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Background and Objective: In the COVID-19 pandemic, the demand of masks has been increased by health professionals and the general population. In this context, it is necessary to summarize the features and indications of the different types of masks., Material and Methods: To consult and to compile the different recommendations disseminated by prestigious institutions such as the World Health Organization, the European Center for Disease Prevention, the Center for Evidence-Based Medicine, or the Ministry of Health of the Government of Spain has been reviewed., Results: The institutions consulted recommend reserving FFP respirators for healthcare workers, especially when carrying out aerosol-generating procedures (AGPs) (minimum FFP2 protection) and consider some reutilization systems during times of scarcity. The use of surgical masks is recommended to professionals who do not perform AGPs and to the symptomatic population but exist variations in its indications intended for the general healthy population., Conclusion: In the context of shortage of personal protective equipment due to the COVID-19 pandemic, a prioritization and rationalization of the use of each type of mask should be established according to the user and the activity performed., (Copyright © 2020 FECA. Publicado por Elsevier España, S.L.U. All rights reserved.)

In the human population, social contacts are a key for transmission of bacteria and viruses. The use of face masks seems to be critical to prevent the transmission of SARS-CoV-2 for the period, in which therapeutic interventions are lacking. In this review, we describe the history of masks from the middle age to modern times.

Introduction: Transmission of SARS-CoV-2 to health care workers (HCW) poses a major burden in the current COVID-19 pandemic. Unprotected exposure to a COVID-19 patient is a key risk factor for HCWs. Transmission mainly occurs by droplet transmission, or by aerosol generating procedures. Respirators such as filtering face piece masks (FFP2), also called respirators, are required to prevent transmission during aerosol generating procedures, as part of the personal protective equipment (PPE) for HCWs. However, many HCW were infected due to lack of PPE, or failure to use them. Therefore, the worldwide shortage of respirators triggered the development of reprocessing used FFP2 respirators or N95 respirators as standard in the US. Our proposal with H 2 O 2 plasma sterilization for decontamination allows to reprocess FFP2, while they still meet the filtration efficiency required by EN 149. The protocol is simple, uses available resources in hospitals and can be rapidly implemented to decrease the shortage of respirators during this crisis. The goal of the study was the evaluate if respirators can be reprocessed and still fulfill the requirements for filtration efficiency outlined by EN 149., Methods: Used FFP2 respirators - Model 3 M Aura™ 1862+ - were sterilized using a low temperature process hydrogen peroxide (H 2 O 2 ), V-PRO® maX Low Temperature, a FDA (Food and Drug Administration) approved method to decontaminate FFP2 respirators. Decontaminated respirators were further checked for residual peroxide by a single-gas detector for H 2 O 2 . The total inward leakage of the protective respirators was quantitatively tested with 10 test persons in an atmosphere charged with paraffin aerosol according to the European Standard EN 149. The fit factor was calculated as the inverse of the total inward leakage., Results: Ten new and ten decontaminated FFP2 respirators were tested for filtration efficiency. None of the respirators exceeded the maximum acceptable concentration of peroxide. More than 4000 respirators have been reprocessed so far, at cost of approximately 0.3 Euro/piece., Conclusions: FFP2 respirators can be safely reprocessed once after decontamination with plasma peroxide sterilization, whereafter they still fulfill EN 149 requirements. This allows to almost double the current number of available FFP2 respirators.

Summary: During COVID-19 pandemic crisis, Italian Government has approved Law Decree no. 18 of 17 march 2020, in which art. 15 allows enterprises to produce, import and commercialize surgical masks notwithstanding the current rules of product certification. It is just required that the interested enterprises send to the Italian National Institute of Health a selfcertification in which they declare the technical characteristics of the masks and that masks are produced according to the safety requirements. In this context, a technical-scientific unit was established at the University of Napoli Federico II to provide interested enterprises with state-of-the-art consultancy, testing and measurement services, adhering to rigorous scientific protocols. Characterization tests were carried out on 163 surgical masks and/or materials for their construction and they have enabled the identification of pre-screening criteria to simplify the procedure for evaluating surgical masks using methods for assessing the filtration efficiency of particles and aerosols. Based on experimental results, it has been observed that a filtration efficiency for particles with sizes larger that 650 nm (PFE>650) exceeding 35% might guarantees a bacterial filtration efficiency (BFE) higher than 95% while BFE values higher than 98% are obtained when the PFE>650 is larger than 40%. PFE measurement is extremely simpler with respect to BFE, the latter being time-consuming and requiring specific equipment and methods for its realization. Many tested materials have shown the capability to assure high filtration efficiencies but Spundonded-Meltblown-Spunbonded (SMS), that are layers of non-woven fabric with different weights of Meltblown, can simultaneously guarantee high particle filtration efficiencies with pressure drop values (breathability) in the limits to classify the surgical masks as Type II/IIR. In fact, the fabric products analyzed so far have not been able to simultaneously guarantee adequate BFE and breathability values. On the contrary, Spunbonds of adequate weights can virtually verify both requirements and accredit themselves as possible materials for the production of surgical masks, at least of Type I. Further studies are needed to verify the possibility of producing low-cost, reusable surgical masks that could meet the criteria of circular economy., Competing Interests: The authors of this article have no conflict of interests to disclose., (Copyright© by GIMLE.)

