As pandemic threats emerge, will better respirators be ready?
'The best respirator ever – if it's not used – is not going to help the worker.'
A patient with influenza coughs. Viral particles fly across the room and linger in the air. A health care worker walks into the room and breathes in the invisible contaminant.
That scenario illustrates some of the concerns about transmission of influenza and the challenge of protecting health care workers. With an eye on the possibility of a new influenza pandemic – and a new SARS-like virus emerging in the Mideast – researchers and safety experts recently met in Atlanta to discuss respiratory protection in health care.
They acknowledged gaps – in knowledge of disease transmission, in the comfort of respirators, and in the compliance of health care workers.
"We have a lot of unknowns in health care that need to be addressed," said Maryann M. D'Alessandro, PhD, associate director for science at the National Personal Protective Technology Lab (NPPTL) of the National Institute for Occupational Safety and Health, at a stakeholder meeting.
"A lot of research is dedicated to [learning about transmission of respiratory diseases] and the answers are still not there," she said.
Yet progress is being made toward improving respirators. Manufacturers are developing prototypes of respirators designed to be more comfortable for health care workers. NIOSH is moving forward with a "total inward leakage" rule that will add fit as a criterion for respirator certification. And researchers are developing elements and test methods that could be the basis for a B95 respirator – to specifically protect against biologics.
"Health care is a unique environment with different challenges," said Ron Shaffer, PhD, senior scientist with NPPTL. "You really need to have a respirator designed specifically for health care."
Gap in compliance
NIOSH has typically hosted a stakeholders' meeting on respiratory protection that addresses several major industries. But the agenda of this health care-only meeting revealed some of the specific concerns in the hospital setting, where a pandemic could require employees to wear a respirator for hours at a time.
It was a good news-bad news report. N95 filtering facepiece respirators are highly protective, said William Lindsley, PhD, a NIOSH research biomedical engineer. "If you're wearing an N95 and it fits right, virtually nothing is going to get through that," he said.
But often, health care workers don't know when or why they need to use respirators – or how to use them properly, said Kristina Peterson, director of the occupational safety and health program at RTI International in Research Triangle Park, NC.
"The biggest gap and the lowest rates of adherence involved aerosol-generating procedures with patients who have seasonal influenza," said Peterson, who reported on the REACH II study that involved interviews with 1,105 health care workers and 260 managers at 98 hospitals in six states.
The Centers for Disease Control and Prevention advises health care workers to wear a face mask for routine care of patients with seasonal influenza (droplet precautions) but calls for an N95 or greater protection when performing aerosol-generating procedures.
CDC recommends airborne precautions (gowns, gloves, eye protection and respiratory protection of an N95 or greater) when caring for patients with suspected or confirmed novel Middle East Respiratory Syndrome (MERS-CoV) or H7N9 influenza. (As of mid-July, neither disease had been detected in the United States.)
Donning and doffing the respirator is also a problem, Peterson said. Health care workers are especially lax about user seal checks, which are supposed to occur every time a respirator is worn, and proper removal of respirators, she said. Respiratory protection programs need better monitoring and evaluation, she said.
"Our conclusions are that all hospital staff need to have more information about a number of topics," including transmission risk, airborne precautions and proper respirator use, she said.
A better-fitting respirator
Fit-testing has been another troublesome area for hospitals, but employee health professionals may find greater success with fit-testing once NIOSH adds fit as a criterion. The proposed total inward leakage rule, first released in 2009, is being revised based on comments from stakeholders and further scientific research, said D'Alessandro.
The rule would set a strict limit for how much of an air contaminant could penetrate a respirator – both through the filter and face seal. The goal is to have N95 filtering facepiece respirators that fit better right out of the box – which would mean fewer failures in fit-testing, safety experts say.
NIOSH has scheduled a stakeholders' meeting on September 17 in Pittsburgh to discuss changes in the proposed rule, which largely relate to the human test panels used to determine fit, D'Alessandro said.
Meanwhile, NIOSH is trying to determine a set of tests that could be used to certify a specific B95 half-mask filtering facepiece respirator for health care. They would likely include comfort-related issues such as breathing resistance and facial heat, says Shaffer.
But a proposed B95 rule is still well in the future, Shaffer and other NIOSH researchers acknowledged. "We need more data, and we need to be able to prove we can produce a better respirator," said Ziqing Zhuang, PhD, acting branch chief of the NPPTL Research Branch.
NIOSH also is considering a health care version of the powered air-purifying respirator (PAPR), which would be light-weight, less noisy and more comfortable.
In addition, two manufacturers say they have made progress toward a prototype of a better N95. One innovation: New respirators may be made of different materials.
"Higher performance filter media will help allow us to reduce respirator thickness, weight and pressure drop, increase comfort and service life, and expand our design options," Lauri Alvarez, senior technical service engineer at 3M in St. Paul, MN, said at a meeting sponsored by the National Personal Protective Technology Lab (NPPTL) of the National Institute for Occupational Safety and Health.
Scott Safety of Monroe, NC, has experimented with design changes that make it easier for health care workers to remove a respirator without contaminating their hands and would enable respirators to be reused.
Georgia Institute of Technology also is experimenting with a form-fitting device that would not need to be fit-tested.
The new respirator design emerged from Project BREATHE (Better Respiratory Equipment using Advanced Technologies for Healthcare Employees), which was initiated by the Veterans Health Administration.
A better respirator for health care will need to be accompanied by an awareness and education campaign to encourage the proper use, Shaffer said.
"Even if we build the best respirator ever, if it's not used it's still not going to help the worker in reducing their exposure," he said.
[Editor's note: More information about the NPPTL meeting is available at www.cdc.gov/niosh/npptl/resources/certpgmspt/meetings/06182013/HealthcareInvitationLttr06182013.html.]
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MERS update: Use N95s The Centers for Disease Control and Prevention recommends standard, contact and airborne precautions when caring for hospitalized patients with known or suspected Middle East Respiratory Syndrome Coronavirus (MERS-CoV). That means health care workers should wear gloves, gowns, goggles or face shields, and respiratory protection at least as protective as an N95 respirator when they enter a patient room or care area, CDC says. Patients should be placed in an airborne infection isolation room and should wear a face mask when they are not in an airborne infection isolation room. CDC suggests evaluating anyone who develops severe acute respiratory illness that is not explained by some other cause if they have traveled to the Arabian Peninsula or neighboring countries or had close contact with someone who traveled to that region within 14 days. Information updates are available at www.cdc.gov/coronavirus/mers/index.html. |
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