Robust Design Optimization of Powered Air Purifying Respirator System by Iterative Process

The personal protective equipment (PPE) has protected the frontline health workers from getting affected in COVID 19 spread situations to a certain level. Among the PPEs, PAPRs (Powered Air Purifying Respirators) are considered as one of the most efficient equipment for protection purposes. In pandemic spread situations, the PAPR becomes very much essential considering its protection. The PAPR is mainly imported to India. But the cost of PAPR being on the higher side (Rupees (Rs) 100000) becomes unaffordable to many frontline health workers. This paper focuses on the development of a cost-effective PAPR that is affordable to them. This paper projects a detailed step-by-step process of design and development of PAPR, and its evolution in each iteration. The study was conducted with the medical officers from AIMS Hospital and engineers from AMMACHI labs to bring out effective solutions for frontline health workers during a pandemic. © 2022 IEEE.

Overcoming Communication Barriers: An evaluation of communication devices for healthcare providers wearing powered air-purifying respirators (PAPRs).

Introduction: The COVID-19 pandemic has resulted in an increased use of Powered Air Purifying Respirators (PAPRs), by health care providers to mitigate the risk of viral transmission, especially for aerosol-generating procedures. In this study, we evaluate communication devices that could be used concurrently with PAPRs to promote improved communication. Methods: We tested two devices, a Bluetooth earpiece and a throat microphone that operated over mobile networks, against a control scenario in a simulated operating room environment with participants donning PAPRs. Participants read a short paragraph to each other, transcribed short phrases, and evaluated the scenarios according to speech intelligibility, ease of use, and comfort. Results: There were 30 participants of varying PAPR experience. The Bluetooth headset had the most accurate transcriptions, followed by control, and lastly the neckpiece (94.7%vs 88.4%vs 76%, p<0.001). Conclusion: Communication devices have the potential to bridge but also worsen communications barriers between providers donning PAPRs.

Tolerability, user acceptance and preference for a novel reusable respirator among health care workers.

BACKGROUND: The CleanSpace Technology Halo respirator combines a clear face mask and a powered air supply, without belts or hoses. Although providing higher protection than other respirators used in health care, user acceptance of this device has not been assessed with validated tools. METHODS: We surveyed healthcare workers (HCWs) within a US medical system using Halo respirators in 2021. Subjects completed 3 surveys over 8 weeks, which included the Respirator Comfort, Wearing Experience, and Function Instrument (R-COMFI), a validated tool to assess respirator tolerability. The survey included additional questions about user acceptability and respirator preference. Responses were evaluated for change over time and for significant predictors. RESULTS: Of 113 HCWs who completed the initial survey (29% response rate), mean ± SD R-COMFI score was 9.1± 5.1, (scale 0-47, lower = more tolerable) and did not change over time (P = .42). Fewer years in healthcare significantly predicted better R-COMFI score (P = .01). Many users preferred Halo in both usual care (45%-52%) and care of patients with COVID-19 (60%-64%). DISCUSSION: Halo respirators received favorable tolerability scores by HCWs, who often preferred them, especially during care of patients with COVID-19. CONCLUSIONS: Given demand for respirator use in health care, the innovative design provides higher protection than other respirators with a favorable user experience.

Awake craniotomy for glioblastoma in COVID-19-positive patients and delivering the standard of care: illustrative case.

