Search Results (33)

Objectives: Low tidal volume ventilation (LTVV) is a ventilatory strategy with the advantages of minimizing diaphragm movements and reducing hypercapnia and barotrauma risks. This preliminary study aims to report on the safety and effectiveness of LTVV applied during percutaneous US-guided liver ablations of focal malignancies. Methods: Patients affected by focal liver malignancies treated with percutaneous microwaves ablation were retrospectively included in this single-center analysis. Arterial gas analysis was performed immediately before and after ablation to evaluate the arterial pH, partial pressure of carbon dioxide (pCO₂), partial pressure of oxygen (pO₂), and plasma lactate levels. The primary endpoint of this study was to evaluate the safety and efficacy of LTVV during percutaneous liver cancer ablation. The secondary endpoint was to assess the procedural technical success in terms of correct needle probe targeting without the need for repositioning. Results: Ten patients affected by a single liver lesion had been analyzed. The ASA score was three in all patients, with three patients also suffering from COPD. The procedural technical success was 100%: ablations were performed with a single liver puncture without the need for changing access or repositioning the needle. No variations in post-ablation arterial gas analysis requiring anesthesiological management remodulation occurred. Lactate levels remained stable and hemodynamic balance was preserved during all procedures. No switch to standard volume ventilation was required. Conclusions: In this preliminary study, LTVV was a safe and effective anesthesiological protocol in patients treated with percutaneous ablations of liver malignancies, offering an ideal balance between patient safety and percutaneous needle probe positioning precision. Larger prospective studies are needed to confirm these findings. Full article

Automated ventilator controllers have the potential to simplify oxygen and carbon dioxide management for trauma. In the pre-hospital or military medicine environment, trauma care can be required for prolonged periods by personnel with limited ventilator management training. As such, there is a need for closed-loop control systems that can adapt ventilator management to a complex, ever-changing medical environment. Here, we present a novel hardware-in-loop test platform for the independent troubleshooting and evaluation of oxygen and carbon dioxide automated ventilator management capabilities. The oxygen management system provides an analogue blood oxygen signal that is responsive to the fraction of inspired oxygen and the peak inspiratory pressure ventilator settings. A tested oxygenation controller successfully reached the target oxygen saturation within 5 min. The carbon dioxide removal system integrates with commercial ventilator technology and mimics carbon dioxide generation, lung compliance, and airway resistance while providing an end-tidal carbon dioxide level that is responsive to changes in the tidal volume and respiratory rate settings. A test mechanical ventilator controller was able to regulate EtCO₂ regardless of the starting value within 10 min. This highlights the system’s functionality and provides proof-of-concept demonstrations for how the hardware-in-loop test platforms can be used for evaluating closed-loop controller technologies. Full article

Spontaneous ventilation lung surgery (SVLS) without intubation is aimed at avoiding adverse effects of mechanical ventilation lung surgery (MVLS) entailing one-lung mechanical ventilation through a double-lumen tracheal tube. This innovative strategy has evolved following the publication of a small randomized study of thoracoscopic pulmonary wedge resection carried out under spontaneous ventilation without tracheal intubation in fully awake patients. It now entails target-controlled sedation, the use of a laryngeal mask, and thoracic analgesia by intercostal or paravertebral blocks and has shown promise both in unicenter and multicenter studies, resulting in optimal feasibility and safety and highly satisfactory results, particularly in patients undergoing lung cancer resection and metastasectomy, lung biopsy for undetermined interstitial lung disease, lung volume reduction surgery for end-stage emphysema, and bullectomy for primary and secondary spontaneous pneumothorax. However, concerns and unresolved issues still exist regarding the advantages and disadvantages of SVLS as well as the identification of optimal indications. This perspective is aimed at providing a critical overview of the current knowledge about SVLS with emphasis on recent data comparing the results with those of MVLS published in the last 10 years. Full article

