Mechanism of Burst-Suppression During General Anesthesia: Review of Narrative Literature

Burst suppression is an electroencephalography pattern that is characterized by periods of high-voltage electrical activity alternating with periods of no activity in the brain. The pattern is found in patients with inactivated brain states, such as from general anaesthesia, coma, or hypothermia. The pseudo-rhythmic pattern of burst suppression is dictated by extracellular calcium depletion and the ability of neurons to restore the concentration. Bursts are accompanied by depletion of extracellular cortical calcium ions to levels that inhibit synaptic transmission, which leads to suppression periods. During suppression, neuronal pumps restore the calcium ion concentrations to normal levels, thus causing the cortex to be subject to the process again. As the brain becomes more inactive, burst periods become shorter and suppression periods become longer. The shortening of bursts and lengthening of suppression is caused by the central nervous system's inability to properly regulate calcium levels due to increased blood brain permeability.