Correlation of the A-Line™ ARX index with acoustically evoked potential amplitude †
| Autor: | Ingobert Wenningmann, S. Strassmann, B. W. Urban, Martin Soehle, S. Paprotny, B. Rehberg, Richard K. Ellerkmann |
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| Rok vydání: | 2006 |
| Předmět: |
Adult
Male Steady state (electronics) Electroencephalography Correlation Depth of anaesthesia Eeg data Monitoring Intraoperative Humans Medicine Evoked potential Rank correlation medicine.diagnostic_test business.industry Reproducibility of Results Signal Processing Computer-Assisted Awareness Middle Aged Anesthesiology and Pain Medicine Amplitude Acoustic Stimulation Anesthesia Evoked Potentials Auditory Female Artifacts business |
| Zdroj: | British Journal of Anaesthesia. 97:666-675 |
| ISSN: | 0007-0912 |
| DOI: | 10.1093/bja/ael223 |
| Popis: | Background Automated indices derived from mid-latency auditory evoked potentials (MLAEP) have been proposed for monitoring the state of anaesthesia. The A-Line™ ARX index (AAI) has been implemented in the A-Line™ monitor (Danmeter, V1.4). Several studies have reported variable and, in awake patients, sometimes surprisingly low AAI values. The purpose of this study was to reproduce these findings under steady-state conditions and to investigate their causes. Methods Ten awake unmedicated volunteers were studied under steady-state conditions. For each subject, the raw EEG and the AAI were recorded with an A-Line™ monitor (V1.4) during three separate sessions of 45.0 (1.6) min duration each. MATLAB™ (Mathworks) routines were used to derive MLAEP responses from EEG data and to calculate maximal MLAEP amplitudes. Results The AAI values ranged from 15 to 99, while 11.4% fell below levels which, according to the manufacturer, indicate an anaesthetic depth suitable for surgery. Inter-individual and intra-individual variation was observed despite stable recording conditions. The amplitudes of the MLAEP varied from 0.8 to 42.0 μV. The MLAEP amplitude exceeded 2 μV in 75.3% of readings. The Spearman's rank correlation coefficient between the MLAEP amplitude and the AAI value was r=0.89 (P Conclusions The version of the A-Line™ monitor used in this study does not exclude contaminated MLAEP signals. Previous publications involving this version of the A-Line™ monitor (as opposed to the newer A-Line/2™ monitor series) should be reassessed in the light of these findings. Before exclusively MLAEP-based monitors can be evaluated as suitable monitors of depth of anaesthesia, it is essential to ensure that inbuilt validity tests eliminate contaminated MLAEP signals. |
| Databáze: | OpenAIRE |
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