Objective： To explore the relationship of postoperative cognitive dysfunction （POCD） in one-lung ventilation （OLV） patients and regional cerebral oxygen saturation （rSO2）. Methods： Twenty-nine male and twenty-...Objective： To explore the relationship of postoperative cognitive dysfunction （POCD） in one-lung ventilation （OLV） patients and regional cerebral oxygen saturation （rSO2）. Methods： Twenty-nine male and twenty-one female cases of OLV received thoracic surgery, with American Standards Association （ASA） physical status being at Grades Ⅰ-Ⅲ. Neuropsychological tests were performed on the day before operation and 7 d after operation, and there was an intraoperative continuous monitoring of rSO2. The values of rSO2 before anesthesia induction （t1）, at the beginning of OLV （t2）, and at the time of OLV 30 min （t3）, OLV 60 min （t4）, the end of OLV （t5）, and the end of surgery （t6） were recorded. The intraoperative average of rSO2 （ rSO2 ）, the intraoperative minimum value of rSO2 （rSO2, rn=n）, and the reduced maximum percentage of rSO2 （rSO2, %max） when compared with the baseline value were calculated. The volume of blood loss, urine output, and the amount of fluid infusion was recorded. Results： A total of 14 patients （28%） in the 50 cases suffered from POCD. The values of mini-mental state examination （MMSE）, the digit span and the digit symbol on the 7th day after the operation for POCD in OLV patients were found to be significantly lower than those before the operation （P〈0.05）. The values of MMSE and vocabulary fluency scores were significantly lower than those in the non-POCD group （P〈0.05）. The values of rSO2 in the POCD group of OLV patients at t2 and t3 and the values of rSO2 in the non-POCD group at t2 were found to be significantly higher than those at tl （P〈0.05）. The values of rSO2, %max in the POCD group were significantly higher than those in the non-POCD group （P〈0.05）. When the value of rSO2, %max is more than 10.1%, it may act as an early warning index for cognitive function changes, Conclusions： POCD after OLV may be associated with a decline in rSO2.展开更多
Background: One-lung ventilation (OLV) is generally adopted for thoracic surgery. The systemic application of a high fraction of inspiratory oxygen (F<sub>1</sub>O<sub>2</sub>) and continuous p...Background: One-lung ventilation (OLV) is generally adopted for thoracic surgery. The systemic application of a high fraction of inspiratory oxygen (F<sub>1</sub>O<sub>2</sub>) and continuous positive airway pressure (CPAP) to the non-ventilated lung is useful for preventing arterial oxygen desaturation. The adverse effects of elevated F<sub>1</sub>O<sub>2</sub> include oxidative lung injury, resorption atelectasis and coronary and peripheral vasoconstriction. It is preferable to avoid hyperoxemia in patients with complications such as chronic obstructive pulmonary disease, idiopathic pneumonia, and bleomycin-treated lungs. We aimed to determine whether the application of 60% O<sub>2</sub> CPAP to the non-ventilated lung is sufficient to provide adequate oxygenation with 60% O<sub>2</sub> to the ventilated lung. Methods: A total of 70 patients scheduled to receive elective thoracic surgery requiring OLV were recruited. Left double-lumen tubes were applicable in all surgeries. Patients were randomly allocated to one of two groups, to receive either 60% O<sub>2</sub> CPAP (60% CPAP group, n = 35), or 100% O<sub>2</sub> CPAP (100% CPAP group, n = 35) at a setting of 2 - 3 cmH<sub>2</sub>O, applied to the non-ventilated lung. Arterial blood gas analyses were obtained at the following stages: RA, spontaneous breathing under room air (RA);TLV, during total lung ventilation (TLV) prior to the initiation of OLV;T5, 5 min after the initiation of OLV;T15, 15 min after the initiation of OLV;T30, 30 min after the initiation of OLV. Results: The PaO<sub>2</sub> value in 60% CPAP group vs. 100% CPAP group at each measurement were as follows: RA (mean [standard deviation: SD], 89.7 [8.2] mmHg vs. 85.8 [11.9] mmHg);TLV (277.9 [52.9] mmHg vs. 269.2 [44.0] mmHg);T5 (191.4 [67.9] mmHg vs. 192.3 [66.0] mmHg);T15 (143.2 [67.3] mmHg vs. 154.7 [60.8] mmHg) and T30 (95.6 [32.0] mmHg vs. 112.5 [36.5] mmHg), respectively. Among the five measurement points, T30 was the only time point at which the 100% CPAP group showed a significantly greater PaO<sub>2</sub> value than the 60% CPAP group (p = 0.0495). The SaO<sub>2</sub> at T30 in the 100% CPAP group (97.4 [2.0]%) was also significantly greater than that in the 60% CPAP group (96.3 [2.2]%, p = 0.039). No differences were found between the groups regarding changes to the overall PaO<sub>2</sub> values (p = 0.44) and SaO<sub>2</sub> values (p = 0.23) during the study period. Conclusions: Oxygenation could be safely maintained in relatively healthy patients with 60% O<sub>2</sub> OLV and 60% O<sub>2</sub> CPAP. The application of 60% O<sub>2</sub> CPAP during OLV for patients who are not suited to exposure to high F<sub>1</sub>O<sub>2</sub> may be an alternative form of respiratory management.展开更多
Fourty-eight patients (ASA physical status Ⅰ - Ⅱ) undergoing selected thoracotomy and pulmonectomy were studied. They were divided into two groups according to different respiratory modes, two-lung ventilation (TLV)...Fourty-eight patients (ASA physical status Ⅰ - Ⅱ) undergoing selected thoracotomy and pulmonectomy were studied. They were divided into two groups according to different respiratory modes, two-lung ventilation (TLV) and onelung ventilation (OLV) or TLV and OLV with a Bain cyclic system for CPAP on the side of operated lung. PETCO2 and PaCO2 were measured after 30 min TLV,30 min and 60 min OLV, and repeated TLV (R-TLV) 30 min after pulmonectomy, to evaluate the difference between PETCO2 and PaCO2 in OLV and to observethe effect of abating hypoxemia and discharge of CO2 in OLV with Bain system.Our results showed that the PaCO2 and PETCO2 in different test groups were normal though the measured values in OLV were slightly higher than that in TLV (P<0. 05) , and then they were recovered after R-TLV (P>0. 05). There was nosignificant difference between group 1. and 2. in OLV (P>0. 05). There was aclose correlation between PETCO2 and PaCO2 (P<0. 05). The differences of the calculated P(a-ET)CO2 and radio of PETCO2/PaCO2 in different ventilation modes were not significant. Hypoxemia in OLV was corrected by Bain system, but the discharge of CO2 was not affected. The results showed that measurement of PET CO2 as a non-invasive procedure can be commonly used to monitor OLV.展开更多
