scholarly journals P057 Virus aerosol propagation by CPAP is proportional to mask leak and can be prevented by use of a hood and air filtration system

2021 ◽  
Vol 2 (Supplement_1) ◽  
pp. A39-A40
Author(s):  
S Landry ◽  
J Barr ◽  
M MacDonald ◽  
G Hamilton ◽  
D Mansfield ◽  
...  
Keyword(s):  
Airway Pressure ◽  
Respiratory Diseases ◽  
High Efficiency ◽  
Positive Airway Pressure ◽  
Low Cost ◽  
Virus Spread ◽  
Air Filtration ◽  
Infectious Risk ◽  
Virus Contamination ◽  
Filtration System

Abstract Introduction Nosocomial transmission of SARS-CoV-2 has caused significant morbidity/mortality in the COVID-19 pandemic. Because patients auto-emit aerosols containing viable virus, these aerosols can be further propagated when patients undergo certain treatments including continuous positive airway pressure (PAP) therapy. This study aimed to assess the degree of viable virus propagated from mask leak in a PAP circuit. Methods Bacteriophage PhiX174 (108copies/mL) was nebulised into a custom PAP circuit. Mask leak was systematically varied to 0, 7, 21, 28 and 42 L/min at the mask interface. Plates containing Escherichia coli assessed the degree of viable virus settling on surfaces around the room. In order to contain virus spread a ventilated headboard and high efficiency particulate air (HEPA) filter was tested. Results Increasing mask leak was associated with virus contamination in a dose response manner (χ2= 58.24, df=4, p<0.001). Clinically relevant levels of leak (≥21 L/min) were associated with virus counts equivalent to using PAP with a standard vented mask. Viable viruses were recorded on all plates (up to 3.86m from source). A plastic hood with HEPA filtration significantly reduced viable viruses on all plates. HEPA exchange rates of 170 and 470m3/hr eradicated all evidence of virus contamination. Discussion Mask leak from PAP circuits may be a major source of environmental contamination and nosocomial spread of infectious respiratory diseases. Subclinical levels of leak should be treated as an infectious risk. Cheap and low-cost patient hoods with HEPA filtration are an effective countermeasure.

Viable virus aerosol propagation by positive airway pressure (PAP) circuit leak and mitigation with a ventilated patient hood

2020 ◽  
pp. 2003666
Author(s):  
Shane A. Landry ◽  
Jeremy J. Barr ◽  
Martin I. MacDonald ◽  
Dinesh Subedi ◽  
Darren Mansfield ◽  
...  
Keyword(s):  
Airway Pressure ◽  
Respiratory Diseases ◽  
High Efficiency ◽  
Positive Airway Pressure ◽  
Low Cost ◽  
Dependent Manner ◽  
Virus Propagation ◽  
Infectious Risk ◽  
Virus Contamination ◽  
Dose Dependent

IntroductionNosocomial transmission of SARS-CoV-2 has been a major feature of the COVID-19 pandemic. Evidence suggests patients can auto-emit aerosols containing viable viruses, these aerosols could be further propagated when patients undergo certain treatments including continuous positive airway pressure (PAP) therapy. Our aim was to assess i) the degree of viable virus propagated from PAP circuit mask leak, ii) the efficacy of a ventilated plastic canopy to mitigate virus propagation.MethodsBacteriophage PhiX174 (108 copies·mL−1) was nebulised into a custom PAP circuit. Mask leak was systematically varied at the mask interface. Plates containing Escherichia coli host quantified viable virus (via plaque forming unit) settling on surfaces around the room. The efficacy of a low-cost ventilated headboard created from a tarpaulin hood and a high efficiency particulate air (HEPA) filter was tested.ResultsMask leak was associated with virus contamination in a dose-dependent manner (χ2=58.24, df=4, p<0.001). Moderate mask leak (≥21 L·min−1) was associated with virus counts equivalent to using PAP with a vented mask. The highest frequency of viruses was detected on surfaces 1 m away, however, viable viruses were recorded up to 3.86 m from the source. A plastic hood with HEPA filtration significantly reduced viable viruses on all plates. HEPA exchange rates ≥170 m3·hr−1 eradicated all evidence of virus contamination.ConclusionMask leak from PAP may be a major source of environmental contamination and nosocomial spread of infectious respiratory diseases. Subclinical mask leak levels should be treated as an infectious risk. Low-cost patient hoods with HEPA filtration are an effective countermeasure.

