Covid-19: Experts question guidance to reuse PPE
BMJ 2020; 369 doi: https://doi.org/10.1136/bmj.m1577 (Published 20 April 2020) Cite this as: BMJ 2020;369:m1577Read our latest coverage of the coronavirus pandemic
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Dear Editor
The shortage of Personal Protective Equipment (PPE), including gowns, face shields, eye protection, and respirators has been a contentious and difficult issue for frontline health care workers, and for care workers in general. Official guidance around use of PPE has been conflicting over the last few weeks, and updated recommendations from Public Health England (PHE) and the WHO seem to be the minimum that health professional groups and occupational health experts are recommending (1,2). Even if stringent protective measures were advised for our frontline workers, as some are now advocating, how will these be met if there isn’t enough PPE? Physicians are rightly questioning the need to reuse or wear PPE for extended periods of time. For respiratory protective equipment (RPE), the potential to safely reuse single or limited use RPE following decontamination is actively being investigated by hospitals. These are not new sanitisation methods, and several have previously been tested before the emergence of the SARS-CoV-2 virus, due to concerns over the very situation we find ourselves in (3–6). Even the US CDC and 3M, a major worldwide respirator manufacturing company, have acknowledged that reuse may be needed and have released summaries of evidence around decontamination methods (7,8).
Duke University has already started using vapourized hydrogen peroxide (VHP) in their hospital, having confidence that both the decontamination is successful and that the treated respirators are able to adequately fit staff (9). VHP and some other methods, however, require investment in specialised and expensive equipment. Heat treatment (up to about 100°C) can also deactivate SARS-Cov-2 and retain the respirator filtration capabilities (10–12). Heat would require nothing more than a low temperature oven with the ability to distribute heat evenly and consistently over time.
We have carried out pilot work on heating respirators of a variety of styles certified to EU FFP2 and FFP3 standards (13). This work involved a pre-treatment quantitative fit test and a post-treatment fit test with the same respirator on the same wearer. We tested nine masks and two failed the second fit test; the masks that failed showed signs of being distorted. From prior tests of heat-treated respirators, it is likely that it is the fit to face which was faulty rather than the filtration efficiency of the respirator, although we did not test this latter aspect specifically. After one heating cycle the fit factor of most of the mask decreased, and as Fischer et al. (10) found, respirator integrity will probably degrade after only a couple cycles of extended wear and decontamination. Still, even one successful reuse of a mask after heat treatment doubles the amount of respirators available. However, it is important to note that effective respirator fit is partly determined by the facial features of the person, and the degradation of mask performance may differ between wearers, as evidenced by the failure of two of the respirators in our study. We had a duplicate of one of the failed respirators, worn by a second tester and this passed both the pre- and post- treatment tests. These are useful results and we plan to undertake more extensive testing of the various types of respirators used across Scotland and to use this to provide advice to hospitals and other care facilities.
RPE decontamination must be undertaken with caution. Even with a new respirator there is no guarantee that the fit will be adequate, nor that the protection it confers remains the same across the time it is worn. Under current circumstances, we need to develop the best practice for decontamination and re-use, recognizing that it is impossible to re-test each decontaminated respirator. In the future we need to evaluate our preparedness for the next public health crisis to avoid the desperation that we face now.
References:
1. Sayburn A. Are UK doctors getting sufficient protective equipment against covid-19? BMJ [Internet]. 2020 Apr 2 [cited 2020 Apr 21];369. Available from: https://www.bmj.com/content/369/bmj.m1297
2. Brosseau LM. Are Powered Air Purifying Respirators a Solution for Protecting Healthcare Workers from Emerging Aerosol-Transmissible Diseases? Ann Work Expo Health [Internet]. [cited 2020 Apr 21]; Available from: https://academic.oup.com/annweh/article/doi/10.1093/annweh/wxaa024/5802550
3. Heimbuch BK, Wallace WH, Kinney K, Lumley AE, Wu C-Y, Woo M-H, et al. A pandemic influenza preparedness study: use of energetic methods to decontaminate filtering facepiece respirators contaminated with H1N1 aerosols and droplets. Am J Infect Control. 2011 Feb;39(1):e1-9.
4. Lindsley WG, Martin SB, Thewlis RE, Sarkisian K, Nwoko JO, Mead KR, et al. Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity. J Occup Environ Hyg. 2015 Jul 1;12(8):509–17.
5. Viscusi DJ, Bergman MS, Eimer BC, Shaffer RE. Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators. Ann Occup Hyg. 2009 Nov;53(8):815–27.
6. Lore MB, Heimbuch BK, Brown TL, Wander JD, Hinrichs SH. Effectiveness of three decontamination treatments against influenza virus applied to filtering facepiece respirators. Ann Occup Hyg. 2012 Jan;56(1):92–101.
