Leg vein pressure pulser (LVPP): a mechatronic device for spinal cord injured patient standing in for the ineffectiveness of paralyzed leg muscles to pump blood from leg veins towards heart

Paraplegic subject often experience an impairment of the cardiovascular function. One of the most important factors in the occurrence of this situation is the drastic reduction in venous return from the muscle at rest, due to the absence of the function of muscle pump that is present in the able-bodied subjects. It is reasonable to assume that an external mechanical force applied on the lower limbs of paraplegic subjects might produce a positive effect on cardiovascular condition. Accordingly, the research aimed to identify and develop a robotic device to restore the cardiovascular function in paraplegics. To test this hypothesis we performed two experimental studies involving healthy subjects where two automatic robotic able to apply an ascendant external pressure to lower limbs were tested. Hemodynamic response was monitored beat-by-beat by means of impedance cardiography and Doppler ultrasound was used to measure cardiac volumes. Results show that the application of robotic mechanical actuators pneumatic is able to generate cycles of compression and decompression on venous structures of the lower limbs similar to what normally happens in the skeletal muscle when subjects are walking. Especially when actuators simulated muscle pattern activation similar to mechanism of walking we were able to further increase cardiac output and end diastolic volume. In conclusion our preliminary finding suggest that is possible to compensate partially the lack of venous return in spinal cord injury population thus increasing the quality of life, reducing the risk of cardiovascular disease and then extend their life expectancy.