Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and opera...Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.展开更多
In order to know the ventilating capacity of imperial smelt furnace(ISF), and increase the output of plumbum, an intelligent modeling method based on gray theory and artificial neural networks(ANN) is proposed, in whi...In order to know the ventilating capacity of imperial smelt furnace(ISF), and increase the output of plumbum, an intelligent modeling method based on gray theory and artificial neural networks(ANN) is proposed, in which the weight values in the integrated model can be adjusted automatically. An intelligent predictive model of the ventilating capacity of the ISF is established and analyzed by the method. The simulation results and industrial applications demonstrate that the predictive model is close to the real plant, the relative predictive error is 0.72%, which is 50% less than the single model, leading to a notable increase of the output of plumbum.展开更多
In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet s...In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis（FEA） in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.展开更多
Severe acute pancreatitis(SAP)can induce acute respiratory distress syndrome(ARDS)and abdominal compartment syndrome(ACS).Although prone position ventilation(PPV)can improve outcomes in patients with ARDS,there is sig...Severe acute pancreatitis(SAP)can induce acute respiratory distress syndrome(ARDS)and abdominal compartment syndrome(ACS).Although prone position ventilation(PPV)can improve outcomes in patients with ARDS,there is significant controversy regarding its concurrent use with ACS owing to concerns of increased risk of intra-abdominal pressure(IAP).[1]We present a case of successful PPV application without adverse eff ects.展开更多
The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,...The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.展开更多
Objective:To investigate the application effect of intelligent empowerment standardized airway management process in patients receiving mechanical ventilation.Methods:A retrospective analysis was conducted on the clin...Objective:To investigate the application effect of intelligent empowerment standardized airway management process in patients receiving mechanical ventilation.Methods:A retrospective analysis was conducted on the clinical data of 79 EICU inpatients who underwent tracheal intubation and mechanical ventilation treatment at our hospital from January 2023 to May 2025.The patients were divided into a control group(conventional airway management process,n=40)and a study group(intelligent empowerment standardized airway management process,n=39)based on the intervention protocols they received.Oral health scores,dental plaque index,oral odor,serum inflammatory markers[C-reactive protein(CRP),procalcitonin(PCT)],clinical pulmonary infection score(CPIS),as well as the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were assessed before and after treatment.Results:The baseline values of all indicators were consistent between the two groups before intervention(p>0.05).After corresponding interventions,both groups showed significant improvements in Beck oral health scores,dental plaque index,and oral odor,with more pronounced improvements observed in the study group(p<0.05).After the intervention,the research group showed a significant decrease in serum CRP and PCT levels,as well as CPIS scores(p<0.05).In contrast,the control group experienced an increase in these three indicators to a certain extent(p<0.05).Moreover,the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were all lower in the research group compared to the control group,while the nurse’s compliance rate with the protocol was higher in the research group(p<0.05).Conclusion:The standardized airway management protocol empowered by intelligent technology can significantly improve nursing compliance,benefit oral health status,reduce the risk of pulmonary infection and systemic inflammation levels,and promote rapid patient recovery,demonstrating considerable potential for widespread adoption.展开更多
Phrenic nerve stimulation(PNS)may preserve diaphragm activation and mitigate multiorgan injury during mechanical ventilation(MV);however,a minimal invasive rat model integrating PNS with MV is lacking.We established a...Phrenic nerve stimulation(PNS)may preserve diaphragm activation and mitigate multiorgan injury during mechanical ventilation(MV);however,a minimal invasive rat model integrating PNS with MV is lacking.We established an omohyoid muscle-based PNS rat model combined with MV.Bilateral nerves were exposed within 20±2 min by transection at the intermediate tendon of omohyoid muscle,minimizing trauma and bleeding.Threshold stimulation(0.6±0.2 mA)correlated with body weight.Ventilator-synchronized stimulation increased compound muscle action potentials by~30%,whereas histology confirmed intact nerve.Physiological parameters remained stable throughout ventilation.This model provides a safe and scalable platform for mechanistic and preclinical studies on PNS-mediated protection against MV-induced organ injury.展开更多
This study aims to mitigate crosswind-induced performance degradation in Natural Draft Dry Cooling Towers used in power plants by developing and assessing windbreak configurations that enhance ventilation while minimi...This study aims to mitigate crosswind-induced performance degradation in Natural Draft Dry Cooling Towers used in power plants by developing and assessing windbreak configurations that enhance ventilation while minimizing additional airflow resistance.Three novel windbreak designs,namely single-windbreak configuration with curved profile,double-windbreak configuration with curved profile,and double-windbreak configuration with inverted curved profile,are proposed accordingly and evaluated against conventional solutions.Three-dimensional numerical models of a 120 m high NDDCT equipped with these windbreaks,together with a conventional Y-shaped windbreak,are developed for systematic comparison.The results demonstrate that windbreak effectiveness strongly depends on crosswind intensity.At low crosswind speeds of 0-6 m/s,the Y-shaped windbreak provides the greatest enhancement,increasing the ventilation rate by 25.45%and the heat rejection rate by 21.37%at 6 m/s compared with the no-windbreak configuration.In contrast,under moderate to strong crosswinds of 6-18 m/s,the single-windbreak configuration with curved profile exhibits superior performance.At 18 m/s,it increases the ventilation rate by 148.88%and the heat rejection rate by 79.74%relative to the baseline case,outperforming the Y-shaped windbreak by 26.59%in ventilation rate and 17.01%in heat rejection capacity.Analysis of airflow structure,temperature fields,and velocity distributions confirms that the single-windbreak configuration with curved profile more effectively suppresses crosswind penetration and promotes stable upward airflow at higher wind speeds.Based on a comprehensive assessment of aerodynamic and thermal performance,the Y-shaped windbreak is recommended for regions where crosswind speeds remain below 6 m/s,whereas the single-windbreak configuration with curved profile is preferable for sites exposed to stronger crosswinds exceeding this threshold.展开更多
