Time to resuscitate cardiopulmonary resuscitation! The 3R/CPR: Refill-Recoil-Rebound.

Introduction Sudden cardiac arrest (SCA) remains a major health issue worldwide with gloomy outcomes due to poor perfusion of cardiopulmonary resuscitation (CPR), deemed unsuitable for hemostatic conditions, cardiotorsal anatomy, electrophysiology and thoracic biomechanics. Alternatively, we propose a new management, implementing rational mobilization of stagnant blood: manually with a novel technique of cardiac massage and mechanically with a circulatory flow restoration (CFR) device. Methods Simulated chest compressions were performed through the 5th intercostal space in professional Lifeguards volunteers, placed in the left lateral decubitus position with raised legs and abdominal compression. Expected results Compared to CPR, bypassing the sternal barrier, refilling the heart and then compressing the chest with a recoil-rebound maneuver (3R / CPR) can significantly promote ROSC. Results of CFR device were previously demonstrated. Conclusion 3R/CPR adapts human morphology promoting adequate perfusion and ROSC safely, under all circumstances. Preclinical computational models can confirm the effectiveness of 3R/CPR versus CPR.

Homogeneous and re-circulatory gas–liquid flow in a bubble column: A numerical investigation using OpenFOAM

This work presents the influence of the sparger opening area, gas velocity, and bubble size on hydrodynamics and transition of the flow regime from uniform to re-circulatory in a rectangular bubble column using OpenFOAM. In the course of development of the model, the effect of several drag closures and lift on the predictability of the CFD model was studied by comparing the predictions with published experimental results. Reynolds number-based drag closure was found to be suitable for uniform sparger whereas Tsuchiya drag (Tsuchiya et al. in Chem Eng Sci 52:3053–3066, 1997. https://doi.org/10.1016/S0009-2509(97)00127-9) was used to simulate gas–liquid flow for other spargers. Simulations were performed for seven different spargers with opening area 18–100% (superficial gas velocity of 2.9–5.8 cm/s) and bubble size of 2–8 mm. The smaller opening area and higher gas velocity promote the re-circulatory flow in the bubble column. Change in bubble size affects the hydrodynamics due to change in lift and drag forces.

SIMULATION OF THE CIRCULATION FLOW AROUND CIRCULAR PIPES BY A FLOW OF HOMOGENEOUS OR LAYERED BOUNDED LIQUID

The paper studies the uncirculatory and circulatory flow around long circular pipes with a flow of homogeneous and two-layer liquid while limiting the flow to a solid bottom and a solid lid. The method of flat sections is used. The boundaries are modeled by dipoles of unknown intensity, whose density is determined from the boundary conditions. Calculations of the lifting force and wave resistance are presented.

Development of a Pulsatile Flow-Generating Circulatory Assist Device (K-Beat) for Use with Veno-Arterial Extracorporeal Membrane Oxygenation in a Pig Model Study

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) preserves the life of heart failure patients by providing an adequate oxygen supply and blood flow to vital organs. For patients with severe cardiogenic shock secondary to acute myocardial infarction or acute myocarditis, V-A ECMO is commonly used as the first choice among cardiac circulatory support devices. While V-A ECMO generates circulatory flow using a centrifugal pump, the provision of pulsatile flow is difficult. We previously reported our development of a new circulatory flow assist device (K-beat) for cardiac management with pulsatile flow. To obtain more efficient pulsatile assist flow (diastolic augmentation), an electrocardiogram (ECG)-analyzing device that can detect R waves and T waves increases the assist flow selectively in the diastole phase by controlling (opening and closing) the magnetic valve of the tamper. Here, we describe the first use of the K-beat on a large animal in combination with a clinical device. In addition, the diastolic augmentation effect of the K-beat as a circulatory flow assist device was examined in a pig V-A ECMO model. The K-beat was stopped every 60 min for a period of a few minutes, and blood pressure waveforms in the pulsatile and non-pulsatile phases were checked. This experiment showed that stable V-A ECMO could be achieved and that hemodynamics were managed in all animals. The pulsatile flow was provided in synchrony with the ECG in all cases. A diastolic augmentation waveform of femoral arterial pressure was confirmed in the pulsatile phase. K-beat could be useful in patients with severe heart failure.

Tissue failure propagation as mediated by circulatory flow

ABSTRACTAging is driven by subcellular processes that are relatively well-understood. However the qualitative mechanisms and quantitative dynamics of how these micro-level failures cascade to a macro-level catastrophe in a tissue or organs remain largely unexplored. Here we experimentally and theoretically study how cell failure propagates in a synthetic tissue in the presence of advective flow. We argue that cells secrete cooperative factors, thereby forming a network of interdependence governed by diffusion and flow, which fails with a propagating front parallel to advective circulation.SIGNIFICANCEMortality rates typically increase for complex organisms as they age. This leads us to suggest that aging depends on interactions between cells. As cells become damaged, the effect propagates to other cells, eventually leading to a systemic catastrophe. Yet it is unclear how this failure dynamically propagates. Here we present experiments with synthetic tissues and analogous analytical models to investigate the dynamics of failure propagation. Our main contribution is a detailed investigation of failure propagation when interactions are mediated by advective flow. We find analytical expressions for when a pronounced propagation occurs, its velocity, and acceleration in terms of system parameters.

On the effect of circulatory flow around objects in marine medium and atmosphere

Analytical expressions of the hydrodynamic reaction of a point dipole in two-layer circulatory fluid flow around it are obtained. The dependence of the wave resistance and the lift force on the flow velocity, the density jump, the circulation and the depth of the sea is investigated. It is shown that the influence of the velocity circulation leads to a change in the lift force acting on the dipole. Moreover, such changes are reversible in a relatively narrow range of the velocity of flow around the pipeline. Along with the pipeline, such features in the nature of the effect of circulation on the lift force can be manifested for self-propelled underwater objects and aerial vehicles.

The Global Stability of 2-D Subsonic Circulatory Flows for the Steady Isothermal Gas

This paper is a complement of our work in (Cui & Li, 2011) where we have established the global subsonic circulatory solution for the polytropic gas. In this paper, we are concerned with the global stability of the 2-D subsonic circulatory flow around a perturbed circular body for the isothermal gas. The flow is assumed to be isothermal, isentropic, irrotational and described by a steady Euler equations, which can be reduced into a second order quasilinear elliptic equation in a exterior domain with suitable physical conditions. The unique existence and the state of the flow at infinity are obtained under nature physical assumption.