Transmission of severe acute respiratory syndrome in an emergency department

Abstract

Severe acute respiratory syndrome (SARS), an infectious disease (1Poutanen S.M. Low D.E. Henry B. et al.Identification of severe acute respiratory syndrome in Canada.N Engl J Med. 2003; 348: 1995-2005Crossref PubMed Scopus (1009) Google Scholar, 2Lee N. Hui D. Wu A. et al.A major outbreak of severe acute respiratory syndrome in Hong Kong.N Engl J Med. 2003; 348: 1986-1994Crossref PubMed Scopus (1875) Google Scholar) caused by a novel coronavirus (3Peiris J. Lai S. Poon L. et al.Coronavirus as a possible cause of severe acute respiratory syndrome.Lancet. 2003; 361: 1319-1325Abstract Full Text Full Text PDF PubMed Scopus (2336) Google Scholar, 4Ksiazek T.G. Erdman D. Goldsmith C.S. et al.A novel coronavirus associated with severe acute respiratory syndrome.N Engl J Med. 2003; 348: 1953-1966Crossref PubMed Scopus (3334) Google Scholar), was first recognized in Singapore in early March 2003 (5Hsu L.-Y. Lee C.-C. Green J.A. et al.Severe acute respiratory syndrome (SARS) in Singapore clinical features of index patient and initial contacts.Emerg Infect Dis. 2003; 9: 713-717Crossref PubMed Scopus (257) Google Scholar). On March 17, the Singapore Ministry of Health designated Tan Tock Seng Hospital, where the initial nosocomial outbreak had occurred, as the national hospital for SARS cases. However, SARS later surfaced in three of the other four large public hospitals (6Centers for Disease Control and PreventionSevere acute respiratory syndrome— Singapore 2003.MMWR Morb Mortal Wkly Rep. 2003; 52: 405-411PubMed Google Scholar). We describe the difficulties associated with recognizing the disease and preventing its transmission in an emergency department of a large teaching hospital. More than 80,000 patients per year present to the emergency department of the National University Hospital; these patients are triaged to three treatment areas: critical care and intermediate care, which are located in a common area with curtains separating the gurneys; and ambulatory care, which has examination rooms and an open waiting area. At the hospital entrance, there are prominent signs highlighting the features of SARS, including fever and respiratory symptoms. Since March 17, all patients have to answer a screening questionnaire, and those meeting World Health Organization (WHO) criteria for SARS (7World Health OrganisationGlobal surveillance for severe acute respiratory syndrome.Wkly Epidemiol Rec. 2003; 78: 100-109PubMed Google Scholar) are transferred immediately to the national SARS hospital by a dedicated ambulance. Screening involves use of thermal scanners, and a national online database is used to check for contact with previous and current SARS patients. Since March 27, all staff have routinely used personal protective equipment, including N95 respirators and water-impermeable gowns and gloves. Caps, shoe covers, and eye protection gear were introduced during the peak of the epidemic (the second week of April), but are now optional, except for eye protection during high-risk procedures. The records of 13 patients with a final diagnosis of SARS who were managed in our emergency department from March 18 until April 22, 2003, were reviewed retrospectively. The study was approved by the hospital's Institutional Review Board. The mean (± SD) age of the 13 patients was 41 ± 20 years (Table); 11 were women and 6 were health care workers. Clinical features included fever, upper respiratory tract symptoms, myalgia, normal leukocyte counts, and lymphopenia. Only 5 patients had an initial diagnosis of possible SARS and were promptly referred to the national SARS hospital. Because of a lack of fever at presentation, patients 6 and 10 were not diagnosed with SARS initially despite positive contact histories. The remaining patients were not recognized as having contact histories because their index cases had not been diagnosed with SARS at the time or because of a strict adherence to the WHO definition of direct contact. Five patients died.TableCharacteristics of the 13 Patients on Presentation and OutcomesPatient No.Age (years)SexHealth Care WorkerInitial Contact HistoryHistory of FeverCoughMyalgiaComorbid ConditionsTemperature (°C)Leukocyte Count (×103/μL)Lymphocyte Count (/μL)Chest RadiographEmergency DispositionOutcome127MYNYNYN38.4NDNDNormalDischargedDied271FNNYNNIschemic heart disease38.74.5800Right basal infiltratesReferred to SARS hospitalSurvived343FYNYYYN36.92.2500NormalDischargedSurvived443FNNYYNHypertension38.919.3900Bilateral infiltratesAdmitted; isolatedDied520FNYYYYN38.53.6800NormalReferred to SARS hospitalSurvived678FNYNNNInterstitial lung disease36.314.71000Bilateral infiltratesAdmitted; isolatedDied752FNNYYNN39.65.4500Bilateral infiltratesAdmitted; isolatedDied863MNNYYYIschemic heart disease35.19.3600Bilateral infiltratesAdmitted; general wardDied928FYYYNYN38NDNDNormalReferred to SARS hospitalSurvived1021FYYYNNN37.86.8900NormalAdmitted; isolatedSurvived1128FYYYNNN38.3NDNDNormalReferred to SARS hospitalSurvived1230FNNYNNN38.23.2500Right