key: cord-0826166-5ekj7zsx authors: Stewart, Camille L.; Thornblade, Lucas W.; Diamond, Don J.; Fong, Yuman; Melstrom, Laleh G. title: Personal Protective Equipment and COVID-19: A Review for Surgeons date: 2020-05-01 journal: Ann Surg DOI: 10.1097/sla.0000000000003991 sha: 94ca9af796b8863fc4cd16a7a3a0840196b5323d doc_id: 826166 cord_uid: 5ekj7zsx There is a long history of personal protective equipment (PPE) used by the surgeon to minimize the transmission of various pathogens. In the context of the present coronavirus disease 2019 pandemic there is significant controversy as to what forms of PPE are appropriate or adequate. This review aims to describe the pathogenic mechanism and route of spread of the causative virus, severe acute respiratory syndrome coronavirus, as it pertains to accumulated published data from experienced centers globally. The various forms of PPE that are both available and appropriate are addressed. There are options in the form of eyewear, gloves, masks, respirators, and gowns. The logical and practical utilization of these should be data driven and evolve based on both experience and data. Last, situations specific to surgical populations are addressed. We aim to provide granular collective data that has thus far been published and that can be used as a reference for optimal PPE choices in the perioperative setting for surgical teams. The concept of personal protective equipment (PPE) for the surgeon has been in place for greater than 100 years. The aim has been to protect both the surgeon and the patient. However, as zoonotic respiratory pathogens emerge, surgeons and their teams will need to adapt quickly to what will adequately protect them and their patients. There has been a generalized call for more personal protective equipment (PPE), however, there is a wide array of PPE available. High quality evidence related to the epidemiology of Coronavirus Disease eyes, or that eye protection beyond what is already routine is helpful in preventing transmission. Nevertheless, eye protection is recommended when caring for a patient with known or suspected COVID-19 infection by the United States Centers for Disease Control and Prevention (CDC) (19), in Korea in a number of different patient care situations (29), and in Hong Kong for high risk patient interactions (16) . Since COVID-19 is thought to spread via droplets, less data regarding the transmission of COVID-19 is focused on gowns and gloves, which are the PPE components of contact precautions. Handwashing has been unequivocally recognized as an essential measure to slow contact transmission; its frequent practice is less reliant on new or additional health care resources and therefore will not be discussed in further detail here. Gowns are rated by ANSI/AAMI (American National Standards Institute/Association for the Advancement of Medical Instrumentation) PB70:2012 standards level 1-4, with level 4 having the greatest protection against viruses (30). During the SARS epidemic, two studies found that uninfected healthcare workers in Hong Kong more often wore gowns as a part of their PPE when compared to infected healthcare workers (11, 28) ; one of these studies also reported a significant difference for wearing gloves (27). Both reported uninfected healthcare workers were more likely to wear all recommended PPE (11, 28) . It should be noted that in a laboratory environment, aerosolized SARS-CoV-2 has a median half-life of 5.6 hours on stainless steel, and 6.8 hours on plastic (31), and has also been detected on surfaces in patient zero transmissions (39) . Of these healthcare workers, 35/41 (85%) were using a surgical mask for respiratory protection (39) . Thus, since surgical face masks filter particles larger than 0.1-5.0 µm and the droplets that carry Sars-CoV-2 are larger, it stands to reason that there should be adequate protection from transmission of COVID-19 in low risk circumstances. These findings have led many institutions to promote use of surgical face masks in lower risk patient interactions, and advocate for the futility of N95 respirator masks especially during times of scarcity. It should be noted, however, that the CDC recommends use of a surgical face mask if a respirator is not available when caring for a patient with known or suspected COVID-19 (19). Filtering facepiece respirators (FFR) are PPE designed to protect against respirable particulate matter (irrespective of whether they are inert or biologic particles). The most commonly used FFR do not require electricity (non-powered), and function simply as a mask. They are classified by