Lung Compliance Research Articles

Navigating the Regulatory Labyrinth: Compliance Dilemmas and Lead User Innovation in the Fintech Sector

Abstract This research article deals with the lead user innovation difficulties in the Kenyan financial technology sector, specifying the regulatory compliance challenges. The flourishing of fintech firms in diverse aspects and sectors have faced numerous dilemmas, particularly in intellectual property, privacy and consumer safety regulations which may lead to lack of adherence. The consequences of non-compliance can be severe, including legal penalties and reputational damage. Despite the importance of innovation in fintech companies, the dilemmas innovators face in navigating regulatory compliance is not yet fully investigated. This research adopts and employs a sequential mixed-method approach that allows complex connection of lead users and regulators in terms of compliance. Survey data from 321 lead users and in-depth interviews with 36 lead users and five regulators revealed a range of compliance challenges. Intellectual property laws scored the least adherence, with the plethora of regulations and overseeing bodies contributing to increased non-compliance. The outcomes highlight the pressing compliance issues faced by lead users and underscore the potential of regulatory bodies to bolster adherence. The outcomes indicate the need for a different approach to regulatory compliance by lead users. This paper underscores the necessity of cooperative engagement between innovators and regulators to effectively maneuver through the dynamic compliance landscape of the financial technology industry.

ALGORITHMIC GOVERNANCE IN THE REAL ESTATE AND TDR EXCHANGE OF INDIA: A STATISTICAL FRAMEWORK FOR REGULATING URBAN INFRASTRUCTURE DEVELOPMENT

This paper presents a mathematical framework for algorithmic governance within the context of the Real Estate and Transferable Development Rights (TDR) Exchange of India, addressing the challenges of urban infrastructure development. The model incorporates key components such as dynamic pricing, compliance enforcement, and optimal resource allocation, which are designed to regulate TDR transactions efficiently, transparently, and sustainably. By developing a dynamic pricing mechanism that adapts to market demand, supply, compliance with regulations, and environmental sustainability factors, this framework ensures that TDRs are allocated to areas with the highest redevelopment potential.The framework integrates regulatory enforcement mechanisms that monitor adherence to urban planning regulations and impose dynamic penalties on non-compliance. The pricing model adjusts based on the demand-supply gap and local environmental constraints, encouraging sustainable urban growth. The paper also explores a multi-objective optimization approach to TDR allocation, ensuring that redevelopment potential is maximized while maintaining environmental thresholds. The proposed algorithmic model provides a scalable solution to urban infrastructure challenges, promoting balanced growth and sustainable resource utilization in Indian cities.

Clinical effect of perioperative stellate ganglion block on mechanical ventilation and respiratory function of elderly patients with septic shock.

Here we investigated the effect of a stellate ganglion block on the perioperative mechanical ventilation and postoperative recovery of respiratory function of elderly patients with infectious shock. Thirty-six elderly patients with septic shock who underwent emergency general anesthesia at our hospital were randomly divided into treatment (T) and control (C) groups (n = 18 each). Group T received a preoperative stellate ganglion block, whereas group C received normal saline. Procalcitonin and C-reactive protein levels were compared preoperatively and at 1 and 7 days postoperative. Mean arterial pressure, oxygen saturation, and mean pulmonary artery pressure were measured preoperative and postoperative as well as at 1 and 7 days later. A blood gas analysis was performed preoperatively, at the end of the operation, during extubation, and at 1 and 7 days postoperative. Intubation under general anesthesia, the completion of anesthesia, and spontaneous respiratory recovery involve pulmonary dynamic compliance, plateau pressure, and mechanical ventilation. General condition did not differ significantly between groups (P > .05). However, mean arterial pressure at the end of surgery and at 1 and 7 days postoperative were significantly higher in group T versus C (P < .05). Furthermore, mean oxygen saturation at the end of surgery and at 1 and 7 days postoperative was significantly lower in group T versus C (P < .05), while procalcitonin and C-reactive protein levels were significantly lower at 1 and 7 days postoperative. Group T had significantly better arterial partial pressure of carbon dioxide, partial pressure of oxygen, and partial pressure of oxygen/fraction of inspired oxygen than group C at the end of surgery, during extubation, and at 1 and 7 days postoperative (P < .05). Group T exhibited superior inflammatory responses and respiratory function. Stellate ganglion block in elderly patients with septic shock reduces inflammation, improves mechanical ventilation perioperatively, and promotes postoperative recovery and respiratory function.

