Ronald Shaffer, Ph.D.
Centers for Disease Control and PreventionNational Institute for Occupational Safety and HealthNational Personal Protective Technology Laboratory
Progress Toward a “B95” Respirator for Healthcare Workers
Interagency Board
February 6, 2013, New Orleans, LA
Outline
· Overview of respiratory protection in healthcare
· Project BREATHE
· Progress toward a “B95” respirator standard
Background· N95 Filtering Facepiece Respirators (FFRs) are often
used by healthcare workers (HCWs), first receivers, and staff performing pre-hospital care to reduce their exposure to infectious aerosols
When should a respirator be worn?· Respirators should be worn when in close contact with
patients suspected of having an aerosol transmitted disease- Avian influenza (strains capable of causing serious disease in
humans)
- Varicella disease (chickenpox, disseminated shingles)
- Measles
- Monkeypox
- Severe acute respiratory syndrome (SARS)
- Smallpox
- Tuberculosis (TB)
· Note: Specific infection control guidance can vary by jurisdiction
FFR Basics· Inward leakage = filter penetration +
face seal leakage
· OSHA Assigned Protection Factor = 10
· Entire facepiece is composed of the filtering medium
· Designed to form tight face seal
· Approximate cost: <~$2 each
· Disposable
· NIOSH 42 CFR Part 84
· FDA “Surgical N95 respirator”
Example Electret Filter Media
· Melt blown - Corona charged (A)
· Melt blown - Highly charged (B)
· Extruded - Split film fiber (C)
· Melt blown - Highly charged (D)
http://www.cdc.gov/niosh/npptl/researchprojects/pdfs/NanoparticleFinalReport041006.pdf
Conventional Single-Fiber Filtration Theory
Filtration of Aerosols with Viable H1N1 Influenza Virus
Avg. Filtration Efficiency (N95 FFR)
Avg. Filtration Efficiency (P100 FFR)
0.8 µm bead 99.85% 99.999%
H1N1 influenza 99.27% 99.998%
• FFRs provided equivalent filtration efficiency for inert bead and viable H1N1 influenza aerosols (p > .05)
• NIOSH approved FFRs with N95 and P100 NIOSH performance ratings provide expected levels of filtration performance against tissue culture adapted H1N1
Face Seal Leakage
• FFR leaks are most common at the nose and cheeks• Studies have shown that face seal leakage > filter
penetration for FFRs
Compliance is Critical· Poor
compliance (e.g., non-use) reduces respirator effectiveness
· Wear time needs to be > ~75% to see a significant difference in exposure reduction Source: adapted from American Industrial Hygiene Association
Respiratory Protection Committee – Terms and DefinitionsNote: values for surgical mask approximate – for illustrative purposes only
Problems & Solutions
Reasons for Non-Compliance
Lack of accountability for non-compliance
Workload issues
Time constraints
Risk perception
Effectiveness concerns
Availability
Uncomfortable
Interference with patient care
Inability to communicate
Possible Ways to Improve Compliance
Improve safety culture
Better training strategies and interventions
Develop & communicate clear recommendations
Study modes of transmission
Conduct effectiveness studies
Faster fit test methods
Better PPE (e.g., Project BREATHE)
Project BREATHE - Better Respirator Equipment using Advanced
Technology for Healthcare Employees · Objective: To improve HCW
respirator compliance
· Approach: Develop (1) information products, (2) respirator performance requirements, and (3) advanced technologies for the next generation of HCW respirators that are more comfortable and tolerable
· Partnership: Veterans Health Administration (VHA)
Project BREATHE Working Group· Identified 28 “Idealized”
characteristics
· Respirators should:- Perform their intended functions safely and
effectively (9 requirements identified including fit & reusability/fomite concerns)
- Support, not interfere with, occupational activities (5 requirements… speech, hearing, etc.)
- Be comfortable and tolerable for the duration of wear (10 requirements… breathing resistance, facial pressure, etc.)
- Comply with current standards and guidelines (4 requirements… OSHA, NIOSH, FDA)
http://www.publichealth.va.gov/docs/cohic/project-breathe-report-2009.pdf
Project BREATHE Working Group· Healthcare is a unique environment with
challenges different from that of industrial workplaces
· Need a new type of respirator (“B95”) designed specifically for HCW
· Path forward:
1. Develop clinically-validated “B95” test methods
2. “B95” prototype development
3. “B95” standards development
NIOSH Comfort Research (2009-)FFR Design
· Surgical masks worn over 1 h at low-moderate work rates have physiological impact similar to N95 FFRs
· Generally no advantage to EVs at these work rates
· Moisture retention in N95 FFR is <0.3 grams over 2 hours of wear and does not impact airflow resistance
· Computer modeling data indicate that areas of highest facial pressure overlap with prior NPPTL thermal imaging data of leak sites on N95 FFR
Microenvironment
· At low-moderate work rates over a 1 h period, wearing an N95 FFR minimally increases core temperature (<0.12 °C), heart rate (<12 bpm), breathing rate (< 2 bpm), and transcutaneous CO2 (< 3.9 mm Hg), whereas O2 saturation is not impacted measurably.