Objective:To study the effect of sevoflurane pretreatment combined with propofol on cerebral oxygen metabolism and inflammatory response during one-lung ventilation.Methods:A total of 92 patients who accepted pulmonar...Objective:To study the effect of sevoflurane pretreatment combined with propofol on cerebral oxygen metabolism and inflammatory response during one-lung ventilation.Methods:A total of 92 patients who accepted pulmonary lobectomy under one-lung ventilation in Changzheng Hospital Affiliated to Second Military Medical University between August 2014 and March 2016 were selected and divided into sevoflurane group and control group. Before one-lung ventilation (T1), 30 min after one-lung ventilation (T2) and 60 min after one-lung ventilation (T3), cerebral oxygen metabolism indexes and serum inflammation indexes were determined;after surgical resection, the lung tissue was collected to determine the expression of inflammatory signaling molecules and hypoxia injury molecules.Results: CjvO2 and ajdDCO2 levels as well as serum ICAM-1, IL-1β and TNF-α contents were not significantly different between two groups of patients at T1;CjvO2 levels as well as serum ICAM-1, IL-1β and TNF-α contents of sevoflurane group at T2 and T3 were significantly lower than those of control group while ajdDCO2 levels were significantly higher than those of control group;after surgical resection, TLR4, NF-kB, AQP-4, p38MAPK, HO-1, GLUT-1, HIF-1毩 and CHOP protein expression in lung tissue of sevoflurane group were significantly lower than those of control group.Conclusion:Sevoflurane pretreatment combined with propofol can improve the cerebral oxygen metabolism and inhibit the inflammatory response during one-lung ventilation.展开更多
Objective:To study the effect of sevoflurane pretreatment before one-lung ventilation on pulmonary compliance, oxygenation function and systemic inflammatory response.Methods:104 patients who accepted one-lung ventila...Objective:To study the effect of sevoflurane pretreatment before one-lung ventilation on pulmonary compliance, oxygenation function and systemic inflammatory response.Methods:104 patients who accepted one-lung ventilation operation in Mianyang Central Hospital between April 2014 and December 2015 were selected and randomly divided into the sevoflurane group who accepted sevoflurane pretreatment combined with routine anesthesia and the control group who accepted routine anesthesia, and the pulmonary compliance and oxygenation function parameters during one-lung ventilation as well as the contents of inflammatory mediators in serum and the contents of inflammation regulation molecules in alveolar lavage fluid were determined.Results: At T1, T2 and T3, Cdyn and PaO2/FiO2 levels of sevoflurane group were significantly higher than those of control group, and serum ICAM-1, IL-6, IL-8 and TNF-α contents were significantly lower than those of control group while IL-10 contents were significantly higher than those of control group;after operation, AQP-1, p38MAPK, TLR4 and NF-κB contents in collapsed alveolar lavage fluid of sevoflurane group were significantly lower than those of control group.Conclusion: Sevoflurane pretreatment before one-lung ventilation can improve the pulmonary compliance and oxygenation function, and inhibit the activation of inflammatory response.展开更多
Objective:To investigate the effect of sevoflurane pretreatment on cerebral oxygen saturation, pulmonary compliance and systemic stress response in patients with one-lung ventilation. Methods:A total of 70 patients wi...Objective:To investigate the effect of sevoflurane pretreatment on cerebral oxygen saturation, pulmonary compliance and systemic stress response in patients with one-lung ventilation. Methods:A total of 70 patients with lung cancer who accepted the selective pulmonary lobectomy in our hospital between January 2012 and December 2015 were collected and divided into observation group and control group (n=35) according to the single-blind randomized control method. After general anesthesia induction, the control group received air/oxygen mixed ventilation, and the observation group received sevoflurane pretreatment for 30 min and received one-lung ventilation after that. Immediately after anesthesia induction (T0), 30 min after sevoflurane pretreatment (T1), 60 min after sevoflurane pretreatment (T2) and at chest wall suture after operation (T3), the cerebral oxygen saturation monitor was used to determine the left and right regional cerebral oxygen saturation (rSO2);end-expiratory airway blocking method and related indexes were used to calculate the contralateral pulmonary static compliance (Cst) and pulmonary dynamic compliance (Cdyn);the RIA method was used to determine serum stress hormone levels.Results:At T0, differences in cerebral oxygen saturation, pulmonary compliance and systemic stress response were not statistically significant between two groups of patients;at T1, T2 and T3, left and right rSO2 levels of observation group were higher than those of control group, Cst and Cdyn levels were significantly higher than those of control group, and serum epinephrine (E), norepinephrine (NE), cortisol (Cor) and angiotensinⅡ (AngⅡ) levels were lower than those of control group.Conclusion:Sevoflurane pretreatment can promote the intraoperative cerebral oxygen saturation and pulmonary compliance, and reduce systemic stress response in patients with one-lung ventilation.展开更多
