Augmentation Of Flow Research Articles

Flow Augmentations Modify an Estuarine Prey Field

Zooplankton density and community composition in estuaries can be affected by variation in freshwater inputs, with important implications for higher trophic levels. In the San Francisco Estuary, management agencies have initiated autumn flow augmentations in the form of changes to reservoir releases or to exported water from the South Delta to increase and improve available habitat for endangered Delta Smelt, Hypomesus transpacificus, during the season when their body condition most influences fecundity. Autumn flow augmentation only occurs in years with higher precipitation, effectively moving the Low-Salinity Zone (LSZ) downstream to key foraging habitats for Delta Smelt in Suisun Bay and Suisun Marsh. To assess whether augmented flow enhanced prey resources for Delta Smelt, we compared autumn zooplankton abundance, biomass, spatial distribution, and community composition in years when flow was augmented (2017, 2019) with reference years when flow was not augmented (2018, 2020). In augmented years, we detected higher total zooplankton abundance and altered community composition in Suisun Bay and Suisun Marsh. Increased freshwater in these regions was associated with higher abundance of Pseudodiaptomus forbesi, a preferred prey of Delta Smelt, while species associated with higher salinities—Acartiella sinensis and Tortanus dextrilobatus—were less abundant. Thus, autumn flow augmentations can influence foraging habitat and prey availability for Delta Smelt, underscoring the complex responses of estuarine zooplankton communities to changes in response to flow and salinity regimes. This study is management- relevant because it shows that important Delta Smelt prey items increase in downstream regions when X2 is lower. Whether that results in a response in Delta Smelt abundance remains to be seen.

Bifurcation of streamlines in channel and tube flow of FENE-P fluid due to peristaltic activity

In this paper, we have analyzed the bifurcation of stagnation points in the non-Newtonian flow of the FENE-P fluid through a channel induced by peristalsis. The stream function for the flow under consideration is developed under negligible inertia and streamline curvature effects. A nonlinear autonomous system is developed for scrutiny of the critical points. A dynamical system approach is used to examine the stability of bifurcation points. Streamline patterns, and local and global bifurcation diagrams are plotted for analysis of the backward flow, trapping, and augmented flow regions. The impacts of important embedded parameters, i.e., extensibility parameter and Deborah number on local and global bifurcation diagrams, are also examined. The whole analysis reveals that two critical conditions appear in the flow field that are actually responsible for the conversion of backward flow to trapping and trapping to augmented flow. It is further seen that bifurcations occur at lower flow rates for increasing Deborah’s number while an opposite trend prevails for increasing the extensibility parameter. A comparison of bifurcations between planar and axisymmetric flows is also performed. It is observed that a greater area of the trapping region is encountered for axisymmetric flow than that for planar flow.

Augmented flow and reduced clogging of particles passing through small apertures by addition of fine grains

The effect on the flow and clogging of a sample of particles passing through an orifice due to the addition of a second fine-graded species is investigated. The flow rate of the main species is measured for various parameters: the mass ratio of the big species, the particle size ratio and the orifice diameter. We show that when the fine grains are added into the system the flow rate of the larger species can be increased and its clogging significantly reduced. In particular, we were able to flow (without clogging) the big species through an orifice only 1.5 times its particle diameter. This allows for applications such as the alignment of particles in a narrow tube without clogging. A simple state diagram is presented to describe the clogging transition for these binary mixtures. The experimental results are compared with various existing models for the flow rate of binary mixtures.

