Postanoxic alpha (theta) coma: a reappraisal of its prognostic significance

Objectives: To appraise the controversial prognostic significance of postan oxic alpha or theta coma (ATC). Methods: We prospectively assessed 14 comatose patients with ATC after card iac arrest by means of a protocol which included repeated clinical examinat ions, EEG, and median somatosensory evoked potentials (SEP). Good outcome w as defined by the reappearance of cognition (Glasgow outcome scale 3-5) at any time during the 1 year follow-up. Results: Nine of 14 patients had a monotonous, frontally accentuated and ar eactive alpha (theta) EEG activity (complete ATC). In these patients ATC wa s recorded a mean of 47 h after resuscitation, the mean Glasgow coma scale (GCS) was 4 at 48 h, and early cortical SEPs were altered or absent in 5 of 7 patients. All nine patients died. In five of 14 patients the alpha (thet a) EEG activity was either not monotonous, partially reactive or posteriorl y dominant (incomplete ATC). In these patients ATC was recorded a mean of 4 3 h after resuscitation, the mean GCS was 8 at 48 h, and early cortical SEP were normal in 4 of 5 patients. Three of 5 patients regained cognition, tw o of them remained however dependent in activities of everyday life. Conclusions: This study and a review 283 cases of postanoxic ATC reported i n the literature suggest the existence of incomplete and complete variants of postanoxic ATC. Whereas complete ATC is invariably associated with a poo r outcome, full recovery is possible in patients with incomplete ATC. The c ombination of EEG, clinical, and SEP findings improves the prognostic accur acy of postanoxic ATC. (C) 2000 Elsevier Science Ireland Ltd. All rights re served.