Objective To investigate the changes of haemodynamics, pulmonary mechanics and blood gas in volume controlled and pressure controlled ventilatory patterns during one-lung ventilation (OLV). Methods 20 patients with pa...Objective To investigate the changes of haemodynamics, pulmonary mechanics and blood gas in volume controlled and pressure controlled ventilatory patterns during one-lung ventilation (OLV). Methods 20 patients with patent ductus arteriosus ( PDA) underwent left thoracotomy PDA ligation with right OLV. The patients were divided into three groups: two-lung ventilation with volume controlled ( TLV-VCV), one-lung ventilation with volume controlled ( OLV-VCV), and one-lung ventilation with pressure controlled (OLV-PCV). After two-lung ventilation with VCV .one-lung ventilation was started by VCV and the ventilation mode was then switched to PCV. All measurements were made 25 min after initiation of the ventilation mode. The respiratory mechanics index was measured by side stream spirometry ( SSS), including peak airway pressure (Ppeak), plateau pressure (Pplat), airway resistance ( Raw), lung compliance ( Cdyn) and inspiratory and expiratory minute ventilation (Mvi, Mve). Cardiac output (CO),stroke volume展开更多
Objective: To study the effect of the adaptive intermittent ventilation before radical operation for lung cancer under one-lung ventilation on non-ventilated lung tissue injury and apoptosis molecule protein expressio...Objective: To study the effect of the adaptive intermittent ventilation before radical operation for lung cancer under one-lung ventilation on non-ventilated lung tissue injury and apoptosis molecule protein expression. Methods: A total of 288 patients who received radical operation for lung cancer in the hospital between February 2015 and January 2017 were divided into control group and observation group by random number table method, each with 144 cases. Control group received routine one-lung ventilation, and observation group received preoperative adaptive intermittent ventilation of non-ventilated lung tissue. The differences in the levels of inflammatory factors and oxidative stress indexes in serum as well as the apoptosis molecule protein expression in affected-side normal lung tissue were compared between the two groups of patients immediately after intubation and at two-lung ventilation (T0) as well as 10 min before operation ended and at one-lung ventilation (T1). Results: At T0, the differences in the levels of inflammatory factors and oxidative stress indexes in serum as well as the apoptosis molecule protein expression in affected-side normal lung tissue were not significantly significant between the two groups of patients;at T1, IL-1β, IL-8, TNF-α, MPO and MDA levels in serum as well as Bax, caspase-2 and caspase-3 protein expression in normal lung tissue of observation group were lower than those of control group while SOD level in serum and Bcl-2 protein expression in normal lung tissue were higher than those of control group. Conclusion: Adaptive intermittent ventilation before radical operation for lung cancer under one-lung ventilation can effectively reduce the non-ventilated lung tissue injury and inhibit the apoptosis of normal lung cells.展开更多
Background：One-lung ventilation （OLV） is a common ventilation technology during thoracic surgery that can cause serious clinical problems.We aimed to conduct a meta-analysis to compare oxygenation and intrapulmonar...Background：One-lung ventilation （OLV） is a common ventilation technology during thoracic surgery that can cause serious clinical problems.We aimed to conduct a meta-analysis to compare oxygenation and intrapulmonary shunt during OLV in adults undergoing thoracic surgery with dexmedetomidine （Dex） versus placebo to assess the influence and safety of using Dex.Methods：Randomized controlled trials comparing lung protection in patients who underwent thoracic surgery with Dex or a placebo were retrieved from PubMed,EMBASE,MEDLINE,Cochrane Library,and China CNKI database.The following information was extracted from the paper：arterial oxygen partial pressure （PaO2）,PaO2/inspired oxygen concentration （PaO2/FiO2,oxygenation index [OI]）,intrapulmonary shunt （calculated as Qs/Qt）,mean arterial pressure （MAP）,heart rate （HR）,tumor necrosis factor-α （TNF-α）,interleukin （IL）-6,superoxide dismutase （SOD）,and malondialdehyde （MDA）.Results：Fourteen randomized controlled trials were included containing a total of 625 patients.Compared with placebo group,Dex significantly increased PaO2/FiO2 （standard mean difference [SMD] =0.98,95% confidence interval [CI] [0.72,1.23],P 〈 0.00001）.Besides,Qs/Qt （SMD=-1.22,95% CI [-2.20,-0.23],P =0.020）,HR （SMD=-0.69,95% CI [-1.20,0.17],P =0.009）,MAP （SMD=-0.44,95% CI [-0.84,0.04],P =0.030）,the concentrations ofTNF-α （SMD =-1.55,95% CI [-2.16,-0.95],P 〈0.001）,and IL-6 （SMD =-1.53,95% CI [-2.37,-0.70],P =0.0003） were decreased in the treated group,when compared to placebo group.No significant difference was found in MDA （SMD =-1.14,95% CI [-3.48,1.20],P =0.340） and SOD （SMD =0.41,95% CI [-0.29,1.10],P =0.250） between the Dex group and the placebo group.Funnel plots did not detect any significant publication bias.Conclusions：Dex may improve OI and reduce intrapulmonary shunt during OLV in adults undergoing thoracic surgery.However,this conclusion might be weakened by the limited number of pooled studies and patients.展开更多
