預測罹患嚴重急性呼吸道症候群發生急性呼吸衰竭之高危險群

Severe Acute Respiratory Syndrome (SARS) is an acute respiratory illness caused by
infection with a new coronavirus, SARS-CoV, identified in March, 2003. The disease is
characterized by high contagious, may progress rapidly to respiratory failure and is
potentially lethal in severe cases. As of June 5, 8,402 cases of SARS had been reported
in the world, and 772 (9.2%) died of the disease. About 10-20% of SARS patients
developed respiratory failure requiring intensive care and mechanical ventilation.
Mortality majorly depends on the age group affected, with an overall estimate of 14%
to 15%. For patients with progressive deterioration, early intubation for impending
respiratory failure and providing best supportive and respiratory care are considered to
be of primary importance. Risk factors that have been reported to be associated with a
progressive disease are: older age, high neutrophil count, high LDH peak; severe
lymphopenia, impaired ALT, delayed starting of ribavirin and steroids; chronic
Hepatitis B infection. However, besides age, no single early markers or clinical
parameters have been identified to predict the progression to respiratory failure or fatal
outcome. Tedious daily laboratory monitoring is necessary to figure out who will
develop progression of the disease. Chest radiographs offer important prognostic clues
for disease progression. However, serial chest films are necessary, and sometimes the
clinical deterioration is too rapid that a regular chest film may not be useful, dramatic
change may appear within one single day. Although a guideline had been proposed for
caring SARS patients, which advised elective and early intubation for SARS patients
with impending respiratory failure, clinical prediction of high risk patient is sometimes
not possible. Emergent intubation or the need of resuscitation seems related to the fatal
outcome. In this study, we plan to establish a prediction system by using the clinical
parameters early in the disease course to identify patients with high risk for acute
respiratory failure, which will help doctors to provide a more intensive monitoring of
high-risk patients.