Induced Coma
Bursts erupt through an otherwise suppressed (electrically silent) EEG.
What is an induced coma?
When a head injury is severe or intracranial bleeding extensive, intracranial pressure (ICP) can build to a dangerous level, leading to serious complications including death. Other patients will develop frequent unremitting seizures known as "status epilepticus" which must be treated immediately for fear of brain damage and death if not stopped. In the case of ICP and status epilepticus the most effective treatment is induced coma. Coma is induced by administering hypnotic drugs until brain pressure has decreased or seizures have ceased.What is burst-suppression and when is it used?
The advent of pharmacologic brain protection in the operating room and ICU means that patients who would have died in past decades from traumatic brain injury or other cerebral insults now survive. Brain protection is attained by inducing burst-suppression, a coma characterized by electrical silence (suppression) punctuated or broken by brief large electrical bursts. Burst-suppresion reduces cerebral metabolism, which attentuates seizures and lowers ICP.Duration of electrical silence corresponds to depth of anesthesia: the longer the suppression, the deeper the coma. In the case of long-term intensive-care-unit (ICU) monitoring, evaluation and charting of burst-suppression events are part of an established patient-management protocol. Visual segmentation of burst-suppression activity is typically performed by nursing staff who attempt to calculate electrical silence duration (i.e., inter-burst interval) in order to titrate anesthesia. But in our experience this process is error-prone and for all practical purposes impossible to perform with any reasonable degree of accuracy. It is burdensome to the staff as they too recognize the difficulty or impossibility of accurately identifying the interval. The usual result is over- or under-sedation of a patient.
Observing this process is what led to the creation of the Wavestate burst-suppression monitor. The burst-suppression monitor uses automated computer-segmentation algorithms so there is no staff guesswork. An interval is calculated with statistical accuracy and displayed clearly. Our EEG monitors are easy to use and understand.