BACKGROUND: Providing the standard of care to patients with glioblastoma (GBM) during the novel coronavirus of 2019 (COVID-19) pandemic is a challenge, particularly if a patient tests positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Further difficulties occur in eloquent cortex tumors because awake speech mapping can theoretically aerosolize viral particles and expose staff. Moreover, microscopic neurosurgery has become difficult because the use of airborne-level personal protective equipment (PPE) crowds the space between the surgeon and the eyepiece. However, delivering substandard care will inevitably lead to disease progression and poor outcomes. OBSERVATIONS: A 60-year-old man with a left insular and frontal operculum GBM was found to be COVID-19 positive. Treatment was postponed pending a negative SARS-CoV-2 result, but in the interim, he developed intratumoral hemorrhage with progressive expressive aphasia. Because the tumor was causing dominant hemisphere language symptomatology, an awake craniotomy was the recommended surgical approach. With the use of airborne-level PPE and a surgical drape to protect the surgeon from the direction of potential aerosolization, near-total gross resection was achieved. LESSONS: Delaying the treatment of patients with GBM who test positive for COVID-19 will lead to further neurological deterioration. Optimal and timely treatment such as awake speech mapping for COVID-19-positive patients with GBM can be provided safely.

Comparative study of the effect of N95 facemask and Powered Air-purifying Respirator (2 fans, N95 filter) on cardiovascular parameters of healthy individuals during exercise.

N95 masks filter 95% of the small particles and respiratory droplets (>0.3 µm diameter). Therefore, they are widely used both by general public and health workers during pandemic. When physical activity or exercise is performed wearing N95 mask, it induces hypercapnic environment. The heat burden is also increased leading to discomfort and reduced compliance. This study was done to compare physiological effects and subjective perceptions while wearing N95 mask and powered air-purifying respirator (PAPR) (2 fans, N95 filter) during incremental exercise. ECG, respiratory movement, SpO2, temperature inside the mask were recorded and perception of discomfort was also assessed. Heart rate variability (HRV) values during baseline were within normal limits in both the mask conditions signifying that cardiac autonomic tone is comparable. During incremental exercise, fall in SpO2 was significantly lesser in PAPR as compared to N95 mask at 60-70% and 70-80% of maximum achievable heart rate. The temperatures inside both the mask conditions were significantly higher than ambient temperature. The scores of humid, hot, breath resistance and fatigue were significantly lower in PAPR than N95 mask. In conditions where prolonged use of mask is required with strenuous physical exertion or exercise, PAPR could be preferred over N95 mask.

Quality Assurance in Pre-Endoscopic Evaluation

Endoscopy is an essential component of gastroenterology, allowing for the diagnosis and management of a variety of gastrointestinal diseases. Although most endoscopies are considered to be low risk procedures, several factors including the sedation, patient, and procedure play a role in determining overall risk. Patient assessment prior to endoscopy is essential to risk-stratification and provides an opportunity to review comorbidities, adjust medications if necessary, and identify an optimal sedation plan. Several best practice recommendations and guidelines have been developed to ensure that safe, high-quality endoscopies are performed to minimize risks and optimize outcomes. The purpose of this review is to highlight best practices related to pre-endoscopic evaluation and, when available, review quality indicators.

A Personal Respirator to Improve Protection for Healthcare Workers Treating COVID-19 (PeRSo).

Introduction: SARS-CoV-2 infection is a global pandemic. Personal Protective Equipment (PPE) to protect healthcare workers has been a recurrent challenge in terms of global stocks, supply logistics and suitability. In some settings, around 20% of healthcare workers treating COVID-19 cases have become infected, which leads to staff absence at peaks of the pandemic, and in some cases mortality. Methods: To address shortcomings in PPE, we developed a simple powered air purifying respirator, made from inexpensive and widely available components. The prototype was designed to minimize manufacturing complexity so that derivative versions could be developed in low resource settings with minor modification. Results: The "Personal Respirator - Southampton" (PeRSo) delivers High-Efficiency Particulate Air (HEPA) filtered air from a battery powered fan-filter assembly into a lightweight hood with a clear visor that can be comfortably worn for several hours. Validation testing demonstrates that the prototype removes microbes, avoids excessive CO2 build-up in normal use, and passes fit test protocols widely used to evaluate standard N95/FFP2 and N99/FFP3 face masks. Feedback from doctors and nurses indicate the PeRSo prototype was preferred to standard FFP2 and FFP3 masks, being more comfortable and reducing the time and risk of recurrently changing PPE. Patients report better communication and reassurance as the entire face is visible. Conclusion: Rapid upscale of production of cheaply produced powered air purifying respirators, designed to achieve regulatory approval in the country of production, could protect healthcare workers from infection and improve healthcare delivery during the COVID-19 pandemic.