The moisture performance of building envelopes largely depends on the building materials,construction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can...The moisture performance of building envelopes largely depends on the building materials,construction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can help dehumidify the wall and indoor air.This paper presents an experimental study of the heat,air,and moisture variations within the envelope wall of a chamber featuring different air interlayer settings under real outdoor air conditions during the summer of 2020 in Shanghai,China.Self-developed humidity-controlling building mate-rials were applied to the inner building envelope.Temperature,humidity,wind velocity,and heat-flow sensors were placed at different positions in the middle of the wall.These parameters were measured and recorded in real-time under three working conditions:humidification,dehumidification,and ventilation.The experimental results show that under the ventilation working conditions,moisture content of 0.52 kg can be removed after a 2-h air layer ventilation,which can benefit the design strategy for the humidification and ventilation of dehu-midification walls.展开更多
Prediction of weaning success from invasive mechanical ventilation remains a challenge in everyday clinical practice.Several prediction scores have been developed to guide success during spontaneous breathing trials t...Prediction of weaning success from invasive mechanical ventilation remains a challenge in everyday clinical practice.Several prediction scores have been developed to guide success during spontaneous breathing trials to help with weaning decisions.These scores aim to provide a structured framework to support clinical judgment.However,their effectiveness varies across patient populations,and their predictive accuracy remains inconsistent.In this review,we aim to identify the strengths and limitations of commonly used clinical prediction tools in assessing readiness for ventilator liberation.While scores such as the Rapid Shallow Breathing Index and the Integrative Weaning Index are widely adopted,their sensitivity and specificity often fall short in complex clinical settings.Factors such as underlying disease pathophysiology,patient characteristics,and clinician subjectivity impact score performance and reliability.Moreover,disparities in validation across diverse populations limit generalizability.With growing interest in artificial intelligence(AI)and machine learning,there is potential for enhanced prediction models that integrate multidimensional data and adapt to individual patient profiles.However,current AI approaches face challenges related to interpretability,bias,and ethical implementation.This paper underscores the need for more robust,individualized,and transparent prediction systems and advocates for careful integration of emerging technologies into clinical workflows to optimize weaning success and patient outcomes.展开更多
During the train meeting events,train equipment compartments are exposed to the worst pressure changes,potentially affecting the ventilation performance of equipment,particularly for electrical facilities equipped wit...During the train meeting events,train equipment compartments are exposed to the worst pressure changes,potentially affecting the ventilation performance of equipment,particularly for electrical facilities equipped with independent air ducts.In this paper,a two-step method is used for numerical computation:(1)obtaining the temporal and spatial transient node data of the flow field sections during the train-passing simulation and(2)using the data as the input data for the equipment compartment simulation.In addition,this paper also compares the difference in equipment ventilation between the single-train and trainpassing scenarios in real vehicle tests.The results indicate that the primary factors influencing ventilation effectiveness are the aerodynamic compression and deceleration of airflow induced by the other train's nose,as well as the instability of the external flow field in the wake of the other train.During train crossing,the air is forced into the air duct,with a maximum ratio of the airflow in-duct to the airflow out-duct reaching 3.2.The average mass flow falls below the rated mass flow for the converter.Compared to the rated air volume of converter,the maximum suppression rates obtained from testing and simulation are-24.5%and-16.8%,respectively.Compared to the single-train operation,the maximum suppression rates obtained from testing and simulation are-15%and-18%,respectively.These findings provide valuable insights into the design and operation of high-speed trains.展开更多
BACKGROUND Acute respiratory distress syndrome(ARDS)is a critical condition characterized by acute hypoxemia,non-cardiogenic pulmonary edema,and decreased lung compliance.The Berlin definition,updated in 2012,classifi...BACKGROUND Acute respiratory distress syndrome(ARDS)is a critical condition characterized by acute hypoxemia,non-cardiogenic pulmonary edema,and decreased lung compliance.The Berlin definition,updated in 2012,classifies ARDS severity based on the partial pressure of arterial oxygen/fractional inspired oxygen fraction ratio.Despite various treatment strategies,ARDS remains a significant public health concern with high mortality rates.AIM To evaluate the implications of driving pressure(DP)in ARDS management and its potential as a protective lung strategy.METHODS We conducted a systematic review using databases including EbscoHost,MEDLINE,CINAHL,PubMed,and Google Scholar.The search was limited to articles published between January 2015 and September 2024.Twenty-three peer-reviewed articles were selected based on inclusion criteria focusing on adult ARDS patients undergoing mechanical ventilation and DP strategies.The literature review was conducted and reported according to PRISMA 2020 guidelines.RESULTS DP,the difference between plateau pressure and positive end-expiratory pressure,is crucial in ARDS management.Studies indicate that lower DP levels are significantly associated with improved survival rates in ARDS patients.DP is a better predictor of mortality than tidal volume or positive end-expiratory pressure alone.Adjusting DP by optimizing lung compliance and minimizing overdistension and collapse can reduce ventilator-induced lung injury.CONCLUSION DP is a valuable parameter in ARDS management,offering a more precise measure of lung stress and strain than traditional metrics.Implementing DP as a threshold for safety can enhance protective ventilation strategies,po-tentially reducing mortality in ARDS patients.Further research is needed to refine DP measurement techniques and validate its clinical application in diverse patient populations.展开更多