middle lobe infiltrateAdmitted; isolatedSurvived1324FYYYNNN384.92100Upper lobe pneumoniaReferred to SARS hospitalSurvivedSummary(number or mean ± SD)40.6 ± 19.711 F6 Y6 Y12 Y5 Y5 Y4 Y37.9 ± 1.27.4 ± 5.6900 ± 5007 abnormal5 referred5 diedF = female; M = male; N = no; ND = not done; SARS = severe acute respiratory syndrome; Y = yes. Open table in a new tab F = female; M = male; N = no; ND = not done; SARS = severe acute respiratory syndrome; Y = yes. Two patients transmitted SARS while in the emergency department. The first patient (patient 8) was a 63-year-old man who presented with dizziness and dyspnea on April 8. He was afebrile and had atrial fibrillation. A chest radiograph showed bilateral lower-zone opacities. He had spent almost 4 hours before admittance to a general medical (nonisolation) ward for heart failure. It was later discovered that his brother whom he had visited at another hospital was the then-unrecognized index case for a number of infections there. Patient 8 had been cared for in gurney 19 of the intermediate care area (Figure). He was neither placed in isolation nor given a mask because his admitting diagnosis was heart failure. A visitor to the patient in gurney 18 was infected with SARS, with onset of symptoms on April 13. Eight other patients were in the intermediate care area during this period. The patient in gurney 8 developed SARS symptoms on April 14, and the patient in gurney 11, on April 18; no other source could be identified for their infections. The remaining 6 patients had no evidence of SARS on extended follow-up. Patient 8 was also the source of infection for 4 health care workers from the inpatient unit (patients 9, 10, 11, and 13). He was transferred to the national SARS hospital where he died 3 days later. The second patient (patient 4) who transmitted SARS in the emergency department was a 43-year-old woman who presented with fever, cough, and dyspnea on March 24. A visitor to the ambulatory waiting area, where patient 4 had waited for 2 hours prior to examination, developed SARS 5 days later. Patient 4 was admitted with a diagnosis of community-acquired pneumonia and was not isolated as she had marked leukocytosis and had no close contact (as defined by the WHO criteria) with SARS patients. She had also waited for 2 hours in gurney 8 of the intermediate care area (Figure) before admission; no patients were infected during this time. She was, however, the source of infection for her son and the intensivist who performed a bronchoscopy on her. She died 8 days after admission. A total of 105 emergency department staff at our hospital have had their temperature monitored, initially three times a day until late August 2003, and now twice daily. Eleven staff members had blood counts and radiographs taken, all for low-grade fevers, and only 1 person was found to have evidence of SARS much later when serologic testing became available. She had a mild febrile illness and there were no changes on five serial chest radiographs. Our case series of 13 SARS patients seen at a general emergency department, with 2 patients causing disease transmission and only 5 recognized immediately as having SARS, illustrates some of the problems associated with the primary care of patients with this emerging infectious disease. The WHO definition of SARS requires a fever >38°C, respiratory symptoms, and close contact with a person with SARS, defined as having cared for, having lived with, or having had direct contact with respiratory secretions and body fluids of an infected person (7World Health OrganisationGlobal surveillance for severe acute respiratory syndrome.Wkly Epidemiol Rec. 2003; 78: 100-109PubMed Google Scholar). The transmission of SARS to patients in gurneys 8 and 11 was possibly by fomites or the gloved hands of a health care worker, as these patients had no direct contact with patient 8 (who was in gurney 19). Close contact was only evident in 6 patients, 2 of whom did not have notable fevers and thus were not identified immediately although they were isolated. Hence, during an epidemic, the index of suspicion should be high even without a positive contact history. In an unaffected area, a detailed travel history is likewise critical. We found that the presentation of SARS was very nonspecific (1Poutanen S.M. Low D.E. Henry B. et al.Identification of severe acute respiratory syndrome in Canada.N Engl J Med. 2003; 348: 1995-2005Crossref PubMed Scopus (1009) Google Scholar, 2Lee N. Hui D. Wu A. et al.A major outbreak of severe acute respiratory syndrome in Hong Kong.N Engl J Med. 2003; 348: 1986-1994Crossref PubMed Scopus (1875) Google Scholar, 8Booth C.M. Matoukas L.M. Tomlinson G.A. et al.Clinical features and short-term outcomes of 144 patients with SARS in the Greater Toronto area.JAMA. 2003; 289: 2801-2809Crossref PubMed Scopus (1095) Google Scholar), especially in patients with chronic comorbid conditions (9Fisher D.A. Lim T.K. Lim Y.T. Singh K.S. Tambyah P.A. Atypical presentations of SARS.Lancet. 