Binder Free Diaphragm Pacing Stimulation and Airway Clearance Assistance

DESCRIPTION (provided by applicant): A low cost, low risk approach to diaphragm pacing stimulation has been developed by Synapse Biomedical and is currently being studied in patients with high level spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS). The initial results have demonstrated a high-level (> 90%) of success in allowing the SCI patients to breathe without a mechanical ventilator. Our objective is to enhance this successful device with capabilities of abdominal muscle control and airway clearance to further improve the function and health benefits for these patient populations. In both of these patient populations an additional problem is the inability to control abdominal musculature and have adequate airway clearance. If the abdominal muscles are weak or flaccid during inspiration the contraction of the diaphragm will result in a distension of the abdomen and an ineffective inspiration. The current means to avoid this problem is by wearing an external abdominal binder which loosens over time and causes irritation of the skin. Airway clearance (i.e. cough) is controlled by active contraction of the abdominal muscles following an inspiration. If these muscles are weak or flaccid they will not be able to produce the necessary strength of contraction to gain effective airway clearance. Our proposed project is to expand the number of stimulation channels of our current four channel diaphragm pacing system and add the necessary interfaces and algorithms to effect control of the abdominal muscles. One mode of stimulation would synchronize abdominal stimulation with the diaphragm stimulation to eliminate the abdominal binder. The second mode of stimulation would provide an "on-demand" airway clearance which would be done through the natural cough mechanism of the body - inspiration followed by a forceful exhalation. Upon successful design and bench testing of the system for this phase I project we will supplement our currently approved clinical investigations to incorporate these advances as part of a phase II project.