A century of channel change caused by flow augmentation on Sixth Water Creek and Diamond Fork River, Utah, USA

AbstractThe Diamond Fork River in central Utah, USA experienced extreme flow augmentation via transbasin flows. Beginning in 1916, irrigation water was delivered through a tributary, Sixth Water Creek, with daily summer flows regularly exceeding a 500‐year flood at the point of introduction. Flows were dramatically reduced by management action in 2004 but with mandated minimum flows. We examined the geomorphic response of Sixth Water and Diamond Fork using aerial imagery, lidar, topographic cross sections, and sediment transport measurements. River channel response varied with valley confinement and with position in the watershed, which determined the magnitude of augmented flow relative to natural floods and the amount of sediment supply. Confined, steep sections of Sixth Water incised many meters into bedrock, whereas partially confined and unconfined sections developed a braided form even under conditions of general incision. With the removal of flow augmentation, smaller natural floods on Sixth Water are unable to transport bed material and the channel remains static. On the alluvial lower Diamond Fork, a lower slope, upstream sediment supply, and larger natural floods produced a dynamic shifting channel that widened in response to natural floods. After flow augmentation, a coarsened bed is partially mobile and channel narrowing appears to be limited by artificial baseflow, which prevent vegetation establishment in the channel.

Right Ventricular Outflow Tract Stenting is a Safe and Effective Bridge to Definitive Repair in Symptomatic Infants With Tetralogy of Fallot1.

Right ventricular outflow tract (RVOT) stent angioplasty is a palliative procedure for neonates and infants with symptomatic tetralogy of Fallot prior to surgical repair. We review our institutional outcomes of RVOT stenting. Retrospective review of all infants with tetralogy of Fallot under 3 months of age who underwent primary native RVOT stent angioplasty at The Children's Hospital at Westmead, Sydney, Australia between January 2010 and December 2020. Demographics and echocardiographic pulmonary artery dimensions were collected pre-stent angioplasty and prior to surgical repair. Twenty (20) infants underwent primary RVOT stenting. Median age at stent was 14 days (interquartile range [IQR] 7-32) and median weight 2.7 kg (IQR 2.1-3.4). Three patients underwent hybrid per-ventricular procedures. Indication for RVOT stenting was recurrent hyper-cyanotic spells in 12 (60%) and duct-dependent pulmonary blood flow in 8 (40%). Saturations increased from a median of 80% (IQR 75-85) to 91% (IQR 90-95) post procedure (P<0.001). A single major complication occurred: transient complete atrioventricular dissociation requiring isoprenaline infusion for <24 hours. Twelve (12, 60%) required catheter re-intervention prior to definitive repair for further augmentation of pulmonary blood flow. There were two non-cardiac deaths distant from the stent procedure, but prior to surgical repair. Median right and left pulmonary artery Z-scores increased respectively from -2.06 (IQR -2.99 to -0.17) and -1.2 (IQR -2.59 to -0.14) prior to RVOT stent, to -0.74 (IQR [-1.21 to 0.26], P=0.01) and 0.06 (IQR [-1.87 to 1.15], P=0.006) by the time of definitive repair. Eighteen (18) patients achieved definitive repair at a median age of 6.1 months (IQR 4.7-7.3). Palliation with more than one RVOT stent was associated with an increased duration of cardiac bypass (P=0.035) and cross-clamp (P=0.044) time at definitive repair. In symptomatic neonates and infants with tetralogy of Fallot at high-risk of peri-operative complications, RVOT stent angioplasty can safely and effectively augment pulmonary blood flow prior to definitive repair.

Numerical investigation on conjugate behavior of heat transfer and its augmentation in a turbulent wall-jet flow on a heated plate in motion

The present research involves a computational investigation by adopting a conjugate technique in a turbulent wall jet flow on a moving plate heated isothermally at the bottom. The low-Reynolds-number YS model is adopted for the simulation to predict the thermal and fluid behavior in the near wall regime. The wall jet enters a quiescent environment of Prandtl number of 7 at a constant Reynolds number of Re = 15000 at the inlet. The thermal parameters considered for observing the thermal behavior are solid-fluid conduction ratio ( K ) , plate-jet thickness ratio ( S ) , and plate to jet velocity ratio ( U p ) . The temperature distributions in the plate domain, temperature at the solid-fluid interface, local Nusselt number, and average Nusselt number provided evidence of the effects of plate movement in the present cases. The plate motion strongly influences the distribution of the local and the averaged Nusselt number along with the temperature at the interface. The average Nusselt number calculated suggests that plate motion is crucial in enhancing heat transfer rate.

