Questions arise about pandemic use of respirators
Current models difficult to use, studies show
In an influenza pandemic, health care workers may find their respirators difficult to tolerate for long hours.1 Without additional training, they also are likely to forget how to don the respirator properly or even which respirator model they should wear.
Those are the findings of two recent studies that raise questions about the state of respiratory protection for health care workers. They underscore the need for respirators that are designed specifically for health care, researchers say.
"We expected to find one or two of the models we were using to be reasonably well tolerated so we could have health care workers wearing them for most of their work shift," says Lewis J. Radonovich, MD, director of the Center for Occupational Safety and Infection Control in the Veterans Health Administration and director of Biosecurity Programs at the Malcolm Randall Veterans Affairs Medical Center in Gainesville, FL.
"It doesn't matter what type of respirator you're wearing," he says. "Health care workers don't seem to tolerate them for long periods."
Health care worker confidence in their respiratory protection not only affects their safety on the job, but it could impact their willingness to work during a pandemic, Radonovich notes. "We would want to pick a respirator that is as comfortable as possible and effective," he says.
Meanwhile, Canadian researchers questioned large-scale efforts to fit-test health care workers. Employees who are fit-tested but then don't wear a respirator for six months or longer often forget how to wear them with the best fit.2
"Fit-testing large groups of people who then don't use the respirator might not be a good strategy," says A. Mark Joffe, MD, FRCPC, medical director of infection prevention services at Royal Alexandra Hospital in Edmonton.
"We looked at whether our employees could take a respirator out of the box, put it on and achieve an adequate fit," he says. "About half of them did. For employees who don't use the respirator very often, they don't do much better by fit-testing and training them than by just taking it out of the box."
Even surgical masks are uncomfortable
Being able to tolerate a respirator is vital to maintaining protection. In the epidemic of severe acute respiratory syndrome (SARS), health care workers found it difficult to wear N95 respirators continuously throughout their work shifts. Later reports speculated that some health care workers may have been contaminated through improper donning and doffing of the respirators.3
At the VA medical center, Radonovich and his colleagues asked 27 health care workers to wear respirators for eight hours, with breaks of 15 or 30 minutes every two hours. On different days, they wore a total of eight respirators or face masks, including a half-face elastomeric respirator, a powered air-purifying respirator (PAPR), an N95 filtering facepiece respirator with an exhalation valve, an N95 covered with a surgical mask, other common models of N95s, and a surgical mask. They were asked to imagine that they were in the midst of a pandemic.
"Approximately half of all the health care workers we studied were unable to tolerate the respirators they were asked to wear for the duration of eight hours," says Radonovich. Respirators also interfered with communication, he says.
Even the surgical mask was not well tolerated, even though it does not have a tight face seal and doesn't qualify as respiratory protection, he says. "Most of the health care workers weren't willing to wear the surgical mask for the whole work shift."
"We think that's in part because the people who participated in our trial were not accustomed to wearing any facial or respiratory protection for long periods," Radonovich says. Typically, health care workers will wear the respirators only when they enter a patient's room and then remove it after their encounter.
Health care workers might become accustomed to the respirators over time, he says.
In all, the PAPRs and N95s with an exhalation valve had the greatest tolerability. Yet the decision about pandemic preparedness takes into account cost and availability. The VA may decide to stockpile elastomeric respirators in addition to N95s, says Radonovich.
"In the event of a national or international crisis, when there is a shortage of disposable models, the reusable model has obvious advantages, even though the data from our work suggest there are tolerability problems with the reusable models as well," he says.
New respirator aims for a truly universal fit
FaceSeal uses medical-grade adhesive
A newly approved respirator may be the closest thing yet to a "universal fit." The new FaceSeal respirator (www.facesealtechnologies.com) uses a medical-grade adhesive to attach the mask to the face. The National Institute for Occupational Safety and Health (NIOSH) certified the mask in late 2008.
