Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases Personal Protective Equipment for Healthcare Personnel: Update 2010 (2011) / Chapter Skim
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3 Designing and Engineering Effective PPE
3 Designing and Engineering Effective PPE
Pages 71-112
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From page 71... ...
This chapter focuses on research on designing and engineering effective PPE. The chapter begins with a brief overview of the 2008 report, followed by a synopsis of research that has been conducted in the past several years.
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From page 72... ...
• Facilitates communication with others (verbal, facial) • Variety of styles • Product cost • Easy to • Total lifecycle and colors • Customizable decontaminate and cost • Minimal environ discard disposable elements mental impact • Easy to clean and replace parts in reusable PPE FIGURE 3-1 A structured approach to evidence-based performance requirements for personal protective equipment (PPE)
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From page 73... ...
, follow standard particle filtration theory, and therefore a number of types of filters are effective. Less is known about issues regarding inward face seal leakage and other aspects of respirator fit.
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From page 74... ...
. Healthcare personnel's use of gloves can serve several purposes in infection control -- creating a barrier to direct contact with contaminated surfaces, preventing patient-to-patient contamination if gloves are changed between patients and proper hand hygiene is performed, and increasing awareness of the potential for self-inoculation when gloved hands touch the mucosa of the mouth, nose, or eyes.
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investigated the protection factor of face masks and respirators with a challenge of particles representing bacterial and viral size ranges (aerodynamic size: 0.04 to 1.3 µm) and found that none of the masks had protection factors > 10.
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From page 76... ...
The authors suggested that further research is needed with cyclic flows with high peak inspiratory flows. A study of the filtration performance of five N95 and two P100 filtering facepiece respirators against monodisperse silver aerosol particles 1 The MPPS is the particle size that has the lowest filtration efficiency.
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From page 77... ...
They performed the same against the inert beads. The authors concluded that infectious microorganisms and inert particles of the same size have the same impact on the filtering efficiency of filtering facepiece respirators.
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From page 78... ...
. NIOSH- or European Norm–certified filtering facepiece respirators achieved expected filtration performance when challenged with nanoparticle aerosols (Eninger et al., 2008a; Eshbaugh et al., 2009; Rengasamy et al., 2008, 2009)
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From page 79... ...
None of the masks tested attained an individual fit factor of 100, the minimum passing level required by the Occupational Safety and Health Administration (OSHA) for a half-mask filtering facepiece respirator.
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From page 80... ...
Janssen and colleagues (2007) evaluated the workplace protection factor of an N95 filtering facepiece respirator during light, moderate, and heavy intensity tasks in a steel foundry and found a large variability in protection because of removing and re-donning the respirator.
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From page 81... ...
Further research on leakage of nanoparticles is important to better understand the effectiveness of filtering facepiece respirators in workplaces where nanoparticles are present.
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From page 82... ...
Sealing an N95 to the source using Vaseline® yielded a simulated workplace protection factor of 4,082, and sealing it to the receiver resulted in a protection factor of 118. The authors concluded that the face masks worn at the source resulted in greater protection than a face mask or respirator worn on the receiver.
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identified the need for a user seal check that works, continuous fit checking rather than a no-fit test, and a respirator that can be put on easily multiple times.
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. Respirators: Decontamination Reuse of filtering facepiece respirators has been suggested as a strategy to counteract anticipated supply shortages during a pandemic and to reduce costs.
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on three models each of N95, P100, and surgical N95 filtering facepiece respirators. Ethylene oxide and UV germicidal irradiation were the only methods that did not cause any observable physical changes to the respirators.
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assessed the amount of residual chemicals on six models of filtering facepiece respirators after seven decontamination methods: ethylene oxide, vaporized hydrogen peroxide, UV light, and four liquids (hydrogen peroxide, bleach, mixed oxidants, and dimethyl dioxirane)
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From page 87... ...
Additional research with enveloped influenza viruses is needed. Treated Filter Media Several studies investigated the decontamination efficacy of treated filter media.
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From page 88... ...
Protective equipment, such as respirators or face shields, may create pressure points that cause discomfort. The breathing resistance and dead volume of the respirators may alter respiration and lead to a build-up of carbon dioxide.
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Although most healthcare personnel appear to be assigned N95 respirators for use, elastomeric respirators represent an alternative type of respiratory protection that could be used. Roberge and colleagues (2010c)
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Overall, 56 percent of respondents believe there is a need to develop a new N95 respirator for healthcare personnel, 44 percent preferred an N95 that does not require fit testing, and 60 percent preferred wearing a
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From page 91... ...
