Session: 07-08-03: Biomedical Devices, Sensors, and Actuators III

Paper Number: 167670

Smart External Ventricular Drain 

Cerebrospinal fluid (CSF) is a clear and colorless fluid that fills the ventricles of the brain and the central canal of the spinal cord. CSF is produced in the choroid plexus of the brain at a rate of 450–500 mL per 24-hour period. CSF surrounds the brain and spinal cord, providing buoyancy, which reduces the mechanical load on neuronal tissue and allows it to function despite its low mechanical strength. CSF also regulates intracranial pressure and blood flow, as well as removes metabolic waste products from the brain, draining them into the venous system.

Patients with brain trauma or stroke can develop acute hydrocephalus due to brain swelling or intracerebral hemorrhage (ICH). Such patients are treated with an external ventricular drainage device (EVD), which drains CSF externally for a period of five to fifteen days. ICH is caused by the rupture of blood vessels within the brain and occurs as a result of several conditions, the most prevalent being stroke, trauma, or brain tumors. The incidence rate of ICH in the United States is 15 cases per 100,000 inhabitants, while brain trauma leading to ICH has an incidence rate of 90 cases per 100,000 inhabitants. Collectively, these conditions lead to approximately 25,000 annual placements of EVDs to relieve intracranial pressure.

EVDs commonly fail due to two primary issues—occlusion and infection. When occluded, intracranial pressure (ICP) rises, resulting in a medical emergency. Conversely, overdrainage can lead to additional bleeding, making continuous monitoring of EVDs essential.

This paper describes the development of a smart EVD that measures ICP, monitors CSF flow rate, and automatically adjusts drainage ICP during the treatment of ICH. Using pressure and flow data, it is demonstrated that occlusion of the drain can be detected. The system also features automatic adjustment of drainage pressure, allowing for increased patient mobility.

In vitro experiments using artificial CSF were conducted. The experimental apparatus included a peristaltic pump, which emulated the pulsatile flow generated by the human heart, and a variable cross-section manometric column, simulating the pressure-volume characteristics of the human brain.

Results from the experiments provided quantitative data on the effects of catheter occlusion at 10%, 30%, 50%, 70%, and 90% on measured flow and pressure data. Occlusion was detected through changes in pressure-flow characteristics, which were captured in real time using  recursive estimation of flow resistance. 

The practical implementation of the described smart EVD system is likely to augment existing drainage bags by incorporating low-cost in-line sensors and actuators, reducing the need for human intervention in EVD management.

Presenting Author: Eniko Enikov University of Arizona

Presenting Author Biography: Eniko T. Enikov is Professor in the Department of Aerospace and Mechanical Engineering. He is a faculty member in the BIO5 Institute. Dr. Enikov received his PhD from the Dept. of Mechanical Engineering at the University of Illinois at Chicago, Chicago, IL in 1998 and a Postdoctoral Training at the University of Minnesota, Minneapolis, MN. Since 2000, he has been with the University of Arizona. Dr. Enikov has a wide range of research interests in the field of micro-electromechanical systems (MEMS), nanotechnology, sensors, actuators, biomedical devices, applied control theory, signal processing, and modelling of electro-mechanical systems. He is the author or coauthor of more than 133 scholarly products. He is the editor, author or co-author of: Bona, Francesco, and Eniko T. Enikov, eds. “Microsystems Mechanical Design”, Springer Vienna, 2006; Enikov, Eniko T. "Structures and Materials." The Mechatronics Handbook. CRC Press, Boca Raton, 2001, 2017. Dr Enikov is an inventor or co-inventor on five US patents in the area of micro-technology and biomedical diagnostic devices.

Authors:

Eniko T. Enikov University of Arizona
Rein Anton University of Arizona
Daniel Mack University of Arizona