An open-source powered and ergonomic personal protective respirator for frontline COVID-19 response.

Intending to shield front-liners who are currently exposed to COVID-19, and because of the lack of proper powered air-purifying respirator, this study shows the design and development of an open-source ergonomic respirator with a washable filter. This device has an estimated working time of 12 h, and the tests' airflow always showed a value over 4.5 cubic feet per minute, a higher value than the national institute for occupational safety and health specification for full-face closed respirators. The proposal relies on 3D printing technology for all the custom-design parts and usages easy-to-access components for the rest of the material. The mask for the APRPAPR in the article has a defogging feature, 180 degrees of viewing angle, an ergonomic profile, and no obstruction on the mouth to show the user's full face. This respirator has an estimated cost of 318 USD, approximately one-third of the market's price of well-known brands.

Powered air-purifying respirators used during the SARS-CoV-2 pandemic significantly reduce speech perception.

BACKGROUND: Due 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. METHODS: Acoustic 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. RESULTS: Audiological 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. CONCLUSIONS: The 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.

Effective disinfecting of protective devices used in the course of treating SARS-CoV2-positive patients.

BACKGROUND: Powered Air-Purifying Respirator (PAPR) was widely used in Sengkang General Hospital (SKH) during the SARS-CoV-2 outbreak. Ensuring a sustained supply of clean and reusable PAPR masks for frontline medical team is an immediate challenge. The Central Sterile Supplies Unit (CSSU) adopts existing disinfection methods and technology for the reprocessing of reusable personal protective equipment (PPE) such as PAPR masks and goggles. OBJECTIVE: To determine an effective disinfecting method for protective devices used in the course of treating SARS-CoV2-positive patients. METHOD: A comparison on surface disinfection and modified thermal disinfection outcome was conducted on 30 PAPR masks through detecting the presence of adenosine triphosphate (ATP) by swab following both disinfecting methods. RESULTS: The modified thermal cycles emerged as the recommended disinfection method. DISCUSSION: The outcome of this study has enhanced understanding on the risk imposed on frontline healthcare personnel who perform surface disinfecting on masks for reuse during the work shift. Leveraging on the current expertise from existing instrument logistics, CSSU takes charge of the processing and stock management of SKH's PAPR masks. An additional workflow is needed to establish reprocessing methods for other reusable PPEs such as face shields or overalls.

Headache Related to PPE Use during the COVID-19 Pandemic.

PURPOSE OF REVIEW: Personal protection equipment (PPE)-associated headache is an unusual secondary headache disorder that predominantly occurs in healthcare workers as a consequence of the donning of protective respirators, face masks and/or eyewear. The appreciation of this entity is important given the significant ramifications upon the occupational health of healthcare workers and could additionally have an impact on persons living with pre-existing headache disorder(s). RECENT FINDINGS: There has been a renewed interest and recognition of PPE-associated headaches amongst healthcare professionals, largely brought about by the ongoing COVID-19 pandemic which has besieged healthcare systems worldwide. De novo PPE-associated headaches may present with migrainous or tension-type features and can be viewed as a subtype of external compression headache. The prognosis of the disorder is generally favourable, given that most headaches are short-lived without long-term sequalae. Several aetiologies have been postulated to account for the development of these headaches. Notably, these headaches can affect the occupational health and work performance of healthcare workers. In this review, we discuss the epidemiology, clinical characteristics, probable etiopathogenesis, management and prognosis of PPE-associated headaches in the context of the COVID-19 pandemic. Future directions for research and PPE development are proposed.

PPE training and the effectiveness of universal masking in preventing exposures: The importance of the relationship between anesthesia and infection prevention.

