Recommendations for the prevention of transmission of SARS during GI endoscopy

More than two dozen health care workers and patients at a hospital in Washington, D.C., contracted a mysterious although mild respiratory illness in the summer of 2003. Almost all of these cases were linked to the GI endoscopy suite in the hospital. Symptoms of the illness included low-grade fever, nasal congestion, headache, and dry cough. Hospital officials identified the index case as a nurse working in the GI endoscopy suite who had recently returned from a trip to the Philippines.¹ Although this outbreak was not caused by the virus responsible for severe acute respiratory syndrome (SARS), nevertheless, health care workers who display symptoms of a respiratory illness arouse concern, heightened by recent reports around the world that document a high rate of nosocomial transmission of SARS from infected patients to health care workers.2., 3., 4., 5.

SARS, which has wreaked havoc from North America to Southeast Asia, is a potentially fatal, atypical pneumonia etiologically linked to the previously unrecognized SARS-associated coronavirus, or SARS-CoV.⁵ So named because they appear to have a halo or crown-like structure,⁶ coronaviruses, in addition to being linked to SARS, are a major cause of the common cold.6., 7. Reportedly, SARS first appeared in November 2002 in the Guangdong Province of China.2., 7., 8., 9., 10. During the following year, SARS spread to Hong Kong, Singapore, and to more than two dozen countries, including Canada, Indonesia, the Philippines, and Vietnam. To date, more than 8500 cases of SARS have been reported, resulting in more than 900 deaths.¹⁰ Hopes that the worldwide spread of SARS had ended in the summer of 2003 were tempered in the early fall of 2003 when a new probable case was reported in Singapore, thereby raising a concern that the disease may have re-emerged.¹¹

Symptoms, therapy, and modes of transmission

SARS is a contagious disease with an incubation period that is typically between 2 and 7 days, although it can be as long as 10 days.2., 12., 13. Symptoms include fever, with temperature elevations to greater than 100.4°F; dry cough; fatigue; body aches; and shortness of breath, with or without abnormal chest radiographic findings.2., 5., 7., 12. There is currently no specific therapy for SARS, although a “cocktail” of drugs that includes antibiotics, corticosteroids, and antiviral medications may help to improve prognosis and control the spread of the virus.2., 5., 6., 7., 9., 13.

Transmission of SARS-CoV typically requires close contact (within 3 feet) with an infected person and is primarily person-to-person via large, infectious respiratory droplets (i.e., droplet transmission).3., 7., 14., 15., 16., 17., 18. Although community-acquired infection and household transmission have been reported, in a significant number of cases in 2003, transmission of SARS-CoV was nosocomial and was from SARS-infected patients to health care workers in charge of their care.2., 3., 4., 5., 14., 15. In most of these cases, nosocomial transmission occurred in medical facilities in which infection control precautions were lax or were not practiced.¹⁴ In addition, SARS-CoV may be transmitted by direct contact with infected respiratory secretions and other body fluids.7., 15., 16., 19. Indirect contact with contaminated environmental surfaces and inanimate objects (fomites) is suspected to have resulted in the transmission of SARS-CoV, as suggested by reports that health care workers who had no direct contact with SARS-infected patients became infected.5., 6., 9., 15., 16. Data suggest that SARS-CoV can survive on hard surfaces, such as plastic and stainless steel, for several hours, if not days.9., 12., 16. Furthermore, it appears that airborne transmission of SARS-CoV cannot be ruled out.12., 19.

Risk of transmission of SARS during GI endoscopy

In addition to respiratory secretions and other body fluids, SARS-CoV has been identified in human feces.6., 7., 9., 16. Therefore, the potential exists for the transmission of SARS-CoV to health care workers and other patients during GI endoscopy. Bronchoscopy, airway suctioning, and other types of procedures that may induce coughing and may expose health care workers to potentially infected aerosolized respiratory droplets pose an increased risk of transmission of SARS-CoV.¹³ Despite this risk, to date there is no published report of transmission of SARS via a contaminated GI endoscope or bronchoscope.

Recommendations

Health care workers in close contact with infected patients are at risk for exposure to SARS.2., 3., 4., 5., 14. Strict adherence to established infection control guidelines, therefore, is crucial for the prevention of nosocomial transmission of SARS-CoV (and all infectious agents).2., 3., 15., 20. Routine monitoring of infection control practices to ensure compliance with these established guidelines is also to be recommended.

