Quick Guide

Entropy monitoring: A valuable tool for guiding delivery of anesthesia

The GE Entropy™ Module is used during anesthesia to monitor the state of the brain in adult and pediatric patients by acquiring of EEG and frontal electromyograph (FEMG) signals. The Entropy measurement is used as an adjunct to other physiological parameters. This quick guide describes the Entropy Module and explains how to apply it in clinical cases.

Entropy is a measure of irregularity in a signal. During general anesthesia, EEG signals change to more regular patterns and FEMG also quiets down as the brain becomes saturated with anesthetics. The Entropy Module quantifies the irregularity of EEG and FEMG signals. High Entropy values signify that the patient is awake; low Entropy values indicate low probability of consciousness.

There are two Entropy parameters. Fast-acting Response Entropy is sensitive to the activation of facial muscles. The slower-acting State Entropy can be used to estimate the hypnotic effect of anesthetic drugs on the brain. These measurements can be used to:

  • Help titrate anesthetic drugs to suit the individual needs of the patient
  • Help achieve faster emergence from anesthesia and optimize the perioperative process by increasing patient flow efficiency.
  • Help assess adequacy of anesthesia.

By using Entropy with other monitored parameters such as the hemodynamic measurements and NMT, clinicians can get a complete picture of patient status combined on one screen. All values are stored in the monitor memory for trending and information management.

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