Random Forest algorithm. The AUROC of the WPMV model and sSBT model were 0.76 and 0.79, respectively. Conclusions: The weaning predictions using machine learning and parameters from MV and EMRs have acceptable performance. Without manual measurements, a decision-making system would be feasible for the continuous prediction of mode shifting when the novel models process real-time data from MV and EMRs. Full article

Introduction: Septic patients undergoing mechanical ventilation (MV) often experience difficulty in weaning. Th aim of this study was to determine whether inflammatory biomarkers of sepsis could be indicative of the failure or success of spontaneous breathing trial (SBT) in these patients. Methods: Sixty-five patients on MV (42 septic and 23 intubated for other reasons) fulfilling the criteria for SBT were included in the study. Blood samples were collected right before, at the end of (30 min) and 24 h after the SBT. Serum inflammatory mediators associated with sepsis (IL-18, IL-18BP, TNF) were determined and correlated with the outcome of SBT. Results: A successful SBT was achieved in 45 patients (69.2%). Septic patients had a higher percentage of SBT failure as compared to non-septic patients (85% vs. 15%, p = 0.026), with an odds ratio for failing 4.5 times (OR = 4.5 95%CI: 1.16–17.68, p 0.022). IL-18 levels and the relative mRNA expression in serum were significantly higher in septic as compared to non-septic patients (p < 0.05). Sepsis was independently associated with higher serum IL-18 and TNF levels in two time-point GEE models (53–723, p = 0.023 and 0.3–64, p = 0.048, respectively). IL-18BP displayed independent negative association with rapid shallow breathing index (RSBI) (95% CI: −17.6 to −4, p = 0.002). Conclusion: Sustained increased levels of IL-18 and IL-18BP, acknowledged markers of sepsis, were found to be indicative of SBT failure in patients recovering from sepsis. Our results show that, although subclinical, remaining septic inflammation that sustaines for a long time complicates the weaning procedure. Biomarkers for the estimation of the septic burden and the right time for weaning are needed. Full article