Electronic Cough
Spinal Cord Injuries
The spinal cord is the communications network between the brain and the nerves in the rest of the body. When the spinal cord is injured, transmission of information to/from the area below the point of injury may be disrupted or lost. Tetraplegia (formerly referred to as quadriplegia) occurs when the spinal cord is damaged in the cervical spine (the neck area). This can lead to paralysis of the arms and legs and middle of the body. Paraplegia can occur with an injury in the middle to lower section of the spine and may cause paralysis of the legs.
According to the Christopher and Dana Reeve Foundation, about 1.275 million people in the U.S. are living with a spinal cord injury. About 12,000 new cases occur every year. Spinal cord injury is the second leading cause of paralysis in the U.S. (after stroke). Over 80 percent of patients are male. Average age at the time of injury is 40.2 years. The most common causes of spinal cord injury include: motor vehicle accidents (41.3 percent of all cases), falls (27.3 percent) acts of violence (15 percent) and sports (nearly 8 percent).
The Need to Cough
Cough is a normal reflex. Anthony DiMarco, M.D., Research Scientist with MetroHealth Medical Center in Cleveland, OH, says even clearing of the throat is a mild form of a cough. Normally, we do this many times a day, often without thinking or realizing that we are keeping the airways clear and preventing secretions and food from moving into the lungs
In patients with higher levels of spinal cord injury, communication with the muscles that control coughing is lost. Sticky secretions can accumulate in the airways and make their way into the lungs. As a result, it may become more difficult to breath. Bacteria may grow in the mucus, leading to a serious lung infection (pneumonia). In fact, researchers say pneumonia is a leading cause of death for patients with spinal cord injury.
There are several methods that may be used to clear secretions from the airways of someone who is unable to cough. In an assisted cough, an aide forcefully presses on the outside of the stomach in an upwards motion, manually stimulating a cough. The patient may also be positioned in a head down position to allow secretions to flow out of the lungs. A third option is to use mechanical suctioning to pull out the secretions from the airways like a vacuum cleaner. While all of these methods may be somewhat effective, they all require a helper, are often uncomfortable for the patient, and need to be repeated several times a day. This can greatly affect a patient’s quality of life.
Spinal Cord Stimulation for Cough
Researchers at Cleveland’s MetroHealth System are testing a new method of inducing a cough response in patients with spinal cord injuries, using spinal cord stimulation. Surgeons remove tiny sections of bone along the lower thoracic spine to access the spinal cord. Then two to three electrodes are implanted on the surface. A small receiver is implanted in the chest. The system is activated by an external stimulator. The stimulator sends a signal to the receiver, then on to the electrodes. This stimulates the muscles normally used for coughing to initiate the cough reflex.
In most patients with severe spinal cord injury, the coughing muscles have atrophied from non-use. Thus, it takes training for the patient to learn how to use the system effectively. The stimulator can be programmed to deliver a signal at predetermined times (i.e., once every 30 seconds, etc.). In addition, if needed, an aide can push a button on the stimulator to initiate a cough. The strength of the electrical signal can also be adjusted if the cough is too strong or too weak.
DiMarco says the biggest advantage to the spinal cord stimulator for cough is that patients can use the system without caregiver assistance, manual compressions or suction. Thus, patients’ quality of life may be greatly improved and the risk for respiratory infections decreased. The battery in the receiver is expected to last for 15 to 20 years, so patients will not need surgical replacement for some time after the system is implanted. Some patients experience elevation in heart rate and blood pressure, leg jerking and back straightening. These symptoms usually ease with time or by adjusting the strength of the electrical signal.
The spinal cord stimulator for cough is still under study. For more information, or to find out if you are eligible to participate in the clinical trial, call Dana Hromyak, RRT, Research Study Coordinator, at (216) 778-3612.
AUDIENCE INQUIRYFor more information, or to find out if you are eligible to participate in the clinical trial, call: Dana Hromyak, RRT, Research Study Coordinator, at (216) 778-3612.
For general information on spinal cord injuries:
Christopher and Dana Reeve Foundation, http://www.christopherreeve.org
National Institute of Neurological Disorders and Stroke, http://www.ninds.nih.gov
Spinal Cord Injury Information Network, http://www.spinalcord.uab.edu
BIBLIOGRAPHYBrown, Robert, M.D., et al., “Respiratory Dysfunction and Management in Spinal Cord Injury,” Respiratory Care, August 2006, Vol. 51, No. 8, pp. 853-870.
DiMarco, Anthony, M.D., et al., “Lower Thoracic Spinal Cord Stimulation to Restore Cough in Patients with Spinal Cord Injury: Results of a National Institutes of Health-Sponsored Clinical Trial Part I,” Archives of Physical Medicine and Rehabilitation, May 2009, Vol. 90, No. 5, pp. 717-725.
DiMarco, Anthony, M.D., et al., “Lower Thoracic Spinal Cord Stimulation to Restore Cough in Patients with Spinal Cord Injury: Results of a National Institutes of Health-Sponsored Clinical Trial Part II,” Archives of Physical Medicine and Rehabilitation, May 2009, Vol. 90, No. 5, pp. 726-732.
DiMarco, Anthony, M.D., et al., “A New Method to Produce an Effective Cough in Patients with Spinal Cord Injury,” American Journal of Respiratory and Critical Care Medicine, June 15, 2006, Vol. 173, No. 12, pp. 1386-1389.
Lee, Bonsan, et al., “Surface Functional Electrical Stimulation of the Abdominal Muscles to Enhance Cough and Assist Tracheostomy Decannulation after High-level Spinal Cord Injury,” The Journal of Spinal Cord Medicine, 2008, Vol. 31, No. 1, pp. 78-82.