BACKGROUND Superimposed high-frequency jet ventilation(SHFJV)is suitable for respiratory motion reduction and essential for effective lung tumor ablation.Fluid filling of the target lung wing one-lung flooding(OLF)is ...BACKGROUND Superimposed high-frequency jet ventilation(SHFJV)is suitable for respiratory motion reduction and essential for effective lung tumor ablation.Fluid filling of the target lung wing one-lung flooding(OLF)is necessary for therapeutic ultrasound applications.However,whether unilateral SHFJV allows adequate hemodynamics and gas exchange is unclear.AIM To compared SHFJV with pressure-controlled ventilation(PCV)during OLF by assessing hemodynamics and gas exchange in different animal positions.METHODS SHFJV or PCV was used alternatingly to ventilate the non-flooded lungs of the 12 anesthetized pigs during OLF.The animal positions were changed from left lateral position to supine position(SP)to right lateral position(RLP)every 30 min.In each position,ventilation was maintained for 15 min in both modalities.Hemodynamic variables and arterial blood gas levels were repeatedly measured.RESULTS Unilateral SHFJV led to lower carbon dioxide removal than PCV without abnormally elevated carbon dioxide levels.SHFJV slightly decreased oxygenation in SP and RLP compared with PCV;the lowest values of PaO_(2) and PaO_(2)/FiO_(2) ratio were found in SP[13.0;interquartile range(IQR):12.6-5.6 and 32.5(IQR:31.5-38.9)kPa].Conversely,during SHFJV,the shunt fraction was higher in all animal positions(highest in the RLP:0.30).CONCLUSION In porcine model,unilateral SHFJV may provide adequate ventilation in different animal positions during OLF.Lower oxygenation and CO_(2) removal rates compared to PCV did not lead to hypoxia or hypercapnia.SHFJV can be safely used for lung tumor ablation to minimize ventilation-induced lung motion.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
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
A recent study on the rapid imaging of pulmonary ventilation using hyperpolarized ^(129)Xe MRI has demonstrated the ability to achieve isotropic 3D ventilation imaging with a spatial resolution of 3×3×3mm^(3...A recent study on the rapid imaging of pulmonary ventilation using hyperpolarized ^(129)Xe MRI has demonstrated the ability to achieve isotropic 3D ventilation imaging with a spatial resolution of 3×3×3mm^(3) in humans,within an acquisition time of just 3.5 seconds(https://doi.org/10.1002/mrm.30120).展开更多
With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ...With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.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
The longitudinal ventilation strategy is commonly used for road tunnels in urban environment in Sweden.This is partly due to how tunnels in urban environment was planned and designed before the EU Directive[1](2004/54...The longitudinal ventilation strategy is commonly used for road tunnels in urban environment in Sweden.This is partly due to how tunnels in urban environment was planned and designed before the EU Directive[1](2004/54/EC)came in place.Even in new tunnels both to practical and economic reasons the use of longitudinal ventilation has been an outspoken demand from the Swedish road authority,SRA.Swedish law[2]requires that a risk analysis is carried out to demonstrate that an acceptable level of risk is achieved in the tunnels with longitudinal ventilation if there is a risk of queues.Otherwise transverse or semi-transverse ventilation strategy shall be used.During recent development,or a late awakening,it is clear that dense populated areas in Sweden will experience queues.This threatens the foundation of the Swedish modern tunnel safety concept which calls for enhancement.This paper presents the risk-reducing effect of three alternative strategies,enhancements package,focusing on evacuation safety for road users.It is a combination of traffic management,fixed firefighting systems,reduced distance between escape routes and regulation of traffic with dangerous goods.In addition,it provides a comprehensive review of safety system details,combined with a longitudinal ventilation concept.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
Objective:To explore the role of lung ultrasound combined with multi-organ evaluation in assessing the risk of weaning from mechanical ventilation(MV)in severe patients.Methods:A retrospective analysis was conducted o...Objective:To explore the role of lung ultrasound combined with multi-organ evaluation in assessing the risk of weaning from mechanical ventilation(MV)in severe patients.Methods:A retrospective analysis was conducted on 60 severe patients admitted to the hospital from December 2022 to December 2024,all of whom underwent MV treatment.Based on weaning status,thirty-eight patients were successfully weaned(success group),and 22 patients failed weaning(failure group).All patients underwent lung ultrasound and multi-organ evaluation.The parameter differences between the two groups were compared,risk factors for weaning risk were evaluated,and a receiver operating characteristic curve(ROC)was drawn to assess the predictive value of lung ultrasound combined with multi-organ evaluation for weaning risk.Results:The lung ultrasound score(LUS)of the success group was lower than that of the failure group,the left ventricular ejection fraction(LVEF)was higher than that of the failure group,and the diaphragmatic excursion(DE)and diaphragmatic thickening fraction(DTF)were higher than those of the failure group(P<0.05).Multifactor analysis showed that LUS was a risk factor for weaning risk,while LVEF,DE,and DTF were protective factors(P<0.05).The ROC showed that the area under the curve(AUC)of a single parameter for weaning risk was smaller than that of the combined parameters(P<0.05).Conclusion:Lung ultrasound combined with multi-organ evaluation can predict the weaning risk of severe patients undergoing MV treatment,and the diagnostic efficiency of multiple parameters combined evaluation is higher.展开更多