The emergence of a pandemic affecting the respiratory system can result in a significant demand for face masks. This includes the use of cloth masks by large sections of the public, as can be seen during the current global spread of COVID-19. However, there is limited knowledge available on the performance of various commonly available fabrics used in cloth masks. Importantly, there is a need to evaluate filtration efficiencies as a function of aerosol particulate sizes in the 10 nm to 10 μm range, which is particularly relevant for respiratory virus transmission. We have carried out these studies for several common fabrics including cotton, silk, chiffon, flannel, various synthetics, and their combinations. Although the filtration efficiencies for various fabrics when a single layer was used ranged from 5 to 80% and 5 to 95% for particle sizes of <300 nm and >300 nm, respectively, the efficiencies improved when multiple layers were used and when using a specific combination of different fabrics. Filtration efficiencies of the hybrids (such as cotton-silk, cotton-chiffon, cotton-flannel) was >80% (for particles <300 nm) and >90% (for particles >300 nm). We speculate that the enhanced performance of the hybrids is likely due to the combined effect of mechanical and electrostatic-based filtration. Cotton, the most widely used material for cloth masks performs better at higher weave densities ( i.e. , thread count) and can make a significant difference in filtration efficiencies. Our studies also imply that gaps (as caused by an improper fit of the mask) can result in over a 60% decrease in the filtration efficiency, implying the need for future cloth mask design studies to take into account issues of "fit" and leakage, while allowing the exhaled air to vent efficiently. Overall, we find that combinations of various commonly available fabrics used in cloth masks can potentially provide significant protection against the transmission of aerosol particles.

The 2019 coronavirus outbreak (COVID-19) is affecting over 210 countries and territories, and it is spreading mainly by respiratory droplets. The use of disposable surgical masks is common for patients, doctors, and even the general public in highly risky areas. However, the current surgical masks cannot self-sterilize in order to reuse or be recycled for other applications. The resulting high economic and environmental costs are further damaging societies worldwide. Herein, we reported a unique method for functionalizing commercially available surgical masks with outstanding self-cleaning and photothermal properties. A dual-mode laser-induced forward transfer method was developed for depositing few-layer graphene onto low-melting temperature nonwoven masks. Superhydrophobic states were observed on the treated masks' surfaces, which can cause the incoming aqueous droplets to bounce off. Under sunlight illumination, the surface temperature of the functional mask can quickly increase to over 80 °C, making the masks reusable after sunlight sterilization. In addition, this graphene-coated mask can be recycled directly for use in solar-driven desalination with outstanding salt-rejection performance for long-term use. These roll-to-roll production-line-compatible masks can provide us with better protection against this severe virus. The environment can also benefit from the direct recycling of these masks, which can be used for desalinating seawater.

The coronavirus disease 2019 (COVID-19) pandemic has led to a major shortage of N95 respirators, which are essential for protecting healthcare professionals and the general public who may come into contact with the virus. Thus, it is essential to determine how we can reuse respirators and other personal protective equipment in these urgent times. We investigated multiple commonly used disinfection schemes on media with particle filtration efficiency of 95%. Heating was recently found to inactivate the virus in solution within 5 min at 70 °C and is among the most scalable, user-friendly methods for viral disinfection. We found that heat (≤85 °C) under various humidities (≤100% relative humidity, RH) was the most promising, nondestructive method for the preservation of filtration properties in meltblown fabrics as well as N95-grade respirators. At 85 °C, 30% RH, we were able to perform 50 cycles of heat treatment without significant changes in the filtration efficiency. At low humidity or dry conditions, temperatures up to 100 °C were not found to alter the filtration efficiency significantly within 20 cycles of treatment. Ultraviolet (UV) irradiation was a secondary choice, which was able to withstand 10 cycles of treatment and showed small degradation by 20 cycles. However, UV can potentially impact the material strength and subsequent sealing of respirators. Finally, treatments involving liquids and vapors require caution, as steam, alcohol, and household bleach all may lead to degradation of the filtration efficiency, leaving the user vulnerable to the viral aerosols.

As the global pandemic caused by the COVID-19 virus continues to spread, researchers from across the world are harnessing their skills and opening their labs to contribute to solutions for managing and addressing the health crisis. One area identified by hospitals and medical providers as a critical need has been the shortage of personal protective equipment (PPE), which is required to keep health care providers safe from exposure to the virus as they care for patients. In response, manufacturers such as 3M have promised to increase production in order to fulfill the extensive orders. However, medical providers may not see the bulk of these outputs for weeks even as current supplies are running low.

The current COVID-19 pandemic has led to a worldwide shortage of respiratory protective equipment. In order to offer maximum protection against infection for all healthcare workers, we need to optimise our use of the available equipment. This article provides practical advice on which type of mask is indicated in what specific situation, what requirements the mask should meet and how to optimise the local workflow, including the re-use of masks after decontamination.

Background: To assess the arterial oxygen partial pressure (PaO2) at defined time points during preoxygenation and to compare high-flow heated humidified nasal oxygenation with standard preoxygenation using oxygen insufflation via a facemask for at least 5 minutes, before intubation during induction of general anesthesia., Methods: This randomized, single-blinded, prospective study will be conducted in patients undergoing head and neck surgery. After standard monitoring, the artery catheter at the radial artery or dorsalis pedis artery will be placed and arterial blood gas analysis (ABGA) for baseline values will be performed simultaneously. Each group will be subjected to 1 of 2 preoxygenation methods (high-flow nasal cannula or simple facemask) for 5 minutes, and ABGA will be performed twice. After confirming intubation, we will start mechanical ventilation and check the vital signs and perform the final ABGA., Discussion: This trial aims to examine the trajectory of PaO2 levels during the whole preoxygenation procedure and after intubation. We hypothesize that preoxygenation with the high-flow nasal cannula will be superior to that with the face mask., Study Registration: This trial was registered with the Clinical Trial Registry (NCT03896906; ClinicalTrials.gov).

Background: Noninvasive ventilation (NIV) reduces intubation and mortality in patients with COPD exacerbation who present with respiratory failure, and the type of mask may affect its success. Our objective was to compare the performance of 3 different NIV masks in a lung model., Methods: We set the lung simulator mechanics and respiratory rate, and tested a small oronasal mask, a total face mask, and a large oronasal mask. We added CO 2 at a constant rate into the system and monitored the end-tidal carbon dioxide. We used a mechanical ventilator to deliver NIV in 8 different combinations of inspiratory effort, pressure support, and expiratory positive airway pressure. We measured end-tidal carbon dioxide mask leakage, tidal volume, trigger time, time to achieve 90% of the inspiratory target during inspiration, and excess inspiratory time., Results: We presented the mean ± SD of the 8 simulated conditions for each mask. The mean ± SD leakage was higher for the total face mask (51 ± 6 L/min) than for the small oronasal mask (37 ± 5 L/min) and for the large oronasal mask (21 ± 3 L/min), P < .001; but end-tidal carbon dioxide and tidal volume were similar. The mean ± SD 90% of the inspiratory target during inspiration was faster for the small oronasal mask (585 ± 49 ms) compared with the large oronasal (647 ± 107 ms) and total face mask (851 ± 105 ms), P < .001, all other variables were similar., Conclusions: In this model, we found that the type of mask had no impact on CO 2 washout or on most synchrony variables., (Copyright © 2019 by Daedalus Enterprises.)