Tidal volume selection in volume-controlled ventilation guided by driving pressure versus actual body weight in healthy anesthetized and mechanically ventilated dogs: A randomized crossover trial

ObjectiveTo compare static compliance of the respiratory system (CstRS) and the ratio of partial pressure of end-tidal to arterial carbon dioxide (Pe′CO2/PaCO2), in healthy dogs using two approaches for tidal volume (VT) selection during volume-controlled ventilation: body mass based and driving pressure (ΔPaw) guided. Study designRandomized, nonblinded, crossover, clinical trial. AnimalsA total of 19 client-owned dogs anesthetized for castration and ovariohysterectomy. MethodsAfter a stable 10 minute baseline, each dog was mechanically ventilated with a VT selection strategy, randomized to a constant VT of 15 mL kg–1 of actual body mass (VTBW) or ΔPaw-guided VT (VTΔP) of 7–8 cmH2O. Both strategies used an inspiratory time of 1 second, 20% end-inspiratory pause, 4 cmH2O positive end-expiratory pressure and fraction of inspired oxygen of 0.4. Respiratory frequency was adjusted to maintain Pe′CO2 between 35 and 40 mmHg. Respiratory mechanics, arterial blood gases and Pe′CO2/PaCO2 were assessed. Continuous variables are presented as mean ± SD or median (interquartile range; quartiles 1–3), depending on distribution, and compared with Wilcoxon signed-rank tests. ResultsThe VT was significantly higher in dogs ventilated with VTΔP than with VTBW strategy (17.20 ± 4.04 versus 15.03 ± 0.60 mL kg–1, p = 0.036). CstRS was significantly higher with VTΔP than with VTBW strategy [2.47 (1.86–2.86) versus 2.25 (1.79–2.58) mL cmH2O−1 kg–1, p = 0.011]. There were no differences in Pe′CO2/PaCO2 between VTΔP and VTBW strategies (0.94 ± 0.06 versus 0.92 ± 0.06, p = 0.094). No discernible difference in ΔPaw was noted between the strategies. Conclusions and clinical relevanceWhile no apparent difference was observed in the Pe′CO2/PaCO2 between the VT selection strategies employed, CstRS significantly increased during the VTΔP approach. A future trial should explore if VTΔP improves perioperative gas exchange and prevents lung damage.

Cardiopulmonary effects of apneustic anesthesia ventilation in anesthetized pigs: a new mode of ventilation for anesthetized veterinary species

ObjectiveTo compare the cardiopulmonary effects of apneustic anesthesia ventilation (AAV) and conventional mechanical ventilation (CMV) in anesthetized pigs and to describe a new mode of ventilation for anesthetized veterinary species.Study designRandomized, crossover design without washout.AnimalsTwelve healthy, female white Landrace pigs.MethodsFollowing ketamine-midazolam premedication and anesthetic induction with propofol, the trachea was intubated, and each pig was positioned in dorsal recumbency. Anesthesia was maintained with propofol and sufentanil infusions. Pigs were instrumented and their lungs were sequentially ventilated with each mode, in random order, for 1 h according to predefined criteria [fraction of inspired oxygen (FiO2) = 0.21, 10 mL kg−1 tidal volume (VT), and arterial carbon dioxide tension (PaCO2) within 40–45 mmHg]. Cardiopulmonary data were collected at baseline, 30 and 60 min. In 8 pigs, thoracic computed tomography (CT) was performed following the 60 min time point for each mode of ventilation and images were analyzed to quantify lung aeration. The effects of ventilation mode, time, and order were analyzed using repeated measures ANOVA. Paired t-tests were used to compare lung aeration between modes. Significance was defined as p &amp;lt; 0.05.ResultsData from 12 pigs were analyzed. A significant effect of mode was found for heart rate, mean arterial pressure (MAP), pulmonary artery occlusion pressure, cardiac index (CI), stroke volume index, systemic vascular resistance, pulmonary vascular resistance, oxygen delivery index (DO2I), oxygen extraction ratio (O2ER), VT, arterial oxygen tension, arterial hemoglobin saturation, PaCO2, end-tidal carbon dioxide tension, alveolar dead space (VDalv/VTalv), venous admixture (Q.s/Q.t), mean airway pressure, and dynamic compliance index (CRSI). Order effects were also observed for some cardiovascular and respiratory variables. For the eight pigs that underwent thoracic CT, AAV resulted in significantly larger proportions of normally and hyperaerated lung while CMV resulted in larger proportions of hypoaerated and atelectatic lung.ConclusionsIn dorsally recumbent anesthetized pigs, ventilated with FiO2 = 0.21, both modes of ventilation supported adequate oxygenation while AAV resulted in higher CRSI, and lower VDalv/VTalv and Q.s/Q.t, compared with CMV. AAV was also associated with lower MAP, CI, and DO2I and higher O2ER compared with CMV. Further investigation of AAV in anesthetized animals is warranted.