BACKGROUND There has been a growing interest in noninvasive ventilation(NIV)in comparison to invasive mechanical ventilation(IMV)as a standard of care for acute respiratory failure(ARF),especially in the post-covid er...BACKGROUND There has been a growing interest in noninvasive ventilation(NIV)in comparison to invasive mechanical ventilation(IMV)as a standard of care for acute respiratory failure(ARF),especially in the post-covid era,but direct head-to-head cost comparisons between the two modalities are not available in literature.AIM To compare the cost along with the clinical effectiveness of NIV in comparison to IMV in ARF.METHODS A prospective observational single-center case control study including adult patients with ARF(PaO2/FiO2 ratio<300)admitted from January 1,2024 to December 31,2024 in medical intensive care unit(ICU)of a tertiary care hospital requiring either NIV or invasive ventilation.NIV and IMV groups were compared based on average length of ICU and hospital stay,mortality,net cost of ICU treatment,need for intubation and tracheostomy.RESULTS A total of 319 patients were included in the study(197 in NIV,122 in IMV group).Statistically significant difference in length of ICU stay(NIV group:5±3.25 days,IMV group:9±2.6 days;P<0.05)and mortality rate was seen(11%NIV vs 34%IMV;P<0.01).On multivariate analyses,mortality showed a stronger association with IMV[odds ratio(OR)=7.73;95%CI:3.12-19.18]as compared to ICU stay(OR=2.73;95%CI:2.15-3.48).A total of 33 patients(17%)in NIV group required intubation of which 3 were tracheostomized,while 14 patients(11%)in IMV group needed tracheostomy.The net average cost of ICU stay was₹83902 in NIV group while in IMV group,the net ICU cost was₹476216.The average cost of ICU stay was five times higher with IMV.CONCLUSION NIV has potential economic and clinical benefits as compared to invasive ventilation in ARF.展开更多
https://www.sciencedirect.com/journal/energy-and-buildings/vol/342/suppl/C Volume 342,1 September 2025[OA](1)Experimental validation of neural network-based prediction of natural ventilation bulk airflow rate by Jo ao...https://www.sciencedirect.com/journal/energy-and-buildings/vol/342/suppl/C Volume 342,1 September 2025[OA](1)Experimental validation of neural network-based prediction of natural ventilation bulk airflow rate by Jo ao Carlos Sim oes,Guilherme Carrilho da Graca,Article115871Abstract:To fully exploit natural ventilation(NV)as an energysaving strategy in mixed-mode buildings,accurate real-time prediction of NV airflow rates is essential.Current approaches for NV airflow rates prediction often rely heavily on expertise knowledge and computationally demanding methods such as Computational Fluid Dynamics(CFD)as well as expensive and complex direct airflow measurements.展开更多
BACKGROUND A major cause of mortality in the coronavirus disease 2019(COVID-19)pandemic was acute respiratory distress syndrome(ARDS).Currently,moderate to severe ARDS induced by COVID-19(COVID ARDS)and other viral an...BACKGROUND A major cause of mortality in the coronavirus disease 2019(COVID-19)pandemic was acute respiratory distress syndrome(ARDS).Currently,moderate to severe ARDS induced by COVID-19(COVID ARDS)and other viral and non-viral etiologies are treated by traditional ARDS protocols that recommend 12-16 hours of prone position ventilation(PPV)with neuromuscular blocking agents(NMBA)and a trial of inhaled vasodilators(IVd)if oxygenation does not improve.However,debate on the efficacy of adjuncts to PPV and low tidal volume ventilation persists and evidence about the benefits of IVd/NMBA in COVID ARDS is sparse.In our multi-center retrospective review,we evaluated the impact of PPV,IVd,and NMBA on outcomes and lung mechanics in COVID ARDS patients with moderate to severe ARDS.AIM To evaluate the impact of PPV used alone or in combination with pulmonary IVd and/or NMBA in mechanically ventilated patients with moderate to severe ARDS during the COVID-19 pandemic.METHODS A retrospective study at two tertiary academic medical centers compared outcomes between COVID ARDS patients receiving PPV and patients in the supine position.PPV patients were divided based on concurrent use of ARDS adjunct therapies resulting in four subgroups:(1)PPV alone;(2)PPV and IVd;(3)PPV and NMBA;and(4)PPV,IVd,and NMBA.Primary outcomes were hospital and intensive care unit(ICU)length of stay(LOS),mortality,and venovenous extracorporeal membrane oxygenation(VV-ECMO)status.Secondary outcomes included changes in lung mechanics at 24-hour intervals for 7 days.RESULTS Total 114 patients were included in this study.Baseline respiratory parameters and Sequential Organ Failure Assessment scores were significantly worse in the PPV group.ICU LOS and LOS were significantly longer for patients who were proned,but no mortality benefit or difference in VV-ECMO status was found.Among the subgroups,no difference in primary outcomes were found.In the secondary analysis,PPV was associated with a significant improvement in arterial oxygen partial pressure(PaO_(2))/fractional inspired oxygen(FiO_(2))(P/F)ratio from day 1 to day 4(P<0.05)and higher driving pressures day 5 to day 7(P<0.05).The combination of PPV and IVd together resulted in improvements in P/F ratio from day 1 to day 7 and plateau pressure on day 4 and day 6(P<0.05).PPV with NMBA was not associated with improvements in any of the secondary outcomes.The use of all three rescue therapies together resulted in improvements in lung compliance on day 2(P<0.05)but no other improvements.CONCLUSION In mechanically ventilated patients diagnosed with moderate to severe COVID ARDS,PPV and PPV with the addition of IVd produced a significant and sustained increase in P/F ratio.The combination of PPV,IVd and NMBA improved compliance however this did not reach significance.Mortality and LOS did not improve with adjunct therapies.Further research is warranted to determine the efficacy of these therapies alone and in combination in the treatment of COVID ARDS.展开更多
BACKGROUND:In this study,we aimed to evaluate the impact of mechanical ventilator(MV)utilizaton during cardiopulmonary resuscitation(CPR)on out-of-hospital cardiac arrest(OHCA)patient clinical outcomes in the emergenc...BACKGROUND:In this study,we aimed to evaluate the impact of mechanical ventilator(MV)utilizaton during cardiopulmonary resuscitation(CPR)on out-of-hospital cardiac arrest(OHCA)patient clinical outcomes in the emergency department.METHODS:This single-centered,retrospective,case-control study analyzed electronic medical records.Patients aged>18 years with non-traumatic OHCA who were treated at an emergency medical center between January 2019 and December 2023 were included.These patients were accessed according to the ventilatory method used:MV ventilation(volume control,tidal volume 6-8 mL/kg,frequency 10 beat per minute,inspiratory time 1 s)and manual resuscitator bag valve(BV)ventilation.The primary outcome was the return of spontaneous circulation(ROSC).After 1:1 propensity score matching,the clinical outcomes were analyzed.RESULTS:A total of 649 patients were enrolled in this study.Before matching,the clinical outcomes and pneumothorax incidence did not differ between the MV and BV groups.After 1:1 matching between the two groups using propensity scores,522 patients(261 MV and 261 BV)were analyzed.Propensity score matching yielded an adequate balance(standardized mean difference<0.10)for all covariates.The estimated odds ratio(OR)for ROSC was 1.23(95%confidence interval[CI]:0.85-1.77;P=0.267),for survival at hospital admission was 1.02(95%CI:0.68-1.53;P=0.918),for survival at hospital discharge was 2.31(95%CI:1.10-5.20;P=0.033),and for good neurologic outcome was 2.56(95%CI:0.84-9.43;P=0.116).CONCLUSION:In patients with OHCA admitted to the emergency department,MV ventilation during CPR showed clinical outcomes similar to those of BV ventilation in most measures.However,survival at hospital discharge was significantly higher in the MV group,suggesting potential benefits of MV use in selected patients.展开更多
