Using Two Statewide Medical Operations Coordination Centers to Load Balance in Pediatric Hospitals During a Severe Respiratory Surge in the United States.

OBJECTIVES: Report on the use of two statewide Medical Operations Coordination Centers (MOCCs) to manage a rapid surge in pediatric acute and critical care patient needs. DESIGN: Brief report. SETTING: The states of Washington and Oregon during the pediatric respiratory surge in November 2022/December 2022 which overwhelmed existing pediatric acute and critical care hospital capacity. PATIENTS: Pediatric patients requiring hospitalization in Washington and Oregon. INTERVENTIONS: Adaptations to the use of two existing statewide MOCCs to provide pediatric patient load balancing through surveillance, modifications of existing referral agreements, coordinated expansion of resources, activation of regional crisis standards of care, and integration of pediatric critical care physicians from Harborview Medical Center as subject matter experts (SMEs). MEASUREMENTS AND MAIN RESULTS: The Washington and Oregon MOCCs managed 183 pediatric requests from hospitals unable to transfer pediatric patients between November 1, 2022, and December 14, 2022. Sixteen percent of requests were for children younger than 3 months and 37% were for children between 3 months and 1 year; most had acute viral respiratory disease. Requests for children older than 13 years old were primarily intentional drug ingestions. Fifty-eight percent were for critically ill children and 17% originated from critical access hospitals. Washington's SMEs were utilized in nearly a quarter of cases with the disposition changing in 38% of these. CONCLUSIONS: Washington and Oregon statewide MOCCs have leveraged centralized coordination to effectively load balance a surge in pediatric patients which has overwhelmed existing pediatric hospital resources. Centralized coordination and surveillance informed pediatric hospitals and policy makers of unmet clinical needs and facilitated rapid expansion of clinical capacity and modifications to referral processes. Integration of pediatric SMEs enabled efficient triage of these resources. MOCCs provide an adaptable centralized resource for addressing surge and have been effective in managing overwhelmed pediatric hospital resources in Washington and Oregon.

Structure and Rheology in Vertex Models under Cell-Shape-Dependent Active Stresses.

Biological cells can actively tune their intracellular architecture according to their overall shape. Here we explore the rheological implication of such coupling in a minimal model of a dense cellular material where each cell exerts an active mechanical stress along its axis of elongation. Increasing the active stress amplitude leads to several transitions. An initially hexagonal crystal motif is first destabilized into a solid with anisotropic cells whose shear modulus eventually vanishes at a first critical activity. Increasing activity beyond this first critical value, we find a re-entrant transition to a regime with finite hexatic order and finite shear modulus, in which cells arrange according to a rhombile pattern with periodically arranged rosette structures. The shear modulus vanishes again at a third threshold beyond which spontaneous tissue flows and topological defects of the nematic cell shape field arise. Flow and stress fields around the defects agree with active nematic theory, with either contractile or extensile signs, as also observed in several epithelial tissue experiments.

Curvature gradient drives polarized tissue flow in the Drosophila embryo.

Tissue flow during morphogenesis is commonly driven by local constriction of cell cortices, which is caused by the activation of actomyosin contractility. This can lead to long-range flows due to tissue viscosity. However, in the absence of cell-intrinsic polarized forces or polarity in forces external to the tissue, these flows must be symmetric and centered around the region of contraction. Polarized tissue flows have been previously demonstrated to arise from the coupling of such contractile flows to points of increased friction or adhesion to external structures. However, we show with experiments and modeling that the onset of polarized tissue flow in early Drosophila morphogenesis occurs independent of adhesion and is instead driven by a geometric coupling of apical actomyosin contractility to tissue curvature. Particularly, the onset of polarized flow is driven by a mismatch between the position of apical myosin activation and the position of peak curvature at the posterior pole of the embryo. Our work demonstrates how genetic and geometric information inherited from the mother interact to create polarized flow during embryo morphogenesis.

Stiffening of under-constrained spring networks under isotropic strain.

