Decontamination and re-use of surgical masks and respirators during the COVID-19 pandemic.

OBJECTIVES: The coronavirus disease 2019 pandemic increased global demand for personal protective equipment (PPE) and resulted in shortages. The study evaluated the re-use of surgical masks and respirators by analysing their performance and safety before and after reprocessing using the following methods: oven, thermal drying, autoclave, and hydrogen peroxide plasma vapour. METHODS: In total, 45 surgical masks and 69 respirators were decontaminated. Visual integrity, air permeability, burst resistance, pressure differential and particulate filtration efficiency of new and decontaminated surgical masks and respirators were evaluated. In addition, 14 used respirators were analysed after work shifts before and after decontamination using reverse transcription polymerase chain reaction (RT-PCR) and viral culturing. Finally, reprocessed respirators were evaluated by users in terms of functionality and comfort. RESULTS: Oven decontamination (75 °C for 45 min) was found to be the simplest decontamination method. Physical and filtration assays indicated that all reprocessing methods were safe after one cycle. Oven decontamination maintained the characteristics of surgical masks and respirators for at least five reprocessing cycles. Viral RNA was detected by RT-PCR in two of the 14 used respirators. Four respirators submitted to viral culture were PCR-negative and culture-negative. Reprocessed respirators used in work shifts were evaluated positively by users, even after three decontamination cycles. CONCLUSION: Oven decontamination is a safe method for reprocessing surgical masks and respirators for at least five cycles, and is feasible in the hospital setting.

Analysis of SteraMist ionized hydrogen peroxide technology in the sterilization of N95 respirators and other PPE.

The COVID-19 pandemic has led to widespread shortages of personal protective equipment (PPE) for healthcare workers, including of N95 masks (filtering facepiece respirators; FFRs). These masks are intended for single use but their sterilization and subsequent reuse has the potential to substantially mitigate shortages. Here we investigate PPE sterilization using ionized hydrogen peroxide (iHP), generated by SteraMist equipment (TOMI; Frederick, MD), in a sealed environment chamber. The efficacy of sterilization by iHP was assessed using bacterial spores in biological indicator assemblies. After one or more iHP treatments, five models of N95 masks from three manufacturers were assessed for retention of function based on their ability to form an airtight seal (measured using a quantitative fit test) and filter aerosolized particles. Filtration testing was performed at a university lab and at a National Institute for Occupational Safety and Health (NIOSH) pre-certification laboratory. The data demonstrate that N95 masks sterilized using SteraMist iHP technology retain filtration efficiency up to ten cycles, the maximum number tested to date. A typical iHP environment chamber with a volume of ~ 80 m3 can treat ~ 7000 masks and other items (e.g. other PPE, iPADs), making this an effective approach for a busy medical center.

Modeling the Stability of SARS-CoV-2 on Personal Protective Equipment (PPE).

We modeled the stability of SARS-CoV-2 on personal protective equipment (PPE) commonly worn in hospitals when carrying out high-risk airway procedures. Evaluated PPE included the visors and hoods of two brands of commercially available powered air purifying respirators, a disposable face shield, and Tyvek coveralls. Following an exposure to 4.3 log10 plaque-forming units (PFUs) of SARS-CoV-2, all materials displayed a reduction in titer of > 4.2 log10 by 72 hours postexposure, with detectable titers at 72 hours varying by material (1.1-2.3 log10 PFU/mL). Our results highlight the need for proper doffing and disinfection of PPE, or disposal, to reduce the risk of SARS-CoV-2 contact or fomite transmission.

A laboratory-based study examining the properties of silk fabric to evaluate its potential as a protective barrier for personal protective equipment and as a functional material for face coverings during the COVID-19 pandemic.

The worldwide shortage of single-use N95 respirators and surgical masks due to the COVID-19 pandemic has forced many health care personnel to use their existing equipment for as long as possible. In many cases, workers cover respirators with available masks in an attempt to extend their effectiveness against the virus. Due to low mask supplies, many people instead are using face coverings improvised from common fabrics. Our goal was to determine what fabrics would be most effective in both practices. Under laboratory conditions, we examined the hydrophobicity of fabrics (cotton, polyester, silk), as measured by their resistance to the penetration of small and aerosolized water droplets, an important transmission avenue for the virus causing COVID-19. We also examined the breathability of these fabrics and their ability to maintain hydrophobicity despite undergoing repeated cleaning. Laboratory-based tests were conducted when fabrics were fashioned as an overlaying barrier for respirators and when constructed as face coverings. When used as material in these two situations, silk was more effective at impeding the penetration and absorption of droplets due to its greater hydrophobicity relative to other tested fabrics. We found that silk face coverings repelled droplets in spray tests as well as disposable single-use surgical masks, and silk face coverings have the added advantage over masks such that they can be sterilized for immediate reuse. We show that silk is a hydrophobic barrier to droplets, can be more breathable than other fabrics that trap humidity, and are re-useable via cleaning. We suggest that silk can serve as an effective material for making hydrophobic barriers that protect respirators, and silk can now be tested under clinical conditions to verify its efficacy for this function. Although respirators are still the most appropriate form of protection, silk face coverings possess properties that make them capable of repelling droplets.