Background: Early prediction of ICU death in acute hypoxemic respiratory failure (AHRF) could inform clinicians for targeting therapies to reduce harm and increase survival. We sought to determine clinical modifiable and non-modifiable features during the first 24 h of AHRF associated with ICU death. Methods: This is a development, testing, and validation study using data from a prospective, multicenter, nation-based, observational cohort of 1241 patients with AHRF (defined as PaO₂/FiO₂ ≤ 300 mmHg on mechanical ventilation [MV] with positive end-expiratory pressure [PEEP] ≥ 5 cmH₂O and FiO₂ ≥ 0.3) from any etiology. Using relevant features captured at AHRF diagnosis and within 24 h, we developed a logistic regression model following variable selection by genetic algorithm and machine learning (ML) approaches. Results: We analyzed 1193 patients, after excluding 48 patients with no data at 24 h after AHRF diagnosis. Using repeated random sampling, we selected 75% (n = 900) for model development and testing, and 25% (n = 293) for final validation. Risk modeling identified six major predictors of ICU death, including patient’s age, and values at 24 h of PEEP, FiO₂, plateau pressure, tidal volume, and number of extrapulmonary organ failures. Performance with ML methods was similar to logistic regression and achieved a high area under the receiver operating characteristic curve (AUROC) of 0.88, 95%CI 0.86–0.90. Validation confirmed adequate model performance (AUROC 0.83, 95%CI 0.78–0.88). Conclusions: ML and traditional methods led to an encouraging model to predict ICU death in ventilated AHRF as early as 24 h after diagnosis. More research is needed to identify modifiable factors to prevent ICU deaths. Full article

A car cabin’s small volume makes it vulnerable to discomfort if temperature, humidity, and carbon dioxide levels are poorly regulated. In electric vehicles, the HVAC system draws energy from the car battery, reducing the driving range by several dozen kilometres under extreme conditions. A 1D simulation model calibrated for the Renault ZOE was used to evaluate the effects of ventilation parameters on thermal comfort, humidity, and power consumption. The results highlighted the interdependence of factors such as the recirculation ratio and blower flow rate, showing that energy-efficient settings depend on ambient conditions and other factors (such as occupancy, vehicle speed, infiltration). Adjustments can reduce heat pump energy use, but no single setting optimally balances power consumption and thermal comfort across all scenarios. The opti-CO₂ mode is proposed as a trade-off, offering energy savings while maintaining safety and comfort. This mode quickly achieves the cabin temperature target, limits carbon dioxide concentration at a safe level (1100 ppm), minimises fogging risks, and reduces heat pump power consumption. Compared to fresh air mode, the opti-CO₂ mode extends the driving range by 9 km in cold conditions and 26 km in hot conditions, highlighting its potential for improving energy efficiency and occupant comfort in electric vehicles. Full article

Background/Objectives: Lauric acid (LA), a medium-chain fatty acid, is a promising drug for asthma treatment. This study evaluated the toxicity of repeated doses and the effect of LA on pulmonary ventilation and tracheal reactivity in asthmatic Wistar rats and identified possible molecular targets of LA action in silico. Methods: The rats were divided into control (CG) and LA-treated groups at 100 mg/kg (AL100G) for toxicity analysis. Pulmonary ventilation and tracheal reactivity were assessed in the control (CG), asthmatic (AG), asthmatic treated with LA at 25, 50, or 100 mg/kg (AAL25G, AAL50G, and AAL100G), and dexamethasone-treated groups (ADEXAG). Results: The results showed that LA at a dose of 100 mg/kg did not cause death or toxicity. A pulmonary ventilation analysis indicated that AG had reduced minute volume, which was prevented in AAL25G. LA at all doses prevented carbachol-induced tracheal hyper-responsiveness and reduced the relaxing effect of aminophylline, as observed in AG. An in silico analysis revealed that LA had a good affinity for nine proteins (β₂-adrenergic receptor, Ca_V, BK_Ca, K_ATP, adenylyl cyclase, PKG, eNOS, iNOS, and COX-2). Conclusions: LA at 100 mg/kg has low toxicity, prevents hyper-responsiveness in an asthma model in rats, and acts as a multitarget compound with a good affinity for proteins related to airway hyper-responsiveness. Full article

