Monitoring and Assessment of Cardiovascular Regulation in Spinal Cord Injured Patients

Spinal cord injured patients suffer from unstable regulation of their cardiovascular function due to nerve damage caused by the injury. Currently there is no well established method for continuous monitoring and assessment of cardiovascular regulation in spinal cord injured patients during rehabilitation. Therefore, a design for a cardiovascular regulation monitoring device capable of detecting blood flow is proposed in this study. The proposed design is based on using photoplethysmographic (PPG) sensors which detect the fluctuations of light absorption in tissue during blood flow. These fluctuations oscillate at the heart cycle rate owing to the cardiac induced increase in the tissue blood volume during systole. Using the device, heart rate variability, and variations in the PPG signal (both amplitude and baseline which reflect the vessels compliance and blood flow) are analysed to assess the cardiovascular regulation function. The sensors may be located at different body sites and therefore allow inspection of the correlation of blood flow at various body locations, thus assessing the tone of the variations from a central origin in SCI patients. The described device has been designed for early clinical investigation and test results demonstrate that it has the capabilities of providing quantitative assessment of spinal cord injured patient´s cardiovascular regulation