7. Decontamination Methods for 3M N95 Respirators [Internet]. 2020 [cited 2020 Apr 21]. Available from: https://multimedia.3m.com/mws/media/1824869O/decontamination-methods-for...
8. CDC. Coronavirus Disease 2019 (COVID-19) [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2020 Apr 11]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontaminati...
9. Duke Starts Novel Decontamination of N95 Masks to Help Relieve Shortages | Duke School of Medicine [Internet]. [cited 2020 Apr 21]. Available from: https://medschool.duke.edu/about-us/news-and-communications/med-school-b...
10. Fischer R, Morris DH, Doremalen N van, Sarchette S, Matson J, Bushmaker T, et al. Assessment of N95 respirator decontamination and re-use for SARS-CoV-2. medRxiv. 2020 Apr 15;2020.04.11.20062018.
11. Massey T, Paik S, Fuhrer K, Bora M, Haque R, Baxamusa SH. Quantitative form and fit of N95 filtering facepiece respirators are retained after dry and humid heat treatments for coronavirus deactivation. medRxiv. 2020 Apr 20;2020.04.15.20065755.
12. Smith JS, Hanseler H, Welle J, Rattray R, Campbell M, Brotherton T, et al. Effect of various decontamination procedures on disposable N95 mask integrity and SARS-CoV-2 infectivity. medRxiv. 2020 Apr 15;2020.04.11.20062331.
13. Loh M, Clark R, Cherrie JW. Heat treatment for reuse of disposable respirators during Covid-19 pandemic: Is filtration and fit adversely affected? medRxiv. 2020 Apr 25;2020.04.22.20074989.
Competing interests: No competing interests
Dear Editor
Don't forget the tremendous work and the problems of nurses and other parmedical and logistic people working in and out of hospital!
Competing interests: No competing interests
Dear Editor
Health workers are a precious resource, and one cannot manufacture them as easily as PPE! In one data set, about 20% of cases were reported to be health care workers, though the proportion of these workers amongst employed is not more than 12% in that scenario.(1,2) This high proportion is expected to be due to more awareness and reporting but mortality is still high in this group where we expect early and best health seeking practices. Though mortality amongst health workers might be considerably lower than general population (somewhere near 0.5% as compared to 4%, data form a well off nation(1,3)), think of it as an aware group taking all precautions, using PPE, reporting early for care and the risk is considerable despite the best preventive measures.
In such a scenario, it is shocking how those who lead public health seem to recommend insensitively, irresponsibly and without taking pains to search for available alternatives.(4) At this challenging time, it is important to have decision making power with epidemiologists, who can provide scientifically sound solutions. Equally important is to give moral and psychological support to a highly stressed group. Viable alternatives like minimising and prioritising the use should be explored and added. (5) It is important to understand the gravity of the consequences of casual recommendations.
References:
1. https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e6.htm?s_cid=mm6915e6_xAcce... on 21/04/2020.
2. https://www.kff.org/other/state-indicator/health-care-employment-as-tota.... 3. Accessed on 21/04/2020.currentTimeframe=0&sortModel=%7B%22colId%22:%22Location%22,%22sort%22:%22asc%22%7D2.Accessed on 21/04/2020.
3. https://www.nytimes.com/2020/04/17/us/coronavirus-death-rate.html.Accessed on 21/04/2020.
4. https://www.gov.uk/government/publications/wuhan-novel-coronavirus-infec.... Accessed on 21/04/2020.
5. https://www.cdc.gov/niosh/topics/hcwcontrols/recommendedguidanceextuse.html. Accessed on 21/04/2020.
Competing interests: No competing interests
Is there any justification for reuse of advanced PPE in dentistry?
Dear Editor
Despite existing guidelines addressing health care needs, there is a growing confusion concerning the reuse of advanced personal protective equipment (PPE) by dental care providers outside hospital settings. Unlike general medical practitioners, dentists are involved in aerosol generating procedures (AGP) and are exposed to potentially infectious, virus-containing splatter on daily clinical basis [1]. Whilst the COVID-19 pandemic is far from over and its second wave is deemed as unavoidable, the reuse of advanced PPE (FFP2/FFP3 respirators, long-sleeved fluid repellent disposable gowns, enhanced visors and goggles) should be also carefully taken into consideration, according to Public Health England (PHE) [2], especially in situations, when the extreme shortages of PPE might hamper the primary health care [3]. Currently, the accessibility of PPE around the world does not seem to be vastly affected [4], compared to the beginning of COVID-19 outbreak [5].
