Clinical trial NCT00599066: Intraoperative M-Entropy Measurements
Official title: Same-patient Reproducibility of Intraoperative M-Entropy Measurements
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: General Anesthesia
Keywords: M-Entropy
Lead sponsor: University of Oklahoma
Sponsor class: OTHER
First posted: 2008-01-23
Enrollment: 24
Sex: ALL
Minimum age (years): 18
Maximum age (years): 90
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: CASE_ONLY
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients that are scheduled to have surgery under general anesthesia for which an intraoperative M-Entropy monitoring is planned. Suitable candidates will be identified by speaking to the attending anesthesiologists working at OU Presbyterian hospital.

Brief summary: The purpose of this study is to learn more about an Entropy monitor that the anesthesiologist will be using.

Detailed description: 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.

The 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.

Eligibility criteria: Inclusion Criteria:

* Patients scheduled to have surgery under general anesthesia, with a minimum of 60 minutes expected duration.

Exclusion Criteria:

* Non-English speaker
* Patients younger than 18 years of age

Primary outcomes:
measure: The investigators hypothesize that simultaneous M-Entropy measurements from the left and right side of the forehead of a person do not differ during general anesthesia.
timeFrame: 1 year
Secondary outcomes:
Other outcomes:
Locations:
city: Oklahoma City
country: United States
facility: OU MEDICAL CENTER, Presbyterian Tower, OR
state: Oklahoma
Study officials:
affiliation: The University of Oklahoma Health Sciences Center, Department of Anesthesiology
name: Mehemet Ozcan, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Niedhart DJ, Kaiser HA, Jacobsohn E, Hantler CB, Evers AS, Avidan MS. Intrapatient reproducibility of the BISxp monitor. Anesthesiology. 2006 Feb;104(2):242-8. doi: 10.1097/00000542-200602000-00007.
citation: Ozcan MS, Gravenstein D. The presence of working memory without explicit recall in a critically ill patient. Anesth Analg. 2004 Feb;98(2):469-470. doi: 10.1213/01.ANE.0000096184.32247.D0.