PANDEMIC PLANNING

Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings

Background

This document recommends practices for extended use and limited reuse of NIOSH-certified N95 filtering facepiece respirators (commonly called “N95 respirators”). The recommendations are intended for use by professionals who manage respiratory protection programs in healthcare institutions to protect health care workers from job-related risks of exposure to infectious respiratory illnesses.

Supplies of N95 respirators can become depleted during an influenza pandemic (1-3) or wide-spreadoutbreaks of other infectious respiratory illnesses.(4) Existing CDC guidelines recommend a combination of approaches to conserve supplies while safeguarding health care workers in such circumstances. These existing guidelines recommend that health care institutions:

• Minimize the number of individuals who need to use respiratory protection through the preferential use of engineering and administrative controls;
• Use alternatives to N95 respirators (e.g., other classes of filtering facepiece respirators, elastomeric half-mask and full facepiece air purifying respirators, powered air purifying respirators) where feasible;
• Implement practices allowing extended use and/or limited reuse of N95 respirators, when acceptable; and
• Prioritize the use of N95 respirators for those personnel at the highest risk of contracting or experiencing complications of infection.

This document focuses on one of the above strategies, the extended use and limited reuse of N95 respirators only; please consult the CDC or NIOSH website for guidance related to implementing the other recommended approaches for conserving supplies of N95 respirators.

There are also non-emergency situations (e.g., close contact with patients with tuberculosis) where N95 respirator reuse has been recommended in healthcare settings and is commonly practiced.(5-9) This document serves to supplement previous guidance on this topic.

Definitions

Extended use refers to the practice of wearing the same N95 respirator for repeated close contact encounters with several patients, without removing the respirator between patient encounters. Extended use may be implemented when multiple patients are infected with the same respiratory pathogen and patients are placed together in dedicated waiting rooms or hospital wards. Extended use has been recommended as an option for conserving respirators during previous respiratory pathogen outbreaks and pandemics.(10, 11)

Reuse¹ refers to the practice of using the same N95 respirator for multiple encounters with patients but removing it (‘doffing’) after each encounter. The respirator is stored in between encounters to be put on again (‘donned’) prior to the next encounter with a patient. For pathogens in which contact transmission (e.g., fomites) is not a concern, non-emergency reuse has been practiced for decades.(7) For example, for tuberculosis prevention, CDC recommends that a respirator classified as disposable can be reused by the same worker as long as it remains functional² and is used in accordance with local infection control procedures.(9) Even when N95 respirator reuse is practiced or recommended, restrictions are in place which limit the number of times the same FFR is reused.Thus, N95 respirator reuse is often referred to as “limited reuse”. Limited reuse has been recommended and widely used as an option for conserving respirators during previous respiratory pathogen outbreaks and pandemics.(2, 3, 10-12)

Implementation

The decision to implement policies that permit extended use or limited reuse of N95 respirators should be made by the professionals who manage the institution’s respiratory protection program, in in consultation with their occupational health and infection control departments with input from the state/local public health departments. The decision to implement these practices should be made on a case by case basis taking into account respiratory pathogen characteristics (e.g., routes of transmission, prevalence of disease in the region, infection attack rate, and severity of illness) and local conditions (e.g., number of disposable N95 respirators available, current respirator usage rate, success of other respirator conservation strategies, etc.). Some healthcare facilities may wish to implement extended use and/or limited reuse before respirator shortages are observed, so that adequate supplies are available during times of peak demand. For non-emergency (routine) situations, current CDC recommendations (6, 9) specific to that pathogen should also be consulted.

The following sections outline specific steps to guide implementation of these recommendations, minimize the challenges caused by extended use and reuse, and to limit risks that could result from these practices.

Respirator Extended Use Recommendations

Extended use is favored over reuse because it is expected to involve less touching of the respirator and therefore less risk of contact transmission. Please see the section on Risks of Extended Use and Reuse of Respirators for more information about contact transmission and other risks involved in these practices.

