Diaphragm Pacing in Spinal Cord Injury Successful in Weaning Patients from Ventilators, Bridging to Independent Respiration
Diaphragm pacing (DP) stimulation in spinal cord-injured patients is successful not only in weaning patients from mechanical ventilators, but also in bridging patients to independent respiration, where they could breathe on their own without the aid of a ventilator or stimulation, according to a new study published in the Journal of Trauma and Acute Care Surgery.
The stimulation is provided by the NeuRX® Diaphragm Pacing System (DPS), a technology providing electrical stimulation to nerves running through the diaphragm, the major muscle involved in breathing. When stimulated, the diaphragm contracts, allowing patients to breathe more naturally than having air forced into their lungs as a mechanical ventilator would do. The system is implanted through minimally invasive laparoscopic surgery.
The study examined the records of 29 patients – with an average age of 31 – at 16 hospitals in the United States where DP implantation is approved. Shepherd Center is one of those facilities. Causes of spinal cord injury (SCI) in these patients included car and diving accidents, gunshot wounds, falls and sports-related injuries. Elapsed time from injury to surgery was 40 days, which was considerably shorter than an initial FDA trial in which patients did not have DP testing and surgery for more than a year after injury. All but two patients were men. A goal of this study was to determine if earlier testing and DP implants provided benefit.
Of the patients whose diaphragm muscles responded to stimulation, 16 of 22 patients (72 percent) were completely free of ventilator support in an average of 10 days. Of the remaining six patients, two had a delayed weaning of six months, three had partial weans using DP at times during the day. (One patient successfully implanted went to a long-term acute care hospital and subsequently had life-prolonging measures withdrawn.) Seven of the 29 patients were found to have diaphragms that could not be stimulated because of nerve damage.
Eight patients (36 percent) had complete recovery of respiration, and DP wires were removed.
“This study provides compelling new information,” said Andrew Zadoff, M.D., medical director of respiratory and critical care services at Shepherd Center, which is one of the medical facilities implanting DPS. “The idea of placing DPS early for quicker weaning is exciting. It corresponds with the concept of losing muscle strength in the diaphragm because of the loss of spontaneous breathing.”
One of the inventors of DPS and an author of the new study, Raymond Onders, M.D., of University Hospitals (UH) Case Medical Center and a professor of surgery at Case Western Reserve University School of Medicine in Cleveland, Ohio, noted several important observations made in the study.
“Most notably, laparoscopic diaphragm mapping – an electronic reading of the diaphragm nerves – is safe and can be performed in multiple centers with success,” Dr. Onders said. “In addition, early diaphragm mapping can quickly determine if a phrenic nerve injury is complete, allowing for early ventilator planning and prevention of weaning trials if we find the patient will not be able to be weaned from the ventilator. Finally, DP can successfully wean traumatic cervical SCI patients as evidenced by 72 percent of the implanted patients being completely weaned from ventilators and 36 percent with complete recovery and DP removal.
“DP is a major step in improving the quality of life for patients who have spinal cord injuries and cannot breathe without the help of a ventilator,” Dr. Onders added. “Based on testimonials I’ve received from patients who have been in the clinical trials, DP provides patients with a freedom of mobility that they never imagined. They’ve sent photographs or videos of themselves parachuting from planes, sailing solo or enjoying rides at amusement parks with their families – activities impossible to do with a ventilator.”
Traumatic spinal cord injuries that require chronic ventilator dependence are relatively rare: Less than 4 percent or 480 cases out of the estimated 12,000 traumatic SCIs occurring annually in the United States.
DPS has also been approved for patients with amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s disease) and is being used in patients with other conditions, as well.
DPS is made by Synapse Biomedical Inc., a company co-founded by Dr. Onders and located in Oberlin, Ohio. Dr. Onders, University Hospitals Case Medical Center and Case Western Reserve University have intellectual property rights in Synapse.
For more information about DPS implantation at Shepherd Center, click here.
Shepherd Center, located in Atlanta, Georgia, is a private, not-for-profit hospital specializing in medical treatment, research and rehabilitation for people with spinal cord injury, brain injury, multiple sclerosis, spine and chronic pain, and other neuromuscular conditions. Founded in 1975, Shepherd Center is ranked by U.S. News & World Report among the top 10 rehabilitation hospitals in the nation. In its more than four decades, Shepherd Center has grown from a six-bed rehabilitation unit to a world-renowned, 152-bed hospital that treats more than 935 inpatients, 541 day program patients and more than 7,300 outpatients each year.