the percentage of challenge particles >0.3 µm filtered out during testing (95%, 99%, 99.9%) and by the type of particles filtered out. -R‖ rated FFR are somewhat resistant to oil, -P‖ rated FFR are more strongly resistant to oil, while -N‖ rated FFR are not resistant to oil. FFRs have an assigned protection factor (APF) of 10 meaning they can reduce aerosol concentration to 1/10 th of the ambient air (i.e. blocking 90% of airborne particles). They must meet certification tests established by NIOSH (National Institute of Occupational Safety and Health), however, the FDA does not perform independent testing of any FFR other than surgical N95 masks (40) . Surgical N95 masks are constructed to prevent contamination of the sterile field while providing the same protection of conventional N95s. The FDA publishes certified vendors of surgical N95s as a resource for individuals and for purchasing institutions (41) . The different types of FFRs are presented in Table 2 . Copyright © 2020 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. FFRs have been tested against ultrafine viral particles (0.02-0.5 um) (42) . Results varied slightly by the type of viral particle, but with airflow rates for non-strenuous breathing, N95 penetration was 0.23-1.68%, and N99 penetration was 0.96-1.03%. Of note, viral penetration did increase with moderate airflow (simulating strenuous breathing), up to ~5% for N99 and N95 FFRs (41) . Another study compared viral penetration of N95 masks to surgical masks, and showed that while N95 penetration was 5%, level 2 surgical mask penetration was 21%, and level 1 surgical mask penetration was 85% for moderate airflow (43) . The extrapolation of this data to infection by droplet transmission may be flawed, however, due to the larger size of the droplets (10-100 µm) that carry SARS-CoV-2 viral particles in a non-experimental setting. An example of this is the similar transmission rates of influenza to healthcare workers using N95 or surgical masks described above (33, 35) . There are several studies that examine N95 use as it relates to transmission of SARS-CoV and SARS-CoV-2. As mentioned above, Yen at al. compared hospitals with and without infected healthcare workers during the SARS-CoV epidemic in Taiwan and found that 100% of hospitals with zero SARS-CoV healthcare worker infections used N95 masks in -zones of risk‖ (36) . A case matched study of healthcare workers infected with SARS-CoV compared their PPE use to healthcare workers who were not infected (28). Nearly 100% of the participants used either a surgical mask or an N95 mask, and there was no difference in the type of mask used when comparing infected and non-infected healthcare workers (28). A study specifically examining critical care nurses also found no differences in the rates of becoming infected when using a surgical mask compared to an N95 mask (44) . Wang et al. published healthcare worker infection rates from Wuhan University from December 2019 and showed that none of the 278 staff members who wore N95 masks became infected (45) . Doctors and nurses on surgical floors who did not interact with COVID19 patients were considered low risk and did not wear masks, and 10/215 (4.6%) of these individuals ultimately became infected (45) . Currently, the CDC recommends use of an N95 mask when caring for a patient with known or suspected COVID-19 if available and recommends an N95 or higher respirator when performing or present for aerosol-generating procedures (19). In Korea, N95 masks at minimum have been recommended for all hospital interactions except disposal of medical waste (28). In Hong Kong, they are recommended for staff working in triage, with confirmed COVID-19 cases, and when performing aerosol generating procedures (16) . Because of the COVID-19 pandemic, resource scarcity has raised the prospect of reuse of FFRs. Extended single use of FFR is favored over limited reuse because of the risk of self-inoculation (45) . For extended single use, this is most practical when patients are cohorted (patients with a common diagnosis in the same unit) (46) . It has been shown that donning an FFR up to 20 times maintains good fit however quality of fit decreases with subsequent uses and best fit was seen after the first 5 donnings (47) . A Veterans Administration study also revealed the median tolerance time for FFR masks to be 6-7 hours due to heat and facial discomfort, suggesting that health care workers cannot be expected to work prolonged shifts (>=12 hours) in an environment which requires continuous FFR (48) . It should also be noted that bleach and