In treating obstructive sleep apnea (OSA), the use of oronasal masks with continuous positive airway pressure (CPAP) has been reported to increase pressure levels and reduce compliance. These reports come mostly from large observational studies. In this study, we examined the impact that oronasal masks have on 95th centile pressures, the residual apnea-hypopnea index (AHI) and compliance compared with nasal masks. A randomised crossover design was implemented. Participants already established on CPAP were randomly allocated to a nasal mask or oronasal mask with auto-titrating positive airway pressure (APAP) for 2 weeks. Participants then crossed over to use the alternate mask for another 2 weeks. Seventy-one participants were recruited but only 60 completed the trial. There were no differences in median 95th centile pressure (nasal, 11.5 cm H 2 O; oronasal, 11.7 cm H 2 O; p = 0.115), median residual AHI (nasal, 4.9 events/hr; oronasal, 5.3 events/hr; p = 0.234) or median compliance (nasal, 7.3 hr/night; oronasal, 7.3 hr/night; p = 0.961). Only four patients had 95th centile pressures that were at least 1.5 cm H 2 O greater with oronasal masks. Oronasal masks do not systematically increase therapeutic CPAP requirements. Rather, a small subset of patients display significant differences in CPAP levels., (© 2018 European Sleep Research Society.)

An ASTM International subcommittee on Respiratory Protection, F23.65 is currently developing a consensus standard for assessing respirator fit capability (RFC) criteria of half-facepiece air-purifying particulate respirators. The objective of this study was to evaluate if the test methods being developed for half-facepiece respirators can reasonably be applied to nonpowered full-facepiece-air-purifying respirators (FF-APR). Benchmark RFC test data were collected for three families of FF-APRs (a one-size-only family, a two-size family, and a three-size family). All respirators were equipped with P100 class particulate filters. Respirators were outfitted with a sampling probe to collect an in-mask particle concentration sample in the breathing zone of the wearer. Each of the six respirator facepieces was tested on the National Institute for Occupational Safety and Health 25-subject Bivariate Panel. The RFC test assessed face seal leakage using a PortaCount fit test. Subjects followed the corresponding Occupational Safety and Health Administration-accepted fit test protocol. Two donnings per subject/respirator model combination were performed. The panel passing rate (PPR) (number or percentage of subjects in the panel achieving acceptable fit on at least one of two donnings) was determined for each respirator family at specified fit factor passing levels of 500, 1,000, and 2,000. As a reasonable expectation based on a previous analysis of alpha and beta fit test errors for various panel sizes, the selected PPR benchmark for our study was >75%. At the fit factor passing level of 500 obtained on at least one of two donnings, the PPRs for three-, two-, and one-size families were 100, 79, and 88%, respectively. As the fit factor passing criterion increased from 500 to 1,000 or 2,000, PPRs followed a decreasing trend. Each of the three tested families of FF-APRs are capable of fitting ≥75% of the intended user population at the 500 fit factor passing level obtained on at least one of two donnings. The methods presented here can be used as a reference for standards development organizations considering developing RFC test requirements.

Background: Noninvasive ventilation (NIV) is used to treat respiratory failure because it reduces the risks of endotracheal intubation and postextubation respiratory failure. A wide range of different interfaces is available, but concerns exist about rebreathing. This study evaluated a total face mask with a 2-limb ventilation circuit and separate access for inflow and outflow gas, which was developed to reduce rebreathing., Methods: In a bench test, a standard total face mask (with a single connector to the ventilation circuit) and the modified total face mask were applied to a mannequin connected to an active breathing simulator. A known CO 2 flow (V̇ CO 2 ) was delivered to the mannequin's trachea. We tested the following settings: CPAP with the mechanical PEEP valve set at 8 cm H 2 O (with 60 and 90 L/min continuous flow) and pressure support of 6 and 12 cm H 2 O (with 2 and 15 L/min bias flow). The settings were tested at simulated breathing frequencies of 15 and 30 breaths/min and with V̇ CO 2 of 200 and 300 mL/min. The active simulator generated a tidal volume of 500 mL. Airway pressure, air flow, CO 2 concentration, and CO 2 flow as the product of air flow and CO 2 were recorded., Results: The mean volume of CO 2 rebreathed and the minimum CO 2 inspiratory concentration were significantly lower with the modified mask than with the standard mask. The 15 L/min bias flow significantly decreased rebreathing with the DiMax0 mask, whereas it had no effect with the traditional mask., Conclusions: A face mask with a two-limb ventilation circuit and separate access for inflow and outflow gas reduces rebreathing during NIV. The addition of bias flow enhances this effect. Further studies are required to verify the clinical relevance., (Copyright © 2019 by Daedalus Enterprises.)

