Clinical comparison of three different anaesthetic depth monitors during cardiopulmonary bypass

Abstract

SummaryThe lack of a gold standard complicates the evaluation and comparison of anaesthetic depth monitors. This randomised study compares three different depth-of-anaesthesia monitors during cardiopulmonary bypass (CPB) at 34°C with fentanyl ⁄ propofol anaesthesia adjusted clinically and blinded to the monitors. Coronary artery bypass grafting patients (n = 21) were randomly assigned to all three possible paired combinations of three monitors: Bispectral Index (Aspect Medical), AAI TM auditory evoked potential (Danmeter), Entropy TM (Datex-Ohmeda). Indices were manually recorded every 5 min during CPB. Agreement between paired indices was classified as good, non-, or disagreement. Anaesthesia was classed as adequate, inadequate, or excessive according to recommended index values. Of the 255 paired indices recorded, 62% showed good agreement, 33% showed non-agreement, and 5% showed disagreement. Using good agreement between two monitors as a gold standard, a quarter of the measurements indicate inappropriate anaesthetic depth monitoring during CPB with clinically titrated anaesthetic depth.

Comparison of Spectral Entropy and Bispectral Index Electroencephalography in Coronary Artery Bypass Graft Surgery

“…Tiren and colleagues [15] reported an acceptable agreement only in approximately 60% of the 109 simultaneously detected data pairs of RE and SE and BIS during CPB and anesthesia with midazolam/fentanyl and propofol. This may be due to the predominant midazolam-fentanyl based anesthesia with added propofol used in their study.…”

Positive state observer for the automatic control of the depth of anesthesia—Clinical results

“…The depth of anesthesia (DoA) is related to the intensity of these two latter components and is achieved by the administration of two drugs: a hypnotic and an analgesic. According to several studies (Tirén et al [1], Grindsta and Tobias [2], Ekman et al [3], Wodey et al [4], Whyte and Booker [5]) the DoA may be measured by means of the bispectral index (BIS). This index is a single dimensionless number, which is computed from the electroencephalogram (EEG) and ranges from 0 (equivalent to EEG silence) to 100 (equivalent to a fully awake and alert state).…”

Automatic control of the depth of anesthesia - clinical results

“…These latter two components contribute to the depth of anesthesia (DoA) which may be measured by the bispectral-index (BIS) (Tirén et al (2005), Grindstaff and Tobias (2004), Ekman et al (2004), Wodey et al (2005), Whyte and Booker (2003)). The BIS value is computed according to the measurements of an electroencephalogram and ranges between 0 and 97.7.…”