Project description:In the hope of reducing the air supply flow of the powered air-purifying respirator (PAPR) and extending the service life of the filter, a breath-following powered air-purifying respirator (BF-PAPR) that can dynamically adjust the air supply flow according to the breathing flow is proposed. The BF-PAPR changes the air supply flow by adjusting the speed of the variable-frequency centrifugal fan according to the air velocity at the half mask outlet (vhm) monitored by the modular wind speed transmitter. In the study, the air supply flow adjustment model of the BF-PAPR is developed. It is found that the filtration resistance barely influences vhm. In addition, under the same mean inhalation flow, the minimum outlet air velocity increases first and then decreases with the increase of the duty cycle variation coefficient (λ), while the maximum outlet air velocity decreases first and then increases. Moreover, the minimum air supply flow of the BF-PAPR is achieved when the standard value of the air velocity is 13.4 m/s and the value of λ is 1. The BF-PAPR can reduce the air supply flow by 6.5%-8.6% and the energy consumption by approximately 20% compared with the PAPR, which is beneficial for reducing the usage cost and extending the continuous working time.
Project description:BackgroundDue to the coronavirus disease 2019 (COVID-19) pandemic, interventions in the upper airways are considered high-risk procedures for otolaryngologists and their colleagues. The purpose of this study was to evaluate limitations in hearing and communication when using a powered air-purifying respirator (PAPR) system to protect against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) transmission and to assess the benefit of a headset.MethodsAcoustic properties of the PAPR system were measured using a head and torso simulator. Audiological tests (tone audiometry, Freiburg speech test, Oldenburg sentence test (OLSA)) were performed in normal-hearing subjects (n = 10) to assess hearing with PAPR. The audiological test setup also included simulation of conditions in which the target speaker used either a PAPR, a filtering face piece (FFP) 3 respirator, or a surgical face mask.ResultsAudiological measurements revealed that sound insulation by the PAPR headtop and noise, generated by the blower-assisted respiratory protection system, resulted in significantly deteriorated hearing thresholds (4.0 ± 7.2 dB hearing level (HL) vs. 49.2 ± 11.0 dB HL, p < 0.001) and speech recognition scores in quiet (100.0 ± 0.0% vs. 2.5 ± 4.2%, p < 0.001; OLSA: 20.8 ± 1.8 dB vs. 61.0 ± 3.3 dB SPL, p < 0.001) when compared to hearing without PAPR. Hearing with PAPR was significantly improved when the subjects were equipped with an in-ear headset (p < 0.001). Sound attenuation by FFP3 respirators and surgical face masks had no clinically relevant impact on speech perception.ConclusionsThe PAPR system evaluated here can be considered for high-risk procedures in SARS-CoV-2-positive patients, provided that hearing and communication of the surgical team are optimized by the additional use of a headset.
Project description:BackgroundHealthcare workers (HCWs) are at particular risk during pandemics and epidemics of highly virulent diseases with significant morbidity and case fatality rate. These diseases include severe acute respiratory syndrome coronaviruses, SARS-CoV-1 and SARS-CoV-2, Middle Eastern Respiratory Syndrome (MERS), and Ebola. With the current (SARS-CoV-2) global pandemic, it is critical to delineate appropriate contextual respiratory protection for HCWs. The aim of this systematic review was to evaluate the effect of powered air-purifying respirators (PAPRs) as part of respiratory protection versus another device (egN95/FFP2) on HCW infection rates and contamination.MethodsOur primary outcomes included HCW infection rates with SARS-CoV-2, SARS-CoV-1, Ebola, or MERS when utilizing PAPR. We included randomized controlled trials, non-randomized controlled trials, and observational studies. We searched the following databases: MEDLINE, EMBASE, and Cochrane Library (Cochrane Database of Systematic Reviews and CENTRAL). Two reviewers independently screened all citations, full-text articles, and abstracted data. Due to clinical and methodological heterogeneity, we did not conduct a meta-analysis. Where applicable, we constructed evidence profile (EP) tables for each individual outcome. Confidence in cumulative evidence for each outcome was classified according to the GRADE system.ResultsWe identified 689 studies during literature searches. We included 10 full-text studies. A narrative synthesis was provided. Two on-field studies reported no difference in the rates of healthcare workers performing airway procedures during the care of critical patients with SARS-CoV-2. A single simulation trial reported a lower level of cross-contamination of participants using PAPR compared to alternative respiratory protection. There is moderate quality evidence that PAPR use is associated with greater heat tolerance but lower scores for mobility and communication ability. We identified a trend towards greater self-reported wearer comfort with PAPR technology in low-quality observational simulation studies.ConclusionField observational studies do not indicate a difference in healthcare worker infection utilizing PAPR devices versus other compliant respiratory equipment. Greater heat tolerance accompanied by lower scores of mobility and audibility in PAPR was identified. Further pragmatic studies are needed in order to delineate actual effectiveness and provider satisfaction with PAPR technology.Systematic review registrationThe protocol for this review was prospectively registered with the International Register of Systematic Reviews identification number CRD42020184724 .