Indoor air quality(IAQ)is often overlooked,yet a poorly maintained environment can lead to significant health issues and reduced concentration and productivity in work or educational settings.This study presents an in...Indoor air quality(IAQ)is often overlooked,yet a poorly maintained environment can lead to significant health issues and reduced concentration and productivity in work or educational settings.This study presents an innovative control system for mechanical ventilation specifically designed for university classrooms,with the dual goal of enhancing IAQ and increasing energy efficiency.Two classrooms with distinct construction characteristics were analyzed:one with exterior walls and windows,and the other completely underground.For each classroom,a model was developed using DesignBuilder software,which was calibrated with experimental data regarding CO_(2) concentration,temperature,and relative humidity levels.The proposed ventilation system operates based on CO_(2) concentration,relative humidity,and potential for free heating and cooling.In addition,the analysis was conducted for other locations,demonstrating consistent energy savings across different climates and environments,always showing an annual reduction in energy consumption.Results demonstrate that mechanical ventilation,when integrated with heat recovery and free cooling strategies,significantly reduces energy consumption by up to 25%,while also maintaining optimal CO_(2) levels to enhance comfort and air quality.These findings emphasize the essential need for well-designed mechanical ventilation systems to ensure both psychophysical well-being and IAQ in enclosed spaces,particularly in environments intended for extended occupancy,such as classrooms.Furthermore,this approach has broad applicability,as it could be adapted to various building types,thereby contributing to sustainable energy management practices and promoting healthier indoor spaces.This study serves as a model for future designs aiming to balance energy efficiency with indoor air quality,especially relevant in the post-COVID era,where the importance of indoor air quality has become more widely recognized.展开更多
基金supported by the Foundation of Shandong Science and Technology Project(No.2011YD18070),China
文摘Objective： To explore the relationship of postoperative cognitive dysfunction （POCD） in one-lung ventilation （OLV） patients and regional cerebral oxygen saturation （rSO2）. Methods： Twenty-nine male and twenty-one female cases of OLV received thoracic surgery, with American Standards Association （ASA） physical status being at Grades Ⅰ-Ⅲ. Neuropsychological tests were performed on the day before operation and 7 d after operation, and there was an intraoperative continuous monitoring of rSO2. The values of rSO2 before anesthesia induction （t1）, at the beginning of OLV （t2）, and at the time of OLV 30 min （t3）, OLV 60 min （t4）, the end of OLV （t5）, and the end of surgery （t6） were recorded. The intraoperative average of rSO2 （ rSO2 ）, the intraoperative minimum value of rSO2 （rSO2, rn=n）, and the reduced maximum percentage of rSO2 （rSO2, %max） when compared with the baseline value were calculated. The volume of blood loss, urine output, and the amount of fluid infusion was recorded. Results： A total of 14 patients （28%） in the 50 cases suffered from POCD. The values of mini-mental state examination （MMSE）, the digit span and the digit symbol on the 7th day after the operation for POCD in OLV patients were found to be significantly lower than those before the operation （P〈0.05）. The values of MMSE and vocabulary fluency scores were significantly lower than those in the non-POCD group （P〈0.05）. The values of rSO2 in the POCD group of OLV patients at t2 and t3 and the values of rSO2 in the non-POCD group at t2 were found to be significantly higher than those at tl （P〈0.05）. The values of rSO2, %max in the POCD group were significantly higher than those in the non-POCD group （P〈0.05）. When the value of rSO2, %max is more than 10.1%, it may act as an early warning index for cognitive function changes, Conclusions： POCD after OLV may be associated with a decline in rSO2.
文摘Background: One-lung ventilation (OLV) is generally adopted for thoracic surgery. The systemic application of a high fraction of inspiratory oxygen (F<sub>1</sub>O<sub>2</sub>) and continuous positive airway pressure (CPAP) to the non-ventilated lung is useful for preventing arterial oxygen desaturation. The adverse effects of elevated F<sub>1</sub>O<sub>2</sub> include oxidative lung injury, resorption atelectasis and coronary and peripheral vasoconstriction. It is preferable to avoid hyperoxemia in patients with complications such as chronic obstructive pulmonary disease, idiopathic pneumonia, and bleomycin-treated lungs. We aimed to determine whether the application of 60% O<sub>2</sub> CPAP to the non-ventilated lung is sufficient to provide adequate oxygenation with 60% O<sub>2</sub> to the ventilated lung. Methods: A total of 70 patients scheduled to receive elective thoracic surgery requiring OLV were recruited. Left double-lumen tubes were applicable in all surgeries. Patients were randomly allocated to one of two groups, to receive either 60% O<sub>2</sub> CPAP (60% CPAP group, n = 35), or 100% O<sub>2</sub> CPAP (100% CPAP group, n = 35) at a setting of 2 - 3 cmH<sub>2</sub>O, applied to the non-ventilated lung. Arterial blood gas analyses were obtained at the following stages: RA, spontaneous breathing under room air (RA);TLV, during total lung ventilation (TLV) prior to the initiation of OLV;T5, 5 min after the initiation of OLV;T15, 15 min after the initiation of OLV;T30, 30 min after the initiation of OLV. Results: The PaO<sub>2</sub> value in 60% CPAP group vs. 100% CPAP group at each measurement were as follows: RA (mean [standard deviation: SD], 89.7 [8.2] mmHg vs. 85.8 [11.9] mmHg);TLV (277.9 [52.9] mmHg vs. 269.2 [44.0] mmHg);T5 (191.4 [67.9] mmHg vs. 192.3 [66.0] mmHg);T15 (143.2 [67.3] mmHg vs. 154.7 [60.8] mmHg) and T30 (95.6 [32.0] mmHg vs. 112.5 [36.5] mmHg), respectively. Among the five measurement points, T30 was the only time point at which the 100% CPAP group showed a significantly greater PaO<sub>2</sub> value than the 60% CPAP group (p = 0.0495). The SaO<sub>2</sub> at T30 in the 100% CPAP group (97.4 [2.0]%) was also significantly greater than that in the 60% CPAP group (96.3 [2.2]%, p = 0.039). No differences were found between the groups regarding changes to the overall PaO<sub>2</sub> values (p = 0.44) and SaO<sub>2</sub> values (p = 0.23) during the study period. Conclusions: Oxygenation could be safely maintained in relatively healthy patients with 60% O<sub>2</sub> OLV and 60% O<sub>2</sub> CPAP. The application of 60% O<sub>2</sub> CPAP during OLV for patients who are not suited to exposure to high F<sub>1</sub>O<sub>2</sub> may be an alternative form of respiratory management.