Development of a Digital Model for Predicting the Variation in Bearing Preload and Dynamic Characteristics of a Milling Spindle under Thermal Effects

The spindle tool is an important module of the machine tool. Its dynamic characteristics directly affect the machining performance, but it could also be affected by thermal deformation and bearing preload. However, it is difficult to detect the change in the bearing preload through sensory instruments. Therefore, this study aimed to establish a digital thermal–mechanical model to investigate the thermal-induced effects on the spindle tool system. The technologies involved include the following: Run-in experiments of the milling spindle at different speeds, the establishment of the thermal–mechanical model, identification of the thermal parameters, and prediction of the thermal-induced preload of bearings in the spindle. The speed-dependent thermal parameters were identified from thermal analysis through comparisons with transient temperature history, which were further used to model the thermal effects on the bearing preload and dynamic compliance of the milling spindle under different operating speeds. Current results of thermal–mechanical analysis also indicate that the internal temperature of the bearing can reach 40 °C, and the thermal elongation of the spindle tool is about 27 µm. At the steady state temperature of 15,000 rpm, the bearing preload is reduced by 40%, which yields a decrease in the bearing rigidity by approximately 16%. This, in turn, increases the dynamic compliance of the spindle tool by 22%. Comparisons of the experimental measurements and modeling data show that the variation in bearing preload substantially affects the modal frequency and stiffness of the spindle. These findings demonstrated that the proposed digital spindle model accurately mirrors real spindle characteristics, offering a foundation for monitoring performance changes and refining design, especially in bearing configuration and cooling systems.

Pulmo-protection of long-term swimming exercise via improving insulin sensitivity in monocrotaline-induced pulmonary hypertensive rats

Exercise has been recognized as an effective intervention in the treatment of pulmonary arterial hypertension (PAH), supported by numerous studies. However, the precise effects of exercise on pulmonary function remain to be fully elucidated. In this study, using a rat model of swimming exercise training and monocrotaline-induced PAH, we aimed to explore its impact on pulmonary morphology and function. Our investigations revealed that MCT-treated rats exhibited augmented mean pulmonary arterial pressure (MPAP) and pulmonary vascular remodeling, which can be attenuated by 4 weeks of swimming exercise training (60 min/day, 5 days/week). Notably, MCT-treated rats showed impaired pulmonary function, as manifested by decreased tidal volume and dynamic compliance, which were reversed by exercise training. Assessment of pulmonary substrate in PAH rats indicated a prominent pro-inflammatory substrate, evidenced by macrophage accumulation through quantitative immunohistological analysis of macrophage-like cell expression (CD68), and extracellular matrix remodeling, evaluated by Masson staining. Importantly, both the pro-inflammatory substrate and extracellular matrix remodeling were ameliorated by swimming exercise training. Additionally, serum biochemical analysis demonstrated elevated levels of low-density lipoprotein cholesterol and Apolipoprotein B following MCT treatment, which were reduced with exercise intervention. Moreover, exercise enhanced systemic insulin sensitivity in both MCT-treated and untreated rats. Notably, MCT and exercise treatment both decreased fasting blood glucose (FBG) levels in rats, whereas exercise training reinstated FBG levels to normal in MCT-treated rats. In summary, our study suggests that swimming exercise confers a pulmonary protective effect in MCT-induced PAH rats, highlighting the potential importance of exercise-based rehabilitation in the management of PAH.

Assessment of Autoregulation of the Cerebral Circulation during Acute Lung Injury in a Neonatal Porcine Model.

In neonates with acute lung injury (ALI), targeting lower oxygenation saturations is suggested to limit oxygen toxicity while maintaining vital organ function. Although thresholds for cerebral autoregulation are studied for the management of premature infants, the impact of hypoxia on hemodynamics, tissue oxygen consumption and extraction is not well understood in term infants with ALI. We examined hemodynamics, cerebral autoregulation and fractional oxygen extraction, as measured by near-infrared spectroscopy (NIRS) and blood gases, in a neonatal porcine oleic acid injury model of moderate ALI. We hypothesized that in ALI animals, cerebral oxygen extraction would be increased to a greater degree than kidney or gut oxygen extraction as indicative of the brain's adaptive efforts to increase cerebral oxygen extraction at the expense of splanchnic end organs. Fifteen anesthetized, ventilated 5-day-old neonatal piglets were divided into moderate lung injury by treatment with oleic acid or control (sham injection). The degree of lung injury was quantified at baseline and after establishment of ALI by blood gases, ventilation parameters and calculated oxygenation deficit, hemodynamic indices by echocardiography and lung injury score by ultrasound. PaCO2 was maintained constant during ventilation. Cerebral, renal and gut oxygenation was determined by NIRS during stepwise decreases in inspired oxygen from 50% to 21%, correlated with PaO2 and PvO2; changes in fractional oxygen extraction (ΔFOE) were calculated from NIRS and from regional blood gas samples. The proportion of cerebral autoregulation impairment attributable to blood pressure, and to hypoxemia, was calculated from autoregulation nomograms. ALI manifested as hypoxemia with increasing intrapulmonary shunt fraction, decreased lung compliance and increased resistance, and marked increase in lung ultrasound score. Brain, gut and renal NIRS, obtained from probes placed over the anterior skull, central abdomen and flank, respectively, correlated with concurrent SVC (brain) or IVC (gut, renal) PvO2 and SvO2. Cerebral autoregulation was impaired after ALI as a function of blood pressure at all FiO2 steps, but predominantly by hypoxemia at FiO2 < 40%. Cerebral ΔFOE was higher in ALI animals at all FiO2 steps. We conclude that in an animal model of neonatal ALI, cerebrovascular blood flow regulation is primarily dependent on oxygenation. There is not a defined oxygenation threshold below which cerebral autoregulation is impaired in ALI. Cerebral oxygen extraction is enhanced in ALI, reflecting compensation for exhausted cerebral autoregulation due to the degree of hypoxemia and/or hypotension, thereby protecting against tissue hypoxia.