Early in the pandemic, infection prevention (IP), in collaboration with our local anesthesia leadership, took the approach of ensuring all members of the Anesthesia Department understood the importance of universal masking, were individually trained on the use of the Controlled Air Purifier Respirator, as well the appropriate method for donning/doffing N95 respirators. Multiple providers in the department tested positive for COVID, resulting in the IP Department to conduct the routine contact tracing investigation. During the investigation, it was determined that all persons who met the CDC (Centers for Disease Control & Prevention) contact exposure guidelines would undergo COVID testing, which consequently was 109 team members due to the exposure risk identified in the break room space. IP worked with the Anesthesia Preoperative Clinic to test all team members identified over a 3-day period (approximately 5-7 days postexposure). Out of the 109 team members who were tested postexposure, there were 0 conversions. The department attributes this to the consistency in personal protective equipment training, support and collaboration between anesthesia and IP which led to successful care for COVID patients with a limited provider infection rate.

Carbon dioxide increases with face masks but remains below short-term NIOSH limits.

BACKGROUND AND PURPOSE: COVID-19 pandemic led to wide-spread use of face-masks, respirators and other personal protective equipment (PPE) by healthcare workers. Various symptoms attributed to the use of PPE are believed to be, at least in part, due to elevated carbon-dioxide (CO2) levels. We evaluated concentrations of CO2 under various PPE. METHODS: In a prospective observational study on healthy volunteers, CO2 levels were measured during regular breathing while donning 1) no mask, 2) JustAir® powered air purifying respirator (PAPR), 3) KN95 respirator, and 4) valved-respirator. Serial CO2 measurements were taken with a nasal canula at a frequency of 1-Hz for 15-min for each PPE configuration to evaluate whether National Institute for Occupational Safety and Health (NIOSH) limits were breached. RESULTS: The study included 11 healthy volunteers, median age 32 years (range 16-54) and 6 (55%) men. Percent mean (SD) changes in CO2 values for no mask, JustAir® PAPR, KN95 respirator and valve respirator were 0.26 (0.12), 0.59 (0.097), 2.6 (0.14) and 2.4 (0.59), respectively. Use of face masks (KN95 and valved-respirator) resulted in significant increases in CO2 concentrations, which exceeded the 8-h NIOSH exposure threshold limit value-weighted average (TLV-TWA). However, the increases in CO2 concentrations did not breach short-term (15-min) limits. Importantly, these levels were considerably lower than the long-term (8-h) NIOSH limits during donning JustAir® PAPR. There was a statistically significant difference between all pairs (p < 0.0001, except KN95 and valved-respirator (p = 0.25). However, whether increase in CO2 levels are clinically significant remains debatable. CONCLUSION: Although, significant increase in CO2 concentrations are noted with routinely used face-masks, the levels still remain within the NIOSH limits for short-term use. Therefore, there should not be a concern in their regular day-to-day use for healthcare providers. The clinical implications of elevated CO2 levels with long-term use of face masks needs further studies. Use of PAPR prevents relative hypercapnoea. However, whether PAPR should be advocated for healthcare workers requiring PPE for extended hours needs to evaluated in further studies.

New respirator performance monitor (RePM) for powered air-purifying respirators.

Powered air-purifying respirators (PAPRs) that offer protection from particulates are deployed in different workplace environments. Usage of PAPRs by healthcare workers is rapidly increasing; these respirators are often considered the best option in healthcare settings, particularly during public health emergency situations, such as outbreaks of pandemic diseases. At the same time, lack of user training and certain vigorous work activities may lead to a decrease in a respirator's performance. There is a critical need for real-time performance monitoring of respiratory protective devices, including PAPRs. In this effort, a new robust and low-cost real-time performance monitor (RePM) capable of evaluating the protection offered by a PAPR against aerosol particles at a workplace was developed. The new device was evaluated on a manikin and on human subjects against a pair of condensation nuclei counters (P-Trak) used as the reference protection measurement system. The outcome was expressed as a manikin-based protection factor (mPF) and a Simulated Workplace Protection Factor (SWPF) determined while testing on subjects. For the manikin-based testing, the data points collected by the two methods were plotted against each other; a near-perfect correlation was observed with a correlation coefficient of 0.997. This high correlation is particularly remarkable since RePM and condensation particle counter (CPC) measure in different particle size ranges. The data variability increased with increasing mPF. The evaluation on human subjects demonstrated that RePM prototype provided an excellent Sensitivity (96.3% measured on human subjects at a response time of 60 sec) and a Specificity of 100%. The device is believed to be the first of its kind to quantitatively monitor PAPR performance while the wearer is working; it is small, lightweight, and does not interfere with job functions.

