Evaluation of a New Catheter for Simultaneous Intracranial Pressure Monitoring and Cerebral Spinal Fluid Drainage: A Pilot Study

Objectives: Intracranial pressure (ICP) monitoring is a common practice when treating intracranial pathology with risk of elevated ICP. External ventricular drain (EVD) insertion is a standard approach for both monitoring ICP and draining cerebrospinal fluid (CSF). However, the conventional EVD cannot serve these two purposes simultaneously because it cannot accurately measure ICP and its pulsatile waveform while the EVD is open to CSF drainage. A new Integra Camino FLEX Ventricular Catheter (Integra Lifesciences, County Offaly, Ireland) with a double-lumen construction has been recently introduced into the market, and it can monitor ICP waveforms even during CSF drainage. The aim of this study was to evaluate and validate this new FLEX catheter for ICP monitoring in a neurological intensive care unit.

Methods: Six patients with 34 EVD open/close episodes were retrospectively analyzed. Continuous ICP was detected in two ways: through the FLEX sensor at the tip (ICP) and through a fluid-coupled manometer within the FLEX catheter, functioning as a conventional EVD (ICP). The morphologies of ICP and ICP pulses were extracted using Morphological Clustering and Analysis of ICP algorithm, an algorithm that has been validated in previous publications. The mean ICP and waveform shapes of ICP pulses detected through the two systems were compared. Bland-Altman plots were used to assess the agreement of the two systems.

Results: A significant linear relationship existed between mean ICP and mean ICP, which can be described as: mICP = 0.81 × mICP + 1.67 (r = 0.79). The Bland-Altman plot revealed that no significant difference existed between the two ICPs (average of [ICP-ICP] was - 1.69 mmHg, 95% limits of agreement: - 7.94 to 4.56 mmHg). The amplitudes of the landmarks of ICP pulse waveforms from the two systems showed strong, linear relationship (r ranging from 0.89 to 0.94).

Conclusions: This study compared a new FLEX ventricular catheter with conventional fluid-coupled manometer for ICP waveform monitoring. Strong concordance in ICP value and waveform morphology between the two systems indicates that this catheter can be used for reliability for both clinical and research applications.