A Pilot Study to Examine the Effect of Passive Straight Leg Raise Performed During Cardiopulmonary Resuscitation on Cerebral Perfusion Measured by Noninvasive Cerebral Oximetry.

This was a double cross-over physiologic efficacy randomized study. Study in 10 subjects with in-hospital cardiac arrest for whom CPR was undertaken. Subjects were randomized to receive two cycles of CPR with PLR followed by two cycles of CPR without PLR (Group I) or vice-versa (Group II). Subjects had their foreheads (right and left) fitted with near infrared spectroscopy (NIRS) electrodes (O3 System-Masimo, Masimo corporation Forty Parker, Irvine CA) while undergoing CPR during the study. NIRS readings, a measure of mixed venous, arterial, and capillary blood oxygen saturation, act as a surrogate measure of cerebral blood perfusion during CPR. PLR was randomly used "first" in five of them, whereas it was used "second" in the remaining five subjects. In subjects in whom PLR was performed during first two cycles (Group I), NIRS values were initially significantly greater. The performance of PLR during CPR in Group II attenuated the decline in NIRS readings during CPR. PLR during CPR is feasible and leads to augmentation of cerebral blood flow. Furthermore, the expected decline in cerebral blood flow over time during CPR may be attenuated by this maneuver. The clinical significance of these findings will require further investigations.

Electroosmotically augmented peristaltic flow of carbon nanotubes based nanofluid through asymmetrical channel

AbstractThe peristaltic flow of nanofluids is an emerging area of scientific research due to its vital industrial and medical applications. Herein, a model study is conducted to numerically investigate, the electroosmotically augmented peristaltic pumping of electrically conducting aqueous ionic nanofluid through an inclined asymmetric channel. The behavior of the model for various involved parameters is expressed through a set of graphs. The velocity profile gained a significant increment for Joule heating and electroosmotic velocity parameters. The velocity dropped for the Hartmann number, while a dual behavior is noted for the thermal Grashof number. However, the magnetic number enhances the temperature, while a lower temperature is perceived for the electroosmotic velocity and Debye length parameters. The streamline pattern for the fluid flow subject to multiple values of the electroosmotic velocity parameter can be seen to indicate that for negative values of the parameter, a larger number of streamlines are circulated compared to the case when the electric field is absent, that is, . However, in the case of an opposing electric field, that is, for the positive values of the parameter, the streamline bolus occurs across the centerline of the channel.

Patient-specific computational simulation of coronary artery bypass grafting.

Coronary artery bypass graft surgery (CABG) is an intervention in patients with extensive obstructive coronary artery disease diagnosed with invasive coronary angiography. Here we present and test a novel application of non-invasive computational assessment of coronary hemodynamics before and after bypass grafting. We tested the computational CABG platform in n = 2 post-CABG patients. The computationally calculated fractional flow reserve showed high agreement with the angiography-based fractional flow reserve. Furthermore, we performed multiscale computational fluid dynamics simulations of pre- and post-CABG under simulated resting and hyperemic conditions in n = 2 patient-specific anatomies 3D reconstructed from coronary computed tomography angiography. We computationally created different degrees of stenosis in the left anterior descending artery, and we showed that increasing severity of native artery stenosis resulted in augmented flow through the graft and improvement of resting and hyperemic flow in the distal part of the grafted native artery. We presented a comprehensive patient-specific computational platform that can simulate the hemodynamic conditions before and after CABG and faithfully reproduce the hemodynamic effects of bypass grafting on the native coronary artery flow. Further clinical studies are warranted to validate this preliminary data.