scholarly journals Viable virus aerosol propagation by PAP circuit leak and mitigation with a ventilated patient hood: a model for improving health care worker safety in the COVID-19 pandemic

2020 ◽  
Author(s):  
Shane A Landry ◽  
Jeremy Barr ◽  
Martin MacDonald ◽  
Dinesh Subedi ◽  
Darren Mansfield ◽  
...  
Keyword(s):  
High Efficiency ◽  
Positive Airway Pressure ◽  
Low Cost ◽  
Worker Safety ◽  
Virus Propagation ◽  
Air Filter ◽  
Infectious Risk ◽  
Virus Contamination ◽  
Care Worker ◽  
Improving Health Care

Background: Nosocomial transmission of SARS-CoV-2 has been a major cause of morbidity and mortality in the COVID-19 pandemic. Emerging evidence suggests patients auto-emit aerosols containing viable respiratory viruses. These aerosols could be further propagated when patients undergo certain treatments including continuous positive airway pressure (PAP) therapy. This study aimed to assess the degree of viable virus propagated from mask leak in a PAP circuit and the mitigation of virus propagation by an air filter combined with a plastic canopy. Methods: Bacteriophage PhiX174 (108copies/mL) was nebulised into a custom PAP circuit within a non-vented clinical room. Mask leak was systematically varied to allow 0, 7, 21, 28 and 42 L/min at the mask interface. Plates containing Escherichia coli host assessed the degree of viable virus (via plaque forming unit) settling on surfaces around the room. In order to contain virus spread, the efficacy of a simple, low-cost ventilated headboard, created from a plastic tarpaulin hood and a high efficiency particulate air (HEPA) filter was tested. Findings: Increasing mask leak was associated with virus contamination in a dose response manner (chisquared=58.24, df=4, p<0.001). Clinically relevant levels of leak (>21 L/min) were associated with virus counts equivalent to using PAP with a standard vented mask. The highest frequency of viruses was detected on surfaces 1m from the leak source, however, viable viruses were recorded on all plates (up to 3.86m from source). A plastic hood with HEPA filtration significantly reduced viable viruses on all plates. HEPA exchange rates of 170 and 470m3/hr eradicated all evidence of virus contamination. Interpretation: Mask leak from PAP circuits may be a major source of environmental contamination and nosocomial spread of infectious respiratory diseases. Subclinical levels of leak should be treated as an infectious risk. Cheap and low-cost patient hoods with HEPA filtration are an effective countermeasure.

A Low-Resource Oxygen Blender Prototype for Use in Modified Bubble CPAP Circuits

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Jared Floersch ◽  
Elsa Hauschildt ◽  
Adam Keester ◽  
Samuel Poganski ◽  
Kiet Tran ◽  
...  
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Low Cost ◽  
World Health ◽  
Pure Oxygen ◽  
Hypodermic Needle ◽  
Low Resource Settings ◽  
Low Resource ◽  
Tract Infections