A key consideration for safe extended use is that the respirator must maintain its fit and function. Workers in other industries routinely use N95 respirators for several hours uninterrupted. Experience in these settings indicates that respirators can function within their design specifications for 8 hours of continuous or intermittent use. Some research studies (14, 15) have recruited healthcare workers as test subjects and many of those subjects have successfully worn an N95 respirator at work for several hours before they needed to remove them. Thus, the maximum length of continuous use in non-dusty healthcare workplaces is typically dictated by hygienic concerns (e.g., the respirator was discarded because it became contaminated) or practical considerations (e.g., need to use the restroom, meal breaks, etc.), rather than a pre-determined number of hours.

If extended use of N95 respirators is permitted, respiratory protection program administrators should ensure adherence to administrative and engineering controls to limit potential N95 respirator surface contamination (e.g., use of barriers to prevent droplet spray contamination) and consider additional training and reminders (e.g., posters) for staff to reinforce the need to minimize unnecessary contact with the respirator surface, strict adherence to hand hygiene practices, and proper Personal Protective Equipment (PPE) donning and doffing technique.(16) Healthcare facilities should develop clearly written procedures to advise staff to take the following steps to reduce contact transmission after donning:

• Discard N95 respirators following use during aerosol generating procedures.
• Discard N95 respirators contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients.
• Discard N95 respirators following close contact with, or exit from, the care area of any patient co-infected with an infectious disease requiring contact precautions.
• Consider use of a cleanable face shield (preferred³) over an N95 respirator and/or other steps (e.g., masking patients, use of engineering controls) to reduce surface contamination.
• Perform hand hygiene with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the respirator (if necessary for comfort or to maintain fit).

Extended use alone is unlikely to degrade respiratory protection. However, healthcare facilities should develop clearly written procedures to advise staff to:

• Discard any respirator that is obviously damaged or becomes hard to breathe through.

Respirator Reuse Recommendations

There is no way of determining the maximum possible number of safe reuses for an N95 respirator as a generic number to be applied in all cases. Safe N95 reuse is affected by a number of variables that impact respirator function and contamination over time.(18, 19) However, manufacturers of N95 respirators may have specific guidance regarding reuse of their product.The recommendations below are designed to provide practical advice so that N95 respirators are discarded before they become a significant risk for contact transmission or their functionality is reduced.

If reuse of N95 respirators is permitted, respiratory protection program administrators should ensure adherence to administrative and engineering controls to limit potential N95 respirator surface contamination (e.g., use of barriers to prevent droplet spray contamination) and consider additional training and/or reminders (e.g., posters) for staff to reinforce the need to minimize unnecessary contact with the respirator surface, strict adherence to hand hygiene practices, and proper PPE donning and doffing technique, including physical inspection and performing a user seal check.(16) Healthcare facilities should develop clearly written procedures to advise staff to take the following steps to reduce contact transmission:

• Discard N95 respirators following use during aerosol generating procedures.
• Discard N95 respirators contaminated with blood, respiratory or nasal secretions, or other bodily fluids from patients.
• Discard N95 respirators following close contact with any patient co-infected with an infectious disease requiring contact precautions.
• Consider use of a cleanable face shield (preferred³) over an N95 respirator and/or other steps (e.g., masking patients, use of engineering controls), when feasible to reduce surface contamination of the respirator.
• Hang used respirators in a designated storage area or keep them in a clean, breathable container such as a paper bag between uses. To minimize potential cross-contamination, store respirators so that they do not touch each other and the person using the respirator is clearly identified. Storage containers should be disposed of or cleaned regularly.
• Clean hands with soap and water or an alcohol-based hand sanitizer before and after touching or adjusting the respirator (if necessary for comfort or to maintain fit).
• Avoid touching the inside of the respirator. If inadvertent contact is made with the inside of the respirator, discard the respirator and perform hand hygiene as described above.
• Use a pair of clean (non-sterile) gloves when donning a used N95 respirator and performing a user seal check. Discard gloves after the N95 respirator is donned and any adjustments are made to ensure the respirator is sitting comfortably on your face with a good seal.