· Deadspace temperature and humidity at 1 h are markedly elevated over ambient levels
· Deadspace CO2 and O2 levels are not in compliance with OSHA workplace ambient air standards
“B95” prototype development · Project BREATHE
- VHA solicited partners (2009)
- 3M pilot testing (Jan – March 2013)
- “B95” prototypes (Summer 2013)
· Other respirator concepts- Collaborations with Georgia Tech
on BARDA broad agency announcement
Standards Development · Changes to federal standards (e.g., 42 CFR Part 84) can
be time-consuming
· Voluntary consensus standards development organizations (SDO) can fill this gap
· Successful implementation of a voluntary consensus standard requires “remediable-ness” and “legitimacy”
· In some industries, voluntary standards become “quasi-mandatory”
“B95” Standards Development · 42 CFR Part 84 sets the minimum respirator
performance requirements for all workplaces; nothing specific for healthcare
· Voluntary consensus standards can fill this gap
- SDO sets additional requirements for specific workplaces (e.g., healthcare, fire), but requires NIOSH certification as the baseline
- Similar concept used by NFPA for firefighter SCBA
- B95 would be optional for manufacturers
· A successful standard would benefit all parties
Rationale for DRAFT B95 Requirements, Test Methods, and
Pass/Fail Criteria · Starting point - the initial 28 requirements outlined in the
2009 Project BREATHE report
· Re-prioritized the requirements based upon several factors including: - Covered by existing federal standard (FDA, NIOSH)
- Practical – access to test equipment & cost
- Likely to correlate with clinical data (end-user expectations)
- Use peer-reviewed science when possible
· Pass/Fail Criteria: Informal feedback from many users suggest the 3M 1870 is a good baseline
Safety & Effectiveness
Requirement Test Method Criterion
Respirator fit 35 person fit test panel
> 75% (26/35) of subjects pass the fit test
Reuse / Gauging Fit
Measure fit from 10 repeated donnings on a headform
GM fit factors > 100
Advanced Headform for Total Inward Leakage Measurements
Collaboration with DoD (AFRL). Funded by BARDA.
Occupational Interference
Requirement Test Method Criterion
Hearing integrity
Practical performance test?
TBD
Speech intelligibility
Practical performance test?
TBD
Visual field Practical performance test?
TBD
Equipment compatibility
Practical performance test?
TBD
Note: still working with the VHA to better define the requirements, test methods, and pass/fail level.
Comfort – Machine TestsRequirement Test Method Criterion
Breathing resistance
Filter airflow resistance (TSI 8130)
< 10 mm H2O
Air Exchange Average inhaled CO2 < 3%
Average inhaled O2 > 16.5%
Note: measuring inhaled CO2 and O2
using the NIOSH automated breathing & metabolic simulator (0.5 l/min oxygen consumption)
Comfort – Human Subject Requirement Test parameter Criterion
Air exchange Transcutaneous CO2
< 4 mm Hg increase over baseline
O2 saturation < 1% decrease over baseline
Facial heat Air temp inside FFR < 2.5°C increase over baseline
Skin (cheek) temp inside FFR
< 2.5°C increase over baseline
Moisture management
Moisture retention < 4% of respirator weight (g) / hr
Comfort – Human Subject· “Roberge” protocol - 20
subjects walking on treadmill for 1 hr at 3.5 mph (low-moderate work rate)
· Other test parameters still being considered (subjective rating scales, strap tension)
Next Steps· In collaboration with stakeholders, continue
improvement of “B95” requirements , test methods, and criteria (2013-2014)- Focus of discussions at the NIOSH Healthcare Stakeholder
Meeting June 18 (Atlanta, GA)
· Use draft B95 test methods to assess the Project BREATHE B95 prototypes (Summer/Fall 2013)- Opportunity to validate NPPTL’s lab-based test methods
against VHA’s clinical setting simulator data
· Contact SDOs (ASTM, ISO, NFPA, ISEA, etc.) to determine interest in developing “B95” standard that exceeds NIOSH N95 requirements (~2014)
Acknowledgements
· IAB & Bill Haskell for the invitation
· VHA’s Center for Occupational Health and Infection Control (COHIC): Lew Radonovich, Megan Gosch, and Aaron Eagan
· NPPTL/TRB Respiratory Protection Team: Ziqing Zhuang, Mike Bergman, Ed Fisher, and Andy Palmiero
· NPPTL/TRB Human Performance Team: Ray Roberge, Jon Williams, Kenny Kim, and Eddie Sinkule
Quality Partnerships Enhance Worker Safety & Health
Visit Us at: http://www.cdc.gov/niosh/npptl/
Disclaimer:
The findings and conclusions in this presentation have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.