3D-printed protected face shields for health care workers in Covid-19 pandemic.

The coronavirus pandemic resulted in a shortage of protective equipment. To meet the request of eye-protecting devices, an interdisciplinary consortium involving practitioners, researchers, engineers and technicians developed and manufactured thousands of inexpensive 3D-printed face shields, inside hospital setting. This action leads to the concept of "concurrent, agile, and rapid engineering".

Two-drape closed pocket technique: minimizing aerosolization in mastoid exploration during COVID-19 pandemic.

BACKGROUND: Mastoidectomy is associated with extensive bone-drilling which makes it a major aerosol generating procedure. Considering the ongoing COVID-19 global pandemic, it is essential to devise methods to minimize aerosolization and hence ensure safety of the healthcare workers during the operative procedure. METHODS: Two disposable surgical drapes are used to create a closed pocket prior to commencement of mastoid bone-drilling. This limits aerosolization of bone-dust in the external operating theatre environment. CONCLUSION: Two-drape closed pocket technique is an easy, cost-effective and safe method to limit aerosolization of tissue particles during mastoidectomy.

A comparison of droplet and contact contamination using 3 simulated barrier techniques for COVID-19 intubation: a quality assurance study.

BACKGROUND: The intubation of patients with coronavirus disease 2019 (COVID-19) puts health care workers at risk of infection through aerosol, droplet and contact contamination. We evaluated the risk of droplet and contact contamination for health care workers using 3 intubation barrier techniques as part of a quality assurance study at our institution. METHODS: This randomized quality assurance study was completed at a tertiary academic hospital in Vancouver, British Columbia, Canada, on Apr. 4, 2020. Participants in personal protective equipment performed simulated intubations on a manikin with (a) no barrier, (b) a clear plastic sheet covering the manikin and (c) a plexiglass intubation box over the manikin, in random order. Fluorescein was ejected from inside the manikin's mouth to simulate droplet and contact spread during a standard intubation sequence. Two blinded independent assessors evaluated the location and degree of contamination on the intubator and assistant using an ultraviolet light. Contamination severity was rated in a standard fashion (0 = none; 1 = minor; 2 = major). The primary outcome was total contamination score and secondary outcomes were scores between intubator and assistant, anatomic areas contaminated and qualitative feedback on ease of intubation. RESULTS: Five participants completed this study. Total contamination score was different between the 3 groups for the intubator (p = 0.02) but not the assistant (p = 0.2). For the intubator, the total contamination score was higher when the sheet was used (median 29 [interquartile range (IQR) 25-34]) than when the box was used (median 17 [IQR 15-22]) or when no barrier was used (median 18 [IQR 13-21]). All 5 participants reported challenges during intubation using the sheet. INTERPRETATION: Use of a plastic sheet while intubating patients with COVID-19 may increase the risk of droplet and contact contamination during intubation and impede intubation. Further study should be undertaken before implementing barrier techniques in practice.

Sustainable Personal Protective Clothing for Healthcare Applications: A Review.

Personal protective equipment (PPE) is critical to protect healthcare workers (HCWs) from highly infectious diseases such as COVID-19. However, hospitals have been at risk of running out of the safe and effective PPE including personal protective clothing needed to treat patients with COVID-19, due to unprecedented global demand. In addition, there are only limited manufacturing facilities of such clothing available worldwide, due to a lack of available knowledge about relevant technologies, ineffective supply chains, and stringent regulatory requirements. Therefore, there remains a clear unmet need for coordinating the actions and efforts from scientists, engineers, manufacturers, suppliers, and regulatory bodies to develop and produce safe and effective protective clothing using the technologies that are locally available around the world. In this review, we discuss currently used PPE, their quality, and the associated regulatory standards. We survey the current state-of-the-art antimicrobial functional finishes on fabrics to protect the wearer against viruses and bacteria and provide an overview of protective medical fabric manufacturing techniques, their supply chains, and the environmental impacts of current single-use synthetic fiber-based protective clothing. Finally, we discuss future research directions, which include increasing efficiency, safety, and availability of personal protective clothing worldwide without conferring environmental problems.

Protecting Healthcare Workers During the Coronavirus Disease 2019 (COVID-19) Outbreak: Lessons From Taiwan's Severe Acute Respiratory Syndrome Response.