Introduction: Healthcare personnel influenza vaccination can reduce influenza illness and patient mortality. State laws are one tool promoting healthcare personnel influenza vaccination., Methods: A 2016 legal assessment in 50 states and Washington DC identified (1) assessment laws: mandating hospitals assess healthcare personnel influenza vaccination status; (2) offer laws: mandating hospitals offer influenza vaccination to healthcare personnel; (3) ensure laws: mandating hospitals require healthcare personnel to demonstrate proof of influenza vaccination; and (4) surgical masking laws: mandating unvaccinated healthcare personnel to wear surgical masks during influenza season. Influenza vaccination was calculated using data reported in 2016 by short-stay acute care hospitals (n=4,370) to the National Healthcare Safety Network. Hierarchical linear modeling in 2018 examined associations between reported vaccination and assessment, offer, or ensure laws at the level of facilities nested within states, among employee and non-employee healthcare personnel and among employees only., Results: Eighteen states had one or more healthcare personnel influenza vaccination-related laws. In the absence of any state laws, facility vaccination mandates were associated with an 11-12 percentage point increase in mean vaccination coverage (p<0.0001). Facility-level mandates were estimated to increase mean influenza vaccination coverage among all healthcare personnel by 4.2 percentage points in states with assessment laws, 6.6 percentage points in states with offer laws, and 3.1 percentage points in states with ensure laws. Results were similar in analyses restricted only to employees although percentage point increases were slightly larger., Conclusions: State laws moderate the effect of facility-level vaccination mandates and may help increase healthcare personnel influenza vaccination coverage in facilities with or without vaccination requirements., (Published by Elsevier Inc.)

Background: Data on high-flow nasal oxygen after thoracic surgery are limited and confined to the comparison with low-flow oxygen. Different from low-flow oxygen, Venturi masks provide higher gas flow at a predetermined fraction of inspired oxygen (FiO 2 ). We conducted a randomized trial to determine whether preemptive high-flow nasal oxygen reduces the incidence of postoperative hypoxemia after lung resection, as compared to Venturi mask oxygen therapy., Methods: In this single-center, randomized trial conducted in a teaching hospital in Italy, consecutive adult patients undergoing thoracotomic lung resection, who were not on long-term oxygen therapy, were randomly assigned to receive high-flow nasal or Venturi mask oxygen after extubation continuously for two postoperative days. The primary outcome was the incidence of postoperative hypoxemia (i.e., ratio of the partial pressure of arterial oxygen to FiO 2 (PaO 2 /FiO 2 ) lower than 300 mmHg) within four postoperative days., Results: Between September 2015 and April 2018, 96 patients were enrolled; 95 patients were analyzed (47 in high-flow group and 48 in Venturi mask group). In both groups, 38 patients (81% in the high-flow group and 79% in the Venturi mask group) developed postoperative hypoxemia, with an unadjusted odds ratio (OR) for the high-flow group of 1.11 [95% confidence interval (CI) 0.41-3] (p = 0.84). No inter-group differences were found in the degree of dyspnea nor in the proportion of patients needing oxygen therapy after treatment discontinuation (OR 1.34 [95% CI 0.60-3]), experiencing pulmonary complications (OR 1.29 [95% CI 0.51-3.25]) or requiring ventilatory support (OR 0.67 [95% CI 0.11-4.18]). Post hoc analyses revealed that PaO 2 /FiO 2 during the study was not different between groups (p = 0.92), but patients receiving high-flow nasal oxygen had lower arterial pressure of carbon dioxide, with a mean inter-group difference of 2 mmHg [95% CI 0.5-3.4] (p = 0.009), and were burdened by a lower risk of postoperative hypercapnia (adjusted OR 0.18 [95% CI 0.06-0.54], p = 0.002)., Conclusions: When compared to Venturi mask after thoracotomic lung resection, preemptive high-flow nasal oxygen did not reduce the incidence of postoperative hypoxemia nor improved other analyzed outcomes. Further adequately powered investigations in this setting are warranted to establish whether high-flow nasal oxygen may yield clinical benefit on carbon dioxide clearance., Trial Registration: ClinicalTrials.gov, NCT02544477 . Registered 9 September 2015.

Objective: To examine the efficacy of early continuous positive airway pressure (CPAP), delivered using a T-piece-based infant resuscitator (Neopuff) via a face mask, in reducing the severity and duration of transient tachypnea of the newborn (TTN) as well as testing a hypothesis suggesting that rapid clearance of fetal lung fluid to the circulation via CPAP would increase plasma B-type natriuretic peptide (BNP)., Methods: A randomized controlled trial (NCT01859533) was conducted on 64 late preterm/term neonates, delivered by cesarean section and presented by respiratory distress shortly after birth. The Neopuff group included 34 neonates received 20 min of early CPAP and control group included 30 neonates received free flow O 2 . Plasma BNP was measured baseline and 2 h later., Results: The duration of tachypnea was shorter in Neopuff group with less need of neonatal intensive care unit admission and need of mechanical support (p < .05) with no effect on duration of hospitalization (p > .05). Plasma BNP showed no significant difference between pre- and post-Neopuff levels (p > .05). A positive correlation was found between BNP and duration of tachypnea as well as the length of hospitalization (p < .05) among Neopuff group., Conclusion: Early rescue CPAP reduces the duration and severity of respiratory distress among infants with TTN.

Aim of Study: The use of a nebulizer paired with high-flow nasal cannulas (HFNC) has been proposed for drug delivery in bronchiolitis. Particle size nebulized is a relevant factor determining the efficacy of the nebulization. We replicated in vitro the theoretical parameters most widely used in bronchiolitis and we compared the size of the droplet nebulized with a standard nebulizer and a nebulizer integrated into HFNC. Materials and Methods: We used laser diffraction to analyze the particle size nebulized (volume median diameter Dv50). The standard system was a jet nebulizer connected to a facemask with a flow rate of 8 L/min (JN). Three designs were used as nebulizers integrated into HFNC: a vibrating mesh nebulizer set 1) before (HFNC-BH) and 2) after (HFNC-AH) the humidifier, and 3) a jet nebulizer connected before the nasal cannula (HFNC-BNC). HFNC was used with neonatal (3-8 L/min) and infant cannulas (8-15 L/min). Results: Droplet size was similar among the three drugs studied. A lower particle size was obtained when using the nebulization system integrated into HFNC compared to the standard nebulizer, regardless of the flow rate and the nasal cannula used when the position of the nebulizer was before the nasal cannula ( p  < 0.05): 6.89 µm (JN), 2.49 µm (HFNC-BNC 3 L/min), 2.59 µm (HFNC-BNC 5 L/min), 2.44 µm (HFNC-BNC 8 L/min), 3.22 µm (HFNC-BNC 10 L/min), 3.23 µm (HFNC-BNC 13 L/min), 3.16 µm (HFNC-BNC 15 L/min). The particle size was lower in HFNC-BF compared to the HFNC-AH using neonatal nasal cannula (3-8 L/min) ( p  < 0.05). Conclusion: The use of a nebulizer integrated with HFNC has shown promising results in an experimental scenario of bronchiolitis. The particle size achieved with the nebulizer placed before the humidifier is equivalent to the one obtained via conventional nebulization, and it is even smaller when the integrated nebulizer is placed before the nasal cannulas.