Disordered spring networks are a useful paradigm to examine macroscopic mechanical properties of amorphous materials. Here, we study the elastic behavior of under-constrained spring networks, i.e. networks with more degrees of freedom than springs. While such networks are usually floppy, they can be rigidified by applying external strain. Recently, an analytical formalism has been developed to predict the scaling behavior of the elastic network properties close to this rigidity transition. Here we numerically show that these predictions apply to many different classes of spring networks, including phantom triangular, Delaunay, Voronoi, and honeycomb networks. The analytical predictions further imply that the shear modulus G scales linearly with isotropic stress T close to the rigidity transition. However, this seems to be at odds with recent numerical studies suggesting an exponent between G and T that is smaller than one for some network classes. Using increased numerical precision and shear stabilization, we demonstrate here that close to the transition a linear scaling, G ∼ T, holds independent of the network class. Finally, we show that our results are not or only weakly affected by finite-size effects, depending on the network class.

Utilizing eye tracking to assess electronic health record use by pharmacists in the intensive care unit.

PURPOSE: A study was conducted using high-fidelity electronic health record (EHR)-based simulations with incorporated eye tracking to understand the workflow of critical care pharmacists within the EHR, with specific attention to the data elements most frequently viewed. METHODS: Eight critical care pharmacists were given 25 minutes to review 3 simulated intensive care unit (ICU) charts deployed in the simulation instance of the EHR. Using monitor-based eye trackers, time spent reviewing screens, clinical information accessed, and screens used to access specific information were reviewed and quantified to look for trends. RESULTS: Overall, pharmacists viewed 25.5 total and 15.1 unique EHR screens per case. The majority of time was spent looking at screens focused on medications, followed by screens displaying notes, laboratory values, and vital signs. With regard to medication data, the vast majority of screen visitations were to view information on opioids/sedatives and antibiotics. With regard to laboratory values, the majority of views were focused on basic chemistry and hematology data. While there was significant variance between pharmacists, individual navigation patterns remained constant across cases. CONCLUSION: The study results suggest that in addition to medication information, laboratory data and clinical notes are key focuses of ICU pharmacist review of patient records and that navigation to multiple screens is required in order to view these data with the EHR. New pharmacy-specific EHR interfaces should consolidate these elements within a primary interface.

Phase separation dynamics in deformable droplets.

Phase separation can drive spatial organization of multicomponent mixtures. For instance in developing animal embryos, effective phase separation descriptions have been used to account for the spatial organization of different tissue types. Similarly, separation of different tissue types is also observed in stem cell aggregates, where the emergence of a polar organization can mimic early embryonic axis formation. Here, we describe such aggregates as deformable two-phase fluid droplets, which are suspended in a fluid environment (third phase). Using hybrid finite-volume Lattice-Boltzmann simulations, we numerically explore the out-of-equilibrium routes that can lead to the polar equilibrium state of such a droplet. We focus on the interplay between spinodal decomposition and advection with hydrodynamic flows driven by interface tensions, which we characterize by a Peclet number Pe. Consistent with previous work, for large Pe the coarsening process is generally accelerated. However, for intermediate Pe we observe long-lived, strongly elongated droplets, where both phases form an alternating stripe pattern. We show that these "croissant" states are close to mechanical equilibrium and coarsen only slowly through diffusive fluxes in an Ostwald-ripening-like process. Finally, we show that a surface tension asymmetry between both droplet phases leads to transient, rotationally symmetric states whose resolution leads to flows reminiscent of Marangoni flows. Our work highlights the importance of advection for the phase separation process in finite, deformable systems.

Implementation of cellular bulk stresses in vertex models of biological tissues.

Vertex models describe biological tissues as tilings of polygons. In standard vertex models, the tissue dynamics result from a balance between isotropic stresses, which are associated with the bulk of the cells, and tensions associated with cell-cell interfaces. However, in this framework it is less obvious how to describe anisotropic stresses arising from the bulk of cells. In epithelia, such bulk anisotropic stresses could arise for instance through medial myosin fluctuations. Two recent publications-Tlili et al. (Proc Natl Acad Sci USA 116(51):25430-25439, 2019) and Comelles et al. (eLife 10:e57730, 2021)-have proposed different schemes to implement bulk anisotropic stresses in vertex models. Here we show that while both schemes transform in the same way under affine deformations, they lead to significantly different tissue dynamics. Our results are consistent with the interpretation that the Tilli et al. scheme describes bulk stresses that are uniform within each cell, while the Comelles et al. scheme corresponds to non-uniform bulk stresses. Finally, we wondered whether a standard vertex model can be fully expressed in terms of bulk cellular stresses alone. We find that, in general, neither scheme can mimic the vertex forces created by cell-cell interface tensions.

