Phrenic nerve function after pneumonectomy.

Using surface electrodes over the lower chest wall, we measured the phrenic nerve conduction time, ie, the time interval between the stimulation of the phrenic nerve in the neck and the onset of the diaphragmatic muscle action potential, in ten patients who had undergone pneumonectomy several years before (mean, eight years) and in 31 control subjects (bilaterally in 19 of them). The mean (+/- SD) value in the control subjects was 7.0 (+/- 0.9) msec, and no value exceeded 10 msec. All the values obtained in the patients were within the control range. We concluded that phrenic nerve function remains normal after pneumonectomy. This method appears to be the most effective means of identifying phrenic nerve involvement in these patients.