A prospective study of temporal course of phrenic nerve palsy in children after cardiac surgery.

The aim of the study is to determine the temporal course of phrenic nerve palsy in children after cardiac surgery. Prospective electrophysiological measurement of phrenic nerve latencies and diaphragmatic action potential (DAP) amplitudes before and after operation were recorded in 59 children who underwent open heart surgery for congenital heart disease. In patients with phrenic nerve dysfunction, the procedure was repeated at 1 week and 2 weeks after the operation to determine the temporal course. In the early postoperative period, 12 patients had abnormal left phrenic nerve latencies and/or DAP amplitudes, 11 had abnormal right phrenic nerve latencies and/or DAP amplitudes, and 3 had abnormal bilateral phrenic nerve latencies and/or DAP amplitudes. After 2-week follow-up, only one of these patients had persistent left phrenic nerve palsy. Prolonged phrenic nerve latencies and decreased DAP amplitudes often occur in the early postoperative phase in children who undergo cardiac surgery. This palsy is usually transient, and electrophysiologic studies should be repeated at least up to 1 week after surgery before diaphragmatic plication is considered.