Study objectives: Conventional sleep scoring is based on the scoring criteria of the American Association of Sleep Medicine (AASM) but may not be suited to describe sleep in critically ill children admitted to the Pediatric Intensive Care Unit (PICU). In this study, an anomaly detection model using Gaussian Models trained on sleep stages in data from non-critically ill children is developed to assess if polysomnography(PSG)-derived electroencephalography (EEG) data from critically ill children can be categorized into sleep stages based on these AASM scoring criteria.
Methods: A retrospective study at Erasmus MC Sophia Children’s Hospital, using PSG recordings obtained in non-critically ill children between 2017 and 2021 and in critically ill children between 2020 and 2022.
Gaussian Models were individually trained for each sleep stage using data from non-critically ill children. Anomaly detection was carried out by computing the Mahalanobis Distances and assigning datapoints to specific sleep stages or categorizing them as anomalous. Errors were quantified by calculating the ratio of anomalous epochs to the total number of epochs. The trained Gaussian Models were applied to distinct sleep stages in the data from non-critically ill children. Subsequently, the models were applied to data from critically ill children to determine the categorization of their epochs. This was also analyzed over time and involved comparisons related to medication, mechanical ventilation, and the severity of illness assessed by the PELOD-2 score.
Results: In non-critically ill children the models obtained validation errors aligning with the margin error of the training set. The models could not fully differentiate the distinct sleep stages. In critically ill children, the majority of epochs were classified into multiple sleep stages. High error rates were evident for sleep stages N1, R, and N. Some patients exhibited elevated error rates specifically for sleep stage N1. REM sleep was reduced, consistent with findings from previous studies. In contrast, N3 sleep did not show a reduction. When compared to the sleep stage labels assigned by neurophysiologists, the model classified epochs into multiple sleep stages, while neurophysiologists frequently used the label N. A higher PELOD-2 score did not consistently correlate with an increased occurrence of anomalous classifications in the epochs of these patients to those with lower PELOD-2 scores.
Discussion: Overlap of sleep stages was observed in non-critically ill children. Epochs from critically ill children were classified into multiple sleep stages without clear associations in time or severity of illness. Building upon the established anomaly detection framework is recommended by employing more advanced anomaly detection methods using an informative feature selection. This study marks an initial step, indicating that applying the AASM.

Introduction Traumatic brain injury (TBI) is a leading cause of childhood morbidity, disability and mortality worldwide. In the treatment of TBI, neuromonitoring is essential to prevent secondary neurological damage. However, the use of neuromonitoring and specifically therapeutic targets is currently limited evidence-based.
Objective The primary objective is to implement suitable neuromonitoring parameters into a novel bedside dashboard for paediatric TBI patients. In addition, basic insights into neuromonitoring parameters between different outcome groups are provided.
Methods Intracranial pressure (ICP), cumulative ICP (ICP_cum), cerebral perfusion pressure (CPP), pressure reactivity index (PRx), wavelet transform PRx, optimal CPP (CPP_opt), partial pressure of arterial oxygen (P_aO₂), partial pressure of arterial carbon dioxide (P_aCO₂), end tidal CO2 (etCO₂), temperature and sodium levels were implemented into a dashboard. The parameters (except wPRx) were retrospectively analysed in TBI patients admitted to the paediatric intensive care unit (PICU) of the Erasmus MC- Sophia. Patients were divided into a good (GO) or bad (BO) outcome group. Per outcome group, the mean and 95 % confidence interval or the median and interquartile range of parameters were calculated.
Results A total of 35 patients (24 GO, 11 BO) were included. Significant differences between GO and BO were observed in median PRx (-0.06 [-0.13 – 0.01] vs. 0.17 [-0.05 – 0.39]), median percentage outside of the CPP_opt (curve) range (15 % [4 – 26] vs. 30 % [26 – 34]), ICP_cum distributions (12.0 mmHg [8.0 – 16.0] vs. 12.0 mmHg [8.5 – 15.5]) and mean sodium levels (146.4 mmol/L (144.5 – 148.3) vs. 151.2 mmol/L (148.6 – 153.8)).
Conclusion In a retrospective analysis, PRx, CPP_opt (curve) and ICP_cum showed potential to improve prognostication for paediatric TBI and to determine therapeutic targets. Based on our results, we recommend implementing MAP, ICP, ICP_cum, CPP alongside CPP_opt (curve), and sodium levels in a future neuromonitoring dashboard.