Rallying All Resources: A Multidisciplinary Innovation to Plan for the Projected COVID-19 Inpatient Surge.

BACKGROUND: The COVID-19 pandemic resulted in the need for hospitals to plan for a potential "surge" of COVID-19 patients. PROBLEM: Prior to the onset of the COVID-19 pandemic, our hospital adult acute care capacity ranged 90% to 100%, and a potential hospital surge was projected for Oregon that would exceed existing capacity. APPROACH: A multidisciplinary team with stakeholders from nursing leadership, nursing units, nurse-led case management, and physicians from hospital medicine was convened to explore the conversion of an ambulatory surgical center to overflow patient acute care capacity. OUTCOMES: A protocol was rapidly created and implemented, ultimately transferring 12 patients to an ambulatory surgery unit. CONCLUSIONS: This project highlighted the ability for stakeholders and innovators to work together in an interprofessional, multidisciplinary way to rapidly create an overflow unit. While this innovation was designed to address COVID-19, the lessons learned can be applied to any other emerging infectious disease or acute care capacity crisis.

Statewide Real-Time Tracking of Beds and Ventilators During Coronavirus Disease 2019 and Beyond.

This brief report describes the rapid deployment of a real-time electronic tracking board for all hospitals in the state of Oregon. In preparation for the coronavirus disease 2019 surge on hospital resources, and in collaboration across health systems, with health authorities and an industry partner, we combined existing infrastructures to create the first automated tracking board for our entire state, including bed types by health system and geographic area, and with granularity to the individual unit level for each participating hospital. At the time of submission, we have a live snapshot of 87% of beds in the state, including real-time ventilator data across eight health systems. The tracking board allows for rapid assessment of available bed and ventilator resources and pulls electronic health record data that is created through normal care processes rather than relying upon manual entry. It is updated every 5 minutes and is drillable from state to unit level. Together these factors make the data actionable, which is essential in a crisis. The new tracking system integrates seamlessly with our preexisting statewide, manually updated tracking board via bidirectional data sharing to ensure existing processes across the state can continue. This new tool allows any health system in our state to visualize occupancy by type and location in real time. Amid pandemic uncertainty, having a reliable tool for tracking critical hospital resources will enhance our statewide ability to maintain healthcare functionality in a world with coronavirus disease 2019.

Anisotropy links cell shapes to tissue flow during convergent extension.

Within developing embryos, tissues flow and reorganize dramatically on timescales as short as minutes. This includes epithelial tissues, which often narrow and elongate in convergent extension movements due to anisotropies in external forces or in internal cell-generated forces. However, the mechanisms that allow or prevent tissue reorganization, especially in the presence of strongly anisotropic forces, remain unclear. We study this question in the converging and extending Drosophila germband epithelium, which displays planar-polarized myosin II and experiences anisotropic forces from neighboring tissues. We show that, in contrast to isotropic tissues, cell shape alone is not sufficient to predict the onset of rapid cell rearrangement. From theoretical considerations and vertex model simulations, we predict that in anisotropic tissues, two experimentally accessible metrics of cell patterns-the cell shape index and a cell alignment index-are required to determine whether an anisotropic tissue is in a solid-like or fluid-like state. We show that changes in cell shape and alignment over time in the Drosophila germband predict the onset of rapid cell rearrangement in both wild-type and snail twist mutant embryos, where our theoretical prediction is further improved when we also account for cell packing disorder. These findings suggest that convergent extension is associated with a transition to more fluid-like tissue behavior, which may help accommodate tissue-shape changes during rapid developmental events.

Inhaled Iloprost Versus Epoprostenol in Heart Transplant Recipients.