To reduce the chances of decreased protection caused by a loss of respirator functionality, respiratory protection program managers should consult with the respirator manufacturer regarding the maximum number of donnings or uses they recommend for the N95 respirator model(s) used in that facility. If no manufacturer guidance is available, preliminary data(19, 20) suggests limiting the number of reuses to no more than five uses per device to ensure an adequate safety margin. Management should consider additional training and/or reminders for users to reinforce the need for proper respirator donning techniques including inspection of the device for physical damage (e.g., Are the straps stretched out so much that they no longer provide enough tension for the respirator to seal to the face?, Is the nosepiece or other fit enhancements broken?, etc.). Healthcare facilities should provide staff clearly written procedures to:

• Follow the manufacturer’s user instructions, including conducting a user seal check.
• Follow the employer’s maximum number of donnings (or up to five if the manufacturer does not provide a recommendation) and recommended inspection procedures.
• Discard any respirator that is obviously damaged or becomes hard to breathe through.
• Pack or store respirators between uses so that they do not become damaged or deformed.

Secondary exposures can occur from respirator reuse if respirators are shared among users and at least one of the users is infectious (symptomatic or asymptomatic). Thus, N95 respirators must only be used by a single wearer. To prevent inadvertent sharing of respirators, healthcare facilities should develop clearly written procedures to inform users to:

• Label containers used for storing respirators or label the respirator itself (e.g., on the straps(11)) between uses with the user’s name to reduce accidental usage of another person’s respirator.

Risks of Extended Use and Reuse of Respirators

Although extended use and reuse of respirators have the potential benefit of conserving limited supplies of disposable N95 respirators, concerns about these practices have been raised. Some devices have not been FDA-cleared for reuse(21). Some manufacturers’ product user instructions recommend discard after each use (i.e., “for single use only”), while others allow reuse if permitted by infection control policy of the facility.(19) The most significant risk is of contact transmission from touching the surface of the contaminated respirator. One study found that nurses averaged 25 touches per shift to their face, eyes, or N95 respirator during extended use.(15)Contact transmission occurs through direct contact with others as well as through indirect contact by touching and contaminating surfaces that are then touched by other people.

Respiratory pathogens on the respirator surface can potentially be transferred by touch to the wearer’s hands and thus risk causing infection through subsequent touching of the mucous membranes of the face (i.e., self-inoculation). While studies have shown that some respiratory pathogens (22-24) remain infectious on respirator surfaces for extended periods of time, in microbial transfer (25-27) and reaerosolization studies (28-32) more than ~99.8% have remained trapped on the respirator after handling or following simulated cough or sneeze.

Respirators might also become contaminated with other pathogens acquired from patients who are co-infected with common healthcare pathogens that have prolonged environmental survival (e.g., methicillin-resistant Staphylococcus aureas, vancomycin-resistant enterococci, Clostridium difficile, norovirus, etc.). These organisms could then contaminate the hands of the wearer, and in turn be transmitted via self-inoculation or to others via direct or indirect contact transmission.

The risks of contact transmission when implementing extended use and reuse can be affected by the types of medical procedures being performed and the use of effective engineering and administrative controls, which affect how much a respirator becomes contaminated by droplet sprays or deposition of aerosolized particles. For example, aerosol generating medical procedures such as bronchoscopies, sputum induction, or endotracheal intubation, are likely to cause higher levels of respirator surface contamination, while source control of patients (e.g. asking patients to wear facemasks), use of a face shield over the disposable N95 respirator, or use of engineering controls such as local exhaust ventilation are likely to reduce the levels of respirator surface contamination.(18)

While contact transmission caused by touching a contaminated respirator has been identified as the primary hazard of extended use and reuse of respirators, other concerns have been assessed, such as a reduction in the respirator’s ability to protect the wearer caused by rough handling or excessive reuse.(19, 20) Extended use can cause additional discomfort to wearers from wearing the respirator longer than usual.(14, 15) However, this practice should be tolerable and should not be a health risk to medically cleared respirator users.(19)