Project description:BackgroundThe last 2 decades have seen an increasing frequency of zoonotic origin viral diseases leaping from animal to human hosts including Severe Acute Respiratory Syndrome Coronaviruses (SARS-CoV-2). Respiratory component of the infectious disease program against SARS-CoV-2 incorporates use of protective airborne respiratory equipment.MethodsIn this narrative review, we explore the features of Powered Air Purifying Respirators (PAPR) as well as logistical and evidence-based advantages and disadvantages.ResultsSimulation study findings support increased heat tolerance and wearer comfort with a PAPR, versus decreased communication ability, mobility, and dexterity. Although PAPRs have been recommended for high-risk procedures on suspected or confirmed COVID-19 patients, this recommendation remains controversial due to lack of evidence. Guidelines for appropriate use of PAPR during the current pandemic are sparse. International regulatory bodies do not mandate the use of PAPR for high-risk aerosol generating procedures in patients with SARS-CoV-2. Current reports of the choice of protective respiratory technology during the SARS-CoV-2 pandemic are disparate. Patterns of use appear to be related to geographical locations.DiscussionField observational studies do not indicate a difference in healthcare worker infection utilizing PAPR devices versus other compliant respiratory equipment in healthcare workers performing AGPs in patients with SARS-CoV-2. Whether a higher PAPR filtration factor translates to decreased infection rates of HCWs remains to be elucidated. Utilization of PAPR with high filtration efficiency may represent an example of "precautionary principle" wherein action taken to reduce risk is guided by logistical advantages of PAPR system.
Project description: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.
Project description:ObjectivesWe aimed to design and produce a low-cost, ergonomic, hood-integrated powered air-purifying respirator (Bubble-PAPR) for pandemic healthcare use, offering optimal and equitable protection to all staff. We hypothesised that participants would rate Bubble-PAPR more highly than current filtering face piece (FFP3) face mask respiratory protective equipment (RPE) in the domains of comfort, perceived safety and communication.DesignRapid design and evaluation cycles occurred based on the identified user needs. We conducted diary card and focus group exercises to identify relevant tasks requiring RPE. Lab-based safety standards established against British Standard BS-EN-12941 and EU2016/425 covering materials; inward particulate leakage; breathing resistance; clean air filtration and supply; carbon dioxide elimination; exhalation means and electrical safety. Questionnaire-based usability data from participating front-line healthcare staff before (usual RPE) and after using Bubble-PAPR.SettingOverseen by a trial safety committee, evaluation progressed sequentially through laboratory, simulated, low-risk, then high-risk clinical environments of a single tertiary National Health Service hospital.Participants15 staff completed diary cards and focus groups. 91 staff from a range of clinical and non-clinical roles completed the study, wearing Bubble-PAPR for a median of 45 min (IQR 30-80 (15-120)). Participants self-reported a range of heights (mean 1.7 m (SD 0.1, range 1.5-2.0)), weights (72.4 kg (16.0, 47-127)) and body mass indices (25.3 (4.7, 16.7-42.9)).Outcome measuresPreuse particulometer 'fit testing' and evaluation against standards by an independent biomedical engineer.Primary:Perceived comfort (Likert scale).Secondary: Perceived safety, communication.ResultsMean fit factor 16 961 (10 participants). Bubble-PAPR mean comfort score 5.64 (SD 1.55) vs usual FFP3 2.96 (1.44) (mean difference 2.68 (95% CI 2.23 to 3.14, p<0.001). Secondary outcomes, Bubble-PAPR mean (SD) versus FFP3 mean (SD), (mean difference (95% CI)) were: how safe do you feel? 6.2 (0.9) vs 5.4 (1.0), (0.73 (0.45 to 0.99)); speaking to other staff 7.5 (2.4) vs 5.1 (2.4), (2.38 (1.66 to 3.11)); heard by other staff 7.1 (2.3) vs 4.9 (2.3), (2.16 (1.45 to 2.88)); speaking to patients 7.8 (2.1) vs 4.8 (2.4), (2.99 (2.36 to 3.62)); heard by patients 7.4 (2.4) vs 4.7 (2.5), (2.7 (1.97 to 3.43)); all p<0.01.ConclusionsBubble-PAPR achieved its primary purpose of keeping staff safe from airborne particulate material while improving comfort and the user experience when compared with usual FFP3 masks. The design and development of Bubble-PAPR were conducted using a careful evaluation strategy addressing key regulatory and safety steps.Trial registration numberNCT04681365.
