Table 1.
Commercial EEG-based monitoring systems for depth of anesthesia.
| Product | Utilized parameters | Scale | Clinical correlate | References |
|---|---|---|---|---|
| Bispectral index (Covidien) | BSR; Relative beta activity; Synch-Fast-Slow |
0–100 | Awake: 100; Adequate anesthesia: 40–60; No brain activity: 0 |
(16–18) |
| AEP monitor/2 (Danmeter A/S) | ARX model; MLAEP latency and amplitude; BSR |
AAI:0–100 | Awake: 100; Adequate anesthesia: 15–20; Very deep hypnosis: 0 |
(19) |
| aepEX (Medical Device Management Ltd.) | MLAEP latency and amplitude | 0–99 | Awake: 100 Adequate anesthesia: 30–50; No brain activity: 0 |
(20) |
| Entropy Module (GE Healthcare) | Power spectrum Shannon function | RE:0–100 (nociception level) SE: 0–91 (depth of sedation) | Adequate anesthesia for both RE and SE parameters: 40–60 Need for additional analgesic: RE-SE difference ≥ 10 |
(21) |
| Narcotrend (MonitorTechnik) | Burst suppression; AR models; SEF, median frequency, spectral entropy, relative delta, theta, alpha, beta |
Stages: A-F; Index: 0–100 |
Stages A (awake) to F (deep anesthesia), with 15 substages Index values: 100 (awake) to 0 (deep anesthesia), reflecting the continuous change of consciousness |
(22) |
| PSA 4000 Monitor (Physiometrix, Inc) | Power spectrum; | PSI:0–100 | Awake: 0 Adequate anesthesia:40–50 Eyes opening: 80 |
(23, 24) |
| Cerebral State Monitor (Danmeter A/S) | Alpha and beta ratio Alpha-beta difference Burst suppression |
CSI:0–100 | Awake: 90–100 Adequate anesthesia: 40–60 Deep: 10–40 Very deep: 0–10 |
(25) |
BSR, burst suppression ratio; MLAEP, middle latency auditory evoked potentials; RE, response entropy; SE, state entropy; ARX, autoregressive models with exogenous input; AAI, A-line autoregressive index; AR, autoregressive; SEF, spectral edge frequency; PSI, patient state index; CSI, cerebral state index.