With its duckbill shape, it has more surface area than other masks, says Gabor Lantos, MD, PEng, MBA, president of Occupational Health Manage-ment Services in Toronto and director of PPE Development at FaceSeal Technologies, which also is based in Toronto. Lantos is a member of the Hospital Employee Health Editorial Advisory Board.
"Ours is easy enough to breathe through. Even at an N99 or N100, it does not require an exhalation valve to ease breathing," he says.
Because it has no straps and fits securely with the adhesive, the mask conforms to the contours of the face. The U.S. Occupational Safety and Health Administration still mandates initial and annual fit-testing, but Lantos is discussing a waiver of fit-test rules in two provinces in Canada.
The FaceSeal is designed for single use, but if necessary, it can be readhered, Lantos says.
Wearability is part of the NIOSH certification testing, and the testers didn't object to the adhesive, says Heinz Ahlers, JD, MS, chief of the Technology Evaluation Branch of NIOSH's National Personal Protective Technology Laboratory in Pittsburgh.
One advantage of the adhesive mask: It can't be put on upside down. It is actually common for workers to put their respirators on incorrectly, Ahlers says. "The right way to put a respirator on is not necessarily intuitive," he says. "Some respirator manufacturers require the upper strap to go very high up on your head to get the proper fit, others require it just to go above your ears."
Ahlers says the new technology offers a promising alternative to masks currently on the market. "It is a fundamentally new [design]," Ahlers says.
HCWs fail without additional training
Infrequent use of respirators also has implications for respirator fit, another study suggests. Canadian researchers question the practice of fit-testing thousands of health care workers as a part of pandemic preparedness.
"The assumption is that you fit-test the employees and they'll all be protected. We wanted to examine that," says Joffe.
Of 43 health care workers completing a fit- test study at Royal Alexandra Hospital, 19 (44%) achieved an adequate fit by simply donning a 3M 8210 out of the box without training. Others were able to pass a fit- test after training, but 11 (25.6%) needed a different respirator model in order to achieve an adequate fit.
Three months later, only 27 (46.5%) could still pass a fit-test without additional training on donning and properly securing the respirator. At 14 months, 33 (65%) passed without additional training. Neither was a statistically significant better rate than the 50% who passed after pulling a respirator out of the box.
Researchers then looked at 11 nurses who work on a tuberculosis unit and regularly wear respirators. It turned out that four of them were using the wrong respirator. Six of seven of the other nurses passed a fit- test and all passed follow-up fit-tests. (In the province of Alberta, fit-testing is required every two years for health care workers who have potential exposure to airborne infectious diseases.)
Regular use or frequent training help ensure an adequate fit, says lead author M.C. Lee, MD, FRCPC, MSc, medical microbiologist in infectious diseases at DynaLIFEDx Laboratories in Edmonton.
"The adjustment of the bridge around the nose and the correct strapping are the most important [donning and fit-checking] steps that correlate with those people who pass," says Lee. "Even when people do the positive and negative pressure fit-check, they don't necessarily know how to interpret that and adjust accordingly."
Better-fitting respirators that are designed for health care would be an ideal solution, Joffe and Lee say. But the efficacy of current fit-testing protocols needs further study, they say.
"We spend a lot of money and for what gain? There must be better ways of doing it," says Joffe. "This opens up all kinds of questions. We're naive if we think that if we fit-test somebody today, they're actually going to be protected [in a future pandemic]."
1. Radonovich LJ, Cheng J, Shenal BV, et al. Respirator tolerance in health care workers. JAMA 2009; 301:36-38.
2. Lee MC, Takaya S, Long R, et al. Respirator fit-testing: Does it ensure the protection of healthcare workers against respirable particles carrying pathogens? Infect Control Hosp Epidemiol 2008; 29:1,149-1,156.
3. Ofner M, Lem M, Sarwal S, et al. Cluster of Severe Acute Respiratory Syndrome Cases Among Protected Health-Care Workers Toronto, Canada, April 2003. MMWR 2003; 52:433- 436.