Are your HCWs using the right respirator?
Match the hazard to the mask, experts say
Are you providing your employees with adequate respiratory protection? Too often the answer is no, some respiratory protection experts worry. But matching the right device to the hazard remains a difficult task, fraught with conflicting guidance.
For example, in the draft tuberculosis guidelines, expected to become final later this year, the Centers for Disease Control and Prevention (CDC) says hospitals should consider using a higher level of respiratory protection than an N95 filtering facepiece respirator during bronchoscopies with TB patients. Yet some infection control practitioners question the role of respiratory protection in preventing transmission of TB.
Meanwhile, the American National Standards Institute (ANSI) is finalizing a new standard that lowers the assigned protection factor (APF) for N95 filtering facepiece respirators, which would indicate they are half as effective as previously thought.
The U.S. Occupational Safety and Health Administration (OSHA) is finalizing a standard that would keep the APF the same.
Hospitals need to take a serious look at the level of respiratory protection they are providing, says James Johnson, PhD, CIH, QEP, chemical and biological safety section leader at Lawrence Livermore National Laboratory in Livermore, CA.
"If we have a terrorist event, your profession is critical to survival," he adds. "If you don't understand respirators and that safety is compromised because of something simple like not understanding fit-testing or respiratory protection, what a tragedy!"
But sorting out the respiratory risk from other means of transmission is complex. In fact, if a health care worker is uncomfortable and readjusts a mask with contaminated, gloved hands, the device actually may raise the risk of transmission, notes Linda Chiarello, RN, MS, of CDC's division of health care quality promotion.
"If we make using personal protective equipment so cumbersome, people break the technique," she adds.
What does OSHA say about choosing respiratory protection?
"We would always err on the side of safety," notes Craig Moulton, industrial hygienist with OSHA's division of health enforcement.
There are several factors to consider when assessing the need for respiratory protection:
•The health care workers
In the case of an infectious disease outbreak, you want to preserve your health care work force. Although debate continues about whether nurses contracted severe acute respiratory syndrome (SARS) from a respiratory route in the Toronto outbreak in 2003, it's clear that respiratory protection was an important part of the protective gear.
"Staff want to be protected, just like an employee who goes into a chemical hazard wants some protection," says Gabor Lantos, MD, PEng, MBA, president of Occupational Health Management Services, a consulting practice in Toronto.
"If staff do not feel adequately protected, they're just not going to show up for work," he says. "If there's another SARS, or the next bug, [and] if people aren't going to feel adequately protected, we're looking at maybe 25% turnout. People will just call in sick."
Create clear protection policies
Set up a multidisciplinary committee to look at respiratory protection, Lantos advises. The committee should include infection control, occupational health, industrial hygiene (even if you have to contract with an independent provider), purchasing, and a ventilation expert, he says.
That panel should create clear policies on who needs respiratory protection and when they should wear it, Lantos says.
You need to make sure those personnel are adequately trained in how to use the devices and that there are backup staff who can relieve them, if necessary, he adds. An N95 only can be worn for about two to four hours before becoming too uncomfortable, Lantos explains.
"You have to have designated people who are going to respond to airborne infections," he says. "You can't have three different housekeepers rotating through an area and assume everyone's equally qualified. You need a certain number of people who are trained to do this properly."
•The infectious disease
CDC recommends respiratory protection only for diseases with a known or suspected capacity for airborne transmission. That includes TB, SARS, viral hemorrhagic fevers, and smallpox. CDC's draft Guidelines for Isolation Precautions also recommends using N95 filtering facepiece respirators for avian influenza.
The agency also advises, "Due to the increased risk of M. tuberculosis during the performance of bronchoscopy procedures on patients with TB disease, consider using a higher level of respiratory protection than an N95 disposable respirator such as an elastomeric full-facepiece respirator or a PAPR [powered air purifying respirator]."
But what if you don't know whether the patient has one of those respiratory illnesses, or some new infectious disease that has not been previously encountered?
CDC guidelines recommend that coughing patients use "respiratory etiquette" — cover their mouths and, if possible, wear a surgical-type mask. Health care workers in close contact with coughing patients should wear masks also, the CDC says.
