NEW YORK CITY—In March 2003, the World Health Organization (WHO) issued an international alert about an atypical pneumonia of unknown cause that was appearing in Hong Kong, China, and Vietnam. Within three months, more than 8,000 cases of severe acute respiratory syndrome (SARS)—and more than 700 deaths—had been reported worldwide.

Laboratories have found evidence of a novel coronavirus in SARS patients. Despite this, SARS currently remains a syndrome, rather than a specific viral disease.[1] The communicability of SARS is undeniable, however, and among the groups at extreme risk of infection are health care workers in hospitals.

The time between infection and onset of symptoms has been estimated to be between six and 16 days.[2] The time between SARS symptom onset and admission to the hospital has decreased as more is learned about its clinical presentation. This, in turn, allows the rapid isolation of SARS patients. The hospitals that have been most affected by the SARS outbreak have adopted rigorous guidelines aimed at preventing the spread of SARS within an institution and, consequently, the community.

FIRST CONTACT

There is general agreement among clinicians in areas with a high incidence of SARS that patients presenting with respiratory infections must be considered potential SARS cases until proven otherwise. “The most critical time is when the hospital staff do not yet realize that the patient has SARS,” emphasized Randy Wax, MD, Education Director and a staff intensivist at Mount Sinai Hospital in Toronto. Dr. Wax added that initiating SARS-specific infection control procedures early as part of standard practice could avoid in-hospital transmission. “In general, if you can’t rule out SARS, you should treat it as SARS.”

Thomas A. Buckley, MD, a Professor of Anesthesia and Intensive Care at the Chinese University of Hong Kong, agreed, saying, “Exposure of unprotected staff, even at the reception area, can result in introduction of SARS to a hospital. Once the staff are in the infective stage, the possibility exists for rapid spread among health care workers.” At first contact, said Dr. Buckley, “the absolute minimum standard of protection should be an N-95 mask, latex gloves, and eye protection. Protective apparel should be immediately available.”

According to WHO, a suspected case of SARS is a patient with a fever, cough, dyspnea, and either contact with someone believed to have SARS or travel to a country or city that has had documented transmission of SARS. A probable case is someone meeting the criteria for a suspected case who also has radiographic findings of pneumonia, respiratory distress syndrome, or an unexplained respiratory illness.[1]

Infection control guidelines have been expanded to include both suspected and probable SARS cases. Patients with suspected or probable SARS should be cared for in an isolation room with negative pressure.[3]

PERSONAL PROTECTION

The main modes of SARS transmission appear to be infected droplets from coughs and sneezes, respiratory secretions, and direct contact with contaminated surfaces, such as tabletops, light switches, and doorknobs. Coronaviruses can survive in the environment for prolonged periods.[4]

Face and eye protection—a mainstay of infection control—are critical in the prevention of SARS transmission in hospitals. N-95 filtering disposable masks are recommended for anyone in contact with SARS patient areas. Infection control guidelines from the Hong Kong Hospital Authority stress that protection should be chosen according to risk. Gloves, eye protection, face shields, disposable gowns, aprons, and footwear that can be decontaminated are also recommended. Adequate supplies of all personal protection equipment should be maintained in the patient room.[4,5]

Dr. Buckley noted that, initially, N-95 masks can pose a compliance problem. “The mask is tight-fitting and uncomfortable,” he said. “Staff have a tendency to touch the mask, risking contamination, and frequently will lift the mask off the face to allow easier breathing.”

According to Dr. Buckley, the fit test that staff members must undergo for their masks is another, more practical problem. “There is no ‘one mask fits all,’ ” he commented. “The problem with fit testing is that it takes 10 to 15 minutes per person, which is considerable if there are 200 nurses to test for an intensive care unit.”

HAND WASHING

Scrupulous hand washing is highly effective against SARS. The guidelines from the Ontario Ministry of Health and Long-term Care recommend frequent hand washing using a combination of traditional soap and water and alcohol hand rinses following contact with any potentially contaminated surface.[5] “Although most people focus on masks,” Dr. Wax said, “I think hand washing has probably helped to prevent more [SARS] cases from developing in health care workers and other contacts.”

He provided this scenario: “Touching something, adjusting your mask, washing your hands, touching your mask again, and then eating could lead to infection. We do many things unconsciously,” he observed. “Absolute concentration on appropriate hand washing techniques is crucial.”

