Carbogen inhalation during Non-Convulsive Status Epilepticus: A quantitative analysis of EEG recordings

TL;DR

This study investigates the effects of inhaled carbogen on EEG recordings in children with non-convulsive status epilepticus, revealing inconsistent effects possibly due to individual differences and suggesting personalized parameter tuning for better seizure control.

Contribution

First quantitative analysis of carbogen inhalation effects on EEG in NCSE patients, highlighting variability and the need for personalized treatment parameters.

Findings

Inconsistent EEG effects across patients during carbogen inhalation.

Potential influence of aetiology and inhalation duration on outcomes.

Indication that personalized carbogen parameters may enhance seizure suppression.

Abstract

Objective: To quantify the effect of inhaled 5% carbon-dioxide/95% oxygen on EEG recordings from patients in non-convulsive status epilepticus (NCSE). Methods: Five children of mixed aetiology in NCSE were given high flow of inhaled carbogen (5% carbon dioxide/95% oxygen) using a face mask for maximum 120s. EEG was recorded concurrently in all patients. The effects of inhaled carbogen on patient EEG recordings were investigated using band-power, functional connectivity and graph theory measures. Carbogen effect was quantified by measuring effect size (Cohen's d) between "before", "during" and "after" carbogen delivery states. Results: Carbogen's apparent effect on EEG band-power and network metrics across all patients for "before-during" and "before-after" inhalation comparisons was inconsistent across the five patients. Conclusion: The changes in different measures suggest a potentially non-homogeneous effect of carbogen on the patients' EEG. Different aetiology and duration of the inhalation may underlie these non-homogeneous effects. Tuning the carbogen parameters (such as ratio between CO2 and O2, duration of inhalation) on a personalised basis may improve seizure suppression in future.