Phrenic nerve conduction studies in the evaluation of ventilatory problems in patients with cranio-cervical trauma.

Five patients with hypoventilation and paresis of the diaphragm following trauma to the cervical spinal cord, brain stem, or both, were evaluated with phrenic nerve conduction studies while being considered for implantation of a phrenic nerve stimulator. Several distinct patterns of phrenic nerve function were elicited in the various cases, allowing accurate predictions and management decisions to be made. Phrenic nerve conduction studies are felt to be a valuable diagnostic tool in the management of the hypoventilating patient with cranio-cervical trauma. The procedure is safe, rapid, and easily performed at the bedside.