Background: The main function of respiratory protective devices is to provide an intact physical barrier between the environment and the user. To ensure that, a leak-tight fit of the facepiece to the user's face is essential, regardless of the user's individual facial features., Objective: The main objective of this study was to assess the possibilities of developing customized respirators well-fitting to the anthropometric dimensions of the user's face using 3D scanning and 3D printing techniques and to evaluate this custom-made device in terms of protective, usage and strength parameters., Methods: Commercially available twin-filter half-mask type MP22/2 was selected as base model for customization. The 3D scans of the half-mask facepiece were performed using ATOS Core optical 3D scanner. Simultaneously anthropometric measurements of the test subject face were carried out with hand-held 3D scanner Artec EVA. Then digital model of the facepiece was matched to the shape of user's face using Geomagic Touch X haptic device. Customized facepieces were printed out with use of selective laser sintering technique from thermoplastic polyurethane. After assembling, respirators were tested for compliance with the requirements of the European standards., Results: The developed respirators proved to be very well-fitted to the user's face, did not cause any imprints or skin irritations and were assessed positively in terms of protective, usage and strength parameters., Conclusions: The application of 3D scanning and 3D printing techniques for designing and fabricating customized half-mask facepieces constitutes a viable option for the future development of respiratory protective devices.

Airflow during speech production is recorded using a pneumotachograph system wherein typically a mask is placed upon the face. Accurate measures of airflow require mask calibration and a complete seal of the mask rim to the face. Literature frequently cites mask rim leaks as causing flow measurement inaccuracies, but quantitative studies of the inaccuracies are needed. The purpose of this study was to determine the degree of inaccuracy of flow measurement using a Glottal Enterprises aerodynamic system for a variety of mask rim leak conditions. Air was pushed and pulled through the Glottal Enterprises mask system over a wide range of airflow with leaks simulated by small metal tubes of various cross-sectional areas placed between the mask rim and a face-like calibration mold. Two leak locations, single versus multiple leaks, and two different leak tube geometries were used. Results suggest that (1) as leak area increases, the amount of leak flow increases; (2) the amount of flow leak is relatively independent of location; (3) given equivalent leak areas, multiple leak locations provide less leak flow; and (4) quasi-elliptical tubes were more resistive to airflow than rectangular tubes. A general empirical equation was obtained that relates the leak flow between the mask rim and the face, the size of the leak region, and the amount of the upstream airflow toward the mask: Leak(cm 3 /s) = 0.33 × Area(cm 2 ) × Flow(cm 3 /s) for the range of ±2000 cm 3 /s. This equation may provide researchers and clinicians with a tool for generalizing airflow leak effects., (Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Currently, no scientific consensus exists on the relative safety of catcher mask styles and materials. Due to differences in mass and material properties, the style and material of a catcher mask influences the impact metrics observed during simulated foul ball impacts. The catcher surrogate was a Hybrid III head and neck equipped with a six degree of freedom sensor package to obtain linear accelerations and angular rates. Four mask styles were impacted using an air cannon for six 30 m/s and six 35 m/s impacts to the nasion. To quantify impact severity, the metrics peak linear acceleration, peak angular acceleration, Head Injury Criterion, Head Impact Power, and Gadd Severity Index were used. An Analysis of Covariance and a Tukey's HSD Test were conducted to compare the least squares mean between masks for each head injury metric. For each injury metric a P-Value less than 0.05 was found indicating a significant difference in mask performance. Tukey's HSD test found for each metric, the traditional style titanium mask fell in the lowest performance category while the hockey style mask was in the highest performance category. Limitations of this study prevented a direct correlation from mask testing performance to mild traumatic brain injury., Competing Interests: The authors have declared that no competing interests exist.

To get a better fit performance of filtering facepieces, a tight fitting net (TFN) was invented. This study was carried out to evaluate whether the TFN improves fit performance using a quantitative fit test (QNFT). The existing mask was of cup type with an aluminum clip on the nose bridge. The TFN mask was the same as the existing mask, but attached a TFN instead of aluminum clip. One hundred subjects (male 52, female 48) were selected to match fourfold in Korean 25-member facial size category for half-mask (KFCH). Fit factors (FFs) were measured using a QNFT by a Portacount ® Pro+8038. Three QNFTs for each mask on the same subject was conducted and geometric mean FF (GMFF) was determined. The mean and median GMFFs of the TFN masks had higher than those of the existing mask (p=<0.001). The existing masks had tendency to have higher GMFFs with common facial size categories, while the TFN masks were regardless of facial size. The result indicates that putting even pressure on the entire parts of filter media would improve fit performance. In conclusion, to get a good fit when wearing filtering facepieces, a TFN would be an alternative to mask designing.

Mask ventilation and coughing during oro-tracheal suctioning produce aerosols that enhance nosocomial transmission of respiratory infections. We examined the extent of exhaled air dispersion from a human-patient-simulator during mask ventilation by different groups of healthcare workers and coughing bouts. The simulator was programmed to mimic varying severity of lung injury. Exhaled airflow was marked with tiny smoke particles, and highlighted by laser light-sheet. We determined the normalized exhaled air concentration in the leakage jet plume from the light scattered by smoke particles. Smoke concentration ≥20% was considered as significant exposure. Exhaled air leaked from mask-face interface in the transverse plane was most severe (267 ± 44 mm) with Ambu silicone resuscitator performed by nurses. Dispersion was however similar among anesthesiologists/intensivists, respiratory physicians and medical students using Ambu or Laerdal silicone resuscitator, p = 0.974. The largest dispersion was 860 ± 93 mm during normal coughing effort without tracheal intubation and decreased with worsening coughing efforts. Oro-tracheal suctioning reduced dispersion significantly, p < 0.001, and was more effective when applied continuously. Skills to ensure good fit during mask ventilation are important in preventing air leakage through the mask-face interface. Continuous oro-tracheal suctioning minimized exhaled air dispersion during coughing bouts when performing aerosol-generating procedures.