This study aimed to compare the eff ectiveness and safety of diff erent tidal volumes combined with breath-holding during inhalation for clearing airway retention,and to explore optimized strategies for preventing ven...This study aimed to compare the eff ectiveness and safety of diff erent tidal volumes combined with breath-holding during inhalation for clearing airway retention,and to explore optimized strategies for preventing ventilator-associated pneumonia(VAP).The study enrolled 105 adult patients receiving mechanical ventilation at the Emergency ICU of Dalian University of Technology Affiliated Central Hospital from April 2023 to June 2024.Using a randomized digital table method,patients were divided into three groups(A,B,C)with tidal volumes of 8ml/kg,10ml/kg,and 12ml/kg respectively.Standardized VAP prevention measures were implemented alongside daily four-time-point airway clearance through ventilator-assisted breath-holding.Results showed that Group C demonstrated significantly higher post-operation airway clearance(p<0.001)and more frequent coughing(median 3 vs.2 times)compared to Groups A and B,indicating that higher tidal volumes enhance secretions expulsion.No signifi cant diff erences were observed in airway retention characteristics(color,viscosity)among groups(p>0.05).Regarding safety,all groups maintained normal heart rate and blood pressure fl uctuations before and after procedures,with oxygenation index briefly declining but rapidly recovering without severe hypoxemia.However,Group C exhibited a higher proportion of peak airway pressure>35 cmH₂O(8.6%)compared to Groups A and B(2.9%).Clinically,Group C had a lower VAP incidence(14.2%)than Group A(22.9%)but higher than Group B(11.4%),though statistically insignifi cant(p=0.32).ICU length of stay was shorter in Group C,but this diff erence was not statistically signifi cant(p=0.15).No aspiration or suff ocation occurred across all groups.This study demonstrates that the combination of 12ml/kg tidal volume and breath-holding during inhalation can more eff ectively clear airway retention without signifi cantly increasing safety risks.We recommend prioritizing this approach for mechanically ventilated patients with adequate lung function,while adjusting tidal volume through individualized assessment.Future research should further validate long-term outcomes and evaluate its effi cacy across multiple centers.展开更多
BACKGROUND Lung ultrasonography is being increasingly used in mechanically ventilated patients to evaluate the lung aeration during incremental positive end expiratory pressure(PEEP)adjustments and to evaluate the wea...BACKGROUND Lung ultrasonography is being increasingly used in mechanically ventilated patients to evaluate the lung aeration during incremental positive end expiratory pressure(PEEP)adjustments and to evaluate the weaning process from mechanical ventilation.The effects of PEEP may vary across different lung pathologies and may not consistently correlate with changes in lung aeration as assessed by lung ultrasound scores(LUSs).AIM To assess the role of lung ultrasonography in evaluating lung aeration during the application of PEEP in mechanically ventilated patients with various lung pathologies.METHODS An observational study was conducted over 18 months in a tertiary care hospital.Patients of both genders,aged between 18-75 years,who had been admitted to the intensive care unit,and required mechanical ventilation,were studied.A standard ventilatory strategy was used and incremental levels of PEEP[5,10,and 15 cm water(H_(2)O)]were applied.Baseline characteristics,including oxygen saturation(SpO2),LUS,mean arterial pressure(MAP),heart rate(HR),and their changes with incremental PEEP levels,were recorded and analyzed.RESULTS In this study,45.9%of patients required a PEEP of 5 cm H_(2)O to achieve the endpoint of lung aeration(LUS of 0).In addition,86.5% and 13.5% of patients reached the endpoint of lung aeration at PEEP levels of 10 and 15 cm H_(2)O,respectively.The proportion of patients with higher lung scores decreased significantly with increasing PEEP levels(P<0.001 for 5 and 10 cm H_(2)O and P=0.032 for 15 cm H_(2)O).SpO2 increased significantly with higher PEEP levels(P<0.001),confirming the effectiveness of PEEP in improving oxygenation.The results also revealed a significant increase in HR and a decrease in MAP following the application of higher PEEP levels.CONCLUSION Increasing PEEP levels in mechanically ventilated patients improves lung aeration,which can be effectively assessed using bedside lung ultrasonography.展开更多
BACKGROUND Gastroesophageal reflux disease(GERD)is common among neonates,particularly those requiring mechanical ventilation.Pepsin,a reliable marker of gastric aspi-ration,may help detect GER episodes in ventilated n...BACKGROUND Gastroesophageal reflux disease(GERD)is common among neonates,particularly those requiring mechanical ventilation.Pepsin,a reliable marker of gastric aspi-ration,may help detect GER episodes in ventilated neonates and assess associated clinical outcomes.AIM To determine the incidence of GERD,associated risk factors,and morbidities among full-term mechanically ventilated neonates by detecting pepsin in endo-tracheal aspirates(ETA).METHODS This study included 97 full-term neonates admitted to the neonatal intensive care unit at Cairo University Hospitals from April 2023 to March 2024.ETA samples were collected at three intervals:Immediately post-intubation(Sample A),48 hours after intubation(Sample B),and just before extubation(Sample C).Pepsin concentration was measured using enzyme-linked immunosorbent assay.Clinical data,including hospital stay duration and feeding parameters,were correlated with pepsin levels.RESULTS Pepsin was detected in 76(78.4%)of Sample A,78(81.3%)of Sample B,and 47(68.1%)of Sample C.A significant positive correlation was found between pepsin levels and FiO_(2) in Sample B(r=0.203,P=0.047).Prolonged hospital stay was also associated with pepsin detection in Samples B and C(P<0.05).A negative correlation was observed between feeding amount and pepsin levels across all samples(P<0.05).CONCLUSION The incidence of GERD in full-term mechanically ventilated neonates is high,correlating with pepsin levels,FiO_(2),feeding intolerance,and hospital stay,highlighting the importance of early detection.展开更多
Mechanical ventilation is a specialized oxygen therapy and life support technology with significant importance for critically ill patients. In fact, 40%–66% of patients in the intensive care unit(ICU) require mechani...Mechanical ventilation is a specialized oxygen therapy and life support technology with significant importance for critically ill patients. In fact, 40%–66% of patients in the intensive care unit(ICU) require mechanical ventilation.^([1,2]) However, the mechanical ventilation can lead to ventilatorassociated lung injury(VALI),^([3]) ultimately resulting in difficulties in weaning from mechanical ventilation,prolonged hospital stays, and even increased mortality.展开更多
文摘Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.