Based on experience with SARS to date, as well as recommendations for prevention of transmission of other disease-causing agents, e.g., hepatitis C, a number of steps can be taken to prevent transmission of SARS-CoV in the GI endoscopy unit and other health care settings:

• •A program should be established for identification and isolation of patients who are suspected or likely to have SARS.5., 19. Prompt diagnosis of SARS-CoV infection is crucial for the prevention of transmission of the disease.² Screening and evaluation of patients for SARS should be based on the current case definition of SARS as established by the Centers for Disease Control and Prevention (CDC) in the United States. During a known SARS outbreak, a high index of suspicion for infection is warranted.⁵ The current CDC definition (dated January 8, 2004) of a suspect case and a probable case of SARS can be found in the document entitled “Updated interim U.S. case definition for severe acute respiratory syndrome (SARS),” which can be read at the following web link: http://www.cdc.gov/ncidod/sars/casedefinition.htm
• •Health care workers must be educated with respect to the following principles: infection control, standard precautions, contact precautions, and airborne precautions for both suspect and probable SARS-infected patients.3., 6., 19., 20., 21., 22., 23. Steps should be taken to ensure that health care workers properly and diligently practice these important principles, because failure to understand and use each one of them may significantly increase the risk of nosocomial transmission of SARS-CoV. In addition to eye protection, personal protective equipment should be used, including gloves, gowns, and both head and shoe covers.13., 16., 24., 25. Adherence to airborne precautions requires that health care workers be fitted with disposable respirators certified by the National Institute for Occupational Safety and Health as N95 or better,¹⁴ which, unlike surgical masks,5., 26. appear to prevent transmission of SARS. Placement of a SARS-infected patient in an isolated room with negative air pressure also is recommended. Proper hand hygiene and frequent hand washing with soap and water (or an alcohol-based hand rub) are essential, both before and after each patient contact.13., 14., 19., 26., 27., 28. The contribution of hand washing to the prevention of transmission of SARS (and other infectious agents) cannot be overstated.¹⁶ After each patient contact, gloves should be removed and hands washed thoroughly; the use of gloves does not eliminate the need for proper hand hygiene and frequent hand washing. Proper disposal of used gloves is also essential. A surveillance program to monitor and to evaluate compliance with these principles and precautions is advisable.
• •Bronchoscopy, airway suctioning, and other types of procedures that may induce coughing and thereby expose health care workers to potentially infected aerosolized respiratory droplets should be performed with caution on SARS-infected patients and then only when deemed a medical necessity.7., 20., 21.
• •GI endoscopes, bronchoscopes, and other flexible endoscopes and ancillary endoscopic equipment should be thoroughly cleaned and subjected to either high-level disinfection or sterilization as required. Whereas high-level disinfection is recommended for GI endoscopes, bronchoscopes, and other “semicritical” instruments, sterilization is recommended for “critical” instruments, including biopsy forceps, papillotomes, and polypectomy snares. Single, disposable endoscopic accessories and devices are an alternative to sterilization of reusable devices; proper disposal of these devices also is essential. Adherence to current guidelines for reprocessing of endoscopes also is recommended for prevention of transmission of SARS-CoV via both potentially contaminated GI endoscopes and bronchoscopes.
• •Rooms occupied by SARS-infected patients, as well as other areas in a medical facility that may be visited by SARS-infected patients (e.g., the emergency room), should be cleaned and disinfected once per day or more often, as required. Routine and terminal cleaning and disinfection of all necessary bedside equipment, furniture, floors, and other environmental surfaces, particularly surfaces that are touched frequently, are recommended.13., 19., 29. For these purposes, any Environmental Protection Agency registered hospital-grade detergent-disinfectant shown to be effective against coronaviruses is suitable. The label instructions on the product for use and dilution (i.e., concentration), contact time, and care in handling should be followed carefully.²⁹ Although the role of environmental surfaces in the transmission of SARS-CoV is not fully defined, contamination of such surfaces has been reported, suggesting that intensive environmental cleaning and disinfection are essential for both control and prevention of the spread of SARS-CoV.¹⁶