The reuse of PPE in hospitals seems to be relatively well supported by the recent World Health Organization (WHO), as well as PHE guidelines and recommendation implemented in April this year as emergency contingency planning during the peak of COVID-19, when the supply chain was severely affected by global demands [6]. The United States Food and Drug Administration (FDA) has made the emergency use of the Nova2200 to decontaminate compatible N95 respirators available under an emergency access mechanism called an Emergency Use Authorisation (EUA). The EUA is a supported by the Secretary of Health and Human Service’s (HHS’s) declaration that circumstances exist to justify the emergency use of medical devices due to insufficient supply during the COVID-19 pandemic [7]. The reuse of PPE (apart from gloves) can be justifiably utilised by medical and dental clinical staff, in situations when health care must be delivered promptly without any delay and the PPE resources are lacking. In our opinion in case of patients with COVID-19 negative status, the decision concerning the reuse of advanced PPE for dental treatment should be considered in urgent/emergency procedures, when immediate dental care must be delivered and strict procedures regarding the reuse of PPE are present and monitored. The Centers for Disease Control and Prevention (CDC) has acknowledged that an effective Filtering Facepiece Respirator (FFR) decontamination method must reduce the pathogen burden, not harm the fit or filtration of the FFR, and cause no residual chemical hazard. Ultraviolet germicidal irradiation, vaporous hydrogen peroxide, and moist heat have shown the most promise as potential methods to decontaminate FFR. Also, the number of donnings for an N95 FFR (FFP2) should be no more than five per device [8].
However, these recommendations should not be applied for general, routine dental care and dental interventions that require the use of spray-producing equipment within oral cavity, the main (equally with nasal area) 'portal of entry' for microorganisms invading upper and lower respiratory track, including SARS-2-CoV, especially when PPE resources are widely available. In primary dental care sector (general dental care) the reuse of PPE cannot be justified for any non-AGP or AGP, especially not urgent cases, including non-surgical dental extractions as this would jeopardise the main paradigms of cross-infection control rules. This approach inevitably puts dental care providers at serious risk of contracting airborne diseases and causes potentially serious health problems for treated patients [9]. The unjustified (or economically justified) excessive reuse of PPE appears to be particularly harmful when utilised for AGP in vulnerable operator, and as a result, can lead to further health consequences.
‘By definition', the reuse of PPE in any clinical environment has to be treated as the 'very last resort' , in extremely exceptional circumstances, after a formal risk assessment and consideration of benefits/risk for equally the staff and the patients. The consequences that may adversely affect both operators and patients must be assessed and predicted from the medical and legal perspective. The regulatory bodies raised a noticeable concern, that the increased cost of advanced PPE for independent providers might influence their unreasonable and irrational decision to reuse PPE 'on a regular basis' [10]. This should not be allowed to happen in any clinical scenario.
We urge the decision-makers and professional bodies to support dental sector with up-to-date recommendations, based on robustly reviewed and assessed evidence-based medicine sources.
References
[1] Izzetti, R.; Nisi, M.; Gabriele, M.; Graziani, F. COVID-19 Transmission in Dental Practice: Brief Review of Preventive Measures in Italy. J. Dent. Res. 2020, 22034520920580.
[2] Considerations for acute personal protective equipment (PPE) shortages https://www.gov.uk/government/publications/wuhan-novel-coronavirus-infec... (accessed Aug 23, 2020).
[3] Artenstein, A. W. In Pursuit of PPE. N. Engl. J. Med. 2020, 382 (18), e46. https://doi.org/10.1056/NEJMc2010025.
[4] PPE deliveries (England): 17 August to 23 August 2020 https://www.gov.uk/government/statistics/ppe-deliveries-england-17-augus... (accessed Aug 25, 2020).
[5] Rimmer, A. Covid-19: Third of Surgeons Do Not Have Adequate PPE, Royal College Warns. BMJ 2020, 369, m1492. https://doi.org/10.1136/bmj.m1492.
[6] Rational use of personal protective equipment for coronavirus disease (COVID-19) and considerations during severe shortages https://www.who.int/publications-detail-redirect/rational-use-of-persona...(covid-19)-and-considerations-during-severe-shortages (accessed Aug 23, 2020).
[7] Emergency Use Authorization. FDA 2020.
[8] CDC. Coronavirus Disease 2019 (COVID-19) https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/index.html (accessed Aug 23, 2020).
[9] Mahmood, S. U.; Crimbly, F.; Khan, S.; Choudry, E.; Mehwish, S. Strategies for Rational Use of Personal Protective Equipment (PPE) Among Healthcare Providers During the COVID-19 Crisis. Cureus 12 (5). https://doi.org/10.7759/cureus.8248.
[10] Rimmer, A. Covid-19: Experts Question Guidance to Reuse PPE. BMJ 2020, 369.
Competing interests: No competing interests