Project description:The rapid spread of COVID-19 and disruption of normal supply chains resulted in severe shortages of personal protective equipment (PPE), particularly devices with few suppliers such as powered air-purifying respirators (PAPRs). A scarcity of information describing design and performance criteria represents a substantial barrier to new approaches to address these shortages. We sought to apply open-source product development to PAPRs to enable alternative sources of supply and further innovation. We describe the design, prototyping, validation, and user testing of locally manufactured, modular, PAPR components, including filter cartridges and blower units, developed by the Greater Boston Pandemic Fabrication Team (PanFab). Two designs, one with a fully custom-made filter and blower unit housing, and the other with commercially available variants (the "Custom" and "Commercial" designs respectively) were developed. Engineering performance of the prototypes was measured and safety validated using NIOSH-equivalent tests on apparatus available under pandemic conditions, at university laboratories. Feedback on designs was obtained from four individuals, including two clinicians working in an ambulatory clinical setting and two research technical staff for whom PAPR use is a standard part of occupational PPE. Respondents rated the PanFab Custom PAPR a 4 to 5 on a 5 Likert-scale 1) as compared to current PPE options, 2) for the sense of security with use in a clinical setting, and 3) for comfort. The three other versions of the designs (with a commercial blower unit, filter, or both) performed favorably, with survey responses consisting of scores ranging from 3-5. Engineering testing and clinical feedback demonstrate that the PanFab designs represents favorable alternative PAPRs in terms of user comfort, mobility, and sense of security. A nonrestrictive license promotes innovation in respiratory protection for current and future medical emergencies.
Project description:The rapid spread of COVID-19 and disruption of normal supply chains has resulted in severe shortages of personal protective equipment (PPE), particularly devices with few suppliers such as powered air-purifying respirators (PAPRs). A scarcity of information describing design and performance criteria for PAPRs represents a substantial barrier to mitigating shortages. We sought to apply open-source product development (OSPD) to PAPRs to enable alternative sources of supply and further innovation. We describe the design, prototyping, validation, and user testing of locally manufactured, modular, PAPR components, including filter cartridges and blower units, developed by the Greater Boston Pandemic Fabrication Team (PanFab). Two designs, one with a fully custom-made filter and blower unit housing, and the other with commercially available variants (the "Custom" and "Commercial" designs, respectively) were developed; the components in the Custom design are interchangeable with those in Commercial design, although the form factor differs. The engineering performance of the prototypes was measured and safety validated using National Institutes for Occupational Safety and Health (NIOSH)-equivalent tests on apparatus available under pandemic conditions at university laboratories. Feedback was obtained from four individuals; two clinicians working in ambulatory clinical care and two research technical staff for whom PAPR use is standard occupational PPE; these individuals were asked to compare PanFab prototypes to commercial PAPRs from the perspective of usability and suggest areas for improvement. Respondents rated the PanFab Custom PAPR a 4 to 5 on a 5 Likert-scale 1) as compared to current PPE options, 2) for the sense of security with use in a clinical setting, and 3) for comfort compared to standard, commercially available PAPRs. The three other versions of the designs (with a Commercial blower unit, filter, or both) performed favorably, with survey responses consisting of scores ranging from 3 to 5. Engineering testing and clinical feedback demonstrate that the PanFab designs represent favorable alternatives to traditional PAPRs in terms of user comfort, mobility, and sense of security. A nonrestrictive license promotes innovation in respiratory protection for current and future medical emergencies.