Influences of lubrication on asymmetric peristaltic movement and its bifurcation

Peristaltic motions are used in a variety of industrial and real-world problems such as pumping mixture with such a high solid content from the mining sector, biogases, sewers facilities, food flow through the gastrointestinal system, urinary tract, and fallopian tube of human females where extremely abrasive, gritty, and viscous fluids are present. The goal of this theoretical study is to examine the impact of the lubricated walls on the peristaltic transport of a viscous fluid in an asymmetric medium. The interfacial condition is derived under the assumptions of thin film lubrication and long wavelength approximation. The theory of a dynamical system is utilized to examine the lubrication effects on the position and bifurcation of stagnation points in the flow. For this, three flow distributions, backward flow, trapping, and augmented flow, are discussed. The obtained system of equations is solved numerically by the shooting method based on Newton–Raphson root-finding algorithm in Mathematica. The prime findings for the velocity profile, pressure increase, trapping, and reflux criteria are illustrated through graphs. Bifurcation occurs earlier by increasing the influence of lubrication. The trapping area diminishes and the augmented flow section expands with the lubrication parameter. This will be useful for medical engineering, industrial and physiological systems. The comparison for the particular case of no-slip condition is presented and found to be in excellent agreement.

Distributed Networked Microgrids Power Flow

An integrative power flow approach is established for networked microgrids. Our new contributions include: 1) A distributed augmented power flow (APF) algorithm for networked microgrids is devised to incorporate hierarchical control effects in/among microgrids; 2) Based upon APF, an enhanced distributed continuation power flow (CPF <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^+$</tex-math></inline-formula> ) algorithm is established to explore operating regions of droop coefficients and power interchanges for static voltage stability assessment; and 3) A programmable distributed platform is designed to coordinate power interchanges and support plug-and-play while protecting local customers’ privacy. RTDS experiments validate the high fidelity of APF, while its scalability and convergence performance are verified on medium and large networked microgrids. Extensive tests demonstrate the effectiveness of CPF <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^+$</tex-math></inline-formula> in quantifying secure operation regions of networked microgrids.

Optimal Adaptive Droop Design via a Modified Relaxation of the OPF

The ever-increasing penetration of renewable energy resources (RESs) in power distribution networks has brought, among others, the challenge of maintaining the grid voltages within the secure region. Employing droop voltage regulators on the RES’s inverters is an efficient and low-cost solution to reach this objective. However, fixing droop parameters or optimizing them only for overvoltage conditions does not provide the required robustness and optimality under changing operating conditions. In this article, a convex optimization approach is proposed for reconfiguring <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V$ </tex-math></inline-formula> droop regulators during online operation. The objective is to minimize power curtailment, power losses, and voltage deviation subject to electrical security constraints. This enables to optimally operate the grid with high RES penetration under variable conditions while preserving electrical security constraints (e.g., current and voltage limits). As a first contribution, a mixed-integer linear model of the droop characteristics is developed. According to this model, a droop-regulated generation unit is represented as a constant-power generator in parallel with a constant-impedance load. As a second contribution, a modified augmented relaxed optimal power flow (MAR-OPF) formulation is proposed to guarantee that the electrical security constraints are respected in the presence of constant-impedance loads in the network. Sufficient conditions for the feasibility of the MAR-OPF solution are provided. Those conditions can be checked a priori and are valid for several real distribution networks. Furthermore, an iterative approach is proposed to derive an approximate solution to the MAR-OPF that is close to the global optimal one. The performance of the MAR-OPF approach and the accuracy of the proposed model are evaluated on standard 34- and 85-bus test networks.

Genomic evidence uncovers inbreeding and supports translocations in rescuing the genetic diversity of a landlocked seal population

Fragmentation of isolated populations increases the risk of inbreeding and loss of genetic diversity. The endemic Saimaa ringed seal (Pusa hispida saimensis) is one of the most endangered pinnipeds in the world with a population of only ~ 400 individuals. The current genetic diversity of this subspecies, isolated in Lake Saimaa in Finland for ca. 1000 generations, is alarmingly low. We performed whole-genome sequencing on Saimaa ringed seals (N = 30) and analyzed the level of homozygosity and genetic composition across the individual genomes. Our results show that the Saimaa ringed seal population has a high number of runs of homozygosity (RoH) compared with the neighboring Baltic ringed seal (Pusa hispida botnica) reference population (p < 0.001). There is also a tendency for stillborn seal pups to have more pronounced RoH. Since the population is divided into semi-isolated subpopulations within the Lake Saimaa exposing the population to deleterious genomic effects, our results support augmented gene flow as a genetic conservation action. Based on our results suggesting inbreeding depression in the population, we recommend Pihlajavesi as a potential source and Southern Saimaa as a potential recipient subpopulation for translocating individuals. The Saimaa ringed seal is a recognized subspecies and therefore translocations should be considered only within the lake to avoid an unpredictable risk of disease, the introduction of deleterious alleles, and severe ecological issues for the population.

