Assessment of mask efficiency for preventing transmission of airborne illness through aerosols and water vapor

Background: Currently the Center for Disease Control has advised the use of face coverings to prevent transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to those who are unvaccinated. This study seeks to evaluate if cloth masks have increased efficiency with the addition of a filter material. Methods: An adult airway and test lung model were exposed to nebulized ‘coarse’ aerosol droplets (0.5-11 µm) and humidified ‘fine’ water vapor particles (0.03-0.05 µm). Aerosol was quantified based on particles deposited on the face, airway and lung model. Tracheal humidity levels characterized fine particle permeability. Both phases of testing were conducted by evaluating the following testing conditions: 1) no mask;2) cloth mask;3) cloth mask with Swiffer™ filter;4) cloth mask with Minimum Efficiency Reporting Value (MN1 -https://media.proquest.com/media/hms/PFT/1/hK3pM?_a=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%3D%3D&_s=7m0CVC1lZWe%2FPfCJ7CyMM2ys0bg%3D ERV) 15 filter;4) cloth mask with PM2.5 filter 5) surgical mask and 6) N95 respirator. Results: All mask conditions provided greater filtration from coarse particles when compared to no mask (P<0.05). All cloth mask with filter combinations were better at stopping fine particles in comparison to no mask. A cloth mask without a filter and surgical mask performed similarly to no mask with fine particles (P<0.05). The cloth mask with MERV 15 filter and the surgical mask performed similarly to the N95 with course particles, while the cloth mask with Swiffer™ performed similarly to the N95 with the fine particles (P<0.05). Conclusions: Respiratory viruses including SARS-CoV-2 and influenza are spread through exposure to respiratory secretions that are aerosolized by infected individuals. The findings from this study suggest that a mask can filter these potentially infectious airborne particles.

Performance Characteristics of a Novel 3D-Printed Bubble Intermittent Mandatory Ventilator (B-IMV) for Adult Pulmonary Support.

The COVID-19 pandemic has brought attention to the need for developing effective respiratory support that can be rapidly implemented during critical surge capacity scenarios in healthcare settings. Lung support with bubble continuous positive airway pressure (B-CPAP) is a well-established therapeutic approach for supporting neonatal patients. However, the effectiveness of B-CPAP in larger pediatric and adult patients has not been addressed. Using similar principles of B-CPAP pressure generation, application of intermittent positive pressure inflations above CPAP could support gas exchange and high work of breathing levels in larger patients experiencing more severe forms of respiratory failure. This report describes the design and performance characteristics of the BubbleVent, a novel 3D-printed valve system that combined with commonly found tubes, hoses, and connectors can provide intermittent mandatory ventilation (IMV) suitable for adult mechanical ventilation without direct electrification. Testing of the BubbleVent was performed on a passive adult test lung model and compared with a critical care ventilator commonly used in tertiary care centers. The BubbleVent was shown to deliver stable PIP and PEEP levels, as well as timing control of breath delivery that was comparable with a critical care ventilator.

Breath-Synchronized Nebulized Surfactant in a Porcine Model of Acute Respiratory Distress Syndrome.

OBJECTIVES: Effective treatment options for surfactant therapy in acute respiratory distress syndrome and coronavirus disease 2019 have not been established. To conduct preclinical studies in vitro and in vivo to evaluate efficiency, particle size, dosing, safety, and efficacy of inhaled surfactant using a breath-synchronized, nebulized delivery system in an established acute respiratory distress syndrome model. DESIGN: Preclinical study. SETTING: Research laboratory. SUBJECTS: Anesthetized pigs. INTERVENTION: In vitro analysis included particle size distribution and inhaled dose during simulated ventilation using a novel breath-synchronized nebulizer. Physiologic effects of inhaled aerosolized surfactant (treatment) were compared with aerosolized normal saline (control) in an adult porcine model (weight of 34.3 ± 0.6 kg) of severe acute respiratory distress syndrome (Pao2/Fio2 <100) with lung lavages and ventilator-induced lung injury during invasive ventilation. MEASUREMENTS AND MAIN RESULTS: Mass median aerosol diameter was 2.8 µm. In vitro dose delivered distal to the endotracheal tube during mechanical ventilation was 85% ± 5%. Nebulizers were functional up to 20 doses of 108 mg of surfactant. Surfactant-treated animals (n = 4) exhibited rapid improvement in oxygenation with nearly full recovery of Pao2/Fio2 (~300) and end-expiratory lung volumes with nominal dose less than 30 mg/kg of surfactant, whereas control subjects (n = 3) maintained Pao2/Fio2 less than 100 over 4.5 hours with reduced end-expiratory lung volume. There was notably greater surfactant phospholipid content and lower indicators of lung inflammation and pathologic lung injury in surfactant-treated pigs than controls. There were no peridosing complications associated with nebulized surfactant, but surfactant-treated animals had progressively higher airway resistance post treatment than controls with no differences in ventilation effects between the two groups. CONCLUSIONS: Breath-synchronized, nebulized bovine surfactant appears to be a safe and feasible treatment option for use in coronavirus disease 2019 and other severe forms of acute respiratory distress syndrome.

Surfactant therapy for COVID-19 related ARDS: a retrospective case-control pilot study.

BACKGROUND: COVID-19 causes acute respiratory distress syndrome (ARDS) and depletes the lungs of surfactant, leading to prolonged mechanical ventilation and death. The feasibility and safety of surfactant delivery in COVID-19 ARDS patients have not been established. METHODS: We performed retrospective analyses of data from patients receiving off-label use of exogenous natural surfactant during the COVID-19 pandemic. Seven COVID-19 PCR positive ARDS patients received liquid Curosurf (720 mg) in 150 ml normal saline, divided into five 30 ml aliquots) and delivered via a bronchoscope into second-generation bronchi. Patients were matched with 14 comparable subjects receiving supportive care for ARDS during the same time period. Feasibility and safety were examined as well as the duration of mechanical ventilation and mortality. RESULTS: Patients showed no evidence of acute decompensation following surfactant installation into minor bronchi. Cox regression showed a reduction of 28-days mortality within the surfactant group, though not significant. The surfactant did not increase the duration of ventilation, and health care providers did not convert to COVID-19 positive. CONCLUSIONS: Surfactant delivery through bronchoscopy at a dose of 720 mg in 150 ml normal saline is feasible and safe for COVID-19 ARDS patients and health care providers during the pandemic. Surfactant administration did not cause acute decompensation, may reduce mortality and mechanical ventilation duration in COVID-19 ARDS patients. This study supports the future performance of randomized clinical trials evaluating the efficacy of meticulous sub-bronchial lavage with surfactant as treatment for patients with COVID-19 ARDS.