Manual and ventilator hyperinflation parameters used by intensive care physiotherapists in Sri Lanka: An online survey.

Hyperinflation is a common procedure to clear secretion, increase lung compliance and enhance oxygenation in mechanically ventilated patients. Hyperinflation can be provided as manual hyperinflation (MHI) or ventilator hyperinflation (VHI), where outcomes depend upon the methods of application. Hence it is crucial to assess the application of techniques employed in Sri Lanka due to observed variations from recommended practices. This study is aimed to evaluate the application and parameters used for MHI and VHI by physiotherapists in intensive care units (ICUs) in Sri Lanka. An online survey was conducted among physiotherapists who are working in ICUs in Sri Lanka using WhatsApp groups and other social media platforms. A total of 96 physiotherapists responded. The survey comprised of three sections to obtain information about socio-demographic data, MHI practices and VHI practices. Most of the respondents (47%) worked in general hospitals and 74% of participants had a bachelor's degree in physiotherapy; 31.3% had 3-6 years of experience; 93.8% used hyperinflation, and 78.9% used MHI. MHI was performed routinely and as needed to treat low oxygen levels, abnormal breath sounds, and per physician orders while avoiding contraindications. Self-inflation bags are frequently used for MHI (40.6%). Only a few participants (26%) used a manometer or tracked PIP. In addition to the supine position, some participants (37.5%) used the side-lying position. Most physiotherapists followed the recommended MHI technique: slow squeeze (57.3%), inspiratory pause (45.8%), and quick release (70.8%). VHI was practised by 19.8%, with medical approval and it was frequently performed by medical staff compared to physiotherapists. Treatment time, number of breaths, and patient positioning varied, and parameters were not well-defined. The study found that MHI was not applied with the recommended PIP, and VHI parameters were not identified. The study indicates a need to educate physiotherapists about current VHI and MHI practice guidelines.

Driving Pressure During Mechanical Ventilation of Acute Respiratory Distress Syndrome

Background: Driving pressure has been identified as a more accurate indicator of mortality risk than low tidal volume (VT) and pulmonary compliance (Ppl). It was also noted that when this pressure surpasses the 18 cm H2O mark, there is a significant elevation in the relative risk of death. This study aimed to evaluate the effect of driving pressure guided ventilation in acute respiratory distress syndrome (ARDS). Patients and Methods: The study included 64 subjects selected from the respiratory intensive care unit (RICU) of Al-Azhar University Hospital (Damietta). All participants received management through a protective lung strategy that was informed by driving Pressure. The study outcomes included 1). Determination of weaning categories; 2). Adverse events; 3). Length of ICU stay and duration of mechanical ventilation; 4). Mechanical Ventilation-free days, and 5). Organ/s dysfunction. Results: The commonest cause of admission was pneumonia (36%), and least percentage was septic shock (1.6%). The median ICU stay was 7 days (4 to 25 days) and weaning success rate was 76.6% with mortality rate of 23.4%. The severity was mainly severe (40.6%) and moderate (31.2%). Driving pressure at day 1 of ≤ 21 had sensitivity of 97.96%, specificity of 80.0% and area under curve (AUC) of 0.952. The driving pressure was significantly increased in cases with failure weaning than the success weaning (24.67 ± 1.05 vs 16.86 ± 1.24, respectively). In addition, it was significantly increased in died than alive patients. There was progressive significant increase of driving pressure from mild to moderate to severe cases. Pneumothorax was recorded among 9.4% and pleural effusion was recorded for 7.8% of patients. Conclusion: Use of driving pressure guided ventilation in patients with ARDS improves lung compliance, decreases the duration of mechanical ventilation and the length of ICU stay. Driving pressure &lt; 21 can predict mortality.

SCARLET (Supplemental Citicoline Administration to Reduce Lung injury Efficacy Trial): study protocol for a single-site, double-blinded, placebo-controlled, and randomized Phase 1/2 trial of i.v. citicoline (CDP-choline) in hospitalized SARS CoV-2-infected patients with hypoxemic acute respiratory failure

