Performance of the SEDLine Monitor: Age Dependency and Time Delay

Abstract

BACKGROUND: Devices monitoring the hypnotic component of general anesthesia can help to guide anesthetic management. The main purposes of these devices are the titration of anesthesia dose. While anesthesia at low doses can result in awareness with intraoperative memory formation, excessive administration of anesthetics may be associated with an increased risk of postoperative neurocognitive disorder. We have previously shown for various indices that they are significantly influenced by the patient’s age and that the monitors have a significant time delay. Here, we evaluated the influence of patient’s age and time delay on the patient state index (PSI) of the SEDLine monitor. METHODS: To analyze the influence of the patient’s age, we replayed 2 minutes of electroencephalography (EEG) of 141 patients (19–88 years, ASA I–IV) undergoing general anesthesia maintained with desflurane, sevoflurane, or propofol to the SEDLine monitor. We extracted the PSI as well as the spectral edge frequency (SEF) and performed a linear regression analysis. For evaluation of the time delay, we replayed 5 minutes of EEG of stable episodes of adequate anesthesia (PSI between 25 and 50) or light sedation/wake (PSI >70) in different orders to the SEDLine to simulate sudden changes between the states. Time delays were defined as the required time span of the monitor to reach the stable target index. RESULTS: PSI and SEF increased significantly with the patient’s age. These findings did not depend on the administered anesthetic. The evaluation of the correlation between SEF and PSI showed a strong correlation with Spearman’s correlation coefficient of ρ = 0.86 (0.82; 0.89). The time delays depended on the type of transition. We found a median time delay of 54 (Min: 46; Max: 61) seconds for the important transition between adequate anesthesia and awake and 55 (Min: 50; Max: 67) seconds in the other direction. CONCLUSIONS: With our analyses, we show that the indices presented on the SEDLine display, the PSI and the SEF, increase with age for patients under general anesthesia. Additionally, a delay of the PSI to react to sudden neurophysiologic changes due to dose of the maintenance anesthetic is of a time course that is clinically significant. These factors should be considered when navigating anesthesia relying on only the proprietary index for the SEDLine monitor.

Assessment of seizure duration and utility of using SedLine® EEG tracing in veterans undergoing electroconvulsive therapy: a retrospective analysis

“…In our study, there was a trend that age will increase the PSI number. This aligns with a recent retrospective study finding that the patient’s age significantly influences both PSI and SEF (signal edge frequency) [ 19 ]. Previous studies with the BIS monitor also showed an index increase with age [ 20 ].…”

“…The PSI number generation lags behind the real-time tracings displayed on the SedLine ® monitor which are a highly reliable indication of the brain functional state. This delay time by SedLine ® monitor is reported by Obert et al [ 19 ] and is estimated to be more than 50 s. This is longer than qCON and BIS delay that is approximately 25 s [ 21 , 22 ]. Therefore, it is important for the treatment team to be familiar with the interpretation of frontal brain waves in concert with clinical patient assessment during teatment to prevent SedLine ® PSI data misinterpretaion.…”

Using Spectral Edge Frequency to Target Equivalent Brain States Under General Anesthesia Is Like Asking for Apples and Getting Oranges

“…Further support for the dependence of their results on the delivery of excessive doses of propofol can be observed in the reported age gap between the groups with high and low Montreal Cognitive Assessment (MoCA) scores-11 years for propofol and only 4 for sevoflurane-as well as the fact that the cognitively healthy group for sevoflurane was 10 years younger than the cognitively healthy group for propofol. The authors do acknowledge that age presents a significant influence on SEF95 3,4 or median frequency (SEF50) 5 ; however, they fail to acknowledge that this may make their results incomparable. So, in summary, the claim of comparing patients "at similar age and depthof-anesthesia" as stated in the discussion cannot be made in our opinion, and hence, the statement about propofol being a better proxy "preoperative low MoCA" may not hold.…”

“…As outlined in our article, DoA indices like SEF 95 , and bispectral index (BIS), which are largely similar until burst suppression occurs, do not offer a universal solution for monitoring anesthesia depth. 3,4 Nonetheless, currently, using DoA indices provides the most practical strategy for depth comparison between the groups, aligning with everyday clinical practices. 5 Kreuzer et al seem to suggest that, for comparable levels of consciousness, SEF 95 should be higher under propofol than sevoflurane.…”

In Total Intravenous Anesthesia We Trust: Building Confidence in Total Intravenous Anesthesia Techniques

“…In addition, there is a time delay in clinically significant index changes from 30 to 60 seconds, depending on the device. 16 Artifact such as muscle activity under the pEEG sensor, and electrocautery can influence index values.…”