The effects of midazolam on the EEG during sedation of critically ill patients

Abstract

SumnaryPatients who require mechanical ventilation are often sedated with midazolam. As

Evaluation of two processed EEG analyzers for assessment of sedation after coronary artery bypass grafting

“…Their evaluation is controversial due to different processed EEG analyzers, study populations, analgesic and sedative drugs, drug administration protocols, and clinical sedation assessment methods [10,11,12,13,14]. Thus, processed EEG monitoring as a surveillance tool of sedation in ICU patients has not yet been validated and has not been recommended in clinical routine.…”

“…This may be an important reason why only short-term evaluation was made in ICU patients. Veselis et al [12] investigated sedated and mechanically ventilated medical patients and observed a correlation between a fourpoint sedation score and SEF values (r = ±0.43). In contrast to all other studies carried out in an ICU setting, the variability in SEF data was small (SD 5 Hz).…”

“…Interestingly, none of studies using the most established clinical sedation score, the Ramsay score, has observed a correlation with processed EEG data. The two studies which found a correlation between pro-112 cessed EEG data and clinical sedation scores used fourand a seven-point scales [12,14]. Our study used two hypnotics at low concentrations.…”

“…The most commonly used EEG variables for assessing the depth of anesthesia and sedation are spectral edge frequency (SEF) [5,6,7] and EEG bispectral analysis (BIS) [7,8,9]. In contrast to the many investigations carried out during anesthesia, only few studies have reported the feasibility and utility of processed EEG in the ICU, and their results do not lead to definite recommendations [10,11,12,13,14].…”

Use of continuous bispectral EEG monitoring to assess depth of sedation in ICU patients

“…The use of processed EEG variables to assess depth of sedation remains controversial. Veselis et al [3] correlated several power-spectral EEG variables with the clinical level of sedation and concluded that the main effect of midazolam sedation was a shift of the dominant power from high to low frequencies as the sedation level increased, and the spectral-edge frequency 95 % (SEF 95 % = the frequency below which 95 % of the total power is contained) was found to be the most sensitive measure of depth of sedation. Shearer et al [4] reported on the use of the Cerebrotrac 2500, providing a real-time spectral analysis, for continuous monitoring of cerebral function in ICU patients receiving midazolam, morphine and propofol.…”