Cambridge Journals Online

Original Article

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

F. Webera1 c1a, M. Steinbergera2, M. Ritzkaa3a, C. Prassera2 and T. Beina2 a1 Sophia Children’s Hospital, Erasmus University Medical Center Rotterdam, Department of Anesthesiology, Rotterdam, The Netherlands a2 University Hospital Regensburg, Department of Anaesthesia, Franz-JosefStrauss-Allee, Regensburg, Germany a3 University of Regensburg, Department of Neurology, Universitätsstraße, Regensburg, Germany

Article author query weber f   steinberger m   ritzka m   prasser c   bein t

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 (P_K) 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 (P_K 0.75). Using the three-level sedation scale instead, P_K 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.

(Accepted June 19 2007)

Key Words: ELECTRODIAGNOSIS, electroencephalography; HYPNOTICS AND SEDATIVES; PROPOFOL; CRITICAL CARE; RESPIRATION ARTIFICIAL

Correspondence:

^c1 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

Footnotes

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