To the editor,
We thank the authors for their interest in our article and their comments regarding the utility of continuous EEG (cEEG) monitoring in postanoxic coma [1, 2]. However, several points raised in their correspondence suggest a misunderstanding of our study design and the specific clinical guidelines evaluated.
First, the authors inquire about the distribution of cEEGs showing a poor prognosis within the “uncertain prognosis” group. This query misinterprets our methodology. As detailed in our Methods section, patients were classified into prognostic groups (favorable, poor, or uncertain) based on the cEEG findings themselves. Therefore, by definition, a patient cannot have a cEEG pattern indicative of a poor prognosis and remain in the uncertain prognosis group. Our study found that the majority of patients (70.8%) fell into this uncertain category precisely because their cEEG patterns did not meet the strict criteria for either a favorable or poor prognosis.
Second, regarding the value of early cEEG for favorable prognostication, we fully acknowledge that cEEG is a reliable tool for predicting good outcomes, identifying a favorable prognosis in 13.0% of our cohort. However, the primary clinical and ethical dilemma in the ICU typically revolves around the decision to withdraw life-sustaining treatment. Consequently, our analysis of “unique prognostic value” focused on the identification of poor prognosis in patients who lacked other clinical indicators, such as absent brainstem reflexes. While identifying a good prognosis provides reassurance, it rarely alters immediate life-support decisions in the same manner as a confirmed poor prognosis.
Third, the authors suggest that sedation may confound the clinical examination, noting that absent pupillary reflexes were only predictive in a small percentage of patients. We must clarify that per standard practice and the national guideline, sedation is stopped after 24 h, and clinical implementation of the Glasgow Coma Scale and brainstem reflex assessment occurs only after sedation has washed out [3]. Furthermore, regarding the comparative yield, our data showed that in patients where cEEG predicted a poor prognosis, 58% already exhibited poor prognostic signs on clinical examination or were hemodynamically unstable. The “unique value” of 6.7% refers to the small subset of patients where cEEG was the sole indicator of a poor outcome. This low incremental yield—not the absolute yield—is central to the discussion on resource allocation.
Finally, the authors discuss the importance of longer-term monitoring (48–72 h) and the treatment of status epilepticus, citing the TELSTAR trial [4]. While these are valid considerations for seizure management, our study was designed specifically to evaluate the real-world implementation of the Dutch national guideline, which recommends cEEG initiation within 24 h for prognostication [3]. Extending the analysis to late-onset status epilepticus and its treatment falls outside the scope of evaluating the prognostic utility of the standard 24-hour monitoring window currently recommended in The Netherlands.
In conclusion, our findings indicate that while cEEG is a highly accurate prognostic tool, its universal application provides unique, actionable information for poor prognosis in only a minority of patients beyond standard clinical assessment.
Abbreviation
- cEEG
Continuous electroencephalography monitoring
Author contributions
SEK, WHM, JD and MRT designed the study. SEK, WHH, MLFJ and JD gathered all the data and did the analyses. All authors read and approved the final manuscript.
Funding
Not applicable.
Data availability
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Declarations
Ethics approval and consent to participate
Given the retrospective nature of the study, a formal ethical evaluation and the need for informed consent were waived by the local Medical Ethics Committee of Maastricht UMC+ (MUMC+) (METC 2024 − 0333).
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Footnotes
Publisher’s note
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References
- 1.Knapen SE, Hinsenveld WH, Janssen ML, Mess WH, Drenthen J, Tannemaat MR. Utility of continuous EEG monitoring in postanoxic coma: a retrospective multicenter study. Crit Care. 2026;30(1):9. [DOI] [PMC free article] [PubMed]
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.