Permeate Flux Enhancement in Air Gap Membrane Distillation Modules with Inserting Λ-Ribs Carbon-Fiber Open Slots.

A novel design of an air gap membrane distillation (AGMD) module was proposed to enhance the permeate flux improvement for the desalination of pure water productivity. The modeling equations for predicting permeate flux in the AGMD module by inserting Λ-ribs carbon-fiber open slots under various hydrodynamic angles were developed theoretically and experimentally. The temperature distributions of both hot and cold feed streams were represented graphically with the hot saline flow rate, inlet saline temperature, and carbon-fiber hydrodynamic angles as parameters. The results showed a good agreement between the experimental results and theoretical predictions. Designed by inserting Λ-ribs carbon-fiber open slots into the flow channel, the membrane distillation module was implemented to act as an eddy promoter and yield an augmented turbulence flow. The effect of Λ-ribs carbon-fiber open slots not only assured the membrane stability by preventing vibration but also increased the permeate flux by diminishing the temperature polarization of the thermal boundary layer. The permeate flux improvement by inserting Λ-ribs carbon-fiber open slots in the AGMD module provided the maximum relative increment of up to 15.6% due to the diminution of the concentration polarization effect. The experimental data was incorporated with the hydrodynamic angle of Λ-ribs carbon-fiber open slots to correlate the enhancement factor with the Nusselt numbers to confirm the theoretical predictions. The accuracy derivation between the experimental results and theoretical predictions was pretty good, within 9.95≤E≤1.85. The effects of operating and designing parameters of hot saline flow rate, inlet saline temperature, and hydrodynamic angle on the permeate flux were also delineated by considering both the power consumption increment and permeate flux enhancement.

Thermo-convective behavior and entropy generation studies on Alumina and Titania nanofluids flowing through polygonal ducts

The current study emphasizes the thermal performance of 0.05, 0.1, and 0.2% volume concentrated Al2O3/DI water and TiO2/DI water nanofluids flowing through three different ducts (equilateral triangle, square, and hexagonal shaped) were compared with circular tubes. The thermo-convective experiments were carried out in the turbulent regime (5000≤ Re ≤ 10,000) at iso-heat flux conditions. The experimental outcome reveals that the maximum Nusselt number of 78, 74, and 71 were achieved when 0.2% Al2O3/DI water flowed through hexagonal, square, and triangular ducts, respectively. Similarly, the desired lowest friction factor of 0.03692, 0.03688, and 0.03686 was achieved by the same nanofluid through those orientations, which ensured that the Al2O3/DI water outperformed TiO2/DI water. The maximum Performance Evaluation Criteria (PEC) was 1.102 when comparing the 0.2% Al2O3/DI water nanofluid flow through a hexagonal duct with water through a circular tube, and 1.169 when the flow through the duct is compared with DI water flow through the same hexagonal duct. When evaluating the performance of all these augmented flow orientations by Entropy Performance Evaluation Factor (EPEF), the maximum values of 665, 572, 635, and 654 were achieved by 0.2% Al2O3/DI water and 660, 531, 561, and 628 by 0.2% TiO2/DI water while flowing through the circular tube, triangular, square, and hexagonal ducts, respectively. Correlations for Nusselt number and friction factor employable to these orientations were derived based on the dominant dependant parameters.

