Evaluation of respiratory protection programs and practices in California hospitals during the 2009-2010 H1N1 influenza pandemic

Prevalence of Respiratory Protective Devices in U.S. Health Care Facilities: Implications for Emergency Preparedness

An online questionnaire was developed to explore respiratory protective device (RPD) prevalence in U.S. health care facilities. The survey was distributed to professional nursing society members in 2014 and again in 2015 receiving 322 and 232 participant responses, respectively. The purpose of this study was to explore if the emergency preparedness climate associated with Ebola virus disease changed the landscape of RPD use and awareness. Comparing response percentages from the two sampling time frames using bivariate analysis, no significant changes were found in types of RPDs used in health care settings. N95 filtering facepiece respirators continue to be the most prevalent RPD used in health care facilities, but powered air-purifying respirators are also popular, with regional use highest in the West and Midwest. Understanding RPD use prevalence could ensure that health care workers receive appropriate device trainings as well as improve supply matching for emergency RPD stockpiling.

A comparison of facemask and respirator filtration test methods

NIOSH published a Federal Register Notice to explore the possibility of incorporating FDA required filtration tests for surgical masks (SMs) in the 42 CFR Part 84 respirator certification process. There have been no published studies comparing the filtration efficiency test methods used for NIOSH certification of N95 filtering facepiece respirators (N95 FFRs) with those used by the FDA for clearance of SMs. To address this issue, filtration efficiencies of "N95 FFRs" including six N95 FFR models and three surgical N95 FFR models, and three SM models were measured using the NIOSH NaCl aerosol test method, and FDA required particulate filtration efficiency (PFE) and bacterial filtration efficiency (BFE) methods, and viral filtration efficiency (VFE) method. Five samples of each model were tested using each method. Both PFE and BFE tests were done using unneutralized particles as per FDA guidance document. PFE was measured using 0.1 µm size polystyrene latex particles and BFE with ∼3.0 µm size particles containing Staphylococcus aureus bacteria. VFE was obtained using ∼3.0 µm size particles containing phiX 174 as the challenge virus and Escherichia coli as the host. Results showed that the efficiencies measured by the NIOSH NaCl method for "N95 FFRs" were from 98.15-99.68% compared to 99.74-99.99% for PFE, 99.62-99.9% for BFE, and 99.8-99.9% for VFE methods. Efficiencies by the NIOSH NaCl method were significantly (p = <0.05) lower than the other methods. SMs showed lower efficiencies (54.72-88.40%) than "N95 FFRs" measured by the NIOSH NaCl method, while PFE, BFE, and VFE methods produced no significant difference. The above results show that the NIOSH NaCl method is relatively conservative and is able to identify poorly performing filtration devices. The higher efficiencies obtained using PFE, BFE and VFE methods show that adding these supplemental particle penetration methods will not improve respirator certification.

Qualitative Analysis of Origins and Evolution of an Elastomeric Respirator-based Hospital Respiratory Protection Program

Elastomeric respirators (elastomerics) may serve as one alternative to disposable N95 respirator use in healthcare. We explored factors which drove elastomeric adoption and continued use in a large academic medical center. We conducted semi-structured and focus group interviews in 2015 with a) 11 leadership key informants (KIs) with involvement in the respiratory protection program (RPP) when elastomerics were introduced and b) 11 healthcare workers (HCWs) recruited from hospital departments assigned to use elastomerics. Interview transcripts and responses were open-coded to capture emergent themes, which were collapsed into broader categories and iteratively refined. Factors identified by leadership KIs as influencing elastomeric adoption included: 1) N95 shortages during 2009's H1N1 influenza pandemic and 2) the presence of trained, certified safety professionals who were familiar with respiratory protection requirements. Factors identified as influencing ongoing use of elastomerics included: 1) cleaning/decontamination practices, 2) storage, 3) safety culture, 4) HCW respirator knowledge, and 5) risk perception. HCW users expressed dissatisfaction related to breathing, communication and cleaning of elastomerics. Other themes included convenience use of N95s rather than assigned elastomerics, despite perceptions that elastomerics are more protective. Through semi-structured and focus group interviews, we learned that 1) leadership introduced elastomerics due to necessity but now face challenges related to ongoing use, and 2) HCWs were not satisfied with elastomerics for routine care and preferentially used N95s because they were conveniently available at point of use. Although the impetus behind incorporation of elastomerics was clear, the most complex themes related to sustainability of this form of RPP. These themes were used to inform a broader questionnaire and will address the utility of elastomerics as a feasible and acceptable practical alternative to N95s in healthcare.

