Hypoventilation after spinal cord injury.

There are ~12,000 new cases per year in the United States of spinal cord injury (SCI) with life expectancies from 11 to 14 years (ventilator dependent) to 44 years (non-ventilator dependent). Those with SCI (C2-C8) are at great risk for developing hypoventilation, especially during sleep, and this risk increases along with the risk of sleep disordered breathing as they age. Most will have significantly reduced vital capacity and ventilatory reserve because of interruption of neural pathways to the diaphragm, chest, and abdomen, resulting in a restrictive ventilatory impairment with intact diffusing capacity. Diagnosis entails measurement of pCO (2) with capnography both awake and during sleep, optimally along with polysomnography to evaluate for all forms of sleep disordered breathing. Treatment options include diaphragmatic pacing, full positive pressure ventilation through tracheostomy, and noninvasive positive pressure ventilation. Some may require mechanical ventilation only during sleep.