BACKGROUND: Acute right ventricular dysfunction is a challenging problem in the immediate postoperative period following orthotopic heart transplantation. There are no prior reports of the use of inhaled iloprost in the setting of acute right ventricular dysfunction and acute pulmonary hypertension. Our hypothesis was that the use of inhaled iloprost in heart transplant recipients would be associated with a reduction in the duration of mechanical ventilation compared to patients being treated with continuous inhaled epoprostenol. Additionally, we hypothesized that the change in inhaled vasodilatory therapy would not be associated with a significant change in postoperative bleeding or use of vasoactive medications. METHODS: We reviewed charts of 80 consecutive patients undergoing heart transplantation at our institution between July 1, 2003, and August 8, 2008. From July 1, 2003 to March 13, 2006, epoprostenol was our primary vasodilator; subsequently epoprostenol was replaced with iloprost. We included 39 subjects who received epoprostenol and 40 subjects who received iloprost. Data were collected on the use of inhaled vasodilators, comparing periods before and after our institutional protocol change. Demographic data, hemodynamic values, drain output, and any requirement for vasoactive medication infusions were collected. Our primary end point was the natural logarithm of duration of mechanical ventilation. Secondary end points were hemodynamic values and length of ICU and hospital stay. RESULTS: Subjects treated with iloprost were mechanically ventilated for 0.36 ± 0.20 (adjusted mean ± SE) log days, which was shorter (P = .033) than the 1.00 ± 0.22 logdays for subjects treated with epoprostenol. This resulted in an estimated median number of mechanically ventilated days for subjects treated with epoprostenol that was approximately 1.9 times longer than the estimated median number of ventilated days for subjects treated with iloprost (95% CI 1.05-3.4, P = .033). There were no differences in safety end points or length of hospital stay. CONCLUSIONS: Use of inhaled iloprost was associated with shorter duration of mechanical ventilation compared to inhaled epoprostenol, without safety concerns.

A minimal-length approach unifies rigidity in underconstrained materials.

We present an approach to understand geometric-incompatibility-induced rigidity in underconstrained materials, including subisostatic 2D spring networks and 2D and 3D vertex models for dense biological tissues. We show that in all these models a geometric criterion, represented by a minimal length [Formula: see text], determines the onset of prestresses and rigidity. This allows us to predict not only the correct scalings for the elastic material properties, but also the precise magnitudes for bulk modulus and shear modulus discontinuities at the rigidity transition as well as the magnitude of the Poynting effect. We also predict from first principles that the ratio of the excess shear modulus to the shear stress should be inversely proportional to the critical strain with a prefactor of 3. We propose that this factor of 3 is a general hallmark of geometrically induced rigidity in underconstrained materials and could be used to distinguish this effect from nonlinear mechanics of single components in experiments. Finally, our results may lay important foundations for ways to estimate [Formula: see text] from measurements of local geometric structure and thus help develop methods to characterize large-scale mechanical properties from imaging data.

Inferring statistical properties of 3D cell geometry from 2D slices.

Although cell shape can reflect the mechanical and biochemical properties of the cell and its environment, quantification of 3D cell shapes within 3D tissues remains difficult, typically requiring digital reconstruction from a stack of 2D images. We investigate a simple alternative technique to extract information about the 3D shapes of cells in a tissue; this technique connects the ensemble of 3D shapes in the tissue with the distribution of 2D shapes observed in independent 2D slices. Using cell vertex model geometries, we find that the distribution of 2D shapes allows clear determination of the mean value of a 3D shape index. We analyze the errors that may arise in practice in the estimation of the mean 3D shape index from 2D imagery and find that typically only a few dozen cells in 2D imagery are required to reduce uncertainty below 2%. Even though we developed the method for isotropic animal tissues, we demonstrate it on an anisotropic plant tissue. This framework could also be naturally extended to estimate additional 3D geometric features and quantify their uncertainty in other materials.

Electromagnetic Interference with Protocolized Electrosurgery Dispersive Electrode Positioning in Patients with Implantable Cardioverter Defibrillators.

