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Validation of the patient State Index for monitoring sedation state in critically ill patients: a prospective observational study

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An Editorial to this article was published on 02 August 2022

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.

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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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Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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Authors and Affiliations

Authors

Contributions

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.

All authors read and approved the final manuscript.

Corresponding author

Correspondence to Yusuke Seino.

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Conflict of interest/competing interests

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.

Consent to participate

Informed consent was obtained from all individual participants included in the study.

Consent for publication

Patients signed informed consent regarding publishing their data.

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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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