2003; 361: 1740Abstract Full Text Full Text PDF PubMed Scopus (55) Google Scholar). Patient 6 may have been afebrile because of chronic steroid therapy. Heart failure and bilateral pneumonia are often difficult to distinguish, as observed with patient 8. Similarly, leukocytosis, which is more characteristic of bacterial pneumonia, is observed occasionally, as in patients 4 and 6. During the peak of the epidemic, all patients with either unexplained fever or respiratory symptoms were isolated for monitoring even if they did not meet criteria for transfer to the national SARS hospital. We also observed infection of other patients and staff in a crowded emergency department by unrecognized, nonisolated SARS patients, similar to reports in Canada (10Maunder R. Hunter J. Vincent L. et al.The immediate psychological and occupational impact of the 2003 SARS outbreak in a teaching hospital.CMAJ. 2003; 168: 1245-1251PubMed Google Scholar, 11Dwosh H.A. Hong H.H. Austgarden D. Herman S. Schabas R. Identification and containment of an outbreak of SARS in a community hospital.CMAJ. 2003; 168: 1415-1420PubMed Google Scholar). While the 5 diagnosed patients were promptly isolated and were not associated with nosocomial transmission, 6 of the remaining unrecognized patients (only 2 of whom were isolated) were not associated with transmission of SARS. Only 2 undiagnosed patients were associated with transmission, which may have been related to the severity of their illness and viral load (3Peiris J. Lai S. Poon L. et al.Coronavirus as a possible cause of severe acute respiratory syndrome.Lancet. 2003; 361: 1319-1325Abstract Full Text Full Text PDF PubMed Scopus (2336) Google Scholar), or to the so-called super-spreader phenomenon (6Centers for Disease Control and PreventionSevere acute respiratory syndrome— Singapore 2003.MMWR Morb Mortal Wkly Rep. 2003; 52: 405-411PubMed Google Scholar), wherein the majority of SARS patients do not transmit, but a small minority go on to infect large numbers of persons. Even though the SARS outbreak is contained, we still use a “fever tent” with a self-contained radiographic unit in front of the ambulatory area, which is divided into a “red” area for febrile patients who have had contact with an infected person or a history of travel to SARS-affected areas and a “green” area for other patients. Staff at the hospital still use full personal protective equipment. Powered air-purifying respirators are still used for all intubations. One emergency department staff member had a mild seroconversion illness, but there were no clinical cases of SARS, confirming the observations of others that infection control can protect staff effectively (12Seto W.H. Tsang D. Yung R.W. et al.Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS).Lancet. 2003; 361: 1519-1520Abstract Full Text Full Text PDF PubMed Scopus (674) Google Scholar, 13Ho A.S. Sung J.J. Chan-Yeung M. An outbreak of severe acute respiratory syndrome among hospital workers in a community hospital in Hong Kong.Ann Intern Med. 2003; 139: 564-567Crossref PubMed Scopus (87) Google Scholar). We initially had a no-visitor rule to the emergency department to prevent the spread of SARS to the community. This rule is currently limited to the critical and intermediate care areas; the few visitors to these areas are required to wear disposable gowns, N95 masks, and gloves. We also have an electronic surveillance system for all staff, patients, and visitors for contact tracing. The Centers for Disease Control and Prevention have issued new guidelines for responding to SARS, which are supported by our experience (14Centers for Disease Control and Prevention. Draft Public Health Guidance for Community-Level Preparedness and Response to Severe Acute Respiratory Syndrome (SARS). Available at: http://www.cdc.gov/ncidod/sars/sarsprepplan.htm. Accessed October 20, 2003Google Scholar). Emergency departments should design their own protocols for promptly isolating all patients with fever or respiratory tract symptoms during an epidemic. Concerns about a resurgence of SARS have let to continued screening and enhanced infection control precautions in previously affected areas, such as Singapore. With proper staff protection, effective triage and isolation of patients, and control of visitors, we managed to limit the transmission of SARS in our emergency department. However, the sustained effectiveness of these measures remains to be seen as this emerging pathogen evolves worldwide. We would like to thank Dr. Peter Manning, the Emergency Department Director, for overseeing the implementation of personal protective equipment and providing the Figure; Dr. Madeline Chew, for contact tracing all the patients; Dr. C. Y. Loh, for assistance in the literature review; and Prof. Lim Yean Teng, the Chairman of the Medical Board, who facilitated the research and policies responsible for the control of SARS in our hospital. We would also like to thank Ms. Joyce Loke for assistance with the graphics, and all the doctors and nurses of the emergency department of the National University Hospital for taking care of the SARS patients.