HIGH RISK IN THE ICU

The already stringent infection control guidelines are stepped up in critical care areas, particularly when high-risk procedures are performed. These include diagnostic sputum induction, intubation, bronchoscopy, and airway suction. An outbreak of SARS at a hospital in Hong Kong was thought to have been caused by the use of a nebulized bronchodilator in the index patient, which increased the amount of infected airborne droplets.[6]

The use of nebulized therapies, high-frequency oscillation, and noninvasive ventilation should all be avoided. High-risk procedures should be performed by the most experienced person available, in a private room with negative pressure, with minimum attending staff and strict adherence to SARS precautions and hand disinfection.[5]

ADDITIONAL MEASURES

Patient rooms and areas outside the rooms—especially frequently touched surfaces—must be disinfected at least daily. The patient rooms should have negative pressure, and they should not have any recirculation of air within the hospital. There should be constant monitoring of the air supply/exhaust systems.[5]

“Hospitals will need to choose appropriate adjunct protection for people caring for patients with SARS,” noted Dr. Wax. “Systems such as powered air-purifying respirators with adequate filtration and/or positive pressure personal environments need to be considered.” He added that at his hospital training materials were being developed to help staff feel comfortable with additional protective equipment. “Such adjunct devices add a second layer of protection against mishaps and also a well-needed psychological boost to those of us who have seen friends get infected or stuck in precautionary isolation after an inadvertent SARS ‘spill.’ ”

TRAINING AND EDUCATION

Employing infection control consultants to educate staff is another essential practice. “A series of lectures from an infection control team is important in conveying the overall message to a large number of people within the hospital,” Dr. Buckley said, proposing that hands-on teaching be left to designated staff in each department. “Small group tutorials with practical sessions are required to ensure optimal compliance with infection control procedures.”

Dr. Wax stressed the importance of cooperation among colleagues. “Many hospital staff have never been fit tested for N-95 masks and have never been observed entering and leaving SARS patients’ rooms to ensure that they follow appropriate procedures and avoid cross-contamination,” he said. “It is crucial to create a culture in which everyone watches out for everyone else while they practice infection control precautions. Many times breaches occur inadvertently. Feedback from colleagues is an important tool for improving infection control.”

Dr. Buckley agreed. “Each person repeatedly makes small slips,” he observed, “for example, not removing the contaminated cover from a pager before leaving an infected area. Education encourages heightened awareness and almost an obsession with infection control.”

PROGRESS AMID UNCERTAINTY

With the occurrence of the SARS crisis, the need for extreme precautions has forced the evolution of infection control. “The concept of ‘universal precautions’ is now redundant,” said Dr. Buckley, who predicted a complete review and redesign of current hospital infection control procedures.

Dr. Wax concurred, saying that the emergence of SARS has pushed the medical community “to think about the unthinkable and get better prepared. I am more optimistic about our readiness for natural and deliberate biohazards,” he noted.

There is unanimous agreement that the level of cooperation and communication among institutions and clinicians worldwide has been unparalleled. The Internet has served as a forum for sharing experiences with different procedures and protocols and also to circulate updated information as fast as possible.

Julie L. Gerberding, MD, MPH, Director of the CDC, wrote in an editorial for the New England Journal of Medicine, “Even more impressive than the speed of scientific discovery in the global SARS outbreak is the almost instantaneous communication and information exchange that has supported every aspect of the response. The WHO, the CDC, and national and local health agencies across the globe have disseminated up-to-the-minute information tailored for clinicians, public health officials, health care workers, travelers, household contacts, and many other affected parties.”[7]

Dr. Wax noted that without the expertise and support of these groups, “reinventing the wheel would become a new hobby for many.”

FOR MORE INFORMATION

The following Web sites contain frequently updated information on SARS, both general and specific to infection control. Click on the name or URL to be taken directly to the site. CDC www.cdc.gov/ncidod/sars WHO www.who.int/csr/sars/en Hong Kong Department of Health www.info.gov.hk/dh/ap.htm Hong Kong Hospital Authority www.ha.org.hk/sars/sars_index_e.html Critical Care International Listserv www.pitt.edu/˜crippen Mount Sinai Hospital Critical Care Unit—SARS Education Resources sars.medtau.org

—Gale Jurasek