Abstract
Purpose
The Patient State Index (PSI) is a newly introduced electroencephalogram-based tool for objective and continuous monitoring of sedation levels of patients under general anesthesia. This study investigated the potential correlation between the PSI and the Richmond Agitation‒Sedation Scale (RASS) score in intensive care unit (ICU) patients and established the utility of the PSI in assessing sedation levels.
Methods
In this prospective observational study, PSI values were continuously monitored via SedLine® (Masimo, Irvine, CA, USA); the RASS score was recorded every 2 h for patients on mechanical ventilation. Physicians and nurses were blinded to the PSI values. Overall, 382 PSI and RASS score sets were recorded for 50 patients.
Results
The PSI score correlated positively with RASS scores, and Spearman’s rank correlation coefficient between the PSI and RASS was 0.79 (95% confidence interval [CI]: 0.75‒0.83). The PSI showed statistically significant difference among the RASS scores (Kruskal‒Wallis chi-square test: 242, df = 6, P < 2.2-e16). The PSI threshold for distinguishing light (RASS score ≥ − 2) sedation from deep sedation (RASS score ≤ − 3) was 54 (95% CI: 50–65; area under the curve, 0.92 [95% CI: 0.89‒0.95]; sensitivity, 0.91 [95% CI: 0.86‒0.95]; specificity, 0.81 [95% CI: 0.77–0.86]).
Conclusions
The PSI correlated positively with RASS scores, which represented a widely used tool for assessing sedation levels, and the values were significantly different among RASS scores. Additionally, the PSI had a high sensitivity and specificity for distinguishing light from deep sedation. The PSI could be useful for assessing sedation levels in ICU patients.
University Hospital Medical Information Network (UMIN000035199, December 10, 2018).
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Availability of data and material
The data that support the findings of this study are available from the corresponding author, upon reasonable request.
Code availability
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Masafumi Idei, Yusuke Seino: Conceptualization, Methodology, Data curation, Validation, Investigation, Writing- Original draft preparation, Project administration.
Nobuo Sato, Yumi Saishu, Takuya Yoshida, Kimiya Fukui, Masahiro Iwabuchi, Junya Ishikawa, Kei Ota, Daigo Kamei: Conceptualization, Data curation, Writing- Original draft preparation, Writing- Reviewing and Editing.
Masashi Nakagawa, Takeshi Nomura: Conceptualization, Data curation, Supervision, Writing- Reviewing and Editing, Project administration.
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The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethics approval
The study was approved by the Tokyo Women’s Medical University Ethics Committee (Approval No. 4994, November 23, 2018). The procedures used in this study adhere to the tenets of the Declaration of Helsinki.
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Idei, M., Seino, Y., Sato, N. et al. Validation of the patient State Index for monitoring sedation state in critically ill patients: a prospective observational study. J Clin Monit Comput 37, 147–154 (2023). https://doi.org/10.1007/s10877-022-00871-9
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DOI: https://doi.org/10.1007/s10877-022-00871-9