During major epidemic outbreaks, demand for healthcare workers (HCWs) grows even as the extreme pressures they face cause declining availability. We draw on Taiwan's severe acute respiratory syndrome (SARS) experience to argue that a modified form of traffic control bundling (TCB) protects HCW safety and by extension strengthens overall coronavirus disease 2019 (COVID-19) epidemic control.

Reducing potential aerosol generation in flexible nasolaryngoscopy: a novel method.

BACKGROUND: Fibre-optic nasoendoscopy and fibre-optic laryngoscopy are high-risk procedures in the coronavirus disease 2019 era, as they are potential aerosol-generating procedures. Barrier protection remains key to preventing transmission. METHODS: A device was developed that patients can wear to reduce potential aerosol contamination of the surroundings. CONCLUSION: This device is simple, reproducible, easy to use, economical and well-tolerated. Full personal protection equipment should additionally be worn by the operator.

UVC Germicidal Units: Determination of Dose Received and Parameters to be Considered for N95 Respirator Decontamination and Reuse.

The COVID-19 pandemic has resulted in an international shortage of personal protective equipment including N95 filtering facepiece respirators (FFRs), resulting in many institutions using ultraviolet germicidal irradiation (UVGI) technology for N95 FFR decontamination. To ensure proper decontamination, it is crucial to determine the dose received by various parts of the FFR in this process. Recently, our group customized a UVGI unit for N95 decontamination. With experimental and theoretical approach, this manuscript discusses the minimum dose received by various parts of the N95 respirator after one complete decontamination cycle with this UVGI unit. The results demonstrate that all parts of the N95 FFR received at least 1 J cm-2 after one complete decontamination cycle with this unit. As there are a variety of UVGI devices and different types of FFRs, this study provides a model by which UVC dose received by different areas of the FFRs can be accurately assessed to ensure proper decontamination for the safety of healthcare providers.

Health care personnel exposure to a patient with asymptomatic SARS-CoV2 infection during a prolonged surgical intervention.

There is ongoing debate regarding the role of aerosols in the transmission of SARS-CoV2 in the health care environment. Here, we report a case in which multiple operating room health care providers were exposed to a patient with asymptomatic SARS-CoV2 infection during a prolonged orthopedic surgical intervention and had no evidence of COVID-19 during the 14-day post-exposure period.

A hybrid model integrating warm heat and ultraviolet germicidal irradiation might efficiently disinfect respirators and personal protective equipment.

BACKGROUND: The pandemic coronavirus disease 2019 (COVID-19) has taken a heavy toll on human life and has upended the medical system in many countries. The disease has created a system wide worsening shortage of N95, medical masks, and other personal protective equipment (PPE) that is regularly used by healthcare personnel and emergency service providers for their protection. AIM: Considering the number of infected patients and the stressed supplies of PPE, reuse of PPE can serve as an efficient contingency plan. Multiple studies have investigated the effect of different decontamination methods. METHODS: We chose the most user-friendly, easily scalable viral decontamination methods, including ultraviolet irradiation and heat treatment. In this paper, we investigated a unique approach to reuse the mask by creating a hybrid model that efficiently sanitizes the infected mask. RESULTS: The advantages of the proposed hybrid model as compared to the respective single arms is its decontamination efficacy, operational speed, as well as the number of reuse cycles as verified by mathematical analysis and simulation. This model is mainly intended for medical PPE but can also be used for other domestic and personal sanitization during the COVID-19 pandemic. As per the situation, the hybrid system can be used as standalone systems also. This sanitization process is not only limited to the elimination of Severe acute respiratory syndrome coronavirus 2 but can be extended to any other infectious agents. Thus, our results indicate that the proposed hybrid system is more effective, meets disinfection criterion and time saving for the reuse of respirators and PPE.

The challenge of performing mastoidectomy using the operating microscope with coronavirus disease 2019 personal protective equipment (PPE).

OBJECTIVE: Mastoidectomy is considered an aerosol-generating procedure. This study examined the effect of wearing personal protective equipment on the view achieved using the operating microscope. METHODS: ENT surgeons assessed the area of a calibrated target visible through an operating microscope whilst wearing a range of personal protective equipment, with prescription glasses when required. The distance between the surgeon's eye and the microscope was measured in each personal protective equipment condition. RESULTS: Eleven surgeons participated. The distance from the eye to the microscope inversely correlated with the diameter and area visible (p < 0.001). The median area visible while wearing the filtering facepiece code 3 mask and full-face visor was 4 per cent (range, 4-16 per cent). CONCLUSION: The full-face visor is incompatible with the operating microscope. Solutions offering adequate eye protection for aerosol-generating procedures that require the microscope, including mastoidectomy, are urgently needed. Low-profile safety goggles should have a working distance of less than 20 mm and be compatible with prescription lenses.