The burst-suppression electroencephalogram.

The burst-suppression (BS) pattern of the EEG occurs in a rather limited number of conditions. It has been observed in deep stages of general anesthesia and in conjunction with sedative overdoses. It is also known to occur in the wake of cardiorespiratory arrest. Undercutting of the cortex has been found to result in BS activity. Rare neonatal epileptic encephalopathies also give rise to BS. Our personal interest was prompted by the consistent finding of BS activity in rats following cerebral anoxia (nitrogen inhalation, airway obstruction): after periods of EEG flatness, BS activity developed, followed by periodic bursts and diffuse slowing. On the other hand, earlier literature (before 1960) showed virtually no observation of BS, neither in anoxic patients, nor in animal experiments. It is likely that the introduction of modern intensive care treatment has engineered episodes of BS activity, probably due to modifications of the anoxic cerebral pathology.