Evaluation of N95 respirators, modified snorkel masks and low-cost powered air-purifying respirators: a prospective observational cohort study in healthcare workers.

Disposable N95 respirator masks are the current standard for healthcare worker respiratory protection in the COVID-19 pandemic. In addition to shortages, qualitative fit testing can have low sensitivity for detecting poor fit, leading to inconsistent protection. Multiple groups have developed alternative solutions such as modified snorkel masks to overcome these limitations, but validation of these solutions has been lacking. We sought to determine if N95s and snorkel masks with attached high-efficiency filters provide consistent protection levels in healthcare workers and if the addition of positive pressure via an inexpensive powered-air purifying respirator to the snorkel mask would provide enhanced protection. Fifty-one healthcare workers who were qualitatively fitted with N95 masks underwent quantitative mask fit testing according to a simulated workplace exercise protocol. N95, snorkel masks with high-efficiency filters and snorkel masks with powered-air purifying respirators were tested. Respiratory filtration ratios were collected for each step and averaged to obtain an overall workplace protocol fit factor. Failure was defined as either an individual filtration ratio or an overall fit factor below 100. N95s and snorkel masks with high-efficiency filters failed one or more testing steps in 59% and 20% of participants, respectively, and 24% and 12% failed overall fit factors, respectively. The snorkel masks with powered-air purifying respirators had zero individual or overall failures. N95 and snorkel masks with high-efficiency filter respirators were found to provide inconsistent respiratory protection in healthcare workers.

Ambient Noise Levels and Wireless Headsets for Communication in Aerosolizing Otolaryngology Surgery During COVID-19.

The objective of this short scientific communication is to describe and test a strategy to overcome communication barriers in coronavirus disease 2019 (COVID-19) era otolaryngology operating rooms. Thirteen endoscopic sinus surgeries, 4 skull base surgeries, and 1 tracheotomy were performed with powered air-purifying respirators. During these surgeries, surgical team members donned headsets with microphones linked via conference call. Noise measurements and survey responses were obtained and compared to pre-COVID-19 data. Noise was problematic and caused miscommunication as per 93% and 76% of respondents, respectively. Noise in COVID-19 era operating rooms was significantly higher compared to pre-COVID-19 era data (73.8 vs 70.2 decibels, P = .04). Implementation of this headset strategy significantly improved communication. Respondents with headsets were less likely to encounter communication problems (31% vs 93%, P < .001). Intraoperative measures to protect surgical team members during aerosolizing surgeries may impair communication. Linking team members via a conference call is a solution to improve communication.

Consensus-based perioperative protocols during the COVID-19 pandemic.

