Pitfalls and possibilities of using Root SedLine for continuous assessment of EEG waveforms-based metrics in intensive care research

OBJECTIVE

The Root SedLine Device is used for continuous electroencephalography (cEEG) based sedation monitoring in intensive care patients. The cEEG traces can be collected for further processing and calculation of relevant metrics not already provided. Depending on the device settings during acquisition, the acquired traces may be distorted by max/min values cropping or high digitization error. We aimed to systematically assess the impact of those distortions on metrics used for clinical research in the field of neuromonitoring. Approach: A 16h cEEG acquired using the Root SedLine Device at the optimal screen settings was analyzed. Cropping and digitization error effects were simulated by consecutive reduction of the maximum cEEG amplitude by 2µV or by reducing the vertical resolution. Metrics were calculated within ICM+ using minute-by-minute data including total power, alpha delta ratio, and 95% spectral edge frequency. Data were analyzed by creating violin-plots or box-plots. Main Results: Cropping led to a continuous reduction in total and band power leading to corresponding changes in variability thereof. Relative power and alpha delta ratio were less affected. Changes in resolution led to relevant changes. While total power and power of low frequencies were rather stable, power of higher frequencies increased with reducing resolution. Significance: Care must be taken when acquiring and analyzing cEEG waveforms from Root SedLine for clinical research. In order to retrieve good quality metrics, the screen settings must be kept within the central vertical scale while pre-processing techniques must be applied to exclude unacceptable periods. .

Broad Range Eubacterial Polymerase Chain Reaction of Cerebrospinal Fluid Reduces the Time to Exclusion of and Costs Associated with Ventriculostomy-Related Infection in Hemorrhagic Stroke

BACKGROUND

Patients with hemorrhagic stroke and an external ventricular drain in situ are at risk for ventriculostomy-related-infections (VRI). Because of the contamination of the cerebrospinal fluid (CSF) with blood and the high frequency of false negative CSF culture, the diagnosis of VRI remains challenging. This study investigated the introduction of CSF broad range eubacterial polymerase chain reaction (ePCR) and its effect on frequency and duration of antibiotic therapy for VRI, neurocritical care unit (NCCU) length of stay, related costs, and outcome.

METHODS

Between 2020 and 2022, we prospectively included 193 patients admitted to the NCCU of the University Hospital of Zürich with hemorrhagic stroke and an external ventricular drain for more than 48 h. Patient characteristics, serum inflammatory markers, white blood cell count in CSF, use and duration of antibiotic treatment for VRI, microbiological findings (CSF cultures and ePCR tests), and NCCU length of stay were compared in patients with no infection, noncerebral infection, suspected VRI, and confirmed VRI. Data of patients with suspected VRI of this cohort were compared with a retrospective cohort of patients with suspected VRI treated at our NCCU before the introduction of CSF ePCR testing (2013-2019).

RESULTS

Out of 193 patients, 12 (6%) were diagnosed with a confirmed VRI, 66 (34%) with suspected VRI, 90 (47%) with a noncerebral infection, and 25 (13%) had no infection at all. Compared with the retrospective cohort of patients, the use of CSF ePCR resulted in a reduction of patients treated for suspected VRI for the whole duration of 14 days (from 51 to 11%). Furthermore, compared with the retrospective group of patients with suspected VRI (n = 67), after the introduction of CSF ePCR, patients with suspected VRI had shorter antibiotic treatment duration of almost 10 days and, hence, lower related costs with comparable outcome at 3 months.

CONCLUSIONS

The use of CSF ePCR to identify VRI resulted in shorter antibiotic treatment duration without changing the outcome, as compared with a retrospective cohort of patients with suspected VRI.