BackgroundThe SARS CoV-2 pandemic has resulted in more than 1.1 million deaths in the USA alone. Therapeutic options for critically ill patients with COVID-19 are limited. Prior studies showed that post-infection treatment of influenza A virus-infected mice with the liponucleotide CDP-choline, which is an essential precursor for de novo phosphatidylcholine synthesis, improved gas exchange and reduced pulmonary inflammation without altering viral replication. In unpublished studies, we found that treatment of SARS CoV-2-infected K18-hACE2-transgenic mice with CDP-choline prevented development of hypoxemia. We hypothesize that administration of citicoline (the pharmaceutical form of CDP-choline) will be safe in hospitalized SARS CoV-2-infected patients with hypoxemic acute respiratory failure (HARF) and that we will obtain preliminary evidence of clinical benefit to support a larger Phase 3 trial using one or more citicoline doses.MethodsWe will conduct a single-site, double-blinded, placebo-controlled, and randomized Phase 1/2 dose-ranging and safety study of Somazina® citicoline solution for injection in consented adults of any sex, gender, age, or ethnicity hospitalized for SARS CoV-2-associated HARF. The trial is named “SCARLET” (Supplemental Citicoline Administration to Reduce Lung injury Efficacy Trial). We hypothesize that SCARLET will show that i.v. citicoline is safe at one or more of three doses (0.5, 2.5, or 5 mg/kg, every 12 h for 5 days) in hospitalized SARS CoV-2-infected patients with HARF (20 per dose) and provide preliminary evidence that i.v. citicoline improves pulmonary outcomes in this population. The primary efficacy outcome will be the SpO2:FiO2 ratio on study day 3. Exploratory outcomes include Sequential Organ Failure Assessment (SOFA) scores, dead space ventilation index, and lung compliance. Citicoline effects on a panel of COVID-relevant lung and blood biomarkers will also be determined.DiscussionCiticoline has many characteristics that would be advantageous to any candidate COVID-19 therapeutic, including safety, low-cost, favorable chemical characteristics, and potentially pathogen-agnostic efficacy. Successful demonstration that citicoline is beneficial in severely ill patients with SARS CoV-2-induced HARF could transform management of severely ill COVID patients.Trial registrationThe trial was registered at www.clinicaltrials.gov on 5/31/2023 (NCT05881135).Trial statusCurrently enrolling.

Bronchoalveolar Lavage and Oleic Acid Two-hit Model for Inducing Acute Respiratory Distress Syndrome in Swine Models.

Acute respiratory distress syndrome (ARDS) is a widespread and often fatal clinical syndrome marked by the acute onset of pulmonary edema and inflammatory-mediated disruptions in alveolar-capillary permeability resulting in impaired gas exchange and tissue oxygenation with subsequent acute respiratory failure that accounts for 10.4% of all intensive care unit admissions worldwide and boasts a mortality rate of 38.5%. The current treatment for ARDS remains largely supportive. This is largely because of the many challenges of achieving a stable and sustainable animal model that recreates the pathophysiology of ARDS experimentally in a controlled setting to allow research to elucidate potential treatments of ARDS moving forward. The bronchoalveolar lavage and oleic acid models are currently the 2 most frequently used experimental models in inducing ARDS in animal models. This study demonstrated that combining them into a "two-hit model" can produce sustained ARDS in swine models per the Horowitz index (PaO2/FiO2 ratio of ≤300 mmHg). Additionally, expected changes in pH, pCO2, lung compliance, cytokines, and tissue histopathology were observed and add to our confidence and reliability that the "two-hit model" produces symptomatic ARDS in a manner very similar to that observed in humans. In conclusion, we demonstrated a viable animal model of human ARDS that is maintained for a prolonged period, suitable for continuous monitoring of the progression, and evaluation of potential future treatments and procedures to reduce patient morbidity and mortality. To carry out this two-hit model, lung injury was induced through a combination of bronchoalveolar lavage and oleic acid administration and the disease process of ARDS is subsequently tracked through clinically relevant parameters such as respiratory mechanics, cytokine response, aretrial blood gas (ABG) changes, and observation of postmortem histopathologic changes. This promising new model has the capacity to successfully replicate human ARDS which is a well-known and notoriously multifactorial pathogenic process to reproduce experimentally for an extended period of time. The "two-hit model" is a viable and appropriate model for the research of novel treatments for ARDS.

Effect of dexmedetomidine on pulmonary function in obese patients undergoing laparoscopic surgery