Vojtko and colleagues (2008) found small but statistically significant increases in both inhalation and exhalation resistances of a face mask placed over an N95 filtering facepiece respirator for minute volumes of 25 and 40 L/min, but the total did not exceed NIOSH limits (although those are measured at 85 L/min)
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From page 92... ...
The authors did note that face masks decreased oxygen levels in the filtering facepiece respirators at the low work rate and in the respirators with the exhalation valves at the higher work rate. An elastomeric air-purifying respirator resulted in decreased breathing rates and higher tidal volumes at both work rates, although the minute ventilation did not differ.
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From page 93... ...
The second set of trials was performed with elastomeric respirators with and without exhalation valves in an audiometric test room with background noise. All six respirators had scores significantly different from the control, and the three respirators with speech augmentation performed better than those without augmentation.
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The quietest PAPR had the lowest error rates. Their N95 tests with two filtering facepiece respirators and one elastomeric respirator had error rates of 0 to 16 percent, though only 2 volunteers were used.
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Overarching recommendations for future research were to further investigate the relationship between respirator design and fit; to clarify the impact of facepiece design, facepiece sizes, and aging on the relationship between facial measurements and respirator fit; to determine how user seal check impacts respirator fit; to explore new methods for checking facepiece seals; and to determine the impact of environmental conditions and other protective equipment on respirator fit. The Department of Veterans Affairs is leading a collaborative effort with the National Personal Protective Technology Laboratory (NPPTL)
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From page 96... ...
studies showed any evidence of such a burden with N95 filtering facepiece respirators or elastomeric respirators. Respirators do impact communications.
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. A 2008 review of protective clothing for healthcare personnel highlighted additional issues that are considered in designing protective clothing, including antibacterial finishing treatments, the impact of temperature and relative humidity in the work environment, the use of multiple layers, and changes that can result from laundering or cleaning that might impact the protective effects of the clothing (Laing, 2008)
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From page 98... ...
Little is known about how well these devices protect the wearer from direct contact, when this protection is needed regarding transmission from patients to healthcare personnel, and the extent to which extra precautions are needed during aerosol-generating procedures. Face shields may be a useful form of protection in lieu of face masks for workers exposed to droplet spray, particularly regarding comfort and tolerability issues, reduced breathing resistance, and improved speech communication.
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From page 99... ...
and found that face masks, eye shields, and glasses worn by surgeons and scrub nurses had high incidence of blood and body-fluid splashes. Similar studies would be useful to evaluate the exposure of healthcare personnel to droplet spray during patient care and to assess which types and combinations of eye protection and face shields provide the greatest protection.
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From page 100... ...
No studies were performed that assessed the impact of filtering facepiece respirators, elastomeric respirators, or loose-fitting PAPRs on task performance. However, a filtering facepiece respirator or elastomeric respirator is unlikely to have a greater impact on task performance than a full-facepiece airpurifying respirator.
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From page 101... ...
Much research has been done regarding filtration of respirator media, but ways to improve fit, including new technologies specifically for filtering facepiece respirators, need more research because face seal leakage greatly exceeds filter penetration in the overall TIL of respirators. The physiological impact of respirators has been studied in-depth, but research in this area is lacking for other types of PPE.
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From page 102... ...
FINDINGS AND RESEARCH NEEDS This chapter provides an overview of the range of ongoing work on designing and engineering effective PPE to prevent transmission of influenza and other viral respiratory diseases. At its June 2010 workshop and through its literature review, the committee realized that many research efforts have been completed recently and that ongoing research efforts in this area continue.
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From page 103... ...
Fit: Evaluate the impact of facepiece materials and design on o improving the fit of filtering facepiece respirators. Develop improved and simpler fit testing methods.
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From page 104... ...
New technologies: Continue development of an air-purifying o respirator that specifically addresses the needs of healthcare personnel. New materials and technologies should be devel oped specifically for filtering facepiece respirators to im prove fit, comfort, and tolerability.
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American Journal of Infection Control 38(1)
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2009. Methods for the recovery of a model virus from healthcare personal protective equipment.
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2009. Development of a test system to apply virus-containing particles to filtering facepiece respirators for the evaluation of decontamination procedures.
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2007. Workplace protection factors for an N95 filtering facepiece respirator.
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2008. Implementing fit testing for N95 filtering facepiece respirators: Practical information from a large cohort of hospital workers.
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2009. Comparison of nanoparticle filtration performance of NIOSH-approved and CE-marked particulate filtering facepiece respirators.
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2010a. Surgical mask placement over N95 filtering facepiece respirators: Physiological effects on healthcare workers.
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2009. Challenge of N95 and P100 filtering facepiece respirators with particle containing viable H1N1.
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