Longer term follow up of aerobic capacity in children affected by severe acute respiratory syndrome (SARS)

Abstract

Background: A study was undertaken to investigate the aerobic capacity and pulmonary function of children 6 and 15 months after the diagnosis of severe acute respiratory syndrome (SARS). Methods: Thirty four patients of mean age 14.7 years completed both pulmonary function and maximal aerobic capacity tests at 6 months. All had normal clinical examination and were asymptomatic. Their exercise responses were compared with a group of healthy controls. Complete data were collected on 27 of the original 34 cases at 15 months. Results: Compared with normal controls, the patient group had significantly lower absolute and mass related peak oxygen consumption (peak V̇O 2 (p<0.01)), higher ventilatory equivalent for oxygen (p<0.01), lower oxygen pulse (p<0.01), and a lower oxygen uptake efficiency slope (p<0.01) at 6 months. This impairment was unexpected and out of proportion with the degree of lung function abnormality. Residual high resolution computed tomography of thorax (HRCT) abnormalities were present in 14 patients. Those with abnormal HRCT findings had significantly lower mass related peak V̇O 2 than subjects with normal radiology (p<0.01). Absolute and mass related peak V̇O 2 in the patient group remained impaired at 15 months despite normalisation of lung function in all patients. Conclusions: The mechanism for the reduced aerobic capacity in children following SARS is not fully understood, but it is probably a consequence of impaired perfusion to the lungs at peak exercise and deconditioning.