"If you really don't know what you're being exposed to and its means of infection — is it a droplet nuclei, or is it an aerosol? — the thing to do is to err on the side of caution and use, as a minimum, an N95 respirator," says John Steelnack, MS, an industrial hygienist and project officer of OSHA's respiratory standard revision.
"You can always remove them later, but you can't put them on later if you should have been wearing them," he notes.
There are other complicating factors related to infectious disease transmission. Chemical exposures can be calculated, and permissible exposure limits can be set based on toxicity. But infectious doses cannot be quantified in the same way. One person may become infected after a small exposure; another person may never become infected despite repeated exposure.
Patients' transmissibility varies. The so-called "superspreader" phenomenon has been documented with SARS and TB.
Mark Nicas, PhD, MPH, CIH, industrial hygiene program director in the environmental health sciences division at the University of California at Berkeley, is working with a subcommittee of ANSI to develop a standard related to respiratory protection and infectious aerosols.
When it comes to infectivity and superspreaders, "I say you treat all people as if they're highly infectious unless proven otherwise," he suggests.
Nicas argues that the risk of infection can be calculated by using estimates of the airborne concentration of an organism, the duration of exposure, the probability of infection with a given dose, and the leakage properties of the respirator.
He says that CDC and OSHA avoid trying to quantify the risks. "Instead, they [say] things like ‘The risk is low' without ever identifying what they mean by low, or ‘This respirator is acceptable' without saying what they mean by acceptable risk," Nicas continues. "You need to know something about the risk without the respirator and then you need to know what the acceptable risk is."
Infection control experts contend that other measures are much more important in preventing transmission and that it's not clear how much additional protection the respirators provide.
Outbreaks have been controlled by early identification of patients and isolation of patients in negative pressure rooms, Chiarello adds. Surface contamination and inadvertent touching of the mouth or eyes with contaminated hands may be of much greater concern, she says.
Chiarello was in Vietnam during the SARS outbreak and notes, "Nobody was wearing a fit-tested respirator. People weren't even putting them on appropriately. Respiratory protection had nothing to do with interrupting transmission of SARS."
Every N95 respirator is not equal. Some have better inherent fit characteristics. That is, they are more likely to fit well without a fit-test or to pass fit-tests than others. Everyone's facial shape is different, and some respirators will tend to fit a given population better than others.
It is crucial for health care workers to know the brand and size of the respirator that fits them best — and to use that at all times when they need a respirator.
"The whole purpose of the respiratory protection program is to provide the worker with the right respirator and training so they can wear it properly and safely," says Johnson, of the Lawrence Livermore National Laboratory. He also is chair of the ANSI Z-88 secretariat, which sets voluntary respirator standards.
"In the long term, when you look at the benefits over the negatives, annual fit-testing is a really good investment as part of a respiratory protection program," he adds.
"It familiarizes the worker with the mask, [and] it demonstrates and provides data that the mask fits. It also provides the opportunity for hands-on training," Johnson explains.
Hospitals need to select the respiratory protection that matches the hazard. Surgical masks are used only for barrier protection against droplets and provide no respiratory protection, he notes. "I've seen anywhere from 70% to 90% leakage for surgical masks," Johnson says.
N95 filtering facepiece respirators are the lowest level of respiratory protection available.
If the APF for the masks is 5, that means 20% of contaminants can penetrate the mask from leakage around the face seal. If the APF is 10, then only 10% of the contaminated air can leak through.
Elastomeric full-facepiece respirators have an APF of 50, which means they have a leakage value of 2%. The hood-type PAPRs have an APF of 25, which means they have a leakage of 4%.
In other industries, the selection of a respirator is based on the concentration of a toxic substance in the air and the permissible exposure limit.
However, there are no permissible exposure limits for infectious diseases. Infection control practitioners argue that infectious agents can't be treated the same way as construction dust or other industrial contaminants.
But by regulation, they are.
"Right now, we really don't have enough information to separate [bioaerosols] out from the respirator standard," Steelnack adds.