The Cardiorespiratory Graph in Sleep Apnea and Associated Comorbidities

The severity of sleep apnea is often assessed using the apnea/hypopnea index (AHI), which is known to be inaccurate in the phenotyping of apnea patients. Hence, better approaches are needed to characterize these patients and to allow cardiovascular risk stratification. In this context, this work studies the cardiorespiratory interactions in patients suffering from both sleep apnea and apnea associated comorbidities by means of graph theory and kernel methods. Results indicate that the total connectivity of the cardiorespiratory graph is significantly $(p < 0.01)$ reduced with higher AHI. Moreover, in patients with apnea associated comorbidities, this connectivity appears to be significantly reduced around apnea events. These results are in line with studies that report stronger oxygen desaturations in patients with apnea associated comorbidities, and more unstable control systems, which could be used for a better characterization of apnea patients.