IOM affirms CDC guidance on N95 use in H1N1 setting

Sep 3, 2009 (CIDRAP News) – The Institute of Medicine (IOM) today affirmed existing federal guidance that healthcare workers caring for H1N1 influenza patients should wear fit-tested N95 respirators, not just surgical masks, to protect them from the virus.

At the same time, the IOM called for additional research on flu transmission and the effectiveness of various respiratory protection tools in clinical settings, along with efforts to develop new respiratory protection technologies to enhance safety and comfort.

"Based on what we currently know about influenza, well-fitted N95 respirators offer health care workers the best protection against inhalation of viral particles," said Kenneth Shine, chair of the committee that wrote the report, in an IOM news release.

"But there is a lot we still don't know about these viruses, and it would be a mistake for anyone to rely on respirators alone as some sort of magic shield," added Shine, who is executive vice chancellor for health affairs in the University of Texas System, Austin, and former president of the IOM.. "Health care organizations and their employees should establish and practice a number of strategies to guard against infection, such as innovative triage processes, hand washing, disinfection, gloves, vaccination, and antiviral drug use."

But the IOM report drew criticism today from a representative of the Association of Professionals in Infection Control and Hospital Epidemiology (APIC), who said the recommendation to wear N95s fails to recognize the many practical and logistical problems related to N95 use, including discomfort, costs, shortages, and the difficulty of fit testing.

In the face of unclear science concerning flu virus transmission, the IOM prepared the report at the request of the Centers for Disease Control and Prevention (CDC) and the Occupational Safety and Health Administration (OSHA).

The panel, which was given just 8 weeks to write the report, held a 4-day meeting, including a 1 1/2-day public workshop, in August. The panel's assignment specifically excluded the economical and logistical considerations related to personal protective equipment (PPE).

The report notes that the current CDC guidance on protection for health workers caring for H1N1 patients differs from guidance from the World Health Organization (WHO) and Canadian guidance. The CDC recommends use of N95s for all healthcare workers who enter the rooms of patients in isolation with confirmed or suspected H1N1 infection. The same advice goes for emergency medical personnel who come in close contact with such patients.

In contrast, the WHO recommends "standard and droplet precautions (including a medical mask, gown, gloves, eye protection, hand hygiene) for those working in direct contact with patients and additional precautions for aerosol-generating procedures including wearing a facial particulate respirator," the report says. The recommendation allows for "the need for sustainability" in different countries.

Similarly, recently released Canadian guidelines call for using N95s only during aerosol-generating procedures and recommend using medical (surgical) masks in other situations, according to the report.

On the murky question of the extent to which flu viruses spread through the air, the IOM committee concluded that studies show that "airborne (inhalation) transmission is one of the potential routes of transmission."

The panel said it found few studies comparing the effectiveness of N95 respirators and medical masks in clinical settings, although several studies are under way. Hence the group based its decisions on comparisons of the two kinds of protection in controlled experiments. Those studies show that medical masks are unlikely to be effective in preventing aerosol transmission, the report says.

In view of that evidence, the panel recommends that health workers in close contact with patients who have novel H1N1 flu or flu-like illness should wear fit-tested N95 respirators or respirators that are "demonstrably more effective." The report specifically endorses the current CDC guidance and says it should be followed until there is evidence that other forms of protection work as well or better.

In addition, the report advises that employers should make sure that N95 respirators are used and fit-tested in accordance with OSHA regulations.

The panel further found that the need for more research on flu transmission and PPE is "striking." It urges federal agencies and private organizations to support and undertake research to:

  • Answer questions about the relative contribution of different routes of flu transmission
  • Explore the effectiveness of different respiratory protection tools in clinical settings through randomized trials
  • Design and develop new respiratory protection technologies "to enhance safety, comfort, and ability to perform work-related tasks"

The IOM's recommendation to use fit-tested N95s drew criticism on practicality grounds today from Ruth Carrico, an infection control expert at the University of Louisville School of Public Health and Information Sciences and a former APIC board member. Carrico was on a panel of experts who reviewed the IOM report in draft form.

"I think the IOM has missed the mark," Carrico told CIDRAP News.

She acknowledged that the panel of authors was specifically charged with looking only at the science and not the logistical and economic issues. But she said it's difficult to separate the scientific issues from the logistical matters, such as the ability of health workers to follow the guidance and its applicability in clinical settings.

"As a human being, if you're being told this is the best protection for your and you go to work and that protection is not available, how likely are you to go to work the next day?" she asked.

Noting that the recommendation specifically calls for the use of fit-tested respirators, Carrico said there are "lots of gaps" in the information about fit testing. Given the cost and time requirements of fit testing, she said, "Does it really make sense and is it a valid point? We have to be concerned about that in our economic times."

More generally, she said, "Divorcing the recommendations from the practicality of implementation represents a serious problem for healthcare workers who are trying to figure out, 'What do I do to provide care for my patients in a safe manner?'"

Hospitals say they do fit testing as best they can, but "there's no way to be fit tested for all the kinds of respirators used," Carrico continued. For example, this past spring, some hospitals ran out of respirators and hence used respirators from the government's Strategic National Stockpile. Those were a different type from what hospitals normally use, which created a need for additional fit testing, she said.

Keeping respirators on hand is a continuing problem, she added. "There are back orders; there are constant calls about interruptions in supply. We simply do not have the supply line of these types of materials in order to apply these recommendations." As a result, hospitals try to save their respirators for us in the highest-risk settings.

The shortages and other problems lead to inconsistent and changing hospital policies, which confuse workers, she added. "We're hearing about workers who will say 'I refuse to care for this patient because I don't feel safe,'" she said.

Carrico also commented that most workers can wear N95s only a short time before they become hot and uncomfortable.

"At some point you've got to peel the onion and say what's really necessary, what's really practical, and how are we going to enable our healthcare workers to do what needs to be done?" she said.

She also expressed hope that the IOM's appeal for new research will lead to some well-designed studies in clinical settings.

At a press briefing today, CDC Director Dr. Thomas Frieden said the CDC has just received the IOM report and is looking at it.

CDC spokesman Tom Skinner said the agency is considering the recommendations from the IOM and other expert groups on the issue of respiratory protection for health workers. "We hope to have a plan that further addresses this issue very soon," he told CIDRAP News.

See also:

Sep 3 National Academy of Sciences news release about the report

Table of contents page for full IOM report "Respiratory Protection for Healthcare Workers in the Workplace Against Novel H1N1 Influenza A"

Aug 13 CIDRAP News story "Experts air practical PPE considerations to IOM"

Aug 12 CIDRAP News story "IOM hears diverse findings on PPE for flu"

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