Diaphragm pacing with a spinal cord stimulator: current state and future directions

Diaphragm pacing with electrical stimulation of the phrenic nerve is an established treatment for central hypoventilation syndrome. The device, however, is not readily available. We tested the same spinal cord stimulator we use for pain control in phrenic nerve stimulation. We implanted a spinal cord stimulator (Itrel 3 or X-trel, Medtronic, MN) in 6 patients with chronic hypoventilation because of brainstem or high cervical cord dysfunction. The stimulation electrode was placed along the right phrenic nerve in the neck, and the device was implanted in the anterior chest. We used the cyclic mode, and set the parameters at I second ramp up, 2 seconds on, 3 seconds off. The pulse width and the frequency were set at 150 microseconds and 21 Hz, respectively. The amplitude of the output was adjusted to obtain sufficient tidal volume and to maintain PaCO2 at around 40 mm Hg. During a follow-up period up to four years, stable and sufficient ventilation was observed in all patients without any complications. Although further long follow-up is necessary, diaphragm pacing with the spinal cord stimulator is feasible and effective for the treatment of the central hypoventilation syndrome.