ObjectiveThis research aimed to ascertain the effect of dexmedetomidine on pulmonary function in obese patients undergoing laparoscopic surgery.MethodsObese patients undergoing laparoscopic surgery under general anesthesia were separated into the control group (group C) and the dexmedetomidine group (group D) (n = 30). Patients in group D were infused with dexmedetomidine (1 μg/kg) intravenously for 10 min and then at a rate of 0.5 mg/kg h until 30 min before the end of the surgery, and those in group C were infused with an equal volume of saline. The surgery time points were divided into: before anesthesia induction (T0), 5 min after intubation (T1), 30 min after pneumoperitoneum (T2), 10 min after pneumoperitoneum release (T3), at the time of extubation (T4), 3 min after extubation (T5), and 24 h after surgery (T6). Arterial blood was collected for blood gas analysis to record arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2). Dynamic lung compliance (Cdyn), oxygenation index (OI), alveolar-arterial oxygen partial pressure difference (A-aDO2), and respiratory index (RI) were calculated. The time of surgery, anesthesia, CO2 pneumoperitoneum, eye-opening, and time from the end of surgery to extubation were recorded. Plasma IL-8 and IL-10 levels were measured from T0 to T6.ResultsThe time of surgery, anesthesia, CO2 pneumoperitoneum, eye-opening, and time from the end of surgery to extubation in group D were not statistically significant when compared with those in group C. Versus at the T1 time point, A-aDO2 and RI were higher and Cdyn and OI were lower in both groups at T2 and T3 time points. Versus group C, group D had higher Cdyn and OI and lower A-aDO2 and RI at T2 and T3 time points. Versus at the T0 time point, at each time point from T1 to T6, IL-8 and IL-10 levels were higher in both groups. Versus group C, group D had lower IL-8 and higher IL-10 levels at each time point from T1 to T6.ConclusionIn obese patients undergoing laparoscopic surgery under general anesthesia, the use of dexmedetomidine can improve the lung compliance and OI of the patients, inhibit the inflammatory response of the lungs of the patients and thus have a certain protective effect on the lung function.

Truss topology optimization for additively manufactured components with respect to structural stiffness and active cooling

This paper focuses on the use of truss topology optimization in the setting, where we aim to design structures with good structural stiffness and heat dissipation properties. Our technique takes advantage of the truss formulation to incorporate a cooling circuit inside the truss, using identified bars as tubes. This approach is closely connected to additive manufacturing, as the inherent complexity of the resulting structures and the inner cooling circuit make conventional techniques impractical or outright impossible. The traveling salesman problem is used as the basis for the optimized cooling path computation by a modified ant colony optimization algorithm, complemented by Dijkstra’s algorithm for finding the shortest path in a graph. The found cooling channels are then taken as inputs to the problem of minimizing static structural compliance, formulated as a semidefinite program. The method is used to solve two example problems, one two-dimensional and a more complex three-dimensional problem.

Transient heat stress protects from severe endothelial damage and dysfunction during prolonged experimental ex-vivo lung perfusion.

The pulmonary endothelium is the primary target of lung ischemia-reperfusion injury leading to primary graft dysfunction after lung transplantation. We hypothesized that treating damaged rat lungs by a transient heat stress during ex-vivo lung perfusion (EVLP) to elicit a pulmonary heat shock response could protect the endothelium from severe reperfusion injury. Rat lungs damaged by 1h warm ischemia were reperfused on an EVLP platform for up to 6h at a constant temperature (T°) of 37°C (EVLP37°C group), or following a transient heat stress (HS) at 41.5°C from 1 to 1.5h of EVLP (EVLPHS group). A group of lungs exposed to 1h EVLP only (pre-heating conditions) was added as control (Baseline group). In a first protocol, we measured lung heat sock protein expression (HSP70, HSP27 and Hsc70) at selected time-points (n=5/group at each time). In a second protocol, we determined (n=5/group) lung weight gain (edema), pulmonary compliance, oxygenation capacity, pulmonary artery pressure (PAP) and vascular resistance (PVR), the expression of PECAM-1 (CD31) and phosphorylation status of Src-kinase and VE-cadherin in lung tissue, as well as the release in perfusate of cytokines (TNFα, IL-1β) and endothelial biomarkers (sPECAM, von Willebrand Factor -vWF-, sE-selectin and sICAM-1). Histological and immunofluorescent studies assessed perivascular edema and formation of 3-nitrotyrosine (a marker of peroxinitrite) in CD31 lung endothelium. HS induced an early (3h) and persisting expression of HSP70 and HSP27, without influencing Hsc70. Lungs from the EVLP37°C group developed massive edema, low compliance and oxygenation, elevated PAP and PVR, substantial release of TNFα, IL-1β, s-PECAM, vWF, E-selectin and s-ICAM, as well as significant Src-kinase activation, VE-cadherin phosphorylation, endothelial 3-NT formation and reduced CD31 expression. In marked contrast, all these alterations were either abrogated or significantly attenuated by HS treatment. The therapeutic application of a transient heat stress during EVLP of damaged rat lungs reduces endothelial permeability, attenuates pulmonary vasoconstriction, prevents src-kinase activation and VE-cadherin phosphorylation, while reducing endothelial peroxinitrite generation and the release of cytokines and endothelial biomarkers. Collectively, these data demonstrate that therapeutic heat stress may represent a promising strategy to protect the lung endothelium from severe reperfusion injury.

