Phrenic pacing in SCI

1. How does phrenic pacing work?
2. What are contraindications to phrenic pacing?
3. What are benefits of phrenic pacing?
4. What are signs of failure of phrenic pacing?
5. Why might phrenic pacing fail?

Answer:
1. The intact phrenic nerves are stimulated electrically via surgically implanted electrodes.
2. Denervated diaphragm (demonstrated by EMG), denervated anterior horn cells C3-C5, less than 6 mo post-injury (chest too flaccid), significant lung impairment.
3. Increased arterial oxygenation, longer survival, increased daily function.
4. Sharp chest pain, SOB, absence of breath, erratic pacing.
5. Diaphragmatic failure (overly aggressive pacing), infection, meds (sedatives, narcotics), upper airway obstruction, phrenic nerve damage from overstimulation or surgery.