Abstract Continuous positive airway pressure (CPAP) is a method of respiratory support used around the world to treat children with lower respiratory tract infections (LRTI) (WHO, 2016, Oxygen Therapy for Children, World Health Organization, Geneva, Switzerland, Report). Bubble continuous positive airway pressure (bCPAP) is an effective form of CPAP that is currently used in both high- and low-resource countries. Low-cost, modified bCPAP devices have been designed as an ideal form of CPAP in low-resource areas (Bjorklund, A. R., Mpora, B. O., Steiner, M. E., Fischer, G., Davey, C. S., and Slusher, T. M., 2018, “Use of a Modified Bubble Continuous Positive Airway Pressure (bCPAP) Device for Children in Respiratory Distress in Low- and Middle-Income Countries: A Safety Study,” Paediatr. Int. Child Health, 39(3), pp. 1–8). However, patients in low-resource settings undergoing bCPAP treatment are often given pure oxygen, which has been linked to retinopathy of prematurity, cardiovascular complications, and patient mortality (Rodgers, J. L., Iyer, D., Rodgers, L. E., Vanthenapalli, S., and Panguluri, S. K., 2019, “Impact of Hyperoxia on Cardiac Pathophysiology,” J. Cell. Physiol., 234(8), pp. 1–9; Ramgopal, S., Dezfulian, C., Hickey, R. W., Au, A. K., Venkataraman, S., Clark, R. S. B., and Horvat, C. M., 2019, “Association of Severe Hyperoxemia Events and Mortality Among Patients Admitted to a Pediatric Intensive Care Unit,” JAMA Network Open, 2(8), p. e199812). This problem is typically avoided by using commercial oxygen blenders, which can titrate down the concentration of oxygen delivered to the minimum needed; however, these blenders can cost nearly 1000 USD and are almost always unavailable in low-resource settings. The lack of available low-cost oxygen blenders compatible with modified bCPAP circuits creates a barrier for low-resource hospitals to be able to provide blended oxygen to patients. There is a need for a low-cost oxygen blender for use in low-resource settings. We propose a passive oxygen blender that operates via entrainment of atmospheric air. The device can easily be assembled in low-resource areas using a 22 gauge hypodermic needle, two 3 cc syringes, tape or super glue, and the materials required for bCPAP—for approximately 1.40 USD per device. The blender has not been clinically tested yet, but can achieve oxygen concentrations as low as 60% with bCPAP levels of 5 cm H2O (490 Pa) when used in a standard bCPAP circuit without a patient.

scholarly journals Point of emission air filtration enhances protection of health care workers against skin contamination with virus aerosol

2021 ◽  
Author(s):  
Shane Anthony Landry ◽  
Dinesh Subedi ◽  
Martin Ian MacDonald ◽  
Samantha Dix ◽  
Donna Kutey ◽  
...  
Keyword(s):  
Health Care ◽  
Health Care Workers ◽  
High Efficiency ◽  
Environmental Control ◽  
Low Cost ◽  
Personal Exposure ◽  
Air Filtration ◽  
Care Workers ◽  
Skin Contamination ◽  
Air Purifier

Rationale: We recently demonstrated that a patient hood with a high efficiency particulate air filter eliminates virus aerosol contamination when very large quantities of bacteriophage virus are aerosolised into a clinical room. While this containment method is relatively low cost, it is unclear whether similar efficacy can be achieved with lower cost/commercial grade air purifiers, or if such an approach protects healthcare workers against virus aerosol contamination. Method: A total of 109 (10 ml of 108) PhiX174 bacteriophages was nebulized into a sealed clinical room. Surface contamination was detected by settle plates left uncovered during exposure. A healthcare worker remained in the room, personal exposure was determined by skin swabs after exiting the room, following doffing of personal protective equipment (PPE). Four skin areas were swabbed: forearms/hands, neck, forehead, under N95 mask. Three conditions were tested, 1) hood with hospital grade air purifier (IQ Air Health Pro 250), 2) hood with commercial air purifier (Philips 1000i), and 3) control (no hood/air-purification). Findings: The control condition demonstrated extensive environmental and limited skin contamination underneath PPE, which was highest under an N95 mask. The commercial air purifier and hood provided environmental control of virus aerosol and almost zero skin contamination. In comparison, the hospital grade purifier provided complete environmental and skin contamination protection, despite a lower clean air filtration rate (240m3/hr vs 270m3/hr). Virus counts on plates and swabs were significantly lower for both air purifiers and across neck, forehead, and under the N95. There were no statistically significant differences in detected virus counts between air purifiers. Conclusion: This cheap and scalable method may be an effective way to reduce the spread of COVID-19 in hospitals by enhancing the effectiveness of PPE worn by health care workers who care for COVID-19 patients and who are exposed to virus aerosol.

scholarly journals Bubble Nasal Continuous Positive Airway Pressure (bNCPAP): An Effective Low-Cost Intervention for Resource-Constrained Settings

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Walufu Ivan Egesa ◽  
William Mugowa Waibi
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Airway Pressure ◽  
Neonatal Intensive Care ◽  
Positive Airway Pressure ◽  
Low Cost ◽  
Failure Criteria ◽  
Resource Constrained ◽  
Care Package ◽  
Tertiary Hospitals ◽  
Physiological Benefits