Assessing the efficacy of tabs on filtering facepiece respirator straps to increase proper doffing techniques while reducing contact transmission of pathogens

NIOSH-certified N95 filtering facepiece respirators (FFRs) are used in healthcare settings as a control measure to mitigate exposures to airborne infectious particles. When the outer surface of an FFR becomes contaminated, it presents a contact transmission risk to the wearer. The Centers for Disease Control and Prevention (CDC) guidance recommends that healthcare workers (HCWs) doff FFRs by grasping the straps at the back of the head to avoid contact with the potentially contaminated surface. Adherence to proper doffing technique is reportedly low due to numerous factors including difficulty in locating and grasping the straps. This study compares the impact of tabs placed on FFR straps to controls (without tabs) on proper doffing, ease of use and comfort, and reduction of transfer of contamination to the wearer. Utilizing a fluorescent agent as a tracer to track contamination from FFRs to hand and head areas of 20 human subjects demonstrated that there was no difference in tabbed FFR straps and controls with respect to promoting proper doffing (p = 0.48), but did make doffing easier (p = 0.04) as indicated by 7 of 8 subjects that used the tabs. Seven of the 20 subjects felt that FFRs with tabs were easier to remove, while only 2 of 20 indicated that FFRs without tabs were easier to remove. Discomfort was not a factor for either FFR strap type. When removing an FFR with contaminated hands, the use of the tabs significantly reduced the amount of tracer transfer compared to straps without tabs (p = 0.012). FFRs with tabs on the straps are associated with ease of doffing and significantly less transfer of the fluorescent tracer.

Respiratory Protection Toolkit

International travel and infectious respiratory illnesses worldwide place health care workers (HCWs) at increasing risk of respiratory exposures. To ensure the highest quality safety initiatives, one health care system used a quality improvement model of Plan-Do-Study-Act and guidance from Occupational Safety and Health Administration’s (OSHA) May 2015 Hospital Respiratory Protection Program (RPP) Toolkit to assess a current program. The toolkit aided in identification of opportunities for improvement within their well-designed RPP. One opportunity was requiring respirator use during aerosol-generating procedures for specific infectious illnesses. Observation data demonstrated opportunities to mitigate controllable risks including strap placement, user seal check, and reuse of disposable N95 filtering facepiece respirators. Subsequent interdisciplinary collaboration resulted in other ideas to decrease risks and increase protection from potentially infectious respiratory illnesses. The toolkit’s comprehensive document to evaluate the program showed that while the OSHA standards have not changed, the addition of the toolkit can better protect HCWs.

Persistence of Influenza A (H1N1) Virus on Stainless Steel Surfaces

As annual influenza epidemics continue to cause significant morbidity and economic burden, an understanding of viral persistence and transmission is critical for public health officials and health care workers to better protect patients and their family members from infection. The infectivity and persistence of two influenza A (H1N1) virus strains (A/New Caledonia/20/1999 and A/Brisbane/59/2007) on stainless steel (SS) surfaces were evaluated using three different surface matrices (2% fetal bovine serum, 5 mg/ml mucin, and viral medium) under various absolute humidity conditions (4.1 × 10(5) mPa, 6.5 × 10(5) mPa, 7.1 × 10(5) mPa, 11.4 × 10(5) mPa, 11.2 × 10(5) mPa, and 17.9 × 10(5) mPa) for up to 7 days. Influenza A virus was deposited onto SS coupons (7.07 cm(2)) and recovered by agitation and sonication in viral medium. Viral persistence was quantified using a tissue culture-based enzyme-linked immunosorbent assay (ELISA) to determine the median (50%) tissue culture infective dose (TCID50) of infectious virus per coupon. Overall, both strains of influenza A virus remained infectious on SS coupons, with an approximate 2 log10 loss over 7 days. Factors that influenced viral persistence included absolute humidity, strain-absolute humidity interaction, and time (P ≤ 0.01). Further studies on the transfer of influenza A virus from fomites by hand and the impact of inanimate surface contamination on transmission should be performed, as this study demonstrates prolonged persistence on nonporous surfaces.