Patient interface preference is a key factor in positive airway pressure compliance. Local side effects are common. Proper mask fitting and patient education are important. Masks should seal well and fit comfortably. Nasal, nasal pillow, and oronasal masks can be effective interfaces. Most patients with obstructive sleep apnea prefer a nasal mask. Oronasal masks can be a useful alternative. Nasal pillows can reduce mask size and improve comfort. Oronasal masks may require a higher pressure. A significantly lower pressure may be effective with a nasal interface. Proper mask fitting requires testing the mask seal under the treatment pressure., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Poor sleep is common in intensive care unit (ICU) patients, where environmental factors contribute to reduce and fragment sleep. The objective of this study was to evaluate the impact of earplugs and eye mask on sleep architecture in ICU patients., Methods: A single-center randomized controlled trial of 64 ICU patients was conducted from July 2012 to December 2013. Patients were randomly assigned to sleep with or without earplugs and an eye mask from inclusion until ICU discharge. Polysomnography was performed on the first day and night following inclusion. The primary outcome was the proportion of stage N3 sleep over total sleep time. Secondary outcomes were other descriptors of sleep and major outcome variables., Results: In the intervention group, nine (30%) patients did not wear earplugs all night long. The proportion of N3 sleep was 21 [7-28]% in the intervention group and 11 [3-23]% in the control group (p = 0.09). The duration of N3 sleep was higher among the patients in the intervention group who wore earplugs all night long than in the control group (74 [32-106] vs. 31 [7-76] minutes, p = 0.039). The number of prolonged awakenings was smaller in the intervention group (21 [19-26] vs. 31 [21-47] in the control group, p = 0.02). No significant difference was observed between the two groups in terms of clinical outcome variables., Conclusions: Earplugs and eye mask reduce long awakenings and increase N3 duration when they are well tolerated., Trial Registration: ClinicalTrials.gov, NCT02292134 . Registered on 21 Nov 2013.

Introduction: Patient interface is important for the success of continuous positive airway pressure (CPAP), but few trials have examined the influence of mask choice on CPAP adherence., Objectives: To compare the impact of different nasal masks on CPAP in patients with newly-diagnosed obstructive sleep apnea (OSA)., Methods: OSA patients were randomized in a 2:3 ratio to receive CPAP via different first-line nasal masks: ResMed Mirage FX® (MFX) or control mask (Fisher & Paykel Zest ® , HC407 ® or Philips EasyLife ® ). Mask acceptance, CPAP compliance and Home Care Provider (HCP) interventions were compared between groups after 3 months of CPAP therapy using modified intent-to-treat (mITT; after exclusion of patients with mouth leaks during CPAP initiation) and on-treatment (OT; CPAP adherent) analyses., Results: Of 285 randomized patients, 90 requiring a full-face mask were excluded, leaving 195 and 151 in the mITT and OT analyses, respectively. Mask acceptance rate was higher in the MFX versus control group (mITT: 79% vs 68%, P = 0.067; OT: 90% vs 76%, P = 0.022). CPAP compliance was higher (5.9 ± 1.8 vs 5.1 ± 1.6 h/night, P = 0.011) and nasal mask issue-related HCP visits lower (3% vs 17%, P = 0.006) in the MFX group. Nasal mask failures due to mask discomfort (5% vs 1%) or unintentional leakage (5% vs 0%) were higher in control vs MFX group. Mask acceptance was significantly associated with fewer mask leaks (P = 0.002) and higher pressure therapy (P = 0.042)., Conclusions: This study highlights differences between nasal masks for CPAP delivery and shows that initial mask selection can influence adherence and healthcare utilization during CPAP., (© 2016 ResMed Germany Inc. The Clinical Respiratory Journal published by John Wiley & Sons Ltd.)

Many orally inhaled products are supplied with a facemask instead of a mouthpiece, enabling aerosolized medication to be transferred from the inhaler to the lungs when the user lacks the capability to use a mouthpiece. Until recently, laboratory evaluation of an orally inhaled product-facemask was frequently undertaken by removing the facemask, treating the facemask adapter as being equivalent to a mouthpiece. Measurements of delivered drug mass were therefore subject to bias arising from the absence of dead volume, had the facemask been present. We have described the development of the Aerosol Delivery to an Anatomic Model (ADAM) infant, small child, and adult faces and upper airways, and their subsequent evaluation. Each model possesses physical features of appropriate size, and the soft tissues are also simulated. Rudimentary underlying bony structure is also present, because its purpose is only to provide support, enabling the mechanical response of the facial soft tissues when a facemask is applied to be realized. A realistic upper airway (nasopharynx for the infant model, naso- and oropharynx for the child and oropharynx for the adult models) is also incorporated, so that each model can be used to determine the mass of inhaled medication likely to penetrate as far as the lungs where therapy is intended to be applied. Measurements of the mass of pressurized metered-dose inhaler-delivered salbutamol at a filter distal to the upper airway of each model, simulating age-appropriate tidal breathing, were remarkably consistent, almost all being in the range 0.3 to 1.0 μg/kg across the model age ranges, when expressed as a fraction of body weight.

