| Autor: |
Fernández-Muñoz J; Departamento de Ingeniería Informática, Facultad de Ingeniería, Universidad de Santiago de Chile, Santiago 9170022, Chile., Haunton VJ; Department of Cardiovascular Sciences, University of Leicester, Leicester LE1 7RH, UK.; National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK.; British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester LE5 4PW, UK., Panerai RB; Department of Cardiovascular Sciences, University of Leicester, Leicester LE1 7RH, UK.; National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK.; British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester LE5 4PW, UK., Jara JL; Departamento de Ingeniería Informática, Facultad de Ingeniería, Universidad de Santiago de Chile, Santiago 9170022, Chile. |
| Abstrakt: |
Cerebral hemodynamics describes an important physiological system affected by components such as blood pressure, CO 2 levels, and endothelial factors. Recently, novel techniques have emerged to analyse cerebral hemodynamics based on the calculation of entropies, which quantifies or describes changes in the complexity of this system when it is affected by a pathological or physiological influence. One recently described measure is transfer entropy, which allows for the determination of causality between the various components of a system in terms of their flow of information, and has shown positive results in the multivariate analysis of physiological signals. This study aims to determine whether conditional transfer entropy reflects the causality in terms of entropy generated by hypocapnia on cerebral hemodynamics. To achieve this, non-invasive signals from 28 healthy individuals who undertook a hyperventilation maneuver were analyzed using conditional transfer entropy to assess the variation in the relevance of CO 2 levels on cerebral blood velocity. By employing a specific method to discretize the signals, it was possible to differentiate the influence of CO 2 levels during the hyperventilation phase (22.0% and 20.3% increase for the left and right hemispheres, respectively) compared to normal breathing, which remained higher during the recovery phase (15.3% and 15.2% increase, respectively). |