IMPORTANCE

This study tested the ability of two influenza A (H1N1) virus strains to persist and remain infectious on stainless steel surfaces under various environmental conditions. It demonstrated that influenza A (H1N1) viruses can persist and remain infectious on stainless steel surfaces for 7 days. Additional studies should be conducted to assess the role played by contaminated surfaces in the transmission of influenza A virus.

Aerosol transmission of infectious disease

OBJECTIVE

The concept of aerosol transmission is developed to resolve limitations in conventional definitions of airborne and droplet transmission.

METHODS

The method was literature review.

RESULTS

An infectious aerosol is a collection of pathogen-laden particles in air. Aerosol particles may deposit onto or be inhaled by a susceptible person. Aerosol transmission is biologically plausible when infectious aerosols are generated by or from an infectious person, the pathogen remains viable in the environment for some period of time, and the target tissues in which the pathogen initiates infection are accessible to the aerosol. Biological plausibility of aerosol transmission is evaluated for Severe Acute Respiratory Syndrome coronavirus and norovirus and discussed for Mycobacterium tuberculosis, influenza, and Ebola virus.

CONCLUSIONS

Aerosol transmission reflects a modern understanding of aerosol science and allows physically appropriate explanation and intervention selection for infectious diseases.

Respirator Use in a Hospital Setting: Establishing Surveillance Metrics

Information that details use and supply of respirators in acute care hospitals is vital to prevent disease transmission, assure the safety of health care personnel, and inform national guidelines and regulations.

OBJECTIVE

To develop measures of respirator use and supply in the acute care hospital setting to aid evaluation of respirator programs, allow benchmarking among hospitals, and serve as a foundation for national surveillance to enhance effective Personal Protective Equipment (PPE) use and management.

METHODS

We identified existing regulations and guidelines that govern respirator use and supply at Vanderbilt University Medical Center (VUMC). Related routine and emergency hospital practices were documented through an investigation of hospital administrative policies, protocols, and programs. Respirator dependent practices were categorized based on hospital workflow: Prevention (preparation), patient care (response), and infection surveillance (outcomes). Associated data in information systems were extracted and their quality evaluated. Finally, measures representing major factors and components of respirator use and supply were developed.

RESULTS

Various directives affecting multiple stakeholders govern respirator use and supply in hospitals. Forty-seven primary and secondary measures representing factors of respirator use and supply in the acute care hospital setting were derived from existing information systems associated with the implementation of these directives.

CONCLUSION

Adequate PPE supply and effective use that limit disease transmission and protect health care personnel are dependent on multiple factors associated with routine and emergency hospital practices. We developed forty-seven measures that may serve as the basis for a national PPE surveillance system, beginning with standardized measures of respirator use and supply for collection across different hospital types, sizes, and locations to inform hospitals, government agencies, manufacturers, and distributors. Despite involvement of multiple hospital stakeholders, regulatory guidance prescribes workplace practices that are likely to result in similar workflows across hospitals. Future work will explore the feasibility of implementing the collection and reporting of standardized measures in multiple facilities.

