Neuronal Mechanisms of Sensory Processing During General Anesthesia

Condition(s) targeted: General Anesthesia

Intervention: Sevoflurane (Drug); Isoflurane (Drug); Desflurane (Drug); Propofol (Drug); Fentanyl (Drug); Sufentanil (Drug); Alfentanil (Drug); Remifentanil (Drug); Midlatency auditory evoked potentials (Device)

Phase: N/A

Status: Active, not recruiting

Sponsored by: Ludwig-Maximilians - University of Munich

Official(s) and/or principal investigator(s):
Michael AM Daunderer, M.D.,Ph.D., Principal Investigator, Affiliation: Klinik fuer Anaesthesiologie, Ludwig-Maximilians-Universitaet Muenchen

The ability of Mid Latency Auditory Evoked Potentials for a routine monitoring of sensory suppression should be evaluated during a wide spectrum of clinically common forms general anesthesia.

Official title: Neuronale Mechanismen Der Sensorischen Reizverarbeitung in Der Narkose

Study design: Supportive Care, Randomized, Single Blind, Active Control, Parallel Assignment, Safety/Efficacy Study

Primary outcome:

Intraoperative signs of inadequate anesthesia

Postoperative recall of events

MLAEP parameters

Detailed description: Up to now there is no fully functional and precise technique for accurate assessment for monitoring the degree of unconsciousness during general anaesthesia. Previous studies and results obtained during the project regarding the effect of anaesthetics on single neurons and small neuronal networks indicate that it would be most promising to use a method directly correlating to the integrity of the relevant functional systems. As one goal of the project it was formulated to develop and test a new system for recording and analysis of mid latency auditory evoked potentials (MLAEP), suitable to be used in the clinical surrounding of an operation theatre. Step by step an investigational system was developed, that after obtaining legal approvement was functional in a broad spectrum of cases. In a multicenter study the including 4 clinical centres and 426 patients the reliability of the system was proved. Even under the hard conditions of the OR the apparatus was able to record the signals with sufficient reliability and precision. A clear correlation of MLAEP parameters with clinically defined states of consciousness could be identified. Differences in the effect of the used combinations of general anaesthetics and opioids were identified. An algorithm for automatic analysis of the signals was developed, to allow users with limited knowledge of interpretation of MLAEP signals to use them for monitoring anaesthesia.

Minimum age: 18 Years. Maximum age: 65 Years. Gender(s): Both.

Criteria:

Inclusion Criteria:

- Male and female patients

- Scheduled for elective urological, gynaecological or general surgery

- ASA status I or II

- Age 18 to 65

Exclusion Criteria:

- ASA status above II

- Operative procedures involving the neurocranium, neck or require other

neurophysiologic monitoring

- Inability to communicate freely in the german language

- Major hearing deficit

- Regular centrally acting medication including drug abuse within 3 months prior to the

investigation

- Participant of an other clinical investigation

- Lacking or withdrawal of written informed consent

Klinik fuer Anaesthesiologie der Ludwigs-Maximilians-Universitaet Muenchen, Munich 80336, Germany

Klinik für Anaesthesia am Universitaetsklinikum Heidelber, Heidelberg 69120, Germany

Krankenhaus Friedrichshafen, Friedrichshafen 88048, Germany

Klinik fuer Anaesthesiologie am Universitätsklinikum Schleswig Holstein, Campus Luebeck, Lubeck 23538, Germany

homepage of the institute for medical psychology of the Ludwigs-Maximilians-University Munich

Starting date: October 2002
Ending date: December 2003
Last updated: February 12, 2007