Interstitial lung disease (ILD) encompasses a diverse group of parenchymal lung diseases characterized by varying degrees of inflammation and/or fibrosis. Patients with ILD frequently require hospitalization, with many needing intensive care unit (ICU) admission, most often due to respiratory failure. The diagnosis and management of ILD in the ICU present unique challenges. Diagnosis primarily relies on chest CT imaging to identify fibrosis and inflammation. Acute exacerbations, whether in idiopathic pulmonary fibrosis (IPF) or non-IPF ILD, require careful evaluation of potential triggers and differential diagnoses. Bronchoalveolar lavage may provide valuable information, such as the identification of infections, but carries risks of complications. Biopsies, whether transbronchial or surgical, can also be informative but pose significant procedural risks. Corticosteroids are the cornerstone of treatment for acute exacerbations of IPF, with higher doses potentially benefiting non-IPF ILD. Additional immunosuppressive agents may be used in cases with evidence of inflammation. Oxygen supplementation, particularly with high-flow nasal cannula, is often employed to manage severe hypoxemia, while noninvasive ventilation can be useful for worsening hypoxemia and/or hypercapnia. When mechanical ventilation is used, it is recommended to target low tidal volumes to minimize lung injury; high PEEP may be less effective and even associated with increased mortality. Prone positioning can improve oxygenation in severely hypoxemic patients. In addition to ventilatory strategies, careful fluid management and addressing concomitant pulmonary hypertension are essential components of care. Extracorporeal membrane oxygenation is a high-risk intervention reserved for the most severe cases. Lung transplantation may be considered for end-stage ILD patients in the ICU, with outcomes dependent on the urgency of transplantation and the patient’s overall condition. Managing ILD in the ICU requires a multidisciplinary approach, and despite recent advances, mortality remains high, emphasizing the need for continued research and individualized treatment strategies. Full article

The pressure difference in buildings causes indoor and outdoor airflow, significantly impacting the indoor thermal environment and building energy consumption due to the introduction of outdoor air. The pressure difference in buildings is highly variable, influenced by outdoor wind speed, indoor–outdoor temperature differences, and heating, ventilating and air conditioning (HVAC) system operation, making it difficult to consider this factor during general HVAC system operation, potentially leading to an imbalance in indoor and outdoor pressure differences. Therefore, this study proposes an appropriate operation strategy for HVAC system return fans considering indoor–outdoor pressure differences. The proposed strategy involves adjusting the return fan airflow to maintain a constant indoor airflow balance, thereby controlling the indoor–outdoor pressure difference, satisfying the indoor thermal environment, and reducing HVAC system energy consumption. To evaluate the proposed strategy, dynamic simulations using TRNSYS and TRNFLOW were utilized, targeting one floor of an office building equipped with a variable air volume (VAV) system. The evaluation results showed that the maximum pressure difference decreased from −142 Pa to −18 Pa compared to the existing strategy, and the total energy consumption of the HVAC system was reduced by 29%, highlighting the importance of considering pressure differences during HVAC system operation. Full article

An in-depth understanding of gas (oxygen and methane) seepage characteristics in coal mine goafs is essential for the safe production of mines and for advancing sustainable development practices within the mining industry. However, the gas distribution and its flow processes still remain ambiguous. In this article, we developed a three-dimensional porous media mining goaf mathematical model (considering the heterogeneity) to analyze the methane and oxygen flow features. Firstly, based on the variation laws of the “three zones”—the free caving zone, fracture zone, and subsidence zone—porosity changes in the vertical direction were set. A three-dimensional physical model of a fully mechanized caving mining area with a “U”-shaped ventilation system was established as the basis, and a COMSOL Multiphysics multi-field coupled model was built. Secondly, based on the established model, the characteristics of porosity distribution, mixed gas pressure changes, and the volume fraction of oxygen in the goaf were analyzed. The results show that as the distance from the working face increases, the compaction intensity in the mined-out area gradually rises, resulting in a decreasing porosity trend. The porosity distribution characteristics significantly impact the mechanical behavior and gas flow. The gas pressure inside the mined-out area is much higher than the surroundings, decreasing with depth. The upper and middle parts have the highest-pressure concentrations, requiring focused assessment and targeted monitoring measures based on the pressure characteristics of different regions. The oxygen concentration gradually decreases with depth due to poor ventilation, leading to potential explosive gas mixtures, necessitating ventilation system optimization, enhanced monitoring, and emergency preparedness. The gas exhibits vertical stratification, with higher concentrations in the upper and deep regions. Targeted drainage and ventilation methods can effectively control the gas concentration and ensure production safety. Full article