PEEP trial and effect on hemodynamic in cardiogenic shock

Abstract Funding Acknowledgements None. Introduction Congestion is a paramount pathophysiological driver in patients with cardiogenic shock. Almost half of patients admitted due to cardiogenic shock undertake mechanical ventilation although ventilatory parameter, and their potential hemodynamic effect on the hemodynamic and congestion profile are often neglected. Purpose We sought to evaluate the hemodynamic effect of positive end-expiratory pressure (PEEP) titration on patients admitted to intensive care unit for CS. Methods We perform PEEP titration trial on patients undertaking mechanical ventilation for respiratory failure related to CS. The trial consisted in 3 steps of PEEP increase from 5 to 15 cmH2O. For each step arterial saturation, right atrial -RAP- and systemic blood pressure along with heart rate and respiratory mechanics (tidal volume-TV-, dynamic lung compliance- CLdyn, driving- Δ- and plateau pressure- Ppl) were measured. All the measures were taken at end-expiration; RAP trace was analyzed and systolic, mean and diastolic component collected. The final PEEP was decided based on the best matching between saturation, CLdyn and TV. Descriptive and repeated measures with Bonferroni correction were applied as statistical analysis (IBM SPSS 29). Results Twelve patients were included (10 male, 66 ± 7 years old; 8 acute myocardial infarction and 4 acute heart failure). At baseline the mean RAP was 8.44 (± 2.32) ; SBP 106 (IQR 92-112), HR 94 (IQR 88 - 102) Δ and Ppl pressures respectively 7.42 (± 0.79) and 12.08 (± 0.79, ),VT 427(± 65.42) and CLdyn 58.3 (± 7.1). The right atrial pressure (RAP) differed between AMI and AHDF (8.25 ± 2.25 vs 20.25 ± 1.5; p &amp;lt; 0.001), so HR did (113 ± 3.4 versus 96 ± 3.2 betas per minutes; p 0.015). RAP varied consistently during the PEEP trial (either sRAP, dRAP and mRAP- Table and Figure 1). The TV changed signficnatly between the 1st and 3rd step (p 0.004) and the CLdyn varied consistently throughout the 3 steps of the PEEP trial (p &amp;lt;0.001). A significant difference were observed according to aetiology in RAP (AMI Vs ADHF, eman difference 2.4 versus 4.3 mmHg) and in CLdyn (AMI Vs ADHF mean difference 12.31 vs 8 .65, p &amp;lt; 0.01) but not in the other parameters evaluated (p &amp;gt; 0.05). Conclusion This is the first, small, study evaluating the effect of positive pressure ventilation in CS patients according to etiologies. As previously demonstrated PEEP influences the right side hemodynamic by increasing the RAP, although resulting in better CLdyn. The extent of the effect of PEEP increased may be dependent on the underlying aetiology of CS. Considering that the sample size is extremely limited, these results advocate a wider validation. However, the positive pressures induced by the ventilation in patient with CS should be taken in consideration when the comprehensive evaluation of hemodynamic to define congestion profile and phenotype are performed.Table 1.Hemodynamic parametersGraph PEEP vs RAP

Bioinspired Genetic-Algorithm Optimized Ground-Effect Wing Design: Flight Performance Benefits and Aircraft Stability Effects

This paper presents a bioinspired, genetic-algorithm evolutionary process for Ground-Effect vehicle wing design. The study made use of a rapid aerodynamic model generation and results evaluation computational fluid dynamics vortex lattice method software, supervised by a genetic algorithm optimization Python script. The design space for the aircraft wing parametric features drew inspiration from seabirds, under the assumption of their wings being naturally evolved and partially optimized for proximity flight over water surfaces. A case study was based on the A-90 Orlyonok Russian Ekranoplan, where alternative bioinspired wing variations were proposed. The study objective was to investigate the possible increased flight aircraft performance when using bioinspired wings, as well as verify the static and dynamic aircraft stability compliance for Ground-Effect flight. The methodology presented herein along with the study results, provided an incremental step towards advancing Ground-Effect aircraft conceptual designs using computational fluid dynamics.

Relationship of TAPSE Normalized by Right Ventricular Area With Pulmonary Compliance, Exercise Capacity, and Clinical Outcomes.

While tricuspid annular plane systolic excursion (TAPSE) captures the predominant longitudinal motion of the right ventricle (RV), it does not account for ventricular morphology and radial motion changes in various forms of pulmonary hypertension. This study aims to account for both longitudinal and radial motions by dividing TAPSE by RV area and to assess its clinical significance. We performed a retrospective analysis of 71 subjects with New York Heart Association class II to III dyspnea who underwent echocardiogram and invasive cardiopulmonary exercise testing (which defined 4 hemodynamic groups: control, isolated postcapillary pulmonary hypertension, combined postcapillary pulmonary hypertension, and pulmonary arterial hypertension). On the echocardiogram, TAPSE was divided by RV area in diastole (TAPSE/RVA-D) and systole (TAPSE/RVA-S). Analyses included correlations (Pearson and linear regression), receiver operating characteristic, and survival curves. On linear regression analysis, TAPSE/RVA metrics (versus TAPSE) had a stronger correlation with pulmonary artery compliance (r=0.48-0.54 versus 0.38) and peak VO2 percentage predicted (0.23-0.30 versus 0.18). Based on the receiver operating characteristic analysis, pulmonary artery compliance ≥3 mL/mm Hg was identified by TAPSE/RVA-D with an under the curve (AUC) of 0.79 (optimal cutoff ≥1.1) and by TAPSE/RVA-S with an AUC of 0.83 (optimal cutoff ≥1.5), but by TAPSE with only an AUC of 0.67. Similarly, to identify peak VO2 <50% predicted, AUC of 0.66 for TAPSE/RVA-D and AUC of 0.65 for TAPSE/RVA-S. Death or cardiovascular hospitalization at 12 months was associated with TAPSE/RVA-D ≥1.1 (HR, 0.38 [95% CI, 0.11-0.56]) and TAPSE/RVA-S ≥1.5 (HR, 0.44 [95% CI, 0.16-0.78]), while TAPSE was not associated with adverse outcomes (HR, 0.99 [95% CI, 0.53-1.94]). Among 31 subjects with available cardiac magnetic resonance imaging, RV ejection fraction was better correlated with novel metrics (TAPSE/RVA-D r=0.378 and TAPSE/RVA-S r=0.328) than TAPSE (r=0.082). In a broad cohort with suspected pulmonary hypertension, TAPSE divided by RV area was superior to TAPSE alone in correlations with pulmonary compliance and exercise capacity. As a prognostic marker of right heart function, TAPSE/RVA-D <1.1 and TAPSE/RVA-S <1.5 predicted adverse cardiovascular outcomes.