EXTRA SLIDES
Project BREATHE and Related Comfort Research Publications (2010-2012)
1. Roberge, et al. [2010] Physiological impact of filtering facepiece respirators (“N95 Masks”) on healthcare workers. Respiratory Care; 55(5):569-577.
2. Roberge, et al. [2010] Surgical mask placement over N95 filtering facepiece respirators: Physiological effects on health care workers. Respirology; 15:516-521
3. Roberge, et al. [2010] Reusable elastomeric air-purifying respirators: Physiologic impact on health care workers. Am J Infect Control, 38: 381-386.
4. Roberge, et al.. [2010] Earlobe and fingertip oxygen saturation measurements of healthcare workers wearing protective masks. Respiratory Therapy- Journal of Pulmonary Technique, Vol. 6(4):26-29.
5. Roberge, et al. [2010]. Effect of exhaled moisture on breathing resistance of N-95 filtering facepiece respirators. Ann. Occup. Hyg 54,6:671-677.
6. Lei, et al. [2010]. Contact Pressure Study of N95 Filtering Facepiece Respirators Using Finite Element Method. Computer Aided Design and Applications, 7(6): 847-861.
7. Dai, et al. [2011]. Sensitivity Analysis of Important Parameters Affecting Contact Pressure between a Respirator and a Headform. International Journal of Industrial Ergonomics 41, 268-279
8. Roberge R [2011]. Facemask use by children during infectious disease outbreaks. Biosecurity and Bioterrorism: Biodefense Strategy, Practice, and Science (9)3: 225-231.
9. Roberge, et al. [2011] Infrared imaging for leak detection of N95 filtering facepiece respirators: a pilot study. Am J Indust Med 54:628-636.
10. Roberge, et al. [2012]. Protective facemask impact on human thermoregulation: An overview. Ann Occup. Hyg 56(1): 102-112.
11. Lei, et al. [2012]. Headform and N95 filtering facepiece respirator interaction: contact pressure simulation and validation. JOEH 9:1,46-58.
12. Roberge, et al. [2012] N95 Filtering Facepiece Respirator Deadspace Temperature and Humidity, J Occup Environ Hyg 9:166-171.
13. Roberge, et al. [2012]. Absence of consequential changes in physiological, thermal and subjective responses from wearing a surgical mask. Respiratory Physiology and Neurobiology, 181:29-35.
14. Roberge,et al. [2012]. Thermal burden of N95 filtering facepiece respirators. Ann Occup. Hyg 56(7):808-814.
15. Niezgoda et al. [2012]. Analysis of forces generated by N95 filtering facepiece respirator tethering devices: a pilot study. J Occup Environ Hyg 9:517-523.
16. Kim et al [2013] Pulmonary and heart rate responses to wearing N95 filtering facepiece respirators. Am J Infect Control 41:24-27”.
17. Niezgoda, et al [2012]. Forces generated by N95 Filtering Facepiece Respirator straps. J Int Soc Resp Protect (in press)
18. Rozzi et al, [2012] Aromatic Hydrocarbon Adsorption Characteristics of Disposable FFRs that Contain Carbon, J Occup Environ Hyg (in press).
19. Roberge R , [2012] Are exhalation valves on N95 filtering facepiece respirators beneficial at low and moderate work rates: an overview J Occup Environ Hyg 2012;9:617-623.
20. Lei et al, [2013] Simulation of Respirator Face Seal Leaks using CFD and IR imaging Ann Occup Hyg (in press) doi:10.1093/annhyd/mes 085
21. Gosch et al, B95: a new respirator for healthcare personnel (submitted to American Journal of Infection Control)
22. Niezgoda, et al.. [2013] Flat fold and cup-shaped N95 FFR face seal area and pressure determinations: a stereophotogrammetry study. J Occup Environ Hyg (in press)
23. Sinkule et al., [2013] Evaluation of N95 Respirator Use with a Surgical Mask Cover: Effects on Breathing Resistance and Inhaled Carbon Dioxide. Ann. Occup,. Hyg. 2012. (in press)