key: cord-0942747-cbaxg217
authors: Kapoor, Prerna; Kapoor, Aditya; Azim, Afzal
title: A Brief Guidance for Cardiologists for Resource Containment Measures to Mitigate Anticipated Shortages of N-95 Filtering Facepiece Respirators during COVID-19 Pandemic
date: 2020-07-17
journal: Ann Card Anaesth
DOI: 10.4103/aca.aca_97_20
sha: f998709b2542d2cc343097076b68faa01c206886
doc_id: 942747
cord_uid: cbaxg217

nan

The COVID-19 pandemic has had an enormous impact on healthcare systems across the world. It is important to rapidly identify and triage patients who have suspected COVID-19 infection and evolving acute coronary syndrome (ACS).

This is because patients with ACS (who are often sick) may need emergency anesthetic intervention either by oxygen therapy, noninvasive ventilation (NIV), or emergent intubation, which all are aerosol generating procedures.

However, widespread shortage of these PPEs during the COVID-19 pandemic has meant that many healthcare workers (HCWs) including interventional cardiologists, anesthetists, and intensivists are managing patients and performing procedures with inadequate protection or with sub-optimal protection. Lack of availability of sufficient N-95 FFRs for cardiologists/intensivists exponentially increases their risk of exposure to COVID-19 and underscores the vital need for ensuring an uninterrupted supply of N-95 FFRs for cardiology and anesthesia services.

Data reported from the US Strategic National Stockpile in March 2020 projected a grim picture of rapidly depleting stocks, which were just about 1% of the projected annual need in the current situation. [1] While manufacturers are working overtime to ramp up production and supplies, the sheer numbers required to meet the needs of HCWs worldwide mean that a huge gap will continue to exist between supply and demand. Recently, the American College of Cardiology (ACC), the American Heart Association, and 11 other cardiovascular and healthcare societies issued a joint statement expressing concerns and seeking federal action "over the critical shortages of medical equipment, including ventilators, test kits and PPE (masks, face shields, and gowns) to address the public health crisis due to COVID-19." [2] It is therefore very important to be aware of indigenous solutions available in this regard, which may not be standards of care till now, but are being considered acceptable as a crisis management strategy to conserve N-95 FFRs in times of the COVID-19 pandemic. During previous influenza pandemics and outbreaks of infectious respiratory diseases, a similar depletion of N-95 respirators was reported. [3, 4] Existing Centre for Diseases Control and Prevention (CDC) guidelines recommended multiple approaches for healthcare institutions to conserve these supplies in times of crisis [ HCW who is looking after patients with suspected or confirmed COVID-19. One respirator is used daily, following which it is stored in a breathable paper bag. This order of FFR use is then repeated for the next daily, meaning thereby that each worker needs a minimum of five FFRs. It is imperative that the N-95 respirators are stored properly each day (after use) in the individual paper bags provided. At the end of the 5-day cycle, a new set is issued and the cycle repeated. The previous lot is disposed off, taking all precautions. Each HCW should also be strictly instructed that masks once used and put in the paper bags, do not touch each other and individual respirators should not be shared with other people.

However, if resources get even more constrained, making 5 respirators available for each worker who needs them, may also not be possible. In such crisis situations of a pandemic, CDC advises that FFR decontamination may become necessary. [6] While this practice would be inconsistent with the approved use of FFR's, CDC advisory states that this option may need to be considered in times of FFR shortages. FFR decontamination and reuse has previously been shown to be effective and studies have validated decontamination procedures against different respiratory pathogens. [7] [8] [9] Based on research by the NIOSH's National Personal Protective Technology Laboratory (NPPTL) and other studies assessing the impact of various decontamination methods on functionality (filtration, fit) and ability to reduce viable bio-organism load, the methods which hold the most promise are (VHP) and ultraviolet germicidal irradiation. Hence, the CDC recommends that healthcare institutions should focus efforts on the following technologies as decontamination methods [ Preferably not more than 20 cycles Significant reduction in Viruses (99.9999%) Promising method for a potential of high capacity FFRs. [17, 18] Previous studies have reported that UVGI exposures of 1 J/cm 2 can decontaminate influenza virus on N-95 FFRs while exposures of 2-5 mJ/cm 2 are capable inactivating coronaviruses on surfaces. [19, 20] Researchers at University of Nebraska Medical Center, Lincoln, Nebraska have evaluated the efficacy of UV radiation and reported that 15 min of UVC radiation was enough to kill the COVID-19 the virus. [17] In the system evaluated by Lowe et al., (ClorDiSys UVGI Light System, https://www.clordisys.com/products.php) UV sensor readings of 60 mJ/cm 2 equated with a total mask exposure dose of 180-240 mJ/cm 2 while a sensor reading of 300 mJ/cm 2 represented a total mask exposure dose of 900-1,200 mJ/cm 2 depending on the position of mask placement on the mask hanging lines. [17] The amount of delivered UVGI is monitored with a room UVGI meter that is remotely controlled by the technician from outside the UV room, so that potential damage to the eye or skin of the operator is avoided 3. Moist heat (heating at 60-70°C and 80-85% relative humidity has been previously used to decontaminate FFRs with minimal loss of functionality. [21, 22] While it is effective against flu viruses, there is limited data on the parameters (temperature, humidity, and time) required to completely inactivate SARS-COV-2 viral particles.