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: Electromagnetic interference from monopolar electrosurgery may disrupt implantable cardioverter defibrillators.Current management recommendations by the American Society of Anesthesiologists and Heart Rhythm Society are based on expert clinical opinion since there is a paucity of data regarding the risk of electromagnetic interference to implantable cardioverter defibrillators during surgery. WHAT THIS ARTICLE TELLS US THAT IS NEW: With protocolized electrosurgery dispersive electrode positioning in patients with implantable cardioverter defibrillators, the risk of clinically meaningful electromagnetic interference was 7% in above-the-umbilicus noncardiac surgery and 0% in below-the-umbilicus surgery. In cardiac surgery, clinically meaningful electromagnetic interference with use of an underbody dispersive electrode was 29%.Despite protocolized dispersive electrode positioning, the risk of electromagnetic interference in above-the-umbilicus surgery is high, supporting recommendations to suspend antitachycardia therapy when monopolar electrosurgery is used above the umbilicus.With protocolized dispersive electrode positioning, the risk of electromagnetic interference in below-the-umbilicus surgery is negligible, implying that suspending antitachycardia therapy might be unnecessary in these cases.With an underbody dispersive electrode, the risk of electromagnetic interference in cardiac surgery is high. BACKGROUND: The goal of this study was to determine the occurrence of intraoperative electromagnetic interference from monopolar electrosurgery in patients with an implantable cardioverter defibrillator undergoing surgery. A protocolized approach was used to position the dispersive electrode. METHODS: This was a prospective cohort study including 144 patients with implantable cardioverter defibrillators undergoing surgery between May 2012 and September 2016 at an academic medical center. The primary objectives were to determine the occurrences of electromagnetic interference and clinically meaningful electromagnetic interference (interference that would have resulted in delivery of inappropriate antitachycardia therapy had the antitachycardia therapy not been programmed off) in noncardiac surgeries above the umbilicus, noncardiac surgeries at or below the umbilicus, and cardiac surgeries with the use of an underbody dispersive electrode. RESULTS: The risks of electromagnetic interference and clinically meaningful electromagnetic interference were 14 of 70 (20%) and 5 of 70 (7%) in above-the-umbilicus surgery, 1 of 40 (2.5%) and 0 of 40 (0%) in below-the-umbilicus surgery, and 23 of 34 (68%) and 10 of 34 (29%) in cardiac surgery. Had conservative programming strategies intended to reduce the risk of inappropriate antitachycardia therapy been employed, the occurrence of clinically meaningful electromagnetic interference would have been 2 of 70 (2.9%) in above-the-umbilicus surgery and 3 of 34 (8.8%) in cardiac surgery. CONCLUSIONS: Despite protocolized dispersive electrode positioning, the risks of electromagnetic interference and clinically meaningful electromagnetic interference with surgery above the umbilicus were high, supporting published recommendations to suspend antitachycardia therapy whenever monopolar electrosurgery is used above the umbilicus. For surgery below the umbilicus, these risks were negligible, implying that suspending antitachycardia therapy is likely unnecessary in these patients. For cardiac surgery, the risks of electromagnetic interference and clinically meaningful electromagnetic interference with an underbody dispersive electrode were high. Conservative programming strategies would not have eliminated the risk of clinically meaningful electromagnetic interference in either noncardiac surgery above the umbilicus or cardiac surgery.

Cohort Study of Albumin versus Lactated Ringer's for Postoperative Cardiac Surgery Fluid Resuscitation in the Intensive Care Unit.

PURPOSE: A new postcardiac surgery fluid resuscitation strategy was implemented in our cardiovascular intensive care unit (CVICU) to implement evidence-based practice. We transitioned from a primarily albumin fluid-based strategy to a lactated Ringer's fluid-based strategy. We sought to determine whether a new postoperative fluid resuscitation strategy significantly altered the fluid composition for postcardiac surgery patients and what effect that would have on fluid resuscitation costs. Secondary outcomes included various clinical parameters. METHODS: This was a retrospective, before-and-after cohort study of postcardiac surgery patients in an academic quaternary care intensive care unit (ICU) during two different 3-month time intervals. A total of 192 patients were studied: 108 pre-intervention and 84 post intervention. The intervention consisted of surveying stakeholders regarding potential concerns of reducing albumin use, an educational intervention addressing those concerns, and removing albumin from the routine postcardiac surgery ICU admission order set. RESULTS: In the post intervention time period, albumin use decreased significantly compared to pre-invention (p<0.01), and lactated Ringer's volume increased significantly (p<0.01). However, total volume administered for resuscitation was not significantly different pre- and post intervention (1129 ml vs. 1369 ml, p=0.136). There were a net-cost savings between the pre-intervention and post intervention period (3 mo) of $30,549.20, with the albumin reduction accounting for most of those savings. Secondary outcomes were not significantly different between groups. CONCLUSIONS: An albumin fluid reduction strategy was successful in reducing the amount of albumin fluid used for postcardiac surgery patients and resulted in substantial cost savings.

