Numerical simulation of the dynamics of dust in a rotary dust collector with an adjustable air flow

A rotary dust collector has been developed that works on the principle of a centrifugal separator. A feature of its design is the presence of a bypass recirculation channel of cleaned air with a flow regulator, two outlet pipes with flow uncoilers in the form of spiral channels. The calculation of the motion of dust particles with a density of 3000 kg/m3 and a diameter of 1 to 100 microns has been performed. Research has been carried out to improve the efficiency of the apparatus using a central compositional plan and to establish rational design and operating parameters of the mixer for recirculating and purified air.

Control of the expiratory flow in a lung model and in healthy volunteers with an adjustable flow regulator: a combined bench and randomized crossover study

Background Pursed-lips breathing (PLB) is a technique to attenuate small airway collapse by regulating the expiratory flow. During mandatory ventilation, flow-controlled expiration (FLEX), which mimics the expiratory flow course of PLB utilizing a digital system for measurement and control, was shown to exert lung protective effects. However, PLB requires a patient’s participation and coordinated muscular effort and FLEX requires a complex technical setup. Here, we present an adjustable flow regulator to mimic PLB and FLEX, respectively, without the need of a patient’s participation, or a complex technical device. Methods Our study consisted of two parts: First, in a lung model which was ventilated with standard settings (tidal volume 500 ml, respiratory rate 12 min−1, positive end-expiratory pressure (PEEP) 5 cmH2O), the possible reduction of the maximal expiratory flow by utilizing the flow regulator was assessed. Second, with spontaneously breathing healthy volunteers, the short-term effects of medium and strong expiratory flow reduction on airway pressure, the change of end-expiratory lung volume (EELV), and breathing discomfort was investigated. Results In the lung model experiments, expiratory flow could be reduced from − 899 ± 9 ml·s−1 down to − 328 ± 25 ml·s−1. Thereby, inspiratory variables and PEEP were unaffected. In the volunteers, the maximal expiratory flow of − 574 ± 131 ml·s−1 under baseline conditions was reduced to − 395 ± 71 ml·s−1 for medium flow regulation and to − 266 ± 58 ml·s−1 for strong flow regulation, respectively (p < 0.001). Accordingly, mean airway pressure increased from 0.6 ± 0.1 cmH2O to 2.9 ± 0.4 cmH2O with medium flow regulation and to 5.4 ± 2.4 cmH2O with strong flow regulation, respectively (p < 0.001). The EELV increased from baseline by 31 ± 458 ml for medium flow regulation and 320 ± 681 ml for strong flow regulation (p = 0.033). The participants rated breathing with the flow regulator as moderately uncomfortable, but none rated breathing with the flow regulator as intolerable. Conclusions The flow regulator represents an adjustable device for application of a self-regulated expiratory resistive load, representing an alternative for PLB and FLEX. Future applications in spontaneously breathing patients and patients with mandatory ventilation alike may reveal potential benefits. Trial registration: DRKS00015296, registered on 20th August, 2018; URL: https://www.drks.de/drks_web/setLocale_EN.do.

The impact of atrial flow regulator implantation on hemodynamic parameters in patients with heart failure

Background Left atrial decompression has emerged a new option to treat patients with heart failure and dyspnea at rest or during exercise. Here we report the impact of atrial flow regulator (AFR) implantation on hemodynamic parameters in patients at our center with heart failure and with reduced (HFrEF) or with preserved left ventricular ejection fraction (HFpEF).Material and methods The PRELIEVE trial is designed to assess the safety and efficacy of the AFR in patients with HFrEF or HFpEF. Patients with left ventricular end-diastolic pressure ≥15 mmHg at rest or ≥25 mmHg during exercise and with an ejection fraction ≥15 % were enrolled. Echocardiographic data, 6‑min walking distance, Kansas City Cardiomyopathy Questionnaire, and brain natriuretic peptide levels were assessed pre- and post-AFR implantation and at 3 mos. Invasive hemodynamic assessments were also performed pre- and post-AFR implantation and at 3 mos.Results 27 (69.2 %) patients with HFrEF and 12 (30.8 %) patients with HFpEF at our center were enrolled in this study. A significant decrease was observed in pulmonary arterial wedge pressure regardless of EF (p=0.007 for HFrEF and p=0.03 for HFpEF). No significant difference of mean pulmonary arterial pressure, right arterial pressure and cardiac output (CO) existed at 3 months compared with pre-implantation baseline values.Conclusion AFR implantation led to decrease in left ventricle filling pressure without the deleterious impact on CO and right heart function regardless of ejection fraction.

Emergency Use of Occlutech® Atrial Flow Regulator Device Facilitates Weaning From Veno-Arterial Extracorporeal Membrane Oxygenation in a Patient With Severe Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a severe and progressive disease. Treatment options include anti-PAH medications, continuous intravenous therapies, and diuretics. Lung transplant is required in many cases. Atrial septostomy is an under recognized option in symptomatic patients on maximal PAH therapy. However, creating a sustainable and restrictive atrial communication is challenging with existing devices. We describe emergency use of the Occlutech® Atrial Flow Regulator, a novel device, in a 35-year-old female with PAH supported on veno-arterial extracorporeal membrane oxygenation after postpartum decompensation.

Planned reduction in Fontan fenestration size using the Atrial Flow Regulator

Fontan fenestration allows right-to-left shunting increasing cardiac output and oxygen delivery. Increased shunting occurs as cardiac function and ventricular end-diastolic pressures improve, potentially decreasing oxygen saturation. Complete closure may result in impaired Fontan haemodynamics and low cardiac output; however, there are no dedicated devices to reduce fenestration size. We describe Fontan fenestration size reduction using the Atrial Flow Regulator.

Investigation on the Characteristics of a Combination Microflow Control Valve

Flow control valves have broad application prospects in aviation hydraulic systems. This paper proposes a combination microflow control valve (CMCV) instead of the traditional valve to optimize the performance. Influences of structural parameters of CMCV on its characteristics are numerically investigated to determine the static and dynamic characteristics of CMCV. The calculation results indicate that there is a negative feedback control between stages of the flow regulator, the orifice pressure drop is compensated, and the flow regulation deviation is reduced. The orifice area and the flow regulator valve port area have significant effects on flow characteristics. The diameter of orifice, the spring stiffness, the number of throttle holes, and the ultimate displacement of sleeve are positively correlated with the flow rate stability value of the valve. The valve port flow area gradient and initial overlap of the flow regulator affect the flow rate fluctuation range and response time of CMCV.

Transcatheter creation of a pulmonary artery to left atrial fenestration in a failing Fontan circulation using the Atrial Flow Regulator (AFR)

Transcatheter creation of an interatrial communication using the Occlutech Atrial Flow Regulator Device for pulmonary hypertension or heart failure is well described. We report a case of an 8-year-old boy with a failing Fontan circulation, in whom the Atrial Flow Regulator was used to successfully create a fenestration between the pulmonary artery and left atrium, improving his clinical condition.