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Measuring depth of sedation in intensive care patients with the electroencephalographic Narcotrend Index

Published online by Cambridge University Press:  01 February 2008

F. Weber*
Affiliation:
Sophia Children’s Hospital, Erasmus University Medical Center Rotterdam, Department of Anesthesiology, Rotterdam, The Netherlands
M. Steinberger
Affiliation:
University Hospital Regensburg, Department of Anaesthesia, Franz-JosefStrauss-Allee, Regensburg, Germany
M. Ritzka
Affiliation:
University of Regensburg, Department of Neurology, Universitätsstraße, Regensburg, Germany
C. Prasser
Affiliation:
University Hospital Regensburg, Department of Anaesthesia, Franz-JosefStrauss-Allee, Regensburg, Germany
T. Bein
Affiliation:
University Hospital Regensburg, Department of Anaesthesia, Franz-JosefStrauss-Allee, Regensburg, Germany
*
Correspondence to: Frank Weber, Department of Anaesthesiology, Erasmus University Medical Center Rotterdam – Sophia Children’s Hospital, P.O. Box 2060, 3000CB Rotterdam, The Netherlands. E-mail: f.weber@erasmusmc.nl; Tel: +31 463 1145; Fax: +31 463 6804
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Summary

Background and objective

The electroencephalographic Narcotrend Index was evaluated as a measure of sedation in mechanically ventilated intensive care unit patients. Narcotrend Index and conventional electroencephalography parameter values were compared to the Richmond Agitation-Sedation Scale and a simplified three-level sedation scale.

Methods

In all, 100 mechanically ventilated patients, admitted to the cardiac surgical intensive care unit after open-heart surgery, were enrolled in this prospective observational study. The Narcotrend Index was recorded while patients were either sedated by propofol infusion or without sedative medication while being weaned off the ventilator. Clinical assessment of the patients’ level of sedation was performed by means of the Richmond Agitation-Sedation Scale by a single observer who was blinded to the Narcotrend Index.

Results

With the six-level Richmond Agitation-Sedation Scale, the prediction probability (PK) for the Narcotrend Index (0.81) was better than for all other electroencephalography parameters (P < 0.01) except for relative power in the β band (PK 0.75). Using the three-level sedation scale instead, PK values for the Narcotrend Index (0.88) and all electroencephalography parameters improved (P < 0.01), and the Narcotrend Index was now superior to all electroencephalography parameters. Narcotrend Index values were distributed among the various sedation levels with significant overlap.

Conclusion

When used for assessment of propofol sedation in postsurgical cardiac intensive care unit patients, the Narcotrend Index can distinguish between very light and deep sedation. With respect to differentiation between light and moderate or moderate and deep sedation, the Narcotrend Index was not reliable in this study.

Type
Original Article
Copyright
Copyright © European Society of Anaesthesiology 2007

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Footnotes

a

Formerly: Department of Anaesthesia, University Hospital Regensburg, Franz-JosefStrauss-Allee 11, 93053 Regensburg, Germany.

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