PURPOSE: Patients with high spinal cord injury(SCI) face death or life with mechanical ventilation. Ventilators, although life-saving, are inconvenient and associated with significant risks. This report outlines a single institution experience with the diaphragm pacing stimulation (DPS) system since the first implantation 7 years ago.
METHODS: In a prospective FDA trial, patients underwent outpatient laparoscopic diaphragm motor point mapping with electrode implantations. Stimulus/output characteristics of each electrode were determined and diaphragm conditioning initiated. Patients were weaned from their ventilators at home.
RESULTS: A total of 34 patients were implanted, there was a failure to pace in the second patient due to a false positive phrenic nerve study. The amount of time and daily episodes of conditioning the diaphragm affects speed to DPS ventilation. Age and time from injury directly affects conditioning time to achieve 4 continuous hours with DPS from less than 1 week for 18 to 20 year olds on a ventilator for less than one year to 14 weeks for 40 to 50 year olds on ventilators for great than 5 years. Both patients over 65 years took 21 weeks. Two patients requiring surgical correction of scoliosis prior to implantation have required prolonged conditioning to achieve adequate tidal volumes. Additional findings of DPS use include: reduction of airway pressure decreasing risks of barotrauma with a return of negative chest pressure; conversion of fast twitch glycolytic (IIb) to functional slow twitch oxidative muscle (I) fibers; improved posterior lobe lung ventilation with over 60% reduction in secretions and need for suctioning and increased measured respiratory compliance.
CONCLUSION: The DPS system is safe with a 97%s success rate and should replace the ventilator for SCI patients providing them more natural negative pressure ventilation. Ongoing results are being evaluated in a multi-center trial.
CLINICAL IMPLICATIONS: With the safety shown in this trial earlier implantation in tetraplegics would shorten initial implantation and possibly decrease the high rate of ventilator associated pneumonia in this population.
DISCLOSURE: Raymond Onders, No Product/Research Disclosure Information; Shareholder Myself, my university and my hospital have intellectual property rights and founded a company that manufactures some technology used in this study