ClinicalTrials.gov
ClinicalTrials.gov Menu

ERPS, BIS and Entropy for Neuromonitoring in ICU Patients

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT00639548
Recruitment Status : Completed
First Posted : March 20, 2008
Last Update Posted : March 20, 2008
Sponsor:
Collaborator:
GE Healthcare
Information provided by:
University Hospital Inselspital, Berne

Brief Summary:

Most critically ill patients receive sedative and analgesic drugs to attenuate discomfort and pain. The excessive use of sedatives and analgesics has undesirable effects for patients. Whereas undersedation is mostly easy to identify, oversedation with its associated problems is more difficult to recognize. Stopping sedation daily helps to avoid gross oversedation, but this is not always possible. Monitoring the depth of sedation is difficult and is currently based on clinical assessment and the use of clinical scoring systems. These scoring systems cannot be applied continuously, they are subjective and the level of consciousness can be altered when sedation is assessed.

Several methods based on the electroencephalogram have been tested to avoid these problems, but the results have been disappointing so far, so the BIS Monitor an dthe Entropy monitor.We have previously shown that the time-locked cortical response to standard external stimuli (long-latency auditory evoked potentials or event-related potentials; ERPs) can discriminate between clinically relevant light to moderate and deep sedation levels in healthy volunteers, when sedation is induced with a combination of propofol or midazolam with remifentanil.

We therefore hypothesized that ERPs may be used to monitor the depth of sedation in ICU patients as well. As the first step to test this hypothesis, we evaluated the use of ERPs to assess the level of sedation in patients undergoing elective major surgery and admitted to the ICU for short term postoperative mechanical ventilation.


Condition or disease
Deep Sedation Electroencephalography Event-Related Potentials Evoked Potentials, Auditory

Detailed Description:

Most critically ill patients receive sedative and analgesic drugs to attenuate discomfort and pain. The excessive use of sedatives and analgesics prolongs time on mechanical ventilation, the incidence of nosocomial pneumonia, time spent in the intensive care unit, and increases costs. Strategies to reduce the use of sedatives and analgesics may improve the outcome. Whereas undersedation is mostly easy to identify, oversedation with its associated problems is more difficult to recognize, but should be avoided. While stopping sedation daily helps to avoid gross oversedation, this is not always possible, e.g. due to unstable condition of the patient. Also, accumulation of sedatives and analgesics may occur rapidly, especially in patients with renal and/or liver dysfunction. Monitoring the depth of sedation is difficult and is currently based on clinical assessment and the use of clinical scoring systems. These scoring systems cannot be applied continuously, they are subjective and the level of consciousness can be altered when sedation is assessed.

Several methods based on the electroencephalogram have been tested to avoid these problems, but the results have been disappointing so far. A relatively new method of processed EEG is Entropy®. Entropy is a non-linear statistic parameter which describes the order of random repetitive signals. In patients it translates the anesthesia-induced "calmer", more synchronized EEG into a single parameter. Spectral entropy can reproducibly indicate the hypnotic effects of propofol, thiopental and different anesthetic gases. The most popular method of processed EEG for assessment of sedation is the bispectral index (BIS-Index®). While BIS has been tested and validated for the use in the operation room with different anesthetics, data on its use in the ICU setting at less deep levels of sedation are controversial. The multiple concomitant medications and heterogeneity of underlying pathologies present a further challenge to the use of neuromonitoring in the ICU.

We have previously shown that the time-locked cortical response to standard external stimuli (long-latency auditory evoked potentials or event-related potentials; ERPs) can discriminate between clinically relevant light to moderate and deep sedation levels in healthy volunteers, when sedation is induced with a combination of propofol or midazolam with remifentanil.

We therefore hypothesized that ERPs may be used to monitor the depth of sedation in ICU patients as well. As the first step to test this hypothesis, we evaluated the use of ERPs to assess the level of sedation in patients undergoing elective major surgery and admitted to the ICU for short term postoperative mechanical ventilation.


Study Type : Observational
Actual Enrollment : 20 participants
Observational Model: Case-Only
Time Perspective: Prospective
Official Title: Auditory Event-Related Potentials, BIS-Index and Entropy for the Discrimination of Different Levels of Sedation in the ICU Patients
Study Start Date : November 2004
Actual Primary Completion Date : July 2006
Actual Study Completion Date : September 2007



Primary Outcome Measures :
  1. Event related Potentials (Amplitudes, latencies) at different clinically relevant sedation levels [ Time Frame: postoperative awakening ]

Secondary Outcome Measures :
  1. BIS-Index at different clinically relevant sedation levels [ Time Frame: postoperative awaakening ]
  2. Entropy at different clinically relevant sedation levels [ Time Frame: postoperative awakening ]


Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.


Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
patients required an elective thoracic surgical intervention under general anesthesia and who were scheduled to the ICU for postoperative care
Criteria

Inclusion Criteria:

  • 18 Years or older

Exclusion Criteria:

  • ASA class III or higher history of adverse events during former surgery or anesthesia, neurological impairment in the medical history hearing abnormalities.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00639548


Locations
Switzerland
Departement of Intensive Care Medicine - University Hospital Bern - Inselspital
Bern, Switzerland, 3010
Sponsors and Collaborators
University Hospital Inselspital, Berne
GE Healthcare