Preterm birth complications are responsible for almost one-third of the global neonatal mortality burden, and respiratory distress syndrome remains the single most common cause of these preventable deaths. Since its inception, almost half a century ago, nasal continuous positive airway pressure (NCPAP) has evolved to become the primary modality for neonatal respiratory care in both the developed and developing world. Although evidence has demonstrated the effectiveness of low-cost bubble NCPAP in reducing newborn mortality, its widespread use is yet to be seen in resource-constrained settings. Moreover, many tertiary hospitals in developing countries still utilise an inexpensive locally assembled bNCPAP system of unknown efficacy and safety. This review provides a brief overview of the history, physiological benefits, indications, contraindications, and complications of bNCPAP. Evidence regarding the effectiveness of low-cost bNCPAP in the neonatal intensive care unit is also summarised. The article further details a locally assembled bNCPAP system used in resource-constrained settings and highlights the care package for neonates receiving bNCPAP, failure criteria, and strategies for weaning.

Continuous positive airway pressure causes lung injury in a model of sepsis

2005 ◽  
Vol 289 (4) ◽  
pp. L554-L564 ◽  
Author(s):  
Shinya Tsuchida ◽  
Doreen Engelberts ◽  
Matthias Roth ◽  
Colin McKerlie ◽  
Martin Post ◽  
...  
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Lung Injury ◽  
Circuit Design ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Low Cost ◽  
Conventional Mechanical Ventilation ◽  
Pulmonary Atelectasis ◽  
Primary Form

Continuous positive airway pressure, aimed at preventing pulmonary atelectasis, has been used for decades to reduce lung injury in critically ill patients. In neonatal practice, it is increasingly used worldwide as a primary form of respiratory support due to its low cost and because it reduces the need for endotracheal intubation and conventional mechanical ventilation. We studied the anesthetized in vivo rat and determined the optimal circuit design for delivery of continuous positive airway pressure. We investigated the effects of continuous positive airway pressure following lipopolysaccharide administration in the anesthetized rat. Whereas neither continuous positive airway pressure nor lipopolysaccharide alone caused lung injury, continuous positive airway pressure applied following intravenous lipopolysaccharide resulted in increased microvascular permeability, elevated cytokine protein and mRNA production, and impaired static compliance. A dose-response relationship was demonstrated whereby higher levels of continuous positive airway pressure (up to 6 cmH2O) caused greater lung injury. Lung injury was attenuated by pretreatment with dexamethasone. These data demonstrate that despite optimal circuit design, continuous positive airway pressure causes significant lung injury (proportional to the airway pressure) in the setting of circulating lipopolysaccharide. Although we would currently avoid direct extrapolation of these findings to clinical practice, we believe that in the context of increasing clinical use, these data are grounds for concern and warrant further investigation.

2-Stage Air Filtration for Gas Turbine Naval Applications

2019 ◽  
Author(s):  
Gianluca de Arcangelis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Turbine Blades ◽  
Water Repellency ◽  
Air Filtration ◽  
Compressor Blades ◽  
Reduced Pressure ◽  
Filtration System ◽  
Offshore Oil

Abstract Traditional air filtration systems for Gas Turbine Naval applications consist of 3 stages: 1st vane separator + pocket filter + 2nd vane separator. The 2nd vane separator is required to drain out droplets formed by the traditional pocket filter during its coalescing function. Further to technological advancements in the water repellency of filter media, as well as leak-free techniques, it is now possible to implement a pocket filter that avoids leaching water droplets downstream. This enables the elimination of the 3rd stage vane separator in the air filtration system. The result is a suitable 2-stage air filtration system. The elimination of the 3rd stage vane separator provides the obvious following advantages: • Reduced pressure drop • Reduced weight • Reduced foot-print • Reduced cost Latest technological advancements in water repellency and high efficiency melt-blown media also allow the attainment of higher performance such as: • Increased efficiency against water droplet and salt in wet state • Increased efficiency against dry salt and dust This results in higher cleanliness of the Gas Turbines with benefits in terms of compressor fouling, compressor blades corrosion and turbine blades hot erosion. Higher performance also results in simplified maintenance as technicians need only focus on the replacement of the elements as opposed to the cleaning and overhauling of the intake duct. The paper goes through the engineering challenges of evolving from a 3-stage to 2-stage filtration system. The paper provides data from testing at independent laboratories with results that back the claims. Furthermore, reference is made to Offshore Oil & Gas installations and testing that have proven successful with independently measured data.

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