No unjamming transition in a Voronoi model of biological tissue.

Vertex models are a popular approach to simulating the mechanical and dynamical properties of dense biological tissues, describing the tissue as a network of polygons. Recently a class of two-dimensional vertex models was shown to exhibit a disordered rigidity transition controlled by the preferred cellular geometry, which was subsequently echoed by experimental findings. An attractive variant of these models uses a Voronoi tessellation to describe the cells, which reduces the number of degrees of freedom as compared the original vertex model. The Voronoi model was also endowed with a non-equilibrium model of cellular motility, leading to rich, glassy behavior. This glassy behavior was suggested to be inextricably linked to an underlying jamming transition. We test this conjecture, exploring the low-effective-temperature limit of the 2D Voronoi model by studying cell trajectories from detailed dynamical simulations in combination with rigidity measurements of energy-minimized disordered cell configurations. We find that the zero-temperature limit of this model has no unjamming transition. We show that this absence of an unjamming transition is intimately linked to the marginality of the model, i.e. the fact that the constraints imposed on cell areas and perimeters precisely balance the number of degrees of freedom in the model. Our work suggests that constraint counting arguments are useful to understand rigidity in a broad class of models of dense biological tissues.

Periprocedural anticoagulation during left atrial ablation: interrupted and uninterrupted vitamin K-antagonists or uninterrupted novel anticoagulants.

BACKGROUND: There is a lack of data on anticoagulation requirements during ablation of atrial fibrillation (AF). This study compares different oral anticoagulation (OAC) strategies to evaluate risk of bleeding and thromboembolic complications. METHODS: We conducted a single-centre study in patients undergoing left atrial ablation of AF. Three groups were defined: 1) bridging: interrupted vitamin-K-antagonists (VKA), INR ≤2, and bridging with heparin; 2) VKA: uninterrupted VKA and INR of > 2; 3) DOAC: uninterrupted direct oral anticoagulants. Bleeding complications, thromboembolic events and peri-procedural heparin doses were assessed. RESULTS: In total, 780 patients were documented. At 48 h, major complications were more common in the bridging group compared to uninterrupted VKA and DOAC groups (OR: 3.42, 95% CI: 1.29-9.10 and OR: 3.01, 95% CI: 1.19-7.61), largely driven by differences in major pericardial effusion (OR: 4.86, 95% CI: 1.56-15.99 and OR: 4.466, 95% CI, 1.52-13.67) and major vascular events (OR: 2.92, 95% CI: 0.58-14.67 and OR: 9.72, 95% CI: 1.00-94.43). Uninterrupted VKAs and DOACs resulted in similar odds of major complications (overall OR: 1.14, 95% CI: 0.44-2.92), including cerebrovascular events (OR: 1.21, 95% CI: 0.27-5.45). However, whereas only TIAs were observed in DOAC and bridging groups, strokes also occurred in the VKA group. Rates of minor complications (pericardial effusion, vascular complications, gastrointestinal hemorrhage) and major/minor groin hemorrhage were similar across groups. CONCLUSION: Our dataset illustrates that uninterrupted VKA and DOAC have a better risk-benefit profile than VKA bridging. Bridging was associated with a 4.5× increased risk of complications and should be avoided, if possible.

Cell volume changes contribute to epithelial morphogenesis in zebrafish Kupffer's vesicle.

How epithelial cell behaviors are coordinately regulated to sculpt tissue architecture is a fundamental question in biology. Kupffer's vesicle (KV), a transient organ with a fluid-filled lumen, provides a simple system to investigate the interplay between intrinsic cellular mechanisms and external forces during epithelial morphogenesis. Using 3-dimensional (3D) analyses of single cells we identify asymmetric cell volume changes along the anteroposterior axis of KV that coincide with asymmetric cell shape changes. Blocking ion flux prevents these cell volume changes and cell shape changes. Vertex simulations suggest cell shape changes do not depend on lumen expansion. Consistent with this prediction, asymmetric changes in KV cell volume and shape occur normally when KV lumen growth fails due to leaky cell adhesions. These results indicate ion flux mediates cell volume changes that contribute to asymmetric cell shape changes in KV, and that these changes in epithelial morphology are separable from lumen-generated forces.