Project description:BackgroundThe design of personal protective equipment (PPE) may affect well-being and clinical work. PPE as an integrated item may improve usability and increase adherence by healthcare professionals. Human factors design and safety may reduce occupational-acquired diseases. As an integrated PPE, a lightweight protective air-purifying respirator (L-PAPR) could be used during health procedures where healthcare professionals are exposed to airborne pathogens. The human factors affecting the implementation of alternative PPE such as L-PAPR have not been thoroughly studied. The population of interest is health care professionals, the intervention is the performance by PPE during tasks across the three PPE types 1.) N95 respirators and face shields, 2.)traditional powered air-purifying respirator(PAPR), and 3.) L-PAPR. The outcomes are user error, communications, safety, and end-user preferences.ObjectiveThis study will assess whether the L-PAPR improves health care professionals' comfort in terms of perceived workload and physical and psychological burden during direct patient care when compared with the traditional PAPR or N95 and face shield. This study also aims to evaluate human factors during the comparison of the use of L-PAPR with a combination of N95 respirators plus face shields or the traditional PAPRs.MethodsThis is an interventional randomized crossover quality improvement feasibility study consisting of a 3-site simulation phase with 10 participants per site and subsequent field testing in 2 sites with 30 participants at each site. The 3 types of respiratory PPE will be compared across medical tasks and while donning and doffing. We will evaluate the user's perceived workload, usability, usage errors, and heart rate. We will conduct semistructured interviews to identify barriers and enablers to implementation across each PPE type over a single continuous wear episode and observe interpersonal communications across conditions and PPE types.ResultsWe expect the research may highlight communication challenges and differences in usability and convenience across PPE types along with error frequency during PPE use across PPE types, tasks, and time.ConclusionsThe design of PPE may affect overall well-being and hinder or facilitate clinical work. Combining 2 pieces of PPE into a single integrated item may improve usability and reduce occupational-acquired diseases. The human factors affecting the implementation of an alternative PPE such as L-PAPR or PAPR have not been thoroughly studied.International registered report identifier (irrid)PRR1-10.2196/36549.
Project description:IntroductionDuring the coronavirus disease 2019 (COVID-19) pandemic, multiple guidelines have recommended videolaryngoscope (VL) for tracheal intubation. However, there is no evidence that VL reduces time to tracheal intubation, and this is important for COVID-19 patients with respiratory failure.MethodsTo simulate intubation of COVID-19 patients, we randomly assigned 28 elective surgical patients to be intubated with either McGrath™ MAC VL or direct laryngoscope (DL) by specialist anaesthetists who donned 3M™ Jupiter™ powered air-purifying respirators (PAPR) and N95 masks. The primary outcome was time to intubation.ResultsThe median time to intubation was 61 s (interquartile range [IQR] 37-63 s) and 41.5 s (IQR 37-56 s) in the VL and DL groups, respectively ( P = 0.35). The closest mean distance between the anaesthetist and patient during intubation was 21.6 ± 4.8 cm and 17.6 ± 5.3 cm in the VL and DL groups, respectively ( P = 0.045). There were no significant differences in the median intubation difficulty scale scores, proportion of successful intubations at the first laryngoscopic attempt and proportion of intubations requiring adjuncts. All the patients underwent successful intubation with no adverse event.ConclusionThere was no significant difference in the time to intubation of elective surgical patients with either McGrath™ VL or DL by specialist anaesthetists who donned PAPR and N95 masks. The distance between the anaesthetist and patient was significantly greater with VL. When resources are limited or disrupted during a pandemic, DL could be a viable alternative to VL for specialist anaesthetists.