OBJECTIVE: During the COVID-19 pandemic, quaternary-care facilities continue to provide care for patients in need of urgent and emergent invasive procedures. Perioperative protocols are needed to streamline care for these patients notwithstanding capacity and resource constraints. METHODS: A multidisciplinary panel was assembled at the University of California, San Francisco, with 26 leaders across 10 academic departments, including 7 department chairpersons, the chief medical officer, the chief operating officer, infection control officers, nursing leaders, and resident house staff champions. An epidemiologist, an ethicist, and a statistician were also consulted. A modified two-round, blinded Delphi method based on 18 agree/disagree statements was used to build consensus. Significant disagreement for each statement was tested using a one-sided exact binomial test against an expected outcome of 95% consensus using a significance threshold of p < 0.05. Final triage protocols were developed with unblinded group-level discussion. RESULTS: Overall, 15 of 18 statements achieved consensus in the first round of the Delphi method; the 3 statements with significant disagreement (p < 0.01) were modified and iteratively resubmitted to the expert panel to achieve consensus. Consensus-based protocols were developed using unblinded multidisciplinary panel discussions. The final algorithms 1) quantified outbreak level, 2) triaged patients based on acuity, 3) provided a checklist for urgent/emergent invasive procedures, and 4) created a novel scoring system for the allocation of personal protective equipment. In particular, the authors modified the American College of Surgeons three-tiered triage system to incorporate more urgent cases, as are often encountered in neurosurgery and spine surgery. CONCLUSIONS: Urgent and emergent invasive procedures need to be performed during the COVID-19 pandemic. The consensus-based protocols in this study may assist healthcare providers to optimize perioperative care during the pandemic.

High-Risk Aerosol-Generating Procedures in COVID-19: Respiratory Protective Equipment Considerations.

The correct selection and utilization of respiratory personal protective equipment is of the utmost importance in the current COVID-19 pandemic. This is especially true for health care workers exposed to high-risk aerosol-generating procedures, including otolaryngologists, ophthalmologists, neurosurgeons, maxillofacial surgeons, and laparoscopic surgeons. This communication provides a review of approved forms of respiratory protection and compares their characteristics, including surgical masks, N95 respirator, elastomeric respirators, powered air-purifying respirators, and controlled air-purifying respirators. For standard airborne precautions, N95 respirator are appropriate for respiratory protection. However, high-risk aerosol-generating procedures may create aerosolization of high viral loads that represent increased risk to health care workers. In these situations, enhanced respiratory protection with filters certified as 99, 100, or HEPA (high-efficiency particulate air) may be appropriate.

Pressure Optimized PowEred Respirator (PROPER): A miniaturized wearable cleanroom and biosafety system for aerially transmitted viral infections such as COVID-19.

The supply of Personal Protective Equipment (PPE) in hospitals to keep the Health Care Professionals (HCP) safe taking care of patients may be limited, especially during the outbreak of a new disease. In particular, the face and body protective equipment is critical to prevent the wearer from exposure to pathogenic biological airborne particulates. This situation has been now observed worldwide during the onset of the COVID-19 pandemic. As concern over shortages of PPE at hospitals grows, we share with the public and makers' community the Pressure Optimized PowEred Respirator (PROPER) equipment, made out of COTS components. It is functionally equivalent to a Powered Air Purifying Respirator (PAPR). PROPER, a hood-based system which uses open source and easily accessible components is low-cost, relatively passive in terms of energy consumption and mechanisms, and easy and fast to 3D print, build and assemble. We have adapted our experience on building clean room environments and qualifying the bioburden of space instruments to this solution, which is in essence a miniaturized, personal, wearable cleanroom. PROPER would be able to offer better protection than an N95 respirator mask, mainly because it is insensitive to seal fit and it shields the eyes as well. The PROPER SMS fabric is designed for single-use and not intended for reuse, as they may start to tear and fail but the rest of the parts can be disinfected and reused. We provide a set of guidelines to build a low-cost 3D printed solution for an effective PAPR system and describe the procedures to validate it to comply with the biosafety level 3 requirements. We have validated the prototype of PROPER unit for air flow, ISO class cleanliness level, oxygen and carbon-dioxide gas concentrations during exhalation, and present here these results for illustration. We demonstrate that the area inside the hood is more than 200 times cleaner than the external ambient without the operator and more than 175 times with the operator and in an aerosol exposed environment. We also include the procedure to clean and disinfect the equipment for reuse. PROPER may be a useful addition to provide protection to HCPs against the SARS-CoV-2 virus or other potential future viral diseases that are transmitted aerially.