Neurological Applications of Hemodynamics and Pulmonary Monitoring

The elaborate heart-brain axis was historically highlighted by French physiologist, Claude Bernard, in the early twentieth century. The nervous system controls cardio-pulmonary function through a network of neuronal loops and feedback systems. Sensory feedback, such as inadequate neural tissue blood flow, results in signals to increase blood pressure, largely via autonomic output which may lead to variable effects in hemodynamic augmentation or attenuation depending on the clinical scenario. Moreover, the brain has important effects on pulmonary function, largely through control of respiratory patterns (see below), but also indirectly via hemodynamic input. Moreover, neurologic processes can affect pulmonary function on virtually all axes of neurologic function; more specifically, from the intracranial CNS to the spinal cord and peripheral nervous system, to the neuromuscular junction. The impacts produce oxygenation and carbon dioxide abnormalities due to issues with neurogenic pulmonary parenchymal issues, control of breathing, airway dysfunction, and disordered respiratory muscle function. Numerous disease states alter brain-heart and brain-lung interactions. Monitoring for such interactions can provide insight as to neural function and such monitors are reviewed.