Severe acute respiratory syndrome (SARS): infection control

Sir

Severe acute respiratory syndrome (SARS) is a newly discovered infectious disease with high potential for transmission to close contacts, including health-care workers.¹ The disease is transmitted by droplet and direct contact.2, 3 Since early March, 2003, 30 of 163 patients admitted to the general medical ward of the Prince of Wales Hospital, Hong Kong, have been sent to the intensive care unit (ICU) because of respiratory failure. The issue of infection control in ICUs has not been specifically addressed by the guidelines from WHO and the Centers for Disease Control and Prevention (CDC). A special infection-control policy has been implemented at our ICU to avoid transmission.

To group our critically ill patients with SARS in our ICU, all pre-existing patients were transferred to other uncontaminated centres. During the outbreak, the unit is only open to patients with SARS to avoid infection of other patients. All staff and visitors are instructed to put on gowns, gloves, caps, and masks in a designated area before they enter the unit, which are discarded at the end of the visit. Designated “police nurses” are present at the entrance of the unit to ensure compliance. Regular spot checks are done to ensure the correct fitting of masks. Goggles and visors are worn during direct patient care, especially for aerosol generating procedures such as suction or intubation.⁴ Handwashing is important after contact with patients or their body fluids. Inanimate objects, such as pens, are kept within the unit. Every doctor's pager is protected with a plastic cover, discarded when leaving the ICU environment. Measures are enforced by unannounced twice-daily infection-control rounds to inspect staff compliance.

Patients who are spontaneously breathing receive oxygen via nasal catheters or in combination with oxygen masks. A surgical mask is applied if the patient is using nasal catheters alone. Use of high-flow Venturi-type masks is avoided because the high flow might encourage dissemination of droplets if a patient coughs. Nebulisation and non-invasive positive pressure ventilation is avoided for the same reason. For intubated patients, a high efficiency bacterial/viral filter is incorporated into the breathing circuit. A closed-suction system is important to avoid generation of aerosol.

Because of the risk of transmission, all staff have been instructed to avoid sharing food and utensils. A special room distant from the unit is reserved for meals and rest.

Even with these stringent measures in place, three of 160 ICU staff have contracted SARS since the outbreak. These breakthrough cases arose early in the course of the outbreak, however, before the culture of rigid application to infection-control measures developed. We are hopeful that further cases among our staff will be prevented.