文摘In order to know the ventilating capacity of imperial smelt furnace(ISF), and increase the output of plumbum, an intelligent modeling method based on gray theory and artificial neural networks(ANN) is proposed, in which the weight values in the integrated model can be adjusted automatically. An intelligent predictive model of the ventilating capacity of the ISF is established and analyzed by the method. The simulation results and industrial applications demonstrate that the predictive model is close to the real plant, the relative predictive error is 0.72%, which is 50% less than the single model, leading to a notable increase of the output of plumbum.
基金Project supported by the National Natural Science Foundation of China（No.51377140） the National Basic Research Program（973）of China（No.2013CB035604）
文摘In this study, we investigated the torque characteristics of large low-speed direct-drive permanent magnet synchronous generators with stator radial ventilating air ducts for offshore wind power applications. Magnet shape optimization was used first to improve the torque characteristics using two-dimensional finite element analysis（FEA） in a permanent magnet synchronous generator with a common stator. The rotor step skewing technique was then employed to suppress the impacts of mechanical tolerances and defects, which further improved the torque quality of the machine. Comprehensive three-dimensional FEA was used to evaluate accurately the overall effects of stator radial ventilating air ducts and rotor step skewing on torque features. The influences of the radial ventilating ducts in the stator on torque characteristics, such as torque pulsation and average torque in the machine with and without rotor step skewing techniques, were comprehensively investigated using three-dimensional FEA. The results showed that stator radial ventilating air ducts could not only reduce the average torque but also increase the torque ripple in the machine. Furthermore, the torque ripple of the machine under certain load conditions may even be increased by rotor step skewing despite a reduction in cogging torque.
文摘Severe acute pancreatitis(SAP)can induce acute respiratory distress syndrome(ARDS)and abdominal compartment syndrome(ACS).Although prone position ventilation(PPV)can improve outcomes in patients with ARDS,there is significant controversy regarding its concurrent use with ACS owing to concerns of increased risk of intra-abdominal pressure(IAP).[1]We present a case of successful PPV application without adverse eff ects.
基金funded by the National Natural Science Foundation of China(NSFC)under Grant No.52278415the National Key Research and Development Program of China under Grant No.2022YFC3801104+2 种基金Hebei Provincial Department of Education Project under Grant No.QN2025304the Innovation Fund Project of Hebei University of Engineering under Grant No.SJ2401002066the Sichuan Science and Technology Program under Grant No.2023YFS0407。
文摘The diversion effect caused by the linked structure in a metro tunnel with cross-passage complicates the impact of longitudinal fire source location on the smoke backflow layering behavior that has not been clarified,despite the fact that the scenario exists in practice.A series of laboratory-scale experiments were conducted in this study to investigate the smoke back-layering length in a model tunnel with cross-passage.The heat release rate,the velocity of longitudinal air flow,and the location of the fire source were all varied.It was found that the behavior of smoke backflow for the fire source located at the upstream of bifurcation point resembles a single-hole tunnel fire.As the fire source’s position shifts downstream from the bifurcation point,the length of smoke back-layering progressively increases.A competitive interaction exists between airflow diversion and smoke diversion during smoke backflow,significantly affecting the smoke back-layering length in the main tunnel.The dimensionless smoke back-layering length model was formulated in a tunnel featuring a cross-passage,taking into account the positions of longitudinal fire sources.The dimensionless smoke back-layering length exhibits a positive correlation with the 17/18 power of total heat release rate Q and a negative correlation with the 5/2 power of longitudinal ventilation velocity V.
文摘Objective:To investigate the application effect of intelligent empowerment standardized airway management process in patients receiving mechanical ventilation.Methods:A retrospective analysis was conducted on the clinical data of 79 EICU inpatients who underwent tracheal intubation and mechanical ventilation treatment at our hospital from January 2023 to May 2025.The patients were divided into a control group(conventional airway management process,n=40)and a study group(intelligent empowerment standardized airway management process,n=39)based on the intervention protocols they received.Oral health scores,dental plaque index,oral odor,serum inflammatory markers[C-reactive protein(CRP),procalcitonin(PCT)],clinical pulmonary infection score(CPIS),as well as the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were assessed before and after treatment.Results:The baseline values of all indicators were consistent between the two groups before intervention(p>0.05).After corresponding interventions,both groups showed significant improvements in Beck oral health scores,dental plaque index,and oral odor,with more pronounced improvements observed in the study group(p<0.05).After the intervention,the research group showed a significant decrease in serum CRP and PCT levels,as well as CPIS scores(p<0.05).In contrast,the control group experienced an increase in these three indicators to a certain extent(p<0.05).Moreover,the incidence of ventilator-associated pneumonia(VAP),duration of mechanical ventilation,and length of stay in the EICU were all lower in the research group compared to the control group,while the nurse’s compliance rate with the protocol was higher in the research group(p<0.05).Conclusion:The standardized airway management protocol empowered by intelligent technology can significantly improve nursing compliance,benefit oral health status,reduce the risk of pulmonary infection and systemic inflammation levels,and promote rapid patient recovery,demonstrating considerable potential for widespread adoption.
基金Outstanding Young Investigator Program of Capital Medical University,Grant/Award Number:A2308。
文摘Phrenic nerve stimulation(PNS)may preserve diaphragm activation and mitigate multiorgan injury during mechanical ventilation(MV);however,a minimal invasive rat model integrating PNS with MV is lacking.We established an omohyoid muscle-based PNS rat model combined with MV.Bilateral nerves were exposed within 20±2 min by transection at the intermediate tendon of omohyoid muscle,minimizing trauma and bleeding.Threshold stimulation(0.6±0.2 mA)correlated with body weight.Ventilator-synchronized stimulation increased compound muscle action potentials by~30%,whereas histology confirmed intact nerve.Physiological parameters remained stable throughout ventilation.This model provides a safe and scalable platform for mechanistic and preclinical studies on PNS-mediated protection against MV-induced organ injury.
基金supported by the National Natural Science Foundation of China(Grant No.52476206)the Key R&D Program of Shandong Province,China(Grant No.2025CXGC010203)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515012123)the Shandong Natural Science Foundation(Grant No.ZR2022ME008).