Allometric scaling of the parameters characterizing venous return surface in the generalized framework of circulatory equilibrium

Study objective: In the generalized framework of circulatory equilibrium (GCE), the integrated cardiac output (CO) curve characterizes the pumping abilities of the left and right hearts, whereas the venous return (VR) surface characterizes the preloading properties of the systemic and pulmonary circuits. Equilibrium CO (= VR), left (PLA) and right (PRA) atrial pressures are predicted from the intersection between the CO curve and VR surface. In VR surface, VR is theoretically related with stressed blood volume (V), PLA and PRA as: VR =V/W − Gs × PRA − Gp × PLA, where Gs and Gp is a ratio of systemic (Cs) and pulmonary (Cp) vascular compliance to W (time constant of the systemic and pulmonary circuits), respectively. However, there was a concern whether the standard parameters can be applicable to animals with different body size including human. The objective of this study is to experimentally investigate whether an allometric scaling of the parameters (Gs, Gp, W, Cs, Cp) of the VR surface is feasible. Hypothesis: Kleiber’s law indicates that an animal's metabolic rate scales to the 3⁄4 power of the animal's body weight (BW). Based on this, we hypothesize that Cs and Cp may be proportionate to BW, W may be proportionate to BW1/4. Hence, Gs and Gp may be proportionate to BW3/4. Methodology: Seven mongrel dogs (BW 26±2.8 kg) and 4 beagles (BW 9±0.5 kg) were anesthetized, and their left and right hearts were replaced by dual mechanical pumps. While V was kept constant, by controlling the speed of the fluid pumps, VR (ml/min), PLA and PRA (mmHg) were changed variably over a wide range to obtain six sets of VR, PLA and PRA. After the change of a known amount of V (4 mL/kg), six sets of VR, PLA and PRA were obtained in a similar manner. Using 12 sets of VR, PLA and PRA, we obtained Gs, Gp, W, Cs, and Cp using regression analysis in each animal. Finally, we analyzed relations between BW and all these parameters using regression analysis over the 11 animals. Data: Gs (r2=0.73, p value for independent variable piv&lt;0.01; p value for intercept, pi=0.57) and Gp (r2=0.81, piv&lt;0.01, pi=0.64) were proportionate to BW3/4. Cs (r2=0.37, piv=0.027, pi=0.40) and Cp (r2=0.61, piv&lt;0.01, pi=0.48) were proportionate to BW. However, W (r2=-0.11, piv=0.90, pi=0.17) was not associated with BW1/4. Summary of results: All parameters characterizing VR surface except for W were significantly associated with BW. W did not show a significant association with BW, potentially due to the low variations of BW. Conclusions: Allometric scaling of VR surface may be feasible and effective in future clinical application of GCE. NTT Research, Inc. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Vertical vibration of a rigid disc over a transversely isotropic and layered poroelastic half-space

A novel semi-analytical method is proposed for solving the vertical vibration of a rigid disc over a transversely isotropic and layered poroelastic half-space. The fundamental solutions in the layered poroelastic half-space under a vertical patch load on the surface are solved in terms of the newly developed Fourier-Bessel series (FBS) system of vector functions and the unconditionally stable dual-variable and position method. The expansion coefficients in FBS system are discrete, as such the computational efficiency is greatly improved and the accuracy is better than the commonly used integral-transform methods. By virtue of the superposition method, the Green’s function due to vertical ring load is derived in the transform domain. By making use of the integral least-square scheme, the densities of a series of ring loads discretized within the disc area are determined. Finally, the dynamic vertical compliance is derived via the balance between the external applied force and the induced total contact traction. After verifying the reliability of the developed solution, selected numerical examples are presented to investigate the influence of material properties and excitation frequency on the forced vibration of the rigid disc.