Aim: The aim of this study was to compare mask leak with three different peak inspiratory pressure (PIP) settings during T-piece resuscitator (TPR; Neopuff) mask ventilation on a neonatal manikin model., Methods: Participants were neonatal unit staff members. They were instructed to provide mask ventilation with a TPR with three PIP settings (20, 30, 40 cm H 2 O) chosen in a random order. Each episode was for 2 min with 2-min rest period. Flow rate and positive end-expiratory pressure (PEEP) were kept constant. Airway pressure, inspiratory and expiratory tidal volumes, mask leak, respiratory rate and inspiratory time were recorded. Repeated measures analysis of variance was used for statistical analysis., Results: A total of 12 749 inflations delivered by 40 participants were analysed. There were no statistically significant differences (P > 0.05) in the mask leak with the three PIP settings. No statistically significant differences were seen in respiratory rate and inspiratory time with the three PIP settings. There was a significant rise in PEEP as the PIP increased. Failure to achieve the desired PIP was observed especially at the higher settings., Conclusions: In a neonatal manikin model, the mask leak does not vary as a function of the PIP when the flow rate is constant. With a fixed rate and inspiratory time, there seems to be a rise in PEEP with increasing PIP., (© 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).)

Elevated concentrations of diesel exhaust have been linked to adverse health effects. Filtering facepiece respirators (FFRs) are widely used as a form of respiratory protection against diesel particulate matter (DPM) in occupational settings. Previous results (Penconek A, Drążyk P, Moskal A. (2013) Penetration of diesel exhaust particles through commercially available dust half masks. Ann Occup Hyg; 57: 360-73.) have suggested that common FFRs are less efficient than would be expected for this purpose based on their certification approvals. The objective of this study was to measure the penetration of DPM through NIOSH-certified R95 and P95 electret respirators to verify this result. Gravimetric-based penetration measurements conducted using polytetrafluoroethylene (PTFE) and polypropylene (PP) filters were compared with penetration measurements made with a Scanning Mobility Particle Sizer (SMPS, TSI Inc.), which measures the particle size distribution. Gravimetric measurements using PP filters were variable compared to SMPS measurements and biased high due to adsorption of gas phase organic material. Relatively inert PTFE filters adsorbed less gas phase organic material resulting in measurements that were more accurate. To attempt to correct for artifacts associated with adsorption of gas phase organic material, primary and secondary filters were used in series upstream and downstream of the FFR. Correcting for adsorption by subtracting the secondary mass from the primary mass improved the result for both PTFE and PP filters but this correction is subject to 'equilibrium' conditions that depend on sampling time and the concentration of particles and gas phase hydrocarbons. Overall, the results demonstrate that the use of filters to determine filtration efficiency of FFRs challenged with diesel exhaust produces erroneous results due to the presence of gas phase hydrocarbons in diesel exhaust and the tendency of filters to adsorb organic material., (Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2017.)

This study assessed key test parameters and pass/fail criteria options for developing a respirator fit capability (RFC) test for half-mask air-purifying particulate respirators. Using a 25-subject test panel, benchmark RFC data were collected for 101 National Institute for Occupational Safety and Health-certified respirator models. These models were further grouped into 61 one-, two-, or three-size families. Fit testing was done using a PortaCount® Plus with N95-Companion accessory and an Occupational Safety and Health Administration-accepted quantitative fit test protocol. Three repeated tests (donnings) per subject/respirator model combination were performed. The panel passing rate (PPR) (number or percentage of the 25-subject panel achieving acceptable fit) was determined for each model using five different alternative criteria for determining acceptable fit. When the 101 models are evaluated individually (i.e., not grouped by families), the percentages of models capable of fitting >75% (19/25 subjects) of the panel were 29% and 32% for subjects achieving a fit factor ≥100 for at least one of the first two donnings and at least one of three donnings, respectively. When the models are evaluated grouped into families and using >75% of panel subjects achieving a fit factor ≥100 for at least one of two donnings as the PPR pass/fail criterion, 48% of all models can pass. When >50% (13/25 subjects) of panel subjects was the PPR criterion, the percentage of passing models increased to 70%. Testing respirators grouped into families and evaluating the first two donnings for each of two respirator sizes provided the best balance between meeting end user expectations and creating a performance bar for manufacturers. Specifying the test criterion for a subject obtaining acceptable fit as achieving a fit factor ≥100 on at least one out of the two donnings is reasonable because a majority of existing respirator families can achieve an PPR of >50% using this criterion. The different test criteria can be considered by standards development organizations when developing standards.

Inexpensive cloth masks are widely used in developing countries to protect from particulate pollution albeit limited data on their efficacy exists. This study examined the efficiency of four types of masks (three types of cloth masks and one type of surgical mask) commonly worn in the developing world. Five monodispersed aerosol sphere size (30, 100, and 500 nm, and 1 and 2.5 μm) and diluted whole diesel exhaust was used to assess facemask performance. Among the three cloth mask types, a cloth mask with an exhaust valve performed best with filtration efficiency of 80-90% for the measured polystyrene latex (PSL) particle sizes. Two styles of commercially available fabric masks were the least effective with a filtration efficiency of 39-65% for PSL particles, and they performed better as the particle size increased. When the cloth masks were tested against lab-generated whole diesel particles, the filtration efficiency for three particle sizes (30, 100, and 500 nm) ranged from 15% to 57%. Standard N95 mask performance was used as a control to compare the results with cloth masks, and our results suggest that cloth masks are only marginally beneficial in protecting individuals from particles<2.5 μm. Compared with cloth masks, disposable surgical masks are more effective in reducing particulate exposure.

Surgical respirators, surgical masks (SMs), and facemasks for pediatric use (FPUs) are routinely used in the U.S. healthcare industry as personal protective equipment (PPE) against infectious diseases. While N95s including surgical respirators have been routinely studied, SMs and FPUs have not received as much attention, particularly in the context of aerosolized threats. This is because SMs and PFUs are not designed to protect against sub-micron aerosols. However, with the possibility of new or re-emerging airborne diseases or bio-aerosol weapons lingering, combined with the limited availability of respirators and logistical issues associated with fit-testing millions, the general adult and pediatric populations may elect to wear SMs and FPUs, respectively, in the case of a pandemic or a bio-terrorist attack. When a person dons a PPE, gaps are created between the wearer's face and the PPE, and aerosols leaking through these gaps can be an important contributor to the risk of infection compared to filtered aerosols. To understand and quantify the contribution of leakage of aerosols through gaps, with particular emphasis on SMs and FPUs, this study investigated leakage of charge-neutralized, polydispersed, dried sodium-chloride aerosols across different brands of PPE. Different breathing rates, aerosol particle sizes, and gap sizes were considered. A few major findings of this study were: (a) leakage, is not a strong function of sub-micron aerosol size; (b) for the same gap size, leakage of aerosols through surgical respirators can often be higher than in SMs and FPUs; and (c) as the gap size increases, the increase in leakage through surgical respirators is higher compared for SMs and FPUs, implying that some SMs and FPUs that possess electret layers may be preferable to N95s that have not been fit-tested. The results obtained can also be used to explain conflicting findings from clinical studies on the effectiveness of SMs when compared to N95s and can be input into risk-assessment models to determine the increase in infection rate resulting from deployment of PPE under less-than-ideal conditions.

