By: (from left to right) Sydney Moseley, MD, Hussein Alshammari, MD, Scott Woolf, DO, Fawaz Al-Mufti, MD1
1 Department of Neurology and Neurosurgery, Westchester Medical Center at New York Medical College
The authors have no actual or potential conflict of interest in relation to the topics discussed in this column. This article may discuss non-FDA approved devices and “off-label” uses. The NCS and Currents do not endorse any particular device.
Many neurological insults require close monitoring of intracranial pressure (ICP) and simultaneous drainage. The gold standard for ICP monitoring has been a ventricular catheter connected to an external strain gauge transducer or catheter tip pressure transducer device.1 This method of monitoring has its drawbacks especially with need for recalibration to ensure accuracy of measurements, and differences in pressure measurements when there is no access to the ventricle or when there is catheter obstruction.1
Conventional external ventricular drains (EVD have been used for simultaneous drainage and measurement of ICP, however, the measurements of ICP were reportedly lower when compared to measurements with ICP probe done simultaneously. When EVDs are used for both monitoring of ICP and for drainage, the catheter alternates between closed and open respectively. This provides a trend of ICP, but may miss acute elevations, and is less reliable for assessment of cerebrovascular autoregulation.2
Figure 1. Integra ® Camino ® FLEX Ventricular Catheter design. Integra design verification report for camino flex ventricular catheter. 2013. Retrieved from https://www.integralife.com/file/general/1453796957.pdf.
The new Integra ® Camino ® FLEX Ventricular Catheter (ICFVC) (Integra Lifesciences, County Offaly, Ireland) is now being explored to address this issue. The device has a double lumen and the ability to monitor ICP waveforms during CSF drainage.3 The ICFVC has undergone trials in which it has been compared to conventional catheters, and it was found to both measure ICP and accomplish drainage simultaneously with similar efficacy and reported higher accuracy as a conventional EVD.1
A common complication of EVD usage in the neuro ICU is occlusion secondary to blood clotting or ventricular shift. The ICFVC is able to provide continuous monitoring of ICP, including when CSF drainage has been compromised due to an occluded catheter. It is also able to provide accurate measurements regardless of patient’s position and does not require recalibration, which is a common issue encountered with external transducers.4 External transducers require that the device be aligned with an anatomical landmark and when not in the correct position, ICP measurements may differ from control by approximately 0.736 mmHg for each centimeter of vertical distance between the patient’s anatomical landmark of leveling and an external transducer.5
Figure 2. Demonstration of ICP monitoring pre, per and post drainage. Integra design verification report for camino flex ventricular catheter. 2013. Retrieved from https://www.integralife.com/file/general/1453796957.pdf.
The Integra Camino Flex Ventricular Catheter can help overcome some challenges of ICP monitoring in the neuro ICU setting, however, the risks and disadvantages of this device are yet to be fully elucidated, but are likely to be similar to those of their EVD counterpart.
Some limitations should be mentioned. The validation studies enrolled a small number of patients and monitored ICP for a relatively short duration. Therefore it is unclear if one can extrapolate accuracy drifts for long-term monitoring. The FLEX catheter price is also higher compared to the conventional EVD. MRI compatibility is another point of concern. Fortunately, the FLEX catheter has been FDA approved to be MRI compatible at 1.5 and 3.0T.4 Of note, it is also recommended that if monitoring is needed for more than 5 days the catheter should be replaced under sterile conditions, which may be a limitation for use in situations that require longer monitoring.4
As with any new technology, its utility relies on user comfortability and familiarity; thus its shortcomings may be discovered through use and user experience. If these hurdles can be overcome, the device may improve issues with measurement discrepancies that occur with classical EVDs used for both ICP measurement and drainage while providing real time assessments of cerebrovascular autoregulation. Ultimately this will allow for faster detection and intervention of neurological emergencies and increase the quality of care in the neuro ICU.
- Liu X, Zimmermann LL, Ho N, Vespa P, Liao X, Hu X. Evaluation of a New Catheter for Simultaneous Intracranial Pressure Monitoring and Cerebral Spinal Fluid Drainage: A Pilot Study. Neurocrit Care. 2018. https://doi.org/10.1007/s12028-018-0648-z
- Jun Zhong, Manuel Dujovny, Hun K. Park, Eimir Perez, Alfred R. Perlin & Fernando G. Diaz. Advances in ICP monitoring techniques, Neurological Research. 2003; 25:4, 339-350, DOI: 1179/016164103101201661
- Hockel K, Schuhmann MU. ICP Monitoring by Open Extraventricular Drainage: Common Practice but Not Suitable for Advanced Neuromonitoring and Prone to False Negativity. Acta Neurochir Suppl.2018;126:281-286.
- Integra Lifesciences. Integra design verification report for camino flex ventricular catheter. 2013. Retrieved from https://www.integralife.com/file/general/1453796957.pdf.
- William P. Rice, Edward G. Fernandez, Dena Jarog and Alicia Jensen. A Comparison of Hydrostatic Leveling Methods in Invasive Pressure Monitoring. Critical Care Nurse. 2004; 20 – 6