文摘Fourty-eight patients (ASA physical status Ⅰ - Ⅱ) undergoing selected thoracotomy and pulmonectomy were studied. They were divided into two groups according to different respiratory modes, two-lung ventilation (TLV) and onelung ventilation (OLV) or TLV and OLV with a Bain cyclic system for CPAP on the side of operated lung. PETCO2 and PaCO2 were measured after 30 min TLV,30 min and 60 min OLV, and repeated TLV (R-TLV) 30 min after pulmonectomy, to evaluate the difference between PETCO2 and PaCO2 in OLV and to observethe effect of abating hypoxemia and discharge of CO2 in OLV with Bain system.Our results showed that the PaCO2 and PETCO2 in different test groups were normal though the measured values in OLV were slightly higher than that in TLV (P<0. 05) , and then they were recovered after R-TLV (P>0. 05). There was nosignificant difference between group 1. and 2. in OLV (P>0. 05). There was aclose correlation between PETCO2 and PaCO2 (P<0. 05). The differences of the calculated P(a-ET)CO2 and radio of PETCO2/PaCO2 in different ventilation modes were not significant. Hypoxemia in OLV was corrected by Bain system, but the discharge of CO2 was not affected. The results showed that measurement of PET CO2 as a non-invasive procedure can be commonly used to monitor OLV.
基金Natural Science Foundation of China No:81372103.
文摘Objective:To study the effect of sevoflurane pretreatment combined with propofol on cerebral oxygen metabolism and inflammatory response during one-lung ventilation.Methods:A total of 92 patients who accepted pulmonary lobectomy under one-lung ventilation in Changzheng Hospital Affiliated to Second Military Medical University between August 2014 and March 2016 were selected and divided into sevoflurane group and control group. Before one-lung ventilation (T1), 30 min after one-lung ventilation (T2) and 60 min after one-lung ventilation (T3), cerebral oxygen metabolism indexes and serum inflammation indexes were determined;after surgical resection, the lung tissue was collected to determine the expression of inflammatory signaling molecules and hypoxia injury molecules.Results: CjvO2 and ajdDCO2 levels as well as serum ICAM-1, IL-1β and TNF-α contents were not significantly different between two groups of patients at T1;CjvO2 levels as well as serum ICAM-1, IL-1β and TNF-α contents of sevoflurane group at T2 and T3 were significantly lower than those of control group while ajdDCO2 levels were significantly higher than those of control group;after surgical resection, TLR4, NF-kB, AQP-4, p38MAPK, HO-1, GLUT-1, HIF-1毩 and CHOP protein expression in lung tissue of sevoflurane group were significantly lower than those of control group.Conclusion:Sevoflurane pretreatment combined with propofol can improve the cerebral oxygen metabolism and inhibit the inflammatory response during one-lung ventilation.
文摘Objective:To study the effect of sevoflurane pretreatment before one-lung ventilation on pulmonary compliance, oxygenation function and systemic inflammatory response.Methods:104 patients who accepted one-lung ventilation operation in Mianyang Central Hospital between April 2014 and December 2015 were selected and randomly divided into the sevoflurane group who accepted sevoflurane pretreatment combined with routine anesthesia and the control group who accepted routine anesthesia, and the pulmonary compliance and oxygenation function parameters during one-lung ventilation as well as the contents of inflammatory mediators in serum and the contents of inflammation regulation molecules in alveolar lavage fluid were determined.Results: At T1, T2 and T3, Cdyn and PaO2/FiO2 levels of sevoflurane group were significantly higher than those of control group, and serum ICAM-1, IL-6, IL-8 and TNF-α contents were significantly lower than those of control group while IL-10 contents were significantly higher than those of control group;after operation, AQP-1, p38MAPK, TLR4 and NF-κB contents in collapsed alveolar lavage fluid of sevoflurane group were significantly lower than those of control group.Conclusion: Sevoflurane pretreatment before one-lung ventilation can improve the pulmonary compliance and oxygenation function, and inhibit the activation of inflammatory response.
文摘Objective:To investigate the effect of sevoflurane pretreatment on cerebral oxygen saturation, pulmonary compliance and systemic stress response in patients with one-lung ventilation. Methods:A total of 70 patients with lung cancer who accepted the selective pulmonary lobectomy in our hospital between January 2012 and December 2015 were collected and divided into observation group and control group (n=35) according to the single-blind randomized control method. After general anesthesia induction, the control group received air/oxygen mixed ventilation, and the observation group received sevoflurane pretreatment for 30 min and received one-lung ventilation after that. Immediately after anesthesia induction (T0), 30 min after sevoflurane pretreatment (T1), 60 min after sevoflurane pretreatment (T2) and at chest wall suture after operation (T3), the cerebral oxygen saturation monitor was used to determine the left and right regional cerebral oxygen saturation (rSO2);end-expiratory airway blocking method and related indexes were used to calculate the contralateral pulmonary static compliance (Cst) and pulmonary dynamic compliance (Cdyn);the RIA method was used to determine serum stress hormone levels.Results:At T0, differences in cerebral oxygen saturation, pulmonary compliance and systemic stress response were not statistically significant between two groups of patients;at T1, T2 and T3, left and right rSO2 levels of observation group were higher than those of control group, Cst and Cdyn levels were significantly higher than those of control group, and serum epinephrine (E), norepinephrine (NE), cortisol (Cor) and angiotensinⅡ (AngⅡ) levels were lower than those of control group.Conclusion:Sevoflurane pretreatment can promote the intraoperative cerebral oxygen saturation and pulmonary compliance, and reduce systemic stress response in patients with one-lung ventilation.
