Monitoring depth of sedation: evaluating the agreement between the Bispectral Index, qCON and the Entropy Module's State Entropy during flexible bronchoscopy.
BACKGROUND
We investigated the correlation and agreement of three depth of anesthesia indices, Bispectral Index (BIS), qCON and state entropy (SE) during propofol sedation, because there is extensive literature that deals with the comparability of these indices during general anesthesia, but not during sedation.


METHODS
We recorded electroencephalogram (EEG) and SE trend data, using the Entropy Module from 21 patients who underwent elective bronchoscopy with target-controlled infusion of propofol. EEG data were replayed to BIS and qCON with an EEG player. We calculated the Spearman correlation to evaluate similarities in index trend behavior and estimated the general index agreement of displaying the same anesthetic level, i.e., wakefulness, sedation and anesthesia. We used coughing episodes and the bronchoscope placement to investigate the index for possible arousal reactions.


RESULTS
We found a high to very high correlation of the indices' trend during the procedure. Furthermore, qCON was significantly lower than BIS and SE. All indices increased significantly after bronchoscope placement and coughing. The agreement of BIS/SE was 68% and around 50% for BIS/qCON and qCON/SE. The median duration of disagreement by >10 points was 39 s for BIS/SE and around 75 s for qCON with BIS and SE.


CONCLUSIONS
The results indicate a high probability of similar index performance between SE, BIS and qCON with the caveat of a different index scaling for qCON. These results can help the user of these monitoring devices to translate findings from one index to the other.
Department of Anesthesiology, Rechts der Isar Hospital, Technical University of Munich, Munich, Germany.|Medical Clinic and Policlinic, Rechts der Isar Hospital, Technical University of Munich, Munich, Germany.
Johannes N
JN
Müller
Department of Anesthesiology, Rechts der Isar Hospital, Technical University of Munich, Munich, Germany.|Department of Anesthesiology, Atlanta VA Hospital, Decatur, GA, USA.|Emory University Hospital, Atlanta, GA, USA.
Matthias
M
Kreuzer
Department of Anesthesiology, Atlanta VA Hospital, Decatur, GA, USA.|Emory University Hospital, Atlanta, GA, USA.
Paul S
PS
García
Department of Anesthesiology, HELIOS University Hospital, Witten/Herdecke University, Wuppertal, Germany.
Gerhard
G
Schneider
Medical Clinic and Policlinic, Rechts der Isar Hospital, Technical University of Munich, Munich, Germany - hautmann@tum.de.
Hubert
H
Hautmann
D000328:Adult; D001999:Bronchoscopy; D056805:Consciousness Monitors; D000078331:Correlation of Data; D054810:Deep Sedation; D004569:Electroencephalography; D019277:Entropy; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D015742:Propofol / Q000627:therapeutic use*
D006993:Hypnotics and Sedatives; D015742:Propofol