Intraoperative M-Entropy Measurements

2014-07-24 14:19:09 | BioPortfolio


The purpose of this study is to learn more about an Entropy monitor that your anesthesiologist will be using.


Depth of anesthesia monitors are increasingly used in clinical anesthesia practice. Bispectral Index (BIS) and M-Entropy are examples to these devices, both of which are available at our institution. Both BIS and M-Entropy use a unilateral, single channel of EEG to derive a number indicating the anesthetic depth. These devices have similar disposable skin probes that can be applied on either side of the forehead. Since the depth of anesthesia for an individual is the same over the whole brain cortex at a given point in time, BIS numbers obtained over the left and right side of the forehead should agree. The same should be true for M-Entropy as well.

A recent study, however, showed that two separate BIS probes, applied over the left and right forehead of the same patient at the same time, can give significantly different numbers. This has not been studied for M-Entropy. BIS and M-Entropy use different mathematical algorithms that process the raw EEG signal to compute a numeric value. Therefore, it is possible that M-Entropy may show different results in a similar study setup.

Our aim is to investigate the same-patient reproducibility of M-Entropy by monitoring and recording Entropy variables over both the left and the right side of the forehead of patients under general anesthesia.

Study Design

Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Supportive Care


General Anesthesia


Entropy monitor (Datex-Ohmeda S/5 EntropyTM Module)


OU MEDICAL CENTER, Presbyterian Tower, OR
Oklahoma City
United States




University of Oklahoma

Results (where available)

View Results


Published on BioPortfolio: 2014-07-24T14:19:09-0400

Clinical Trials [2066 Associated Clinical Trials listed on BioPortfolio]

Lung Recruitment and Postoperative CPAP

General anesthesia lowers FRC thereby promoting airway closure and absorption atelectasis. Alveolar recruitment manoeuvers recruit collapsed alveoli, increase gas exchange, and improve art...

Spire Medical Health Tag Respiratory Rate Validation in Adults

The primary purpose of this study is to conduct a Respiratory Rate accuracy validation comparing the Spire Medical Health Tag to a FDA cleared End Tidal Carbon Dioxide monitor Reference St...

BIS and Entropy in Deep Brain Simulation

The main objective of the study is to determine whether depth of anesthesia (DOA) monitoring such as Bispectral Index (BIS) and entropy are accurate in patients with neuro-psychological co...

Comparison of the Bispectral Index and the Entropy of the Electroencephalogram During Total Intravenous Anesthesia

To compare Bispectral index and entropy during maintenance of anesthesia

The Effect of Frontal Electromyogram (F-EMG) Activity on the Entropy Index Behavior During General Anesthesia

This study evaluates the effect of frontal EMG activity on Entropy index in burst suppression level of propofol anesthesia and surgery

PubMed Articles [7351 Associated PubMed Articles listed on BioPortfolio]

Spinal anesthesia compared with general anesthesia for neonates with hypertrophic pyloric stenosis. A retrospective study.

Studies of spinal anesthesia in children are limited to a reduced group of high-risk patients and it remains relatively underused compared with general anesthesia in this age group in most institution...

The role of regional vs general anesthesia on arteriovenous fistula and graft outcomes: a single institution experience and literature review.

Multiple studies have demonstrated the benefits of creating arteriovenous fistulas (AVFs) under regional anesthesia. This is most likely due to the avoidance of hemodynamic instability and stress resp...

Monitoring the Depth of Anesthesia through the Use of Cerebral Hemodynamic Measurements Based on Sample Entropy Algorithm.

The aim of this study is to explore the relationship between the depth of anesthesia and the cerebral hemodynamic variables during the complete anesthesia process.

Is regional anesthesia inferior or superior to general anesthesia in day-care arthroscopic knee surgery? The dilemma is still open-ended.

General anesthesia vs local anesthesia during mechanical thrombectomy in acute ischemic stroke.

To investigate the effect of general anesthesia (GA) on functional outcomes and complications rates in acute ischemic stroke (AIS) patients treated with mechanical thrombectomy (MT) compared to the us...

Medical and Biotech [MESH] Definitions

Abnormally slow pace of regaining CONSCIOUSNESS after general anesthesia (ANESTHESIA, GENERAL) usually given during surgical procedures. This condition is characterized by persistent somnolence.

The measure of that part of the heat or energy of a system which is not available to perform work. Entropy increases in all natural (spontaneous and irreversible) processes. (From Dorland, 28th ed)

The period of emergence from general anesthesia, where different elements of consciousness return at different rates.

A barbiturate that is administered intravenously for the production of complete anesthesia of short duration, for the induction of general anesthesia, or for inducing a hypnotic state. (From Martindale, The Extra Pharmacopoeia, 30th ed, p919)

Agents that induce various degrees of analgesia; depression of consciousness, circulation, and respiration; relaxation of skeletal muscle; reduction of reflex activity; and amnesia. There are two types of general anesthetics, inhalation and intravenous. With either type, the arterial concentration of drug required to induce anesthesia varies with the condition of the patient, the desired depth of anesthesia, and the concomitant use of other drugs. (From AMA Drug Evaluations Annual, 1994, p.173)

More From BioPortfolio on "Intraoperative M-Entropy Measurements"

Quick Search

Relevant Topics

An anesthesiologist (US English) or anaesthetist (British English) is a physician trained in anesthesia and perioperative medicine. Anesthesiologists are physicians who provide medical care to patients in a wide variety of (usually acute) situations. ...

Anesthesia is the loss of feeling or sensation in all or part of the body. It may result from damage to nerves or can be induced by an anesthetist (a medical professional) using anesthetics such as thiopental or propofol or sevoflurane during a surgical ...

Searches Linking to this Trial