Cerebrovascular Response to Carbon Dioxide during Hyperventilation for Patients with Postural Orthostatic Tachycardia Syndrome

To study the impaired cerebral autoregulation mechanism of postural orthostatic tachycardia syndrome (POTS) patients under carbon dioxide, a nonlinear regression model was applied to evaluate their cerebrovascular responses to carbon dioxide (CO2). The cerebral blood flow (CBFV), end-tidal carbon dioxide (${{\text{P}}_{{\text{ETC}}{{\text{O}}_2}}}$), and other cardiopulmonary signals were processed for each subject with a tilt table experiment and hyperventilation. The sigmoidal model for cerebrovascular responses to CO2 during the hyperventilation phase for POTS patients demonstrated an observable dissimilarity in comparison with control groups of healthy elders and healthy youths, especially in its range of change in CBFV.