文摘Objective To investigate the changes of haemodynamics, pulmonary mechanics and blood gas in volume controlled and pressure controlled ventilatory patterns during one-lung ventilation (OLV). Methods 20 patients with patent ductus arteriosus ( PDA) underwent left thoracotomy PDA ligation with right OLV. The patients were divided into three groups: two-lung ventilation with volume controlled ( TLV-VCV), one-lung ventilation with volume controlled ( OLV-VCV), and one-lung ventilation with pressure controlled (OLV-PCV). After two-lung ventilation with VCV .one-lung ventilation was started by VCV and the ventilation mode was then switched to PCV. All measurements were made 25 min after initiation of the ventilation mode. The respiratory mechanics index was measured by side stream spirometry ( SSS), including peak airway pressure (Ppeak), plateau pressure (Pplat), airway resistance ( Raw), lung compliance ( Cdyn) and inspiratory and expiratory minute ventilation (Mvi, Mve). Cardiac output (CO),stroke volume
文摘Objective: To study the effect of the adaptive intermittent ventilation before radical operation for lung cancer under one-lung ventilation on non-ventilated lung tissue injury and apoptosis molecule protein expression. Methods: A total of 288 patients who received radical operation for lung cancer in the hospital between February 2015 and January 2017 were divided into control group and observation group by random number table method, each with 144 cases. Control group received routine one-lung ventilation, and observation group received preoperative adaptive intermittent ventilation of non-ventilated lung tissue. The differences in the levels of inflammatory factors and oxidative stress indexes in serum as well as the apoptosis molecule protein expression in affected-side normal lung tissue were compared between the two groups of patients immediately after intubation and at two-lung ventilation (T0) as well as 10 min before operation ended and at one-lung ventilation (T1). Results: At T0, the differences in the levels of inflammatory factors and oxidative stress indexes in serum as well as the apoptosis molecule protein expression in affected-side normal lung tissue were not significantly significant between the two groups of patients;at T1, IL-1β, IL-8, TNF-α, MPO and MDA levels in serum as well as Bax, caspase-2 and caspase-3 protein expression in normal lung tissue of observation group were lower than those of control group while SOD level in serum and Bcl-2 protein expression in normal lung tissue were higher than those of control group. Conclusion: Adaptive intermittent ventilation before radical operation for lung cancer under one-lung ventilation can effectively reduce the non-ventilated lung tissue injury and inhibit the apoptosis of normal lung cells.
文摘Background：One-lung ventilation （OLV） is a common ventilation technology during thoracic surgery that can cause serious clinical problems.We aimed to conduct a meta-analysis to compare oxygenation and intrapulmonary shunt during OLV in adults undergoing thoracic surgery with dexmedetomidine （Dex） versus placebo to assess the influence and safety of using Dex.Methods：Randomized controlled trials comparing lung protection in patients who underwent thoracic surgery with Dex or a placebo were retrieved from PubMed,EMBASE,MEDLINE,Cochrane Library,and China CNKI database.The following information was extracted from the paper：arterial oxygen partial pressure （PaO2）,PaO2/inspired oxygen concentration （PaO2/FiO2,oxygenation index [OI]）,intrapulmonary shunt （calculated as Qs/Qt）,mean arterial pressure （MAP）,heart rate （HR）,tumor necrosis factor-α （TNF-α）,interleukin （IL）-6,superoxide dismutase （SOD）,and malondialdehyde （MDA）.Results：Fourteen randomized controlled trials were included containing a total of 625 patients.Compared with placebo group,Dex significantly increased PaO2/FiO2 （standard mean difference [SMD] =0.98,95% confidence interval [CI] [0.72,1.23],P 〈 0.00001）.Besides,Qs/Qt （SMD=-1.22,95% CI [-2.20,-0.23],P =0.020）,HR （SMD=-0.69,95% CI [-1.20,0.17],P =0.009）,MAP （SMD=-0.44,95% CI [-0.84,0.04],P =0.030）,the concentrations ofTNF-α （SMD =-1.55,95% CI [-2.16,-0.95],P 〈0.001）,and IL-6 （SMD =-1.53,95% CI [-2.37,-0.70],P =0.0003） were decreased in the treated group,when compared to placebo group.No significant difference was found in MDA （SMD =-1.14,95% CI [-3.48,1.20],P =0.340） and SOD （SMD =0.41,95% CI [-0.29,1.10],P =0.250） between the Dex group and the placebo group.Funnel plots did not detect any significant publication bias.Conclusions：Dex may improve OI and reduce intrapulmonary shunt during OLV in adults undergoing thoracic surgery.However,this conclusion might be weakened by the limited number of pooled studies and patients.
文摘BACKGROUND Superimposed high-frequency jet ventilation(SHFJV)is suitable for respiratory motion reduction and essential for effective lung tumor ablation.Fluid filling of the target lung wing one-lung flooding(OLF)is necessary for therapeutic ultrasound applications.However,whether unilateral SHFJV allows adequate hemodynamics and gas exchange is unclear.AIM To compared SHFJV with pressure-controlled ventilation(PCV)during OLF by assessing hemodynamics and gas exchange in different animal positions.METHODS SHFJV or PCV was used alternatingly to ventilate the non-flooded lungs of the 12 anesthetized pigs during OLF.The animal positions were changed from left lateral position to supine position(SP)to right lateral position(RLP)every 30 min.In each position,ventilation was maintained for 15 min in both modalities.Hemodynamic variables and arterial blood gas levels were repeatedly measured.RESULTS Unilateral SHFJV led to lower carbon dioxide removal than PCV without abnormally elevated carbon dioxide levels.SHFJV slightly decreased oxygenation in SP and RLP compared with PCV;the lowest values of PaO_(2) and PaO_(2)/FiO_(2) ratio were found in SP[13.0;interquartile range(IQR):12.6-5.6 and 32.5(IQR:31.5-38.9)kPa].Conversely,during SHFJV,the shunt fraction was higher in all animal positions(highest in the RLP:0.30).CONCLUSION In porcine model,unilateral SHFJV may provide adequate ventilation in different animal positions during OLF.Lower oxygenation and CO_(2) removal rates compared to PCV did not lead to hypoxia or hypercapnia.SHFJV can be safely used for lung tumor ablation to minimize ventilation-induced lung motion.