References

1. Murray, M., J. Grant, E. Bryce, P. Chilton, and L. Forrester: Facial protective equipment, personnel, and pandemics: impact of the pandemic (H1N1) 2009 virus on personnel and use of facial protective equipment. Infection Control and Hospital Epidemiology 31(10): 1011-1016 (2010).
2. Beckman, S., B. Materna, S. Goldmacher, J. Zipprich, M. D’Alessandro, D. Novak et al.: Evaluation of respiratory protection programs and practices in California hospitals during the 2009-2010 H1N1 influenza pandemic. American Journal of Infection Control 41(11): 1024-1031 (2013).
3. Hines, L., E. Rees, and N. Pavelchak: Respiratory protection policies and practices among the health care workforce exposed to influenza in New York State: Evaluating emergency preparedness for the next pandemic. American Journal of Infection Control (2014).
4. Srinivasan, A., D.B. Jernign, L. Liedtke, and L. Strausbaugh: Hospital preparedness for severe acute respiratory syndrome in the United States: views from a national survey of infectious diseases consultants. Clinical Infectious Diseases 39(2): 272-274 (2004).
5. OSHA: “Enforcement procedures and scheduling for occupational exposure to tuberculosis.” [Online] Available at https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=DIRECTIVES&p_id=1586external icon, 1996).
6. Siegel, J.D., E. Rhinehart, M. Jackson, and L. Chiarello: “2007 Guideline for isolation precautions: preventing transmission of infectious agents in health care settings.” [Online] Available at https://www.cdc.gov/hicpac/pdf/isolation/isolation2007.pdfpdf icon, 2007).
7. CDC: “Guidelines for preventing the transmission of Mycobacterium tuberculosis in health care facilities.” [Online] Available at https://www.cdc.gov/mmwr/pdf/rr/rr4313.pdfpdf icon, 1994).
8. Bollinger, N., J. Bryant, W. Ruch, J. Flesch, E. Petsonk, T. Hodous et al.: “TB Respiratory Protection Program in Health Care Facilities, Administrator’s Guide.” [Online] Available at https://www.cdc.gov/niosh/docs/99-143/, 1999).
9. Jensen, P., L. Lambert, M. Iademarco, and R. Ridzon: “Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care settings, 2005.” [Online] Available at https://www.cdc.gov/mmwr/preview/mmwrhtml/rr5417a1.htm, 2005).
10. CDC: “Questions and Answers Regarding Respiratory Protection For Preventing 2009 H1N1 Influenza Among Healthcare Personnel” [Online] Available at https://www.cdc.gov/h1n1flu/guidelines_infection_control_qa.htm, 2010).
11. Rebmann, T., S. Alexander, T. Cain, B. Citarella, M. Cloughessy, and B. Coll “APIC position paper: extending the use and/or reusing respiratory protection in healthcare settings during disasters.” [Online] Available at http://www.apic.org/Resource_/TinyMceFileManager/Advocacy-PDFs/APIC_Position_Ext_the_Use_and_or_Reus_Resp_Prot_in_Hlthcare_Settings1209l.pdfpdf iconexternal icon, 2009).
12. IOM: Reusability of facemasks during an influenza pandemic: facing the flu. Washington, D.C.: National Academies Press, 2006.
13. Lin, C.S.: “FDA Regulation of Surgical Masks and Respirators.” [Online] Available at http://www.iom.edu/~/media/Files/Activity Files/PublicHealth/ReusableFluMasks/FDApresentation12306.ashxexternal icon, 2006).
14. Radonovich Jr, L.J., J. Cheng, B.V. Shenal, M. Hodgson, and B.S. Bender: Respirator tolerance in health care workers. JAMA: The Journal of the American Medical Association 301(1): 36-38 (2009).
15. Rebmann, T., R. Carrico, and J. Wang: Physiologic and other effects and compliance with long-term respirator use among medical intensive care unit nurses. American Journal of Infection Control 41(12): 1218-1223 (2013).