Background and objectives: Respiratory distress syndrome (RDS) frequently necessitates respiratory support. While non-invasive methods are typically the preferred approach, mechanical ventilation becomes necessary for patients with insufficient response. Our study aimed to compare two common respiratory support modes, volume-targeted mechanical ventilation and non-invasive ventilation continuous positive airway pressure (CPAP) and high-flow nasal cannula (HFNC), using electrical impedance tomography. Materials and Methods: Infants with very low birth weight and gestational ages of less than 32 weeks were eligible for inclusion in the study. All enrolled infants were beyond the transitional period (>72 h of age). The infants were divided into two groups: infants receiving invasive respiratory support through an endotracheal tube and infants receiving non-invasive respiratory support. We used electrical impedance tomography to assess end-expiratory lung impedance (EELZ), DeltaZ, heterogeneity, and regional ventilation distribution. Patients were evaluated at 0, 30, and 60 min after assuming the supine position to examine potential time-related effects. Results: Our study initially enrolled 97 infants, and the final analysis included a cohort of 72 infants. Ventilated infants exhibited significantly larger EELZ compared to their non-invasive counterparts (p = 0.026). DeltaZ was also greater in the invasive respiratory support group (p < 0.001). Heterogeneity was higher in the non-invasive group and did not change significantly over time. The non-invasive group demonstrated significantly greater ventilation in the dependent lung areas compared to intubated patients (p = 0.005). Regional distribution in the left lung was lower than in the right lung in both groups; however, this difference was significantly more pronounced in intubated patients (p < 0.001). Conclusions: Our study revealed that volume-targeted mechanical ventilation results in higher EELZ and DeltaZ compared to spontaneously breathing infants receiving non-invasive respiratory support. However, lung heterogeneity was lower during mechanical ventilation. Our study also reaffirmed that spontaneous breathing promotes greater involvement of the dependent lung compared to mechanical ventilation. Full article

Ventilator-induced lung injury (VILI) during mechanical ventilation (MV) has been attributed to airway remodeling involving increased airway smooth muscle cells (ASMCs), but the underlying mechanism is not fully understood. Thus, we aimed to investigate whether MV-associated high stretch (>10% strain) could modulate mechanosensitive Piezo1 expression and thereby alter cell migration of ASMCs as a potential pathway to increased ASMCs in VILI. C57BL/6 mice and ASMCs were subjected to MV at high tidal volume (V_T, 18 mL/kg, 3 h) and high stretch (13% strain, 0.5 Hz, 72 h), respectively. Subsequently, the mice or cells were evaluated for Piezo1 and integrin mRNA expression by immunohistochemical staining and quantitative PCR (qPCR), and cell migration and adhesion by transwell and cell adhesion assays. Cells were either treated or not with Piezo1 siRNA, Piezo1-eGFP, Piezo1 knockin, Y27632, or blebbistatin to regulate Piezo1 mRNA expression or inhibit Rho-associated kinase (ROCK) signaling prior to migration or adhesion assessment. We found that expression of Piezo1 in in situ lung tissue, mRNA expression of Piezo1 and integrin αVβ1 and cell adhesion of ASMCs isolated from mice with MV were all reduced but the cell migration of primary ASMCs (pASMCs) isolated from mice with MV was greatly enhanced. Similarly, cell line mouse ASMCs (mASMCs) cultured in vitro with high stretch showed that mRNA expression of Piezo1 and integrin αVβ1 and cell adhesion were all reduced but cell migration was greatly enhanced. Interestingly, such effects of MV or high stretch on ASMCs could be either induced or abolished/reversed by down/up-regulation of Piezo1 mRNA expression and inhibition of ROCK signaling. High stretch associated with MV appears to be a mechanical modulator of Piezo1 mRNA expression and can, thus, promote cell migration of ASMCs during therapeutic MV. This may be a novel mechanism of detrimental airway remodeling associated with MV, and, therefore, a potential intervention target to treat VILI. Full article

(1) Background: Our survey aimed to gather information on respiratory care in Neonatal Intensive Care Units (NICUs) in the European and Mediterranean region. (2) Methods: Cross-sectional electronic survey. An 89-item questionnaire focusing on the current modes, devices, and strategies employed in neonatal units in the domain of respiratory care was sent to directors/heads of 528 NICUs. The adherence to the “European consensus guidelines on the management of respiratory distress syndrome” was assessed for comparison. (3) Results: The response rate was 75% (397/528 units). In most Delivery Rooms (DRs), full resuscitation is given from 22 to 23 weeks gestational age. A T-piece device with facial masks or short binasal prongs are commonly used for respiratory stabilization. Initial FiO₂ is set as per guidelines. Most units use heated humidified gases to prevent heat loss. SpO₂ and ECG monitoring are largely performed. Surfactant in the DR is preferentially given through Intubation-Surfactant-Extubation (INSURE) or Less-Invasive-Surfactant-Administration (LISA) techniques. DR caffeine is widespread. In the NICUs, most of the non-invasive modes used are nasal CPAP and nasal intermittent positive-pressure ventilation. Volume-targeted, synchronized intermittent positive-pressure ventilation is the preferred invasive mode to treat acute respiratory distress. Pulmonary recruitment maneuvers are common approaches. During NICU stay, surfactant administration is primarily guided by FiO₂ and SpO₂/FiO₂ ratio, and it is mostly performed through LISA or INSURE. Steroids are used to facilitate extubation and prevent bronchopulmonary dysplasia. (4) Conclusions: Overall, clinical practices are in line with the 2022 European Guidelines, but there are some divergences. These data will allow stakeholders to make comparisons and to identify opportunities for improvement. Full article