Resistance to synthetic blood penetration of National Institute for Occupational Safety and Health-approved N95 filtering facepiece respirators and surgical N95 respirators

BACKGROUND

Surgical N95 filtering facepiece respirators (FFRs), certified by the National Institute for Occupational Safety and Health (NIOSH) as a respirator and cleared by the Food and Drug Administration (FDA) as a surgical mask, are often used to protect from the inhalation of infectious aerosols and from splashes/sprays of body fluids in health care facilities. A shortage of respirators can be expected during a pandemic. The availability of surgical N95 FFRs can potentially be increased by incorporating FDA clearance requirements in the NIOSH respirator approval process.

METHODS

Fluid resistance of NIOSH-approved N95 FFRs, and FDA-cleared surgical N95 FFRs and surgical masks was tested using the ASTM F1862 method at 450 and 635 cm/sec velocities and compared with the results from a third-party independent laboratory. Blood penetration through different layers of filter media of masks were also analyzed visually.

RESULTS

Four N95 FFR models showed no test failures at both velocities. The penetration results obtained in the NIOSH laboratory were comparable to those from the third-party independent laboratory. The number of respirator samples failing the test increased with increasing test velocity.

CONCLUSIONS

The results indicate that several NIOSH-approved N95 FFR models would likely pass FDA clearance requirements for resistance to synthetic blood penetration.

Potential demand for respirators and surgical masks during a hypothetical influenza pandemic in the United States

Background. To inform planning for an influenza pandemic, we estimated US demand for N95 filtering facepiece respirators (respirators) by healthcare and emergency services personnel and need for surgical masks by pandemic patients seeking care.

Methods. We used a spreadsheet-based model to estimate demand for 3 scenarios of respirator use: base case (usage approximately follows epidemic curve), intermediate demand (usage rises to epidemic peak and then remains constant), and maximum demand (all healthcare workers use respirators from pandemic onset). We assumed that in the base case scenario, up to 16 respirators would be required per day per intensive care unit patient and 8 per day per general ward patient. Outpatient healthcare workers and emergency services personnel would require 4 respirators per day. Patients would require 1.2 surgical masks per day.

Results and Conclusions. Assuming that 20% to 30% of the population would become ill, 1.7 to 3.5 billion respirators would be needed in the base case scenario, 2.6 to 4.3 billion in the intermediate demand scenario, and up to 7.3 billion in the maximum demand scenario (for all scenarios, between 0.1 and 0.4 billion surgical masks would be required for patients). For pandemics with a lower attack rate and fewer cases (eg, 2009-like pandemic), the number of respirators needed would be higher because the pandemic would have longer duration. Providing these numbers of respirators and surgical masks represents a logistic challenge for US public health agencies. Public health officials must urgently consider alternative use strategies for respirators and surgical masks during a pandemic that may vary from current practices.

Disinfection of reusable elastomeric respirators by health care workers: a feasibility study and development of standard operating procedures

BACKGROUND

This was a feasibility study in a Department of Veterans Affairs Medical Center to develop a standard operating procedure (SOP) to be used by health care workers to disinfect reusable elastomeric respirators under pandemic conditions. Registered and licensed practical nurses, nurse practitioners, aides, clinical technicians, and physicians took part in the study.

METHODS

Health care worker volunteers were provided with manufacturers' cleaning and disinfection instructions and all necessary supplies. They were observed and filmed. SOPs were developed, based on these observations, and tested on naïve volunteer health care workers. Error rates using manufacturers' instructions and SOPs were compared.

RESULTS

When using respirator manufacturers' cleaning and disinfection instructions, without specific training or supervision, all subjects made multiple errors. When using the SOPs developed in the study, without specific training or guidance, naïve health care workers disinfected respirators with zero errors.

CONCLUSION

Reusable facial protective equipment may be disinfected by health care workers with minimal training using SOPs.

Selecting models for a respiratory protection program: what can we learn from the scientific literature?

BACKGROUND

An unbiased source of comparable respirator performance data would be helpful in setting up a hospital respiratory protection program.

METHODS

The scientific literature was examined to assess the extent to which performance data (respirator fit, comfort and usability) from N95 filtering facepiece respirator (FFR) models are available to assist with FFR model selection and procurement decisions.

