# Impact of the 2021 European Resuscitation Council-European Society of Intensive Care Medicine (ERC-ESICM) Guidelines on Neuroprognostication Practices After Cardiac Arrest: A Five-Year Cohort Study

## TL;DR

A study found that following new 2021 guidelines for predicting brain outcomes after cardiac arrest improved patient survival and decision-making in intensive care.

## Contribution

The study evaluates real-world adherence to the 2021 ERC-ESICM guidelines and links it to clinical outcomes for the first time.

## Key findings

- NSE measurement increased significantly after the guidelines, but other methods like SSEP and EEG did not.
- Higher adherence to guidelines was associated with delayed withdrawal of life support and lower mortality rates.
- Adherence scores showed a gradual upward trend from 2018 to 2022, with a sharp increase after 2021.

## Abstract

Background: Accurate neuroprognostication after cardiac arrest (CA) is essential to avoid premature withdrawal of life-sustaining measures (WLSM). The 2021 European Resuscitation Council/European Society of Intensive Care Medicine (ERC-ESICM) guidelines strengthened multimodal prognostication, but real adherence and its relationship with clinical outcomes remain insufficiently evaluated.

Methods: We conducted a retrospective cohort study of adult CA patients admitted to the Intensive Care Unit (ICU) between 2018 and 2022. Adherence to seven guideline-based neuroprognostication parameters was quantified through a composite adherence score (0-7). Cohorts were compared before (pre-guidelines) and after (post-guidelines) March 2021. Temporal trends were examined from 2018 to 2022. Associations between adherence and four clinical outcomes (WLSM ≥ 72 hours, overall WLSM, ICU mortality, and six-month mortality) were assessed using Mann-Whitney U tests and rank-biserial correlations.

Results: A total of 301 patients were included (pre-guidelines: 200; post-guidelines: 101). Neuron-specific enolase (NSE) measurement increased markedly after guideline publication (1% vs. 34.6%, p < 0.01), whereas adherence to somatosensory evoked potentials (SSEP), electroencephalogram (EEG), neuroimaging, neuroprognostication ≥ 72 hours, and deferred WLSM ≥ 72 hours did not differ significantly between cohorts. The composite adherence score increased from 3 (1-4) to 4 (1-5) (p = 0.056). Across 2018-2022, mean adherence demonstrated a gradual upward trend, with the sharpest rise after 2021. Individual parameter trends were heterogeneous, with significant post-guideline increases only in NSE use. Higher adherence scores were significantly associated with WLSM ≥ 72 hours, overall WLSM, and lower ICU and six-month mortality (all p < 0.05). Rank-biserial correlations showed moderate positive associations with WLSM variables and moderate negative associations with mortality outcomes.

Conclusions: Implementation of the 2021 ERC-ESICM guidelines was associated with increased overall adherence, primarily driven by NSE measurement. Higher adherence correlated with more guideline-concordant timing of WLSM and improved survival outcomes. Strengthening multimodal prognostication practice may further reduce variability and prevent premature care limitation.