Augmentation of magnetohydrodynamic nanofluid flow through a permeable stretching sheet employing Machine learning algorithm

An incompressible MHD nanofluid boundary layer flow over a vertical stretching permeable surface employing Buongiorno’s design investigated by considering the convective states. The Brownian motion and thermophoresis effects are used to implement the nanofluid model. Operating the similarity transmutations, to transform the governing partial differential equations into ordinary differential equations consisting of the momentum, energy, and concentration fields and later worked by using a program written together with the stiffness shifting in Wolfram Language. The consequences of various physical parameters on the velocity, temperature, and concentration fields are analyzed, such as magnetic parameter M, Brownian motion parameter Nb, thermophoresis parameter Nt, Lewis number Le, temperature Biot number Biθ, concentration Biot number Biϕ, and suction parameter fw. Furthermore, the Skin friction coefficient, local Nusselt, and local Sherwood numbers concerning magnetic parameter for various values of physical parameters (i.e. fw, Nb) are obtained graphically, then the outcome is validated with other recent works. Finally, introduced a new environment to employ machine learning by performing the sensitivity analysis based on the iterative method for predicting the Skin friction coefficient, reduced Nusselt number, and Sherwood number with respect to magnetic parameter for suction parameter and Brownian motion parameter. Machine learning algorithms provide a strong and quick data processing structure to enhance the actual research procedures and industrial application of fluid mechanics. These techniques have been upgraded and organized for fluid flow characteristics. The present optimization process has the potential for a new perspective on the metallurgical process, heat exchangers in electronics, and some medicinal applications.

Theoretical Aspects on Heat Transfer and Fluid Flow in Micro Channels

The past ten years have seen a lot of research on the issues of heat transfer and fluid flow in micro-channels. With an emphasis on upcoming research requirements, a critical analysis of the state of research as it stands is offered. Following a brief introduction, the study discusses six themes related to transport phenomena in micro-channels: condensation, cooling of electronics, single-phase gas flow, augmentation of single-phase liquid flow and flow boiling, and micro-scale heat exchangers. In this study, we investigate the three-dimensional heat transfer and water flow properties in a set of rectangular micro-channel heat sinks for advanced electronic systems. Over the past ten years, mini/micro channel type compact heat exchangers have received a lot of attention. The ability to make heat exchangers smaller, lighter, and cheaper than those in use now is the primary motivator. Additionally, emerging applications that call for the cooling of small things, such electronics and micro-electro-mechanical devices, need for heat exchangers with tiny channels. Theoretically, it is examined how a nanofluid moves and transfers heat through a horizontal micro channel while being affected by a magnetic field and an electric double layer (EDL). The flow problem for a micro channel with a large aspect ratio is handled as a two-dimensional nonlinear system. The magnetic field and EDL body force are taken into account while calculating momentum equation

Establishing new populations in water-secure locations may benefit species persistence more than interventions in water-stressed locations

The effects of climate and land-use change, coupled with limited management resources, mean that managers are increasingly faced with decisions to invest in some locations at the expense of others. Given their potentially controversial nature, such decisions require predictions of likely outcomes under different management strategies and potential future climates. We develop an approach to prioritise management interventions across multiple locations in highly variable and uncertain environments, using a stochastic model of population dynamics structured to include the (dynamic) effects of environmental conditions on key vital rates. We demonstrate this approach with a case study on the endangered Australian freshwater fish, the Macquarie perch (Macquaria australasica), assessing the effectiveness of seven management interventions under five scenarios of deterministic climate change. All management interventions were predicted to improve Macquarie perch population outcomes (increased abundances, reduced risk of quasi-extinction), with the risk of declines lowest when management included augmented gene flow and enforcement of fishing regulations. The lowest levels of risk occurred in locations with stable environmental conditions, which suggests that reintroducing Macquarie perch to large, regulated rivers with suitable access to spawning habitat may be more beneficial than investment in small, unregulated streams where populations were unlikely to persist under any scenario. Population reintroductions provide opportunities to shift populations from water-stressed to water-secure locations where required (e.g. to preserve unique genetic diversity). This finding likely applies to many aquatic species, and highlights a potential need to supplement threat mitigation in water-stressed locations with efforts to establish new populations in water-secure locations.