RESULTS

Ten studies were identified that met the search criteria for fit, whereas 5 studies met the criteria for comfort and usability.

CONCLUSION

Analysis of these studies indicated that it is difficult to directly use the scientific literature to inform the FFR selection process because of differences in study populations, methodologies, and other factors. Although there does not appear to be a single best fitting FFR, studies demonstrate that fit testing programs can be designed to successfully fit nearly all workers with existing products. Comfort and usability are difficult to quantify. Among the studies found, no significant differences were noted.

Comparing written programs and self-reported respiratory protection practices in acute care hospitals

Airborne biological hazards in hospitals require the use of respiratory protection. A well-implemented respiratory protection program can protect health care workers from these exposures. This study examines the relationship between written respiratory programs and reported practices in health care settings. Twenty-eight hospitals in Illinois and Minnesota were recruited to a study of respiratory protection programs and practices in acute care settings. Interviews were conducted with hospital managers, unit managers, and health care workers from departments where respirators are commonly required. Each hospital's written respiratory protection program was scored for the 11 elements required by the Occupational Safety and Health Administration (OSHA), using a standardized tool, for a maximum possible score of 22 (2 pts. per element). Twenty interview questions associated with program practices were also scored by percent correct responses. Written program scores ranged from 2-17 with an average of 9.2. Hospital and unit managers scored on average 82% and 81%, respectively, when compared to the OSHA standard; health care workers scored significantly lower, 71% (p < 0.001). Minnesota written program scores were not significantly higher than Illinois hospitals (p = 0.16), while all Illinois survey respondents scored higher than those in Minnesota (p < 0.001). There was no trend between written programs and interview responses. Written respiratory protection programs in the study sites did not provide the level of detail required OSHA. Interview responses representing hospital practices surrounding respiratory protection indicated that hospitals were aware of and following regulatory guidelines.

Hospital respiratory protection practices in 6 U.S. states: a public health evaluation study

BACKGROUND

Lessons learned from the influenza A (H1N1) virus revealed a need to better understand hospitals' respiratory protection programmatic practice gaps. This article reports findings from a multistate assessment of hospitals' adherence to the Occupational Safety and Health Administration's respiratory protection program (RPP) requirements and the Centers for Disease Control and Prevention's infection control guidance.

METHODS

Onsite surveys were conducted in 98 acute care hospitals in 6 U.S. states, including >1,500 hospital managers, unit managers, and health care workers. Descriptive statistics were used to assess hospital adherence.

RESULTS

Most acute care hospitals adhere to requirements for initial medical evaluations, fit testing, training, and recommended respiratory protection when in close contact with patients who have suspected or confirmed seasonal influenza. Low hospital adherence was found for respiratory protection with infectious diseases requiring airborne precautions, aerosol-generating procedures with seasonal influenza, and checking of the respirator's user seal. Hospitals' adherence was also low with follow-up program evaluations, medical re-evaluations, and respirator maintenance.

CONCLUSION

Efforts should be made to closely examine ways of strengthening hospitals' RPPs to ensure the program's ongoing effectiveness and workers' proper selection and use of respiratory protection. Implications for improved RPPs and practice are discussed.

Evaluation of Minnesota and Illinois hospital respiratory protection programs and health care worker respirator use

The objective of this study was to assess respiratory protection programs for aerosol-transmissible diseases in acute care hospitals for conformance with regulatory requirements and public health guidelines. Twenty-eight representative hospitals were selected by size, location, and ownership in Minnesota and Illinois. Interviews were conducted with 363 health care workers and 171 managers from high-risk departments. Written programs from each hospital were reviewed for required elements. Seventy-seven health care workers were observed donning and doffing a FFR. The most serious deficiency in many written programs was failure to identify a program administrator. Most written programs lacked adequate details about medical evaluation, fit-testing, and training and did not include a comprehensive risk assessment for aerosol transmissible diseases; tuberculosis was often the only pathogen addressed. Employees with the highest probability of tuberculosis exposure were most likely to pick a respirator for close contact, but higher levels of respiratory protection were rarely selected for aerosol-generating procedures. Surgical masks were most commonly selected for close contact with droplet disease- or influenza-infected patients; better protection (e.g., respirator) was rarely selected for higher-risk exposures. Most of the observed health care workers had access to a NIOSH-certified N95 FFR, properly positioned the facepiece, and formed the nose clip. The most frequent deficiencies were failure to correctly place straps, perform a user seal check, and remove the respirator using straps.

