Severe Acute Respiratory Syndrome (SARS) is an acute respiratory illness caused by infection with a new coronavirus. The sequelae of SARS coronavirus infection remain undefined. The aim of this study is to investigate the pulmonary function and exercise capacity in a group of survivors of SARS.
At 3 months after hospital discharge, 46 survivors of SARS underwent the following evaluation: spirometry, static lung volumes, carbon monoxide transfer factor (TL,CO). Forty-four of these patients underwent cardiopulmonary exercise testing.
No abnormalities were detected in the pulmonary function tests in 23 (50%) of the patients. Abnormalities of FVC, FEV1, FEV1/FVC and diffusing capacity for carbon monoxide (DLCO) were detected in 7 (15%), 12 (26%), 1 (2%), and 18 (39%) patients respectively. All these abnormalities were mild except in 1 case, who had moderate impairment of DLCO. In 18 patients (41%), the maximum aerobic capacity ( O2max) was below the lower limit of the normal range. Breathing reserve was low in 4 patients and significant oxygen desaturation was detected in 4 patients. Comparison of the measured exercise capacity with resting pulmonary function tests showed many cases of discordance in impairment.
Pulmonary function defects were detected in half of the recovered SARS patients at 3 months after hospital discharge but the impairment was mild in almost all cases. Many patients had reduced exercise capacity that cannot be accounted for by impairment in pulmonary function.
Further studies for the evaluation of extra-pulmonary causes of morbidity in recovered SARS patients are required. The finding of reduced ability to exercise without significant impaired lung function impairment in most patients in this study suggests that emphasis on physical and psychosocial rehabilitation after their acute illness is likely to contribute to improved management of these patients.
K.C. Ong, A*STAR Biomedical Research Council