title: A multisensor implant for continuous monitoring of intracranial pressure dynamics.
abstract: In humans, intracranial pressure (ICP) is not only influenced by pathology, but also by orientation in space and body movements. Therefore, it is proposed to measure ICP dynamics and body acceleration simultaneously. An algorithm for acceleration analysis was developed to monitor orientation in space and allow more accurate examination of ICP dynamics during quiet periods. For continuous monitoring, an implant was developed and wireless data transmission was implemented; this prototype was successfully tested in five pigs. Hydrocephalus with increased ICP was experimentally induced in the animals using a surgical kaolin infusion. This model of porcine pathology was then tested with the implant with the aim for eventual use in humans. ICP dynamics and 2D-acceleration data were simultaneously recorded for up to two weeks. This study allowed 24-h monitoring and provided analysable data on porcine ICP dynamics with humanlike ICP waves, the so called B- and P-waves. Results show that acceleration often had a stronger influence on ICP than the amplitudes of the physiological ICP characteristics. With test animals in a standing position, without obvious body movement, ICP varied to an extent that made the characteristic ICP waves difficult to identify. These data allow us to conclude that analysis of both ICP and acceleration may be essential for autonomous implants.
authors.affiliation: Philips Chair of Medical Information Technology, Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, 52074 Aachen, Germany. ssjj@gmx.de
authors.forename: Stefanie
authors.initials: S
authors.lastname: Jetzki
authors.forename: Martin
authors.initials: M
authors.lastname: Weinzierl
authors.forename: Inga
authors.initials: I
authors.lastname: Krause
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hahne
authors.forename: Hubertus
authors.initials: H
authors.lastname: Rehbaum
authors.forename: Michael
authors.initials: M
authors.lastname: Kiausch
authors.forename: Ivanna
authors.initials: I
authors.lastname: Kozubek
authors.forename: Carmen
authors.initials: C
authors.lastname: Hellenbroich
authors.forename: Markus
authors.initials: M
authors.lastname: Oertel
authors.forename: Marian
authors.initials: M
authors.lastname: Walter
authors.forename: Steffen
authors.initials: S
authors.lastname: Leonhardt
mesh_terms: D000054:Acceleration; D000327:Adsorption; D000465:Algorithms; D000818:Animals; D001698:Biomedical Engineering; D002555:Cerebrospinal Fluid / Q000502:physiology; D003201:Computers; D011211:Electric Power Supplies; D004581:Electronics; D004867:Equipment Design; D006801:Humans; D006874:Hydrostatic Pressure; D019586:Intracranial Hypertension / Q000175:diagnosis*; D007427:Intracranial Pressure / Q000502:physiology*; D008991:Monitoring, Physiologic / Q000379:methods; D009991:Oscillometry; D019736:Prostheses and Implants; D012815:Signal Processing, Computer-Assisted; D013314:Stress, Mechanical; D013552:Swine; D014057:Tomography, X-Ray Computed; D059015:Wireless Technology