16. CDC: “Sequence for donning personal protective equipment PPE/Sequence for removing personal protective equipment.” [Online] Available at https://www.cdc.gov/HAI/pdfs/ppe/ppeposter148.pdfpdf icon
17. Roberge, R.J.: Effect of surgical masks worn concurrently over N95 filtering facepiece respirators: extended service life versus increased user burden. Journal of Public Health Management and Practice : JPHMP 14(2): E19-26 (2008).
18. Fisher, E.M., J.D. Noti, W.G. Lindsley, F.M. Blachere, and R.E. Shaffer: Validation and Application of Models to Predict Facemask Influenza Contamination in Healthcare Settings. Risk Analysis in press(2014).
19. Fisher, E.M., and R.E. Shaffer: Considerations for Recommending Extended Use and Limited Reuse of Filtering Facepiece Respirators in Healthcare Settings Journal of Occupational and Environmental Hygiene: (in press) (2014).
20. Bergman, M.S., D.J. Viscusi, Z. Zhuang, A.J. Palmiero, J.B. Powell, and R.E. Shaffer: Impact of multiple consecutive donnings on filtering facepiece respirator fit. American Journal of Infection Control 40(4): 375-380 (2012).
21. FDA: “510(k) Premarket Notification.” [Online] Available at http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfPMN/pmn.cfmexternal icon, 2014).
22. Casanova, L., W.A. Rutala, D.J. Weber, and M.D. Sobsey: Coronavirus survival on healthcare personal protective equipment. Infection Control and Hospital Epidemiology 31(5): 560-561 (2010).
23. Coulliette, A., K. Perry, J. Edwards, and J. Noble-Wang: Persistence of the 2009 Pandemic Influenza A (H1N1) Virus on N95 Respirators. Applied and Environmental Microbiology 79(7): 2148-2155 (2013).
24. Fisher, E.M., and R.E. Shaffer: Survival of bacteriophage MS2 on filtering facepiece respirator coupons. Applied Biosafety: Journal of the American Biological Safety Association 15(2): 71 (2010).
25. Lopez, G.U., C.P. Gerba, A.H. Tamimi, M. Kitajima, S.L. Maxwell, and J.B. Rose: Transfer Efficiency of Bacteria and Viruses from Porous and Nonporous Fomites to Fingers under Different Relative Humidity Conditions. Applied and Environmental Microbiology 79(18): 5728-5734 (2013).
26. Fisher, E.M., C.M. Ylitalo, N. Stepanova, and R.E. Shaffer: Assessing Filtering Facepiece Respirator Contamination During Patient Care in Flu Season: Experimental and Modeling Approaches. In ISRP — Sixteenth International Conference:A Global View on Respiratory Protection. Boston, 2012.
27. Rusin, P., S. Maxwell, and C. Gerba: Comparative surface-to-hand and fingertip-to-mouth transfer efficiency of gram-positive bacteria, gram-negative bacteria, and phage. Journal of Applied Microbiology 93(4): 585-592 (2002).
28. Fisher, E.M., A.W. Richardson, S.D. Harpest, K.C. Hofacre, and R.E. Shaffer: Reaerosolization of MS2 bacteriophage from an N95 filtering facepiece respirator by simulated coughing. Annals of Occupational Hygiene 56(3): 315-325 (2012).
29. Birkner, J.S., D. Fung, W.C. Hinds, and N.J. Kennedy: Particle release from respirators, part I: determination of the effect of particle size, drop height, and load. Journal of Occupational and Environmental Hygiene 8(1): 1-9 (2011).
30. Kennedy, N.J., and W.C. Hinds: Release of simulated anthrax particles from disposable respirators. Journal of Occupational and Environmental Hygiene1(1): 7-10 (2004).
31. Qian, Y., K. Willeke, S.A. Grinshpun, and J. Donnelly: Performance of N95 respirators: reaerosolization of bacteria and solid particles. American Industrial Hygiene Association Journal 58(12): 876-880 (1997).
32. Willeke, K., and Y. Qian: Tuberculosis control through respirator wear: performance of National Institute for Occupational Safety and Health-regulated respirators. American Journal of Infection Control 26(2): 139-142 (1998).