Effects of a pressure release on virus retention with the Ultipor DV20 membrane

2013 ◽  
Vol 111 (3) ◽  
pp. 545-551 ◽  
Author(s):  
Melissa A. Woods ◽  
Andrew L. Zydney
Keyword(s):  
Pressure Release ◽  
Virus Retention

Behaviour of air injection nozzles in dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 25-35 ◽  
Author(s):  
E. M. Rykaart ◽  
J. Haarhoff
Keyword(s):  
Bubble Coalescence ◽  
Second Phase ◽  
Initial Growth ◽  
Two Phase ◽  
Dissolved Air Flotation ◽  
Nozzle Orifice ◽  
Pressure Release ◽  
Air Volume ◽  
Air Flotation ◽  
Dissolved Air

A simple two-phase conceptual model is postulated to explain the initial growth of microbubbles after pressure release in dissolved air flotation. During the first phase bubbles merely expand from existing nucleation centres as air precipitates from solution, without bubble coalescence. This phase ends when all excess air is transferred to the gas phase. During the second phase, the total air volume remains the same, but bubbles continue to grow due to bubble coalescence. This model is used to explain the results from experiments where three different nozzle variations were tested, namely a nozzle with an impinging surface immediately outside the nozzle orifice, a nozzle with a bend in the nozzle channel, and a nozzle with a tapering outlet immediately outside the nozzle orifice. From these experiments, it is inferred that the first phase of bubble growth is completed at approximately 1.7 ms after the start of pressure release.

scholarly journals Mechanistic insights into flow-dependent Virus retention in different nanofilter membranes

2021 ◽  
pp. 119548
Author(s):  
Remo Leisi ◽  
Eleonora Widmer ◽  
Barry Gooch ◽  
Nathan J. Roth ◽  
Carlos Ros
Keyword(s):  
Virus Retention

HIGH FREQUENCY PERCUSSIVE VENTILATION CAN MIMIC AIRWAY PRESSURE RELEASE VENTILATION IN A TEST LUNG MODEL

2004 ◽  
Vol 32 (Supplement) ◽  
pp. A38
Author(s):  
Faera L Byerly ◽  
Bruce A Cairns ◽  
Kathy A Short ◽  
John A Haithcock ◽  
Lynn Shapiro ◽  
...  
Keyword(s):  
High Frequency ◽  
Airway Pressure ◽  
Airway Pressure Release Ventilation ◽  
Lung Model ◽  
Test Lung ◽  
Pressure Release ◽  
Pressure Release Ventilation

scholarly journals Utilization of Airway Pressure Release Ventilation as a Rescue Strategy in COVID-19 Patients: A Retrospective Analysis

2021 ◽  
pp. 088506662110308
Author(s):  
Omar Mahmoud ◽  
Deep Patadia ◽  
James Salonia
Keyword(s):  
Retrospective Analysis ◽  
Airway Pressure ◽  
Minute Ventilation ◽  
Invasive Mechanical Ventilation ◽  
Airway Pressure Release Ventilation ◽  
Inspiratory Time ◽  
Predicted Body Weight ◽  
Pressure Release ◽  
Refractory Hypoxemia ◽  
Pressure Release Ventilation

Background: Airway Pressure Release Ventilation (APRV) is a pressure controlled intermittent mandatory mode of ventilation characterized by prolonged inspiratory time and high mean airway pressure. Several studies have demonstrated that APRV can improve oxygenation and lung recruitment in patients with Acute Respiratory Distress Syndrome (ARDS). Although most patients with COVID-19 meet the Berlin criteria for ARDS, hypoxic respiratory failure due to COVID-19 may differ from traditional ARDS as patients often present with severe, refractory hypoxemia and significant variation in respiratory system compliance. To date, no studies investigating APRV in this patient population have been published. The aim of this study was to evaluate the effectiveness of APRV as a rescue mode of ventilation in critically ill patients diagnosed with COVID-19 and refractory hypoxemia. Methods: We conducted a retrospective analysis of patients admitted with COVID-19 requiring invasive mechanical ventilation who were treated with a trial of APRV for refractory hypoxemia. PaO2/FIO2 (P/F ratio), ventilatory ratio and ventilation outputs before and during APRV were compared. Results: APRV significantly improved the P/F ratio and decreased FIO2 requirements. PaCO2 and ventilatory ratio were also improved. There was an increase in tidal volume per predicted body weight during APRV and a decrease in total minute ventilation. On multivariate analysis, higher inspiratory to expiratory ratio (I: E) and airway pressure were associated with greater improvement in P/F ratio. Conclusions: APRV may improve oxygenation, alveolar ventilation and CO2 clearance in patients with COVID-19 and refractory hypoxemia. These effects are more pronounced with higher airway pressure and inspiratory time.

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