Got N95s? You better, says IOM panel
Got N95s? You better, says IOM panel
Will CDC reverse surgical mask recommendation?
An Institute of Medicine (IOM) panel recently recommended that fit-tested N95 respirators — rather than surgical masks — be worn by health care workers treating H1N1 pandemic influenza A patients.
"Studies on influenza transmission show that airborne (inhalation) transmission is one of the potential routes of transmission," the IOM concluded. "The committee based its decisions on comparisons of the experimental evidence on the efficacy of respirators and medical masks and not on their effectiveness in the clinical setting due to the fact that the availability of data is quite limited on clinical effectiveness. . . . N95 respirators are documented to filter out 95% to 99% of relevant particles and have maximum effectiveness when properly fitted to the face of users through fit testing. Research results on the filtration and fit of medical masks show wide variation in penetration of aerosol particles (4% to 90%) and inadequate fit suggesting that the use of medical masks is unlikely to be effective against airborne transmission."
The Service Employees International Union (SEIU) — the nation's largest organization of health care workers — hailed the IOM report as "the first and only comprehensive scientific review" of the controversial issue.
The Centers for Disease Control and Prevention — which currently recommends N95s for treating H1N1 patients — was expected to issue a ruling by Oct. 1 based on the IOM report and other advisory recommendations. The CDC's Healthcare Infection Control Practices Advisory Committee (HICPAC) recently recommended that the agency officially downgrade the recommendation to surgical masks, a move that many hospitals and health departments have already made independently.
New CDC director Thomas Frieden, MD, MPH, now will have to make what one clinician described as a "Solomonic" decision, as he has esteemed advisors pointing in opposite directions. It's clear Frieden formed his own opinion as recently as May 15 when he still was the New York City Commissioner of Health. Current NYC public health recommendations — still topped by Frieden's name — advise: "Health care workers examining, caring for or obtaining nasal, nasopharyngeal or pharyngeal specimens from patients with probable or confirmed swine influenza should wear a surgical facemask. Staff should be instructed to perform hand hygiene, put facemask on first followed by gloves, then when patient care is complete, remove gloves first then facemask, and perform hand hygiene. Fit-tested N95 masks and eye protection (goggles) are not necessary, except for aerosol-generating procedures."
Clear enough, but disregarding the IOM recommendation now will not sit well with employee unions that see the report as validation of their long-held position. They may decide Frieden is more like Judas than Solomon if he tries to revert to masks now.
"This is not solely a CDC decision — it is a joint HHS/ DOL/ White House decision that also requires a briefing with Congress if the current CDC guidelines now substantiated by the IOM are reduced," says Bill Borwegen, MPH, health and safety director for the SEIU.
For its part, the infection control community bemoaned the decision, questioning the validity and practicality of the findings. "The IOM committee was not permitted to consider issues of supply, feasibility or implementation," says William Schaffner, MD, chairmen of the department of preventive medicine at Vanderbilt University. "There is a substantial amount of concern out there about how the IOM recommendation could be put in place and sustained in clinical practice."
The availability of vaccine for health care workers does not necessarily change the equation. "We never make a recommendation that if a heath care worker is vaccinated against measles they can take care of a measles patient without appropriate protection," Schaffner says.
Another issue is seasonal flu, which has never prompted recommendations for respirator use. "When you have a mixture of H1N1 and seasonal flu, how are you going to handle that?" he says. "To my surprise and annoyance, the IOM was not permitted to address seasonal flu. There is universal agreement in the scientific and public health communities that H1N1 is transmitted just like seasonal flu. So what are we to do? Does this recommendation extend to seasonal flu? Is this what we should be doing each and every year?"
The IOM charge did not include such practical considerations, which nevertheless must be considered now as the CDC makes the final call.
"It is terribly unfortunate that the IOM committee was given this question in isolation. That is not the way the world works," Schaffner says. "The CDC will have to integrate this IOM recommendation into real-world practices."
Concerns about supply have raised such issues as "holding back" some N95s for high-risk procedures like bronchoscopies. Other discussions have raised the issue of whether the respirators could be cleaned and reused for the same worker.
"The only time we instruct them that they are able to reuse it is when they are in a patient's room with suspect or confirmed TB because that is only spread by the airborne route," says Sue Sebazco, infection preventionist and employee health professional at Arlington (TX) Memorial Hospital. "With something like influenza or SARS ideally they would use the N95 respirator once and throw it away. There is the potential for contamination."
There also are issues of comfort, as clinicians report it is difficult to wear N95s for prolonged periods. For example, in a setting such as a pediatric clinic, staff could be wearing them all day.
"There will probably be noncompliance for several reasons," says Richard Wenzel, MD, chairman of the department of internal medicine at Virginia Commonwealth University in Richmond. "The demand may outstrip the supply as it did in the spring when we were first hearing about H1N1. The second issue is when you wear the [respirator] for a long period of time — more than an hour — it gets very uncomfortable and hot. Some older people may have trouble breathing at some point because it really does filter things much more. That will be another problem, particularly in emergency rooms where you are essentially putting these things on for most of the day. It's going to create a lot of controversy because it is at variance with what some of the other societies like SHEA [are recommending]."
Indeed, a joint statement by the major infection prevention organizations supports the use of droplet precautions (i.e., surgical masks) to treat patients with confirmed or suspected H1N1 pandemic influenza A.
"Based on available data and the evolution of the H1N1 outbreak, the Society for Healthcare Epidemiology of America (SHEA), Association for Professionals in Infection Control and Epidemiology Inc. (APIC) and the Infectious Diseases Society of America (IDSA) recently advocated updating the Centers for Disease Control and Prevention guidance to recommend similar infection control practices employed to prevent the transmission of seasonal influenza," read a joint statement posted on the SHEA web site.
The recommendations do extend to particulate respirators such as N95s for aerosol-generating procedures. The groups also took exception to the current CDC guidance to reassign health care personnel at high risk for severe influenza illness so that they do not provide care to H1N1 patients. In addition to known risk factors for complications of seasonal influenza, early data suggest that obese individuals, those with asthma, and pregnant women might be at increased risk for complications from H1N1 virus infection.
"Every day, health care personnel may encounter patients infected with any of a wide array of pathogens that could, in the event health care personnel become infected, result in severe illness in the exposed worker," the groups stated. "Reassignment implies that the current personal protective equipment and health care infection control recommendations are insufficient to prevent health care personnel from acquiring the novel H1N1 influenza A virus from patients. On the contrary, recent data suggest that community exposures, failure to wear appropriate /personal protective equipment, or failure to recognize and isolate affected patients are responsible for the majority of novel H1N1 influenza A illness among health care personnel. Reassignment of health care personnel for this virus based on assessment of risk to the worker is a precedent that opens the door for concern about a wide range of other pathogens that are encountered in the health care setting."An Institute of Medicine (IOM) panel recently recommended that fit-tested N95 respirators rather than surgical masks be worn by health care workers treating H1N1 pandemic influenza A patients.
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