Severe acute respiratory syndrome (SARS) is a newly recognized viral pneumonia caused by a novel coronavirus (SARS-CoV). In the acute stage, it is often complicated by diffuse alveolar damage and respiratory failure. Survivors often report exercise limitation, which is poorly characterized. We aim to study the cardiopulmonary response to exercise in a group of SARS survivors.
Symptom-limited cardiopulmonary exercise testing (CPET) according to the American Thoracic Society guideline was performed in a group of SARS survivors 6 months after discharge. Peak oxygen consumption (VO2max) and the patho-physiologic mechanisms of exercise limitation were determined.
We studied 16 patients (3 male, 13 female, mean age 36.2 ± 8.7 years) who contracted SARS during the epidemic in 2003. They all reported exercise limitation after discharge. At 6 months after discharge, the mean VO2max was 27.2 ± 6.0 ml/kg/min (88.4 ± 13.5% predicted). Four patients (25%) had normal CPET. Of the remaining 12 patients, 7 (43.8%) had reduced work capacity due to deconditioning, 3 (18.8%) had cardiac limitation of exercise (2 had ischemic changes on exercise ECG and 1 had cardiac arrhythmia during exercise), 1 (6.3%) had ventilatory limitation of exercise, and 1 (6.3%) had steroid-induced myopathy. Three patients (18.8%) also had exercise-induced oxygen desaturation (>4%) as an additional limiting factor to exercise, with a mean nadir Sa02 of 93.3 ± 1.2%.
In SARS survivors who reported exercise limitation, a variety of patho-physiologic mechanisms were revealed on CPET at 6 months.
This finding is relevant to disability assessment and rehabilitation in these patients. More studies on exercise physiology in SARS survivors are warranted.
V.L. Chan, None.