# Shunt Dysfunction Assessment in Shunted Patients via Multiparametric Non-Invasive ICP Waveform Monitoring

## TL;DR

This study explores non-invasive methods to assess shunt function in patients with cerebrospinal fluid disorders using brain4care system waveforms.

## Contribution

The study introduces a non-invasive ICP waveform monitoring method to detect shunt dysfunction in CSF patients.

## Key findings

- Overdrainage patients had significantly higher ΔP2/P1 values compared to asymptomatic patients.
- Combining ΔP2/P1 and highest P2/P1 parameters improved diagnostic accuracy for shunt dysfunction.
- Underdrainage was associated with higher P2/P1 averages and intermediate ΔP2/P1 values.

## Abstract

Background/Objectives: Ventriculoperitoneal shunts are the standard treatment for adults diagnosed with several CSF disorders, but often face dysfunction, leading interest in non-invasive methods for diagnosing shunt issues. This study evaluates the potential of non-invasive intracranial pressure waveform monitoring (nICPw) with the brain4care (B4C) system to distinguish overdrainage, underdrainage, and normal shunt function in patients with CSF disorders. Methods: In this single-center, observational study at Hospital das Clínicas, Brazil, adult patients with CSF shunts were enrolled. Patients were categorized as Overdrainage or Underdrainage, based on clinical parameters, with an Asymptomatic group. The B4C system provided nICPw monitoring, and six parameters (including various P2/P1 ratios) were analyzed via MANOVA and ANOVA. Results: Among 30 patients (6 overdrainage, 6 underdrainage, 18 asymptomatic), five asymptomatic patients were excluded from the main analysis due to incomplete data collection, leaving 25 patients. Overdrainage patients had significantly higher ΔP2/P1 values (0.618 ± 0.210) than asymptomatic ones (0.227 ± 0.171). After excluding outliers, differences were more pronounced (H = 10.89; p < 0.01). Underdrainage patients had intermediate ΔP2/P1 values (0.387 ± 0.179) and consistently higher P2/P1 averages (>1.3). ROC analysis indicated that ΔP2/P1 > 0.3 suggested shunt dysfunction (AUC = 0.731), while the highest P2/P1 offered stronger discrimination (AUC = 0.782). A global average P2/P1 > 1.3 was linked to underdrainage, with the lowest P2/P1 values differentiating overdrainage (0.948 ± 0.321) from underdrainage (1.143 ± 0.156). Conclusions: nICPw monitoring with the B4C system demonstrated potential for detecting shunt dysfunction. Combining parameters, especially ΔP2/P1 and highest P2/P1, improves diagnostic accuracy, offering a non-invasive method that may aid in distinguishing normal from abnormal shunt function.