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)