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 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&lt;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.

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 Production and characterization of sophorolipids by Candida bombicola using catfish fat

2019 ◽  
Vol 14 (9) ◽  
pp. 152
Author(s):  
Nguyen Luong Hieu Hoa ◽  
Le Quynh Loan ◽  
Vo Thanh Sang ◽  
Le Van Minh ◽  
Le Viet Dung ◽  
...  
Keyword(s):  
Low Cost ◽  
Radical Scavenging ◽  
Raw Material ◽  
Dependent Manner ◽  
Candida Bombicola ◽  
Main Component ◽  
Seafood Processing ◽  
Layer Chromatography ◽  
Dose Dependent

Catfish fat is a high nutrition by-product of seafood processing industry. In this work, catfish fat has been used as a sustainable and economical raw material for sophorolipids production by Candida bombicola. Sophorolipids yield was maximum as 21.8g/L after 7 days of fermentation at 25oC, pH 6, 180 rpm. The obtained sophorolipids was to contained the main component as lactonic sophorolipids, which has been confirmed by Thin layer chromatography (TLC). Sophorolipids also exhibited the ability to resistant Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and showed the ability of free radical scavenging the dose dependent manner with IC50 was 4.45 mg/ml. These results suggested that sophorolipids could be used in health care products and cosmetic. Catfish fat could be used as the low cost hydrophobic carbon source to replace fatty acid for sophorolipids production.

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.

Recent findings regarding calcium and phytase in poultry nutrition

2017 ◽  
Vol 57 (11) ◽  
pp. 2311 ◽  
Author(s):  
M. Bedford ◽  
X. Rousseau
Keyword(s):  
Low Cost ◽  
Essential Element ◽  
Dependent Manner ◽  
Maximum Value ◽  
Mild Deficiency ◽  
High Doses ◽  
And Performance ◽  
Dose Dependent ◽  
Hydrolysis Of ◽  
Very High

Calcium (Ca) is an essential element for poultry and even a mild deficiency can lead to significant welfare and performance issues. As a result, it is often fed at levels in excess of requirement, partly as an insurance policy and, to some degree, because of its relatively low cost compared with other feed ingredients. However, when diets meet but do not exceed the phosphorus (P) requirements of the bird, a marginal Ca excess can interfere with P digestibility. This problem is exacerbated when phytases are used to provide some of the required P because Ca decreases the efficiency of phytate (IP6) hydrolysis in a dose-dependent manner. More recently, phytases have been used at very high doses (1500 FyTase units (FTU); ‘superdosing’) in commercial diets, to improve bird performance by removing as much of the dietary IP6 and lower esters of phytate (IP5, IP4, IP3 and IP2) as possible, all of which are considered anti-nutrients, and concomitantly producing as much inositol, a nutrient, as possible. In such a regimen, the ability of the phytase to degrade the lower phytate esters, namely IP4, IP3 and IP2, takes on greater importance than does simply releasing phytate P. Calcium has recently been shown to reduce the efficacy of hydrolysis of the lower phytate esters to a greater degree than the extent to which it decreases IP6 hydrolysis. As a result, Ca concentrations in the diet should be monitored frequently if the maximum value of a phytase is to be realised.

Sign in / Sign up

Export Citation Format

Share Document