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.
基金supported by the National Natural Science Foundation of China(81930049 and 82171926).
文摘A recent study on the rapid imaging of pulmonary ventilation using hyperpolarized ^(129)Xe MRI has demonstrated the ability to achieve isotropic 3D ventilation imaging with a spatial resolution of 3×3×3mm^(3) in humans,within an acquisition time of just 3.5 seconds(https://doi.org/10.1002/mrm.30120).
文摘With different structural forms of ventilation pipes have various attenuation effects on incident shock waves while meeting ventilation requirements.The attenuation mechanism and the propagation law of shock waves in ventilation pipes of different structures are investigated by experiments and numerical simulations.Furthermore,for the same structure,the effects of peak pressure and positive pressure time on the attenuation rate are discussed.It is found that the attenuation rate increases with the incident shock wave pressure,and the shock wave attenuation rate tends to reach its limiting value k for the same structure and reasonably short positive pressure time.Under the same conditions,the attenuation rate is calculated using the pressure of the shock wave as follows:diffusion chamber pipe,branch pipe and selfconsumption pipe;the attenuation rate per unit volume is calculated as follows:self-consumption pipe,branch pipe and diffusion chamber pipe.In addition,an easy method is provided to calculate the attenuation rate of the shock wave in single and multi-stage ventilation pipes.Corresponding parameters are provided for various structures,and the margin of error between the formulae and experimental results is within 10%,which is significant for engineering applications.
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The longitudinal ventilation strategy is commonly used for road tunnels in urban environment in Sweden.This is partly due to how tunnels in urban environment was planned and designed before the EU Directive[1](2004/54/EC)came in place.Even in new tunnels both to practical and economic reasons the use of longitudinal ventilation has been an outspoken demand from the Swedish road authority,SRA.Swedish law[2]requires that a risk analysis is carried out to demonstrate that an acceptable level of risk is achieved in the tunnels with longitudinal ventilation if there is a risk of queues.Otherwise transverse or semi-transverse ventilation strategy shall be used.During recent development,or a late awakening,it is clear that dense populated areas in Sweden will experience queues.This threatens the foundation of the Swedish modern tunnel safety concept which calls for enhancement.This paper presents the risk-reducing effect of three alternative strategies,enhancements package,focusing on evacuation safety for road users.It is a combination of traffic management,fixed firefighting systems,reduced distance between escape routes and regulation of traffic with dangerous goods.In addition,it provides a comprehensive review of safety system details,combined with a longitudinal ventilation concept.
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.
基金Sichuan Provincial Medical Scientific Research Project(Project No.:s19085)。
文摘Objective:To explore the role of lung ultrasound combined with multi-organ evaluation in assessing the risk of weaning from mechanical ventilation(MV)in severe patients.Methods:A retrospective analysis was conducted on 60 severe patients admitted to the hospital from December 2022 to December 2024,all of whom underwent MV treatment.Based on weaning status,thirty-eight patients were successfully weaned(success group),and 22 patients failed weaning(failure group).All patients underwent lung ultrasound and multi-organ evaluation.The parameter differences between the two groups were compared,risk factors for weaning risk were evaluated,and a receiver operating characteristic curve(ROC)was drawn to assess the predictive value of lung ultrasound combined with multi-organ evaluation for weaning risk.Results:The lung ultrasound score(LUS)of the success group was lower than that of the failure group,the left ventricular ejection fraction(LVEF)was higher than that of the failure group,and the diaphragmatic excursion(DE)and diaphragmatic thickening fraction(DTF)were higher than those of the failure group(P<0.05).Multifactor analysis showed that LUS was a risk factor for weaning risk,while LVEF,DE,and DTF were protective factors(P<0.05).The ROC showed that the area under the curve(AUC)of a single parameter for weaning risk was smaller than that of the combined parameters(P<0.05).Conclusion:Lung ultrasound combined with multi-organ evaluation can predict the weaning risk of severe patients undergoing MV treatment,and the diagnostic efficiency of multiple parameters combined evaluation is higher.
基金Funding Statement:This research was conducted as part of the Tech4You Project“Technologies for climate change adaptation and quality of life improvement”,n.ECS0000009,CUP H23C22000370006,Italian PNRR,Mission 4,Component 2,Investment 1.5 funded by the European Union-NextGenerationEU.
文摘Indoor air quality(IAQ)is often overlooked,yet a poorly maintained environment can lead to significant health issues and reduced concentration and productivity in work or educational settings.This study presents an innovative control system for mechanical ventilation specifically designed for university classrooms,with the dual goal of enhancing IAQ and increasing energy efficiency.Two classrooms with distinct construction characteristics were analyzed:one with exterior walls and windows,and the other completely underground.For each classroom,a model was developed using DesignBuilder software,which was calibrated with experimental data regarding CO_(2) concentration,temperature,and relative humidity levels.The proposed ventilation system operates based on CO_(2) concentration,relative humidity,and potential for free heating and cooling.In addition,the analysis was conducted for other locations,demonstrating consistent energy savings across different climates and environments,always showing an annual reduction in energy consumption.Results demonstrate that mechanical ventilation,when integrated with heat recovery and free cooling strategies,significantly reduces energy consumption by up to 25%,while also maintaining optimal CO_(2) levels to enhance comfort and air quality.These findings emphasize the essential need for well-designed mechanical ventilation systems to ensure both psychophysical well-being and IAQ in enclosed spaces,particularly in environments intended for extended occupancy,such as classrooms.Furthermore,this approach has broad applicability,as it could be adapted to various building types,thereby contributing to sustainable energy management practices and promoting healthier indoor spaces.This study serves as a model for future designs aiming to balance energy efficiency with indoor air quality,especially relevant in the post-COVID era,where the importance of indoor air quality has become more widely recognized.