microwave decontamination of FFRs may damage or render masks unsafe (49) . Conversely, ultraviolet irradiation and ethylene oxide may be more suitable for decontamination (49) . Researchers at Duke University recently published a verifiable decontamination protocol for N95 respirators using hydrogen peroxide vapor (50). Unpublished data from Stanford University suggests that heating N95 masks to 70 o C for 30 minutes is sufficient to destroy coronavirus particles and does not diminish filtration per hour and may re-circulate air (55) . It is known that aerosol transmission of infectious diseases can be influenced by ventilation (9, 56) , which suggests that transmission of SARS-CoV-2 may be lower in an operating room. This must be weighed, however, against the fact that aerosolizing procedures are much more likely to take place in an operating rom. Intubation is thought to be a particularly high-risk aerosolizing procedure. Viral loads of SARS-CoV-2 are known to be high in the upper respiratory tract of infected patients (57), and a study of critical care nurses from Toronto during the SARS-CoV epidemic found that these nurses were more likely to become infected when present during intubations (44) . For this reason, specific recommendations regarding PPE for intubation of patients with COVID-19 have been made (58). SARS-CoV-2 is also present in bodily tissues; while nearly all patients (93%) have evidence of virus in their sputum, some (29%) also have virus in the stool (59) . Only 1% have evidence of virus in the blood (59) . Taken together, this suggests that pulmonary and upper respiratory surgeries are likely to be higher risk, but that colorectal and GI surgeries may also have greater risk of transmission. Questions have been raised regarding risk during laparoscopic surgery, and if cauterization can aerosolize SARS-CoV-2 (60) . There is evidence that hepatitis B virus and human papillomavirus may become aerosolized during electrocautery (61, 62) , although they both are DNA viruses that have different mechanisms of transmission and sites of infection compared to SARS-CoV-2, challenging this inference. Nevertheless, given the paucity of data, and since it is known that virus RNA may be within the stool, every attempt should be made to minimize the evacuation of cautery smoke into the operating room per current guidelines from the Society of American Gastrointestinal and Endoscopic Surgeons (63) . This can be done using devices that filter released carbon dioxide (63) . A study of 3 patients with SARS-CoV who underwent Caesarean sections reported that no healthcare workers in the operating room were infected when using the following Copyright © 2020 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. PPE: powered air-purifying respirator with a hood covering the face and shoulders, goggles, gown, gloves, and cap (64) . Of note, 2 out of 3 of these patients developed wound infections, but their being treated with high dose steroids may have been a confounder (64) . Prior to the COVID-19 pandemic, use of PAPRs in combination with body suits was already popular in orthopedic surgery. A randomized controlled trial that accrued from [1974] [1975] [1976] [1977] [1978] [1979] demonstrated that orthopedic surgeons who used PAPRs had significantly decreased aerosolized bacterial counts in the operating room and decreased incidence of deep joint sepsis (65) ; the application of this study to modern operating rooms, however, has come into question (66) . A study of simulated joint surgery using fluorescein demonstrated that spread of respirable particulate matter to the proceduralist was eliminated with a powered airpurifying respirator and a level 4 gown (67). A similar study also showed that individuals wearing surgical masks without a PAPR had evidence of particulate matter within their nostrils, eyebrows, and eye lashes (68) . While certainly not definitive, these studies suggest that PAPR may be effective in reducing aerosolized transmission of COVID-19. Table 2 . Comparison of non-powered filtering facepiece respirators that cover the mouth and nose. Minimum efficiency is the efficiency of the respirator to filter out 0.3 µm test particles. APF=assigned protection factor; FDA=US Food and Drug Administration Table 3 . Our hospital's recommendations regarding operating room personal protective equipment during the COVID-19 pandemic. All recommendations are in addition to routine personal protective equipment (eye protection, gown, gloves) used during operations to maintain sterility. 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