Mechanical insufflation–exsufflation to facilitate ventilator weaning and possible decannulation for patients with encephalopathic conditions

BackgroundClinicians are often faced with apparently tracheostomy mechanical ventilation dependent (TMV), patients who are ventilator unweanable due to encephalopathic/upper motor neuron conditions, that hamper return to the community. ObjectivesA protocol is suggested to wean these patients from mechanical ventilation and criteria offered for possible decannulation. MethodsAfter excluding patients with severe muscle weakness due to neuromuscular diseases and high level spinal cord disorders, consecutive, apparently unweanable and unresponsive encephalopathic patients were to be weaned by a protocol that first normalized CO2 levels at full ventilatory support settings. Then, supplemental oxygen was discontinued so that ambient air baseline oxyhemoglobin saturation (O2 Sat) could be determined and subsequently be normalized by using mechanical insufflation–exsufflation (MIE), at 60–70 cmH2O pressures, via the tubes every 2 hours, with the tube cuffs inflated. Once ambient air O2 Sat levels remained normal, ambient air spontaneous, unassisted autonomous breathing “sprints” were initiated and continued until O2 Sat decreased below 95% with respiratory distress. Patients spontaneously moving over 300 mL of air into their lungs without pressure support had very good prognoses for rapid ventilator weaning. Patients were not returned to TMV irrespective of tachypnea. After the “sprint”, they were rested by using 1–3 hours of full ventilatory support before the next sprint. Sprints lengthened until being fully weaned. After weaning, potential decannulation was evaluated using MIE expiratory flows (MIE-EF) and O2 Sat. ResultsO2 Sat normalized from the initial use of MIE via the tube for 7 of 13 patients then 4 weaned from the initial ambient air sprint. Weaning occurred in 4 days or less for 11 of 13. Despite continuous TMV dependence for 31 days to 15 months before the intervention, 7 weaned patients were successfully decannulated, 6 of the 7 with MIE-EF ≥ 190 L/m. All but 2 remained unresponsive, but 6 were discharged home to their families once decannulated. ConclusionOnce primary ventilatory pump failure is excluded and lung disease improved to the extent that the ambient air O2 Sat can be normalized by using MIE via invasive airway tubes to clear airway secretions, encephalopathic patients can have sufficient muscle strength to wean from ventilatory support and possibly be decannulated if mechanically augmented cough flows exceed 190 L/m.

Electrohydraulic Vascular Compression Device (e‐VaC) with Integrated Sensing and Controls

AbstractRight ventricular (RV) failure remains a significant clinical burden particularly during the perioperative period surrounding major cardiac surgeries, such as implantation of left ventricular assist devices (LVADs), bypass procedures or valvular surgeries. Device solutions designed to support the function of the RV do not keep up with the pace of development of left‐sided solutions, leaving the RV vulnerable to acute failure in the challenging hemodynamic environments of the perioperative setting. This work describes the design of a biomimetic, soft, conformable sleeve that can be prophylactically implanted on the pulmonary artery to support RV ventricular function during major cardiac surgeries, through afterload reduction and augmentation of flow. Leveraging electrohydraulic principles, a technology is proposed that is non‐blood contacting and obviates the necessity for drivelines by virtue of being electrically powered. In addition, the integration of an adjacent is demonstrate, continuous pressure sensing module to support physiologically adaptive control schemes based on a real‐time biological signal. In vitro experiments conducted in a pulsatile flow‐loop replicating physiological flow and pressure conditions show a reduction of mean pulmonary arterial pressure of 8 mmHg (25% reduction), a reduction in peak systolic arterial pressure of up to 10 mmHg (20% reduction), and a concomitant 19% increase in diastolic pulmonary flow. Computational simulations further predict substantial augmentation of cardiac output as a result of reduced RV ventricular stress and RV dilatation.