Objectives: Since hypoxia remains one of the most important physiological hazards the aviation environment poses, military aviators are trained to recognize symptoms of hypoxia in order to implement appropriate safety procedures and countermeasures when hypoxia occurs. A widely used commercial instrument for hypoxia training, demonstration, and research is the Reduced Oxygen Breathing Device (ROBD). Here we describe a novel, inexpensive method to use the ROBD's breathing loop pressure (BLP) to measure respiration rate, a critically important response parameter for hypoxia., Methods: The ROBD can be controlled by a computer to export several variables including BLP, via the ROBD's RS232 port. An archived database was reanalyzed to assess the BLP data. New instrumentation added independent measures of respiration and expired oxygen and carbon dioxide; these measures were integrated with the ROBD output., Results: Analysis of the archived data showed that the BLP reflected realistic breathing patterns. The new instrumentation integrated well with the ROBD, and independently supported the potential of the BLP as a valid measure of respiration., Discussion: The ROBD's BLP data may provide a basis for a reliable, sensitive measure of respiration that is available at no additional cost., (Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.)

Speech Intelligibility (SI) is the perceived quality of sound transmission. In healthcare settings, the ability to communicate clearly with coworkers, patients, etc., is crucial to quality patient care and safety. The objectives of this study were to: (1) assess the suitability of the Speech Transmission Index (STI) methods for testing reusable and disposable facial and respiratory personal protective equipment (protective facemasks [PF], N95 filtering facepiece respirators [N95 FFR], and elastomeric half-mask air-purifying respirators [EAPR]) commonly worn by healthcare workers; (2) quantify STI levels of these devices; and (3) contribute to the scientific body of knowledge in the area of SI. SI was assessed using the STI under two experimental conditions: (1) a modified version of the National Fire Protection Association 1981 Supplementary Voice Communications System Performance Test at a Signal to Noise Ratio (SNR) of -15 (66 dBA) and (2) STI measurements utilizing a range of modified pink noise levels (52.5 dBA (-2 SNR) - 72.5 dBA (+7 SNR)) in 5.0 dBA increments. The PF models (Kimberly Clark 49214 and 3 M 1818) had the least effect on SI interference, typically deviating from the STI baseline (no-mask condition) by 3% and 4% STI, respectively. The N95FFR (3 M 1870, 3 M 1860) had more effect on SI interference, typically differing from baseline by 13% and 17%, respectively, for models tested. The EAPR models (Scott Xcel and North 5500) had the most significant impact on SI, differing from baseline by 42% for models tested. This data offers insight into the performance of these apparatus with respect to STI and may serve as a reference point for future respirator design considerations, standards development, testing and certification activities.

Current regulations require annual fit testing before an employee can wear a respirator during work activities. The goal of this research is to determine whether respirator fit measured with two TSI Portacount instruments simultaneously sampling ambient particle concentrations inside and outside of the respirator facepiece is similar to fit measured during an ambient aerosol condensation nuclei counter quantitative fit test. Sixteen subjects (ten female; six male) were recruited for a range of facial sizes. Each subject donned an N95 filtering facepiece respirator, completed two fit tests in random order (ambient aerosol condensation nuclei counter quantitative fit test and two-instrument real-time fit test) without removing or adjusting the respirator between tests. Fit tests were compared using Spearman's rank correlation coefficients. The real-time two-instrument method fit factors were similar to those measured with the single-instrument quantitative fit test. The first four exercises were highly correlated (r > 0.7) between the two protocols. Respirator fit was altered during the talking or grimace exercise, both of which involve facial movements that could dislodge the facepiece. Our analyses suggest that the new real-time two-instrument methodology can be used in future studies to evaluate fit before and during work activities.

This study aimed to quantify the variability between different anthropometric panels in determining the inward leakage (IL) of N95 filtering facepiece respirators (FFRs) and elastomeric half-mask respirators (EHRs). We enrolled 144 experienced and non-experienced users as subjects in this study. Each subject was assigned five randomly selected FFRs and five EHRs, and performed quantitative fit tests to measure IL. Based on the NIOSH bivariate fit test panel, we randomly sampled 10,000 pairs of anthropometric 35 and 25 member panels without replacement from the 144 study subjects. For each pair of the sampled panels, a Chi-Square test was used to test the hypothesis that the passing rates for the two panels were not different. The probability of passing the IL test for each respirator was also determined from the 20,000 panels and by using binomial calculation. We also randomly sampled 500,000 panels with replacement to estimate the coefficient of variation (CV) for inter-panel variability. For both 35 and 25 member panels, the probability that passing rates were not significantly different between two randomly sampled pairs of panels was higher than 95% for all respirators. All efficient (passing rate ≥80%) and inefficient (passing rate ≤60%) respirators yielded consistent results (probability >90%) for two randomly sampled panels. Somewhat efficient respirators (passing rate between 60% and 80%) yielded inconsistent results. The passing probabilities and error rates were found to be significantly different between the simulation and binomial calculation. The CV for the 35-member panel was 16.7%, which was slightly lower than that for the 25-member panel (19.8%). Our results suggested that IL inter-panel variability exists, but is relatively small. The variability may be affected by passing level and passing rate. Facial dimension-based fit test panel stratification was also found to have significant impact on inter-panel variability, i.e., it can reduce alpha and beta errors, and inter-panel variability.