文摘This study aims to mitigate crosswind-induced performance degradation in Natural Draft Dry Cooling Towers used in power plants by developing and assessing windbreak configurations that enhance ventilation while minimizing additional airflow resistance.Three novel windbreak designs,namely single-windbreak configuration with curved profile,double-windbreak configuration with curved profile,and double-windbreak configuration with inverted curved profile,are proposed accordingly and evaluated against conventional solutions.Three-dimensional numerical models of a 120 m high NDDCT equipped with these windbreaks,together with a conventional Y-shaped windbreak,are developed for systematic comparison.The results demonstrate that windbreak effectiveness strongly depends on crosswind intensity.At low crosswind speeds of 0-6 m/s,the Y-shaped windbreak provides the greatest enhancement,increasing the ventilation rate by 25.45%and the heat rejection rate by 21.37%at 6 m/s compared with the no-windbreak configuration.In contrast,under moderate to strong crosswinds of 6-18 m/s,the single-windbreak configuration with curved profile exhibits superior performance.At 18 m/s,it increases the ventilation rate by 148.88%and the heat rejection rate by 79.74%relative to the baseline case,outperforming the Y-shaped windbreak by 26.59%in ventilation rate and 17.01%in heat rejection capacity.Analysis of airflow structure,temperature fields,and velocity distributions confirms that the single-windbreak configuration with curved profile more effectively suppresses crosswind penetration and promotes stable upward airflow at higher wind speeds.Based on a comprehensive assessment of aerodynamic and thermal performance,the Y-shaped windbreak is recommended for regions where crosswind speeds remain below 6 m/s,whereas the single-windbreak configuration with curved profile is preferable for sites exposed to stronger crosswinds exceeding this threshold.
基金financially supported by the National Natural Science Foundation of China(No.51778358)the Shanghai Municipality Natural Science Foundation(No.21ZR1434400)Sponsored by Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education,Chongqing University,Chongqing 400045,China(LNTCCMA-20210103).
文摘The moisture performance of building envelopes largely depends on the building materials,construction tech-niques,and exposure loads from the indoor and outdoor regions.A ventilated air interlayer placed in a wall can help dehumidify the wall and indoor air.This paper presents an experimental study of the heat,air,and moisture variations within the envelope wall of a chamber featuring different air interlayer settings under real outdoor air conditions during the summer of 2020 in Shanghai,China.Self-developed humidity-controlling building mate-rials were applied to the inner building envelope.Temperature,humidity,wind velocity,and heat-flow sensors were placed at different positions in the middle of the wall.These parameters were measured and recorded in real-time under three working conditions:humidification,dehumidification,and ventilation.The experimental results show that under the ventilation working conditions,moisture content of 0.52 kg can be removed after a 2-h air layer ventilation,which can benefit the design strategy for the humidification and ventilation of dehu-midification walls.
文摘Prediction of weaning success from invasive mechanical ventilation remains a challenge in everyday clinical practice.Several prediction scores have been developed to guide success during spontaneous breathing trials to help with weaning decisions.These scores aim to provide a structured framework to support clinical judgment.However,their effectiveness varies across patient populations,and their predictive accuracy remains inconsistent.In this review,we aim to identify the strengths and limitations of commonly used clinical prediction tools in assessing readiness for ventilator liberation.While scores such as the Rapid Shallow Breathing Index and the Integrative Weaning Index are widely adopted,their sensitivity and specificity often fall short in complex clinical settings.Factors such as underlying disease pathophysiology,patient characteristics,and clinician subjectivity impact score performance and reliability.Moreover,disparities in validation across diverse populations limit generalizability.With growing interest in artificial intelligence(AI)and machine learning,there is potential for enhanced prediction models that integrate multidimensional data and adapt to individual patient profiles.However,current AI approaches face challenges related to interpretability,bias,and ethical implementation.This paper underscores the need for more robust,individualized,and transparent prediction systems and advocates for careful integration of emerging technologies into clinical workflows to optimize weaning success and patient outcomes.
基金support by Technology R&D Program of China State Railway Group Co.,Ltd(Grant number N2022J013)the Hunan Provincial Innovation Foundation for Postgraduate(Grant number CX20220279)+1 种基金the Fundamental Research Funds for the Central Universities of Central South University(Grant number 2022ZZTS0193)China Scholarship Council(202106370112)。
文摘During the train meeting events,train equipment compartments are exposed to the worst pressure changes,potentially affecting the ventilation performance of equipment,particularly for electrical facilities equipped with independent air ducts.In this paper,a two-step method is used for numerical computation:(1)obtaining the temporal and spatial transient node data of the flow field sections during the train-passing simulation and(2)using the data as the input data for the equipment compartment simulation.In addition,this paper also compares the difference in equipment ventilation between the single-train and trainpassing scenarios in real vehicle tests.The results indicate that the primary factors influencing ventilation effectiveness are the aerodynamic compression and deceleration of airflow induced by the other train's nose,as well as the instability of the external flow field in the wake of the other train.During train crossing,the air is forced into the air duct,with a maximum ratio of the airflow in-duct to the airflow out-duct reaching 3.2.The average mass flow falls below the rated mass flow for the converter.Compared to the rated air volume of converter,the maximum suppression rates obtained from testing and simulation are-24.5%and-16.8%,respectively.Compared to the single-train operation,the maximum suppression rates obtained from testing and simulation are-15%and-18%,respectively.These findings provide valuable insights into the design and operation of high-speed trains.
文摘BACKGROUND Acute respiratory distress syndrome(ARDS)is a critical condition characterized by acute hypoxemia,non-cardiogenic pulmonary edema,and decreased lung compliance.The Berlin definition,updated in 2012,classifies ARDS severity based on the partial pressure of arterial oxygen/fractional inspired oxygen fraction ratio.Despite various treatment strategies,ARDS remains a significant public health concern with high mortality rates.AIM To evaluate the implications of driving pressure(DP)in ARDS management and its potential as a protective lung strategy.METHODS We conducted a systematic review using databases including EbscoHost,MEDLINE,CINAHL,PubMed,and Google Scholar.The search was limited to articles published between January 2015 and September 2024.Twenty-three peer-reviewed articles were selected based on inclusion criteria focusing on adult ARDS patients undergoing mechanical ventilation and DP strategies.The literature review was conducted and reported according to PRISMA 2020 guidelines.RESULTS DP,the difference between plateau pressure and positive end-expiratory pressure,is crucial in ARDS management.Studies indicate that lower DP levels are significantly associated with improved survival rates in ARDS patients.DP is a better predictor of mortality than tidal volume or positive end-expiratory pressure alone.Adjusting DP by optimizing lung compliance and minimizing overdistension and collapse can reduce ventilator-induced lung injury.CONCLUSION DP is a valuable parameter in ARDS management,offering a more precise measure of lung stress and strain than traditional metrics.Implementing DP as a threshold for safety can enhance protective ventilation strategies,po-tentially reducing mortality in ARDS patients.Further research is needed to refine DP measurement techniques and validate its clinical application in diverse patient populations.