MS2 Coliphage as a Surrogate for 2009 Pandemic Influenza A (H1N1) Virus (pH1N1) in Surface Survival Studies on N95 Filtering Facepiece Respirators

Research on influenza viruses regarding transmission and survival has surged in the recent years due to infectious emerging strains and outbreaks such as the 2009 Influenza A (H1N1) pandemic. MS2 coliphage has been applied as a surrogate for pathogenic respiratory viruses, such as influenza, as it's safe for personnel to handle and requires less time and labor to measure virus infectivity. However, direct comparisons to determine the effectiveness of coliphage as a surrogate for influenza virus regarding droplet persistence on personal protective equipment such as N95 filtering facepiece respirators (FFRs) are lacking. Persistence of viral droplets deposited on FFRs in healthcare settings is important to discern due to the potential risk of infection via indirect fomite transmission. The objective of this study was to determine if MS2 coliphage could be applied as a surrogate for influenza A viruses for studying persistence when applied to the FFRs as a droplet. The persistence of MS2 coliphage and 2009 Pandemic Influenza A (H1N1) Virus on FFR coupons in different matrices (viral media, 2% fetal bovine serum, and 5 mg ml-1 mucin) were compared over time (4, 12, 24, 48, 72, and 144 hours) in typical absolute humidity conditions (4.1 × 105 mPa [18°C/20% relative humidity (RH)]). Data revealed significant differences in viral infectivity over the 6-day period (H1N1- P <0.0001; MS2 - P <0.005), although a significant correlation of viral log10 reduction in 2% FBS (P <0.01) was illustrated. Overall, MS2 coliphage was not determined to be a sufficient surrogate for influenza A virus with respect to droplet persistence when applied to the N95 FFR as a droplet.

Considerations for recommending extended use and limited reuse of filtering facepiece respirators in health care settings

Public health organizations, such as the Centers for Disease Control and Prevention (CDC), are increasingly recommending the use of N95 filtering facepiece respirators (FFRs) in health care settings. For infection control purposes, the usual practice is to discard FFRs after close contact with a patient ("single use"). However, in some situations, such as during contact with tuberculosis patients, limited FFR reuse (i.e., repeated donning and doffing of the same FFR by the same person) is practiced. A related practice, extended use, involves wearing the same FFR for multiple patient encounters without doffing. Extended use and limited FFR reuse have been recommended during infectious disease outbreaks and pandemics to conserve FFR supplies. This commentary examines CDC recommendations related to FFR extended use and limited reuse and analyzes available data from the literature to provide a relative estimate of the risks of these practices compared to single use. Analysis of the available data and the use of disease transmission models indicate that decisions regarding whether FFR extended use or reuse should be recommended should continue to be pathogen- and event-specific. Factors to be included in developing the recommendations are the potential for the pathogen to spread via contact transmission, the potential that the event could result in or is currently causing a FFR shortage, the protection provided by FFR use, human factors, potential for self-inoculation, the potential for secondary exposures, and government policies and regulations. While recent findings largely support the previous recommendations for extended use and limited reuse in certain situations, some new cautions and limitations should be considered before issuing recommendations in the future. In general, extended use of FFRs is preferred over limited FFR reuse. Limited FFR reuse would allow the user a brief respite from extended wear times, but increases the risk of self-inoculation and preliminary data from one study suggest that some FFR models may begin to lose effectiveness after multiple donnings.