[Somatosensory evoked potentials in patients with hypoxic coma--correlation with neurologic prognosis]

Somatosensory evoked potentials to median nerve stimulations were recorded in 21 patients with hypoxic coma within 24 hours from the onset. According to the neurologic prognosis, the patients were classified into 4 groups, such as I, complete recovery (5 patients), II, partial recovery (3 patients), III, vegetable state (8 patients), IV, brain death (5 patients). Measurements performed include central conduction time (N13-N20 interpeak latency) and amplitude ratio between N20 and P25. As N20 and P25 disappeared in 3 of 8 vegetable patients and all of brain death patients, disappearance of these waves indicates poor neurologic prognosis. Central conduction time showed no significant difference. Amplitude ratio between N20 and P25 (P25/N20) revealed significant decrease in vegetative patients for normal control subjects, complete recovery and partial recovery patients (p less than 0.05). Measurement of this ratio in early phase is useful to predict neurologic outcome in patients with hypoxic coma.