RESPIRATORY MUSCLE STIMULATION IN PATIENTS WITH SPINAL CORD INJURY

Spinal cord injuries often cause paralysis of the respiratory muscles. Loss of inspiratory muscle function, including the diaphragm, results in respiratory failure. Loss of expiratory muscle function markedly reduces cough effectiveness. Electrical stimulation techniques have been developed to pace the diaphragm and restore inspiratory muscle function. Bilateral phrenic nerve pacing is commercially available and a clinically accepted technique to restore respiratory muscle function, freeing patients from dependence upon mechanical ventilation. Clinical trials of laparoscopically placed intramuscular diaphragm electrodes are underway as an alternative to phrenic nerve pacing. This method would alleviate the need for a thoracotomy and reduce the possibility of phrenic nerve injury. Clinical studies are also in progress to restore inspiratory intercostal muscle function. Combined intercostal and unilateral diaphragm pacing holds promise as an alternative method of ventilatory support in patients with only unilateral diaphragm function and therefore not candidates for phrenic nerve pacing. Finally, a number of methods of expiratory muscle activation are being evaluated to restore expiratory muscle function. Restoration of an effective cough mechanism may reduce the incidence of respiratory tract infection and atelectasis, common causes of morbidity and mortality in the spinal cord injury population.