Hence based on current evidence, it may be unwise to use this method for FFR decontamination 4. Steam treatment (Microwave generated steam or steam bags with humid microwave sterilization or humid hot air oven sterilization) using 1,100-1,250 W microwave models (range: 40 s to 2 min) have also been investigated as approaches for decontaminating FFRs. [7, 21, 23] Fisher et al. reported that microwave steam bags (used for disinfecting infant feeding equipment) could effectively decontaminate FFRs with 99.9% inactivation of MS2 bacteriophages and no compromise of filtration performance upto 3 cycles of sterilization. [24] In a recent meta-analysis pertaining to decontamination of N-95 FFRs using microwave and heat-based techniques, Gertsman et al. reported that microwave irradiation and moderate temperature heat (< 90°C), in both moist and dry conditions, provided safe and effective decontamination and did not significantly impact the functional parameters of FFRs. [25] However, using steam microwaves to decontaminate FFRs is not without limitations since different microwave have different settings and power outputs and the effect of higher power microwaves on FFRs is unknown. Metal nosebands of FFRs can produce arcing and sparks inside the microwave oven, during exposure to microwaves 5. Other techniques that are not currently recommended for decontamination of respirators are autoclave, 160°C dry heat, 70% isopropyl alcohol, soap and water, bleach, dry heat, microwave, and Ethylene oxide It is important that cath lab personnel involved in active intervention procedures especially primary angioplasty in acute MI or other urgent life saving procedures don full PPE along with N-95 FFRs because such procedures are often done in sick patients and may entail emergent NIV or intubation, which are aerosol generating procedures. The MOHW guidelines also specify that healthcare personnel involved in critical care management in ICU, etc., need to don N-95 FFRs. [28] For resource containment, PPE and N-95 usage should not be advised for nursing and administrative staff not actually involved in the procedures. It is also mandatory to fragment the cath lab staff into smaller teams not only to conserve PPE and N-95 usage, but also to potentially limit the number of staff who may get quarantined in case of inadvertent exposure to a COVID positive case.

While N-95 respirator rotation or decontamination may be done in the unprecedented times of the COVID-19 pandemic, this practice should be done ensuring that it does not impact the performance of the respirator. Due to rapid evolution of the limited available research supporting the effectiveness of above-mentioned decontamination methods, further research on this topic shall give impetus to these strategies. It is imperative that HCWs still observe all precautions prior to using decontaminated FFRs, including visually inspecting it each time to look for any structural defect, checking all components such as the straps, nose bridge, and nose foam material and user seal check. Despite data supporting decontamination, FFRs contaminated with blood, respiratory or nasal secretions or other bodily fluids from patients should not be decontaminated.

Healthcare systems should consider reuse and decontamination strategies before critical resource shortages are observed. Policies outlining decontamination and reuse of N-95 FFRs should be made by teams managing the COVID-19 programs, in collaboration with the local infection control/microbiology departments. These policies need to be implemented considering the local logistics (e.g., number of N-95 respirators available and current and future usage rate) as well as institutional validation of procedural protocols of the chosen decontamination strategy (VHP or UVGI). Awareness about such measures will result in optimal resource management of N-95 FFRs and reduce the risk of exposure of cardiologists and intensivists to possible COVID-19 infection, who can help implement these policies in their institutions.

Nil.

There are no conflicts of interest.

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