Cerebral Autoregulation and Gas Exchange Studied Using A Human Cardiopulmonary Model

We have previously developed a model of human cardiopulmonary (CP) system, which included the whole body circulatory system, gas exchange at both lungs and peripheral tissue, and central nervous control of arterial pressure and ventilation. We now add a more detailed description of cerebral circulation, cerebrospinal fluid (CSF) dynamics and brain gas exchange. Two cerebral blood flow (CBF) regulatory mechanisms are included: autoregulation and CO ₂ reactivity. The cerebral model is first validated in an open-loop configuration using input data generated by the cardiopulmonary model as inputs, then is integrated into the CP model to form an integrated CP model. It is this integrated model that we used to study the response to thigh cuff experiment. Our model demonstrated the ability to closely mimic the experimental findings and to provide predictions regarding the state of cerebral autoregulation and brain tissue gas-exchange. With further refinement, it may serve as a useful tool in clinical evaluation of the cerebral autoregulation and brain oxygenation.