To address the challenge of intelligently controlling air volume in regions affected by the frequent fluctuations in underground ventilation networks, a remote intelligent air regulation method based on machine learning was presented. This method encompasses three core components: local fan frequency conversion regulation, associated branch air resistance regulation, and a comprehensive integration of both. Leveraging foundational mine ventilation theory, the principles behind branch sensitivity air regulation were dissected. By applying these principles, the key performance indicators crucial for the regulation of air volume within the ventilation system were identified. Subsequently, an intelligent model for regional air volume control was constructed. To validate the approach, an experimental platform for intelligent air volume control was established, guided by geometric, dynamic, and kinematic similarity criteria. Then, the experimental methodologies for simulating various ventilation scenarios were discussed, the data acquisition techniques were introduced, and the obtained results were analyzed. Employing machine learning techniques, we utilized five distinct algorithms to predict the operational parameters of targeted air volume ventilation equipment. It enabled precise and efficient control of air volume within the region. The results indicated that the least squares support vector machine (LS-SVM) stood out by delivering high-precision predictions of target air volume ventilation equipment parameters, all while maintaining a relatively short calculation time. This swift generation of feedback data and corresponding air volume control strategies will contribute to the precise management of air volume in the area. This work served as a valuable theoretical and practical guide for intelligent mining ventilation control. Full article

Underground mines have gradually entered the stage of deep mining with the consumption of shallow mineral resources, which makes mine ventilation networks generally complicated and the problem of unstable supply of branch airflow volume in deep-level ventilation networks increasingly serious. The scientific distribution of the airflow volume between operation areas has become an important problem in the optimization of mine ventilation systems. This study takes the ventilation system of the Xinli Submine of Sanshandao Gold Mine as an example to analyze the airflow volume regulation demand of the deep-level section stope to further improve the coordination of the airflow volume distribution in the underground mine. The drawing and equivalent simplification of the ventilation network diagram are completed according to the engineering parameters of the target level roadway, and the sensitivity matrix is calculated using a formula. The optimization of the adjustment branch and the formulation of the adjustment scheme are carried out based on the sensitivity matrix. By realizing the adjustment objective of the branch airflow volume via comparing the airflow volume of the ventilation network before and after adjustment, the adjustment scheme can make the airflow volume distribution in the level more balanced. The results of our study show that branch sensitivity theory is theoretically feasible for analyzing and solving the problem of the mine ventilation network, which has certain practical significance for the adjustment of airflow volume in mines. Full article

Mechanical ventilation (MV) used in patients with acute lung injury (ALI) induces lung inflammation and causes fibroblast proliferation and excessive collagen deposition—a process termed epithelial–mesenchymal transition (EMT). Phosphoinositide 3-kinase-γ (PI3K-γ) is crucial in modulating EMT during the reparative phase of ALI; however, the mechanisms regulating the interactions among MV, EMT, and PI3K-γ remain unclear. We hypothesized that MV with or without bleomycin treatment would increase EMT through the PI3K-γ pathway. C57BL/6 mice, either wild-type or PI3K-γ-deficient, were exposed to 6 or 30 mL/kg MV for 5 h after receiving 5 mg/kg AS605240 intraperitoneally 5 days after bleomycin administration. We found that, after bleomycin exposure in wild-type mice, high-tidal-volume MV induced substantial increases in inflammatory cytokine production, oxidative loads, Masson’s trichrome staining level, positive staining of α-smooth muscle actin, PI3K-γ expression, and bronchial epithelial apoptosis (p < 0.05). Decreased respiratory function, antioxidants, and staining of the epithelial marker Zonula occludens-1 were also observed (p < 0.05). MV-augmented bleomycin-induced pulmonary fibrogenesis and epithelial apoptosis were attenuated in PI3K-γ-deficient mice, and we found pharmacological inhibition of PI3K-γ activity through AS605240 (p < 0.05). Our data suggest that MV augmented EMT after bleomycin-induced ALI, partially through the PI3K-γ pathway. Therapy targeting PI3K-γ may ameliorate MV-associated EMT. Full article