Detection of Consciousness by EEG and Auditory Evoked Potentials

Technical University of Munich

Status and phase: Completed; Phase 4

Conditions: Electroencephalography/ Drug Effect; Anesthesia

Treatments: Drug: Propofol / Remifentanil; Drug: Sevoflurane / Remifentanil

Study type: Interventional

Funder types: Other

Identifiers

NCT01720615

2001

Details and patient eligibility

About

The objective of the present investigation is to analyze EEG and auditory evoked potentials at the transition from consciousness to unconsciousness and vice versa. A set of electroencephalographic and auditory evoked potential parameters should be identified that allows separation of consciousness from unconsciousness (reflected by responsiveness/unresponsiveness to command). The study is based on data of 80 patients undergoing general anesthesia with remifentanil and either sevoflurane or propofol.

Full description

During the past years, monitoring of anesthetic effects on the main target of anesthesia, the brain, has gained increasing attention. Monitoring of the spontaneous electroencephalogram (EEG) and of auditory evoked potentials (AEP) has been suggested. Even if EEG and AEP reflect effects of anesthetic drugs, a visual interpretation is not expedient. As a consequence, several processing methods have been suggested that reduce the electroencephalogram to a numerical value. In the current study, a set of EEG- and AEP parameters based on different analysis methods is tested with respect to the parameters ability in separating consciousness (reflected by responsiveness to command) from unconsciousness at the transition between these stages. Therefore data of 80 unpremedicated patients undergoing general anesthesia with remifentanil and either sevoflurane or propofol is used. The study period is from induction of anesthesia until patients follow command after surgery and includes a reduction of the hypnotic agent after tracheal intubation until patients follow command. The isolated forearm technique is applied before muscle relaxants are given to maintain the ability to squeeze hand to command.

Enrollment: 80 patients

Sex: All

Volunteers: No Healthy Volunteers

Inclusion criteria

• American Society of Anesthesiologists (ASA) physical status 1-2
• Adult patients

Exclusion criteria

• Patients with contraindications to the study drugs
• psychiatric or neurologic disease
• drug abuse or medication known to affect the central nervous system
• pregnancy
• indication for rapid sequence induction

Trial design

Primary purpose: Diagnostic

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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80 participants in 1 patient group

Propofol or Sevoflurane

No Intervention group

Description:

General anesthesia

Treatment:

Drug: Sevoflurane / Remifentanil

Drug: Propofol / Remifentanil