文摘BACKGROUND There has been a growing interest in noninvasive ventilation(NIV)in comparison to invasive mechanical ventilation(IMV)as a standard of care for acute respiratory failure(ARF),especially in the post-covid era,but direct head-to-head cost comparisons between the two modalities are not available in literature.AIM To compare the cost along with the clinical effectiveness of NIV in comparison to IMV in ARF.METHODS A prospective observational single-center case control study including adult patients with ARF(PaO2/FiO2 ratio<300)admitted from January 1,2024 to December 31,2024 in medical intensive care unit(ICU)of a tertiary care hospital requiring either NIV or invasive ventilation.NIV and IMV groups were compared based on average length of ICU and hospital stay,mortality,net cost of ICU treatment,need for intubation and tracheostomy.RESULTS A total of 319 patients were included in the study(197 in NIV,122 in IMV group).Statistically significant difference in length of ICU stay(NIV group:5±3.25 days,IMV group:9±2.6 days;P<0.05)and mortality rate was seen(11%NIV vs 34%IMV;P<0.01).On multivariate analyses,mortality showed a stronger association with IMV[odds ratio(OR)=7.73;95%CI:3.12-19.18]as compared to ICU stay(OR=2.73;95%CI:2.15-3.48).A total of 33 patients(17%)in NIV group required intubation of which 3 were tracheostomized,while 14 patients(11%)in IMV group needed tracheostomy.The net average cost of ICU stay was₹83902 in NIV group while in IMV group,the net ICU cost was₹476216.The average cost of ICU stay was five times higher with IMV.CONCLUSION NIV has potential economic and clinical benefits as compared to invasive ventilation in ARF.
文摘https://www.sciencedirect.com/journal/energy-and-buildings/vol/342/suppl/C Volume 342,1 September 2025[OA](1)Experimental validation of neural network-based prediction of natural ventilation bulk airflow rate by Jo ao Carlos Sim oes,Guilherme Carrilho da Graca,Article115871Abstract:To fully exploit natural ventilation(NV)as an energysaving strategy in mixed-mode buildings,accurate real-time prediction of NV airflow rates is essential.Current approaches for NV airflow rates prediction often rely heavily on expertise knowledge and computationally demanding methods such as Computational Fluid Dynamics(CFD)as well as expensive and complex direct airflow measurements.
文摘BACKGROUND A major cause of mortality in the coronavirus disease 2019(COVID-19)pandemic was acute respiratory distress syndrome(ARDS).Currently,moderate to severe ARDS induced by COVID-19(COVID ARDS)and other viral and non-viral etiologies are treated by traditional ARDS protocols that recommend 12-16 hours of prone position ventilation(PPV)with neuromuscular blocking agents(NMBA)and a trial of inhaled vasodilators(IVd)if oxygenation does not improve.However,debate on the efficacy of adjuncts to PPV and low tidal volume ventilation persists and evidence about the benefits of IVd/NMBA in COVID ARDS is sparse.In our multi-center retrospective review,we evaluated the impact of PPV,IVd,and NMBA on outcomes and lung mechanics in COVID ARDS patients with moderate to severe ARDS.AIM To evaluate the impact of PPV used alone or in combination with pulmonary IVd and/or NMBA in mechanically ventilated patients with moderate to severe ARDS during the COVID-19 pandemic.METHODS A retrospective study at two tertiary academic medical centers compared outcomes between COVID ARDS patients receiving PPV and patients in the supine position.PPV patients were divided based on concurrent use of ARDS adjunct therapies resulting in four subgroups:(1)PPV alone;(2)PPV and IVd;(3)PPV and NMBA;and(4)PPV,IVd,and NMBA.Primary outcomes were hospital and intensive care unit(ICU)length of stay(LOS),mortality,and venovenous extracorporeal membrane oxygenation(VV-ECMO)status.Secondary outcomes included changes in lung mechanics at 24-hour intervals for 7 days.RESULTS Total 114 patients were included in this study.Baseline respiratory parameters and Sequential Organ Failure Assessment scores were significantly worse in the PPV group.ICU LOS and LOS were significantly longer for patients who were proned,but no mortality benefit or difference in VV-ECMO status was found.Among the subgroups,no difference in primary outcomes were found.In the secondary analysis,PPV was associated with a significant improvement in arterial oxygen partial pressure(PaO_(2))/fractional inspired oxygen(FiO_(2))(P/F)ratio from day 1 to day 4(P<0.05)and higher driving pressures day 5 to day 7(P<0.05).The combination of PPV and IVd together resulted in improvements in P/F ratio from day 1 to day 7 and plateau pressure on day 4 and day 6(P<0.05).PPV with NMBA was not associated with improvements in any of the secondary outcomes.The use of all three rescue therapies together resulted in improvements in lung compliance on day 2(P<0.05)but no other improvements.CONCLUSION In mechanically ventilated patients diagnosed with moderate to severe COVID ARDS,PPV and PPV with the addition of IVd produced a significant and sustained increase in P/F ratio.The combination of PPV,IVd and NMBA improved compliance however this did not reach significance.Mortality and LOS did not improve with adjunct therapies.Further research is warranted to determine the efficacy of these therapies alone and in combination in the treatment of COVID ARDS.
文摘BACKGROUND:In this study,we aimed to evaluate the impact of mechanical ventilator(MV)utilizaton during cardiopulmonary resuscitation(CPR)on out-of-hospital cardiac arrest(OHCA)patient clinical outcomes in the emergency department.METHODS:This single-centered,retrospective,case-control study analyzed electronic medical records.Patients aged>18 years with non-traumatic OHCA who were treated at an emergency medical center between January 2019 and December 2023 were included.These patients were accessed according to the ventilatory method used:MV ventilation(volume control,tidal volume 6-8 mL/kg,frequency 10 beat per minute,inspiratory time 1 s)and manual resuscitator bag valve(BV)ventilation.The primary outcome was the return of spontaneous circulation(ROSC).After 1:1 propensity score matching,the clinical outcomes were analyzed.RESULTS:A total of 649 patients were enrolled in this study.Before matching,the clinical outcomes and pneumothorax incidence did not differ between the MV and BV groups.After 1:1 matching between the two groups using propensity scores,522 patients(261 MV and 261 BV)were analyzed.Propensity score matching yielded an adequate balance(standardized mean difference<0.10)for all covariates.The estimated odds ratio(OR)for ROSC was 1.23(95%confidence interval[CI]:0.85-1.77;P=0.267),for survival at hospital admission was 1.02(95%CI:0.68-1.53;P=0.918),for survival at hospital discharge was 2.31(95%CI:1.10-5.20;P=0.033),and for good neurologic outcome was 2.56(95%CI:0.84-9.43;P=0.116).CONCLUSION:In patients with OHCA admitted to the emergency department,MV ventilation during CPR showed clinical outcomes similar to those of BV ventilation in most measures.However,survival at hospital discharge was significantly higher in the MV group,suggesting potential benefits of MV use in selected patients.
