Electroencephalographic changes with hypothermia and cardiopulmonary bypass in children.

Our experience of EEG changes associated with hypothermia, induced predominantly by core cooling, is presented. Easily recognizable, repeatable patterns emerge and four different types of changes are seen, from generalized slowing and loss of faster rhythms progressing to discontinuous activity, burst suppression activity, and finally loss of all cerebral potentials. These patterns were not altered significantly by anesthetic agents or by patient age or weight differences. Abnormalities of various kinds can be distinguished from the hypothermic changes. In particular, continuous epileptiform activity can be recognized and therefore abolished.