文摘This study aimed to compare the eff ectiveness and safety of diff erent tidal volumes combined with breath-holding during inhalation for clearing airway retention,and to explore optimized strategies for preventing ventilator-associated pneumonia(VAP).The study enrolled 105 adult patients receiving mechanical ventilation at the Emergency ICU of Dalian University of Technology Affiliated Central Hospital from April 2023 to June 2024.Using a randomized digital table method,patients were divided into three groups(A,B,C)with tidal volumes of 8ml/kg,10ml/kg,and 12ml/kg respectively.Standardized VAP prevention measures were implemented alongside daily four-time-point airway clearance through ventilator-assisted breath-holding.Results showed that Group C demonstrated significantly higher post-operation airway clearance(p<0.001)and more frequent coughing(median 3 vs.2 times)compared to Groups A and B,indicating that higher tidal volumes enhance secretions expulsion.No signifi cant diff erences were observed in airway retention characteristics(color,viscosity)among groups(p>0.05).Regarding safety,all groups maintained normal heart rate and blood pressure fl uctuations before and after procedures,with oxygenation index briefly declining but rapidly recovering without severe hypoxemia.However,Group C exhibited a higher proportion of peak airway pressure>35 cmH₂O(8.6%)compared to Groups A and B(2.9%).Clinically,Group C had a lower VAP incidence(14.2%)than Group A(22.9%)but higher than Group B(11.4%),though statistically insignifi cant(p=0.32).ICU length of stay was shorter in Group C,but this diff erence was not statistically signifi cant(p=0.15).No aspiration or suff ocation occurred across all groups.This study demonstrates that the combination of 12ml/kg tidal volume and breath-holding during inhalation can more eff ectively clear airway retention without signifi cantly increasing safety risks.We recommend prioritizing this approach for mechanically ventilated patients with adequate lung function,while adjusting tidal volume through individualized assessment.Future research should further validate long-term outcomes and evaluate its effi cacy across multiple centers.
文摘BACKGROUND Lung ultrasonography is being increasingly used in mechanically ventilated patients to evaluate the lung aeration during incremental positive end expiratory pressure(PEEP)adjustments and to evaluate the weaning process from mechanical ventilation.The effects of PEEP may vary across different lung pathologies and may not consistently correlate with changes in lung aeration as assessed by lung ultrasound scores(LUSs).AIM To assess the role of lung ultrasonography in evaluating lung aeration during the application of PEEP in mechanically ventilated patients with various lung pathologies.METHODS An observational study was conducted over 18 months in a tertiary care hospital.Patients of both genders,aged between 18-75 years,who had been admitted to the intensive care unit,and required mechanical ventilation,were studied.A standard ventilatory strategy was used and incremental levels of PEEP[5,10,and 15 cm water(H_(2)O)]were applied.Baseline characteristics,including oxygen saturation(SpO2),LUS,mean arterial pressure(MAP),heart rate(HR),and their changes with incremental PEEP levels,were recorded and analyzed.RESULTS In this study,45.9%of patients required a PEEP of 5 cm H_(2)O to achieve the endpoint of lung aeration(LUS of 0).In addition,86.5% and 13.5% of patients reached the endpoint of lung aeration at PEEP levels of 10 and 15 cm H_(2)O,respectively.The proportion of patients with higher lung scores decreased significantly with increasing PEEP levels(P<0.001 for 5 and 10 cm H_(2)O and P=0.032 for 15 cm H_(2)O).SpO2 increased significantly with higher PEEP levels(P<0.001),confirming the effectiveness of PEEP in improving oxygenation.The results also revealed a significant increase in HR and a decrease in MAP following the application of higher PEEP levels.CONCLUSION Increasing PEEP levels in mechanically ventilated patients improves lung aeration,which can be effectively assessed using bedside lung ultrasonography.
文摘BACKGROUND Gastroesophageal reflux disease(GERD)is common among neonates,particularly those requiring mechanical ventilation.Pepsin,a reliable marker of gastric aspi-ration,may help detect GER episodes in ventilated neonates and assess associated clinical outcomes.AIM To determine the incidence of GERD,associated risk factors,and morbidities among full-term mechanically ventilated neonates by detecting pepsin in endo-tracheal aspirates(ETA).METHODS This study included 97 full-term neonates admitted to the neonatal intensive care unit at Cairo University Hospitals from April 2023 to March 2024.ETA samples were collected at three intervals:Immediately post-intubation(Sample A),48 hours after intubation(Sample B),and just before extubation(Sample C).Pepsin concentration was measured using enzyme-linked immunosorbent assay.Clinical data,including hospital stay duration and feeding parameters,were correlated with pepsin levels.RESULTS Pepsin was detected in 76(78.4%)of Sample A,78(81.3%)of Sample B,and 47(68.1%)of Sample C.A significant positive correlation was found between pepsin levels and FiO_(2) in Sample B(r=0.203,P=0.047).Prolonged hospital stay was also associated with pepsin detection in Samples B and C(P<0.05).A negative correlation was observed between feeding amount and pepsin levels across all samples(P<0.05).CONCLUSION The incidence of GERD in full-term mechanically ventilated neonates is high,correlating with pepsin levels,FiO_(2),feeding intolerance,and hospital stay,highlighting the importance of early detection.
文摘Mechanical ventilation is a specialized oxygen therapy and life support technology with significant importance for critically ill patients. In fact, 40%–66% of patients in the intensive care unit(ICU) require mechanical ventilation.^([1,2]) However, the mechanical ventilation can lead to ventilatorassociated lung injury(VALI),^([3]) ultimately resulting in difficulties in weaning from mechanical ventilation,prolonged hospital stays, and even increased mortality.
