Batteryless on-demand-sampling active radiosonde for intracranial pressure measurement

Macellari, Velio

doi:10.1007/bf02441329

Cited by 7 publications

(4 citation statements)

References 17 publications

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“…Telemetric devices have therefore been proposed as an alternative to the traditional invasive cable bound techniques and are often mentioned as an intermediate step towards completely non-invasive long-term monitoring. Many development attempts based on this proposal have been made throughout the past few decades [203][204][205][206].…”

Section: Telemetric Sensors and Miniature Sensorsmentioning

confidence: 99%

Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement

Evensen¹,

Eide²

2020

Fluids Barriers CNS

105

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Sixty years have passed since neurosurgeon Nils Lundberg presented his thesis about intracranial pressure (ICP) monitoring, which represents a milestone for its clinical introduction. Monitoring of ICP has since become a clinical routine worldwide, and today represents a cornerstone in surveillance of patients with acute brain injury or disease, and a diagnostic of individuals with chronic neurological disease. There is, however, controversy regarding indications, clinical usefulness and the clinical role of the various ICP scores. In this paper, we critically review limitations and weaknesses with the current ICP measurement approaches for invasive, less invasive and non-invasive ICP monitoring. While risk related to the invasiveness of ICP monitoring is extensively covered in the literature, we highlight other limitations in current ICP measurement technologies, including limited ICP source signal quality control, shifts and drifts in zero pressure reference level, affecting mean ICP scores and mean ICP-derived indices. Control of the quality of the ICP source signal is particularly important for non-invasive and less invasive ICP measurements. We conclude that we need more focus on mitigation of the current limitations of today’s ICP modalities if we are to improve the clinical utility of ICP monitoring.

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Section: Telemetric Sensors and Miniature Sensorsmentioning

confidence: 99%

Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement

Evensen¹,

Eide²

2020

Fluids Barriers CNS

105

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“…The device was was aimed at measuring intra-cranial pressure (ICP) instead of flow. Some efforts were carried out to produce a batteryless prototype [8], however these early efforts did not result in a functioning prototype. Maturation of micro-electromechanical system technology over the last 3 decades, has brought about technological advances that make this problem solvable.…”

Section: Introductionmentioning

confidence: 99%

Application of GMR Sensors to Liquid Flow Sensing

Enikov

Edes

Skoch

et al. 2015

J. Microelectromech. Syst.

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This paper presents a feasibility study of the application of giant magneto resistive (GMR) sensors in detecting motion of slow moving fluids. A motivating application for the proposed effort is the development of a smart catheter capable of monitoring the amount of body fluid drained from the ventricles of the brain. Microfabricated ferromagnetic flaps are used to detect motion of the surrounding fluid. The deflection of the flaps is detected by an ultrasensitive GMR sensor placed outside of the lumen of the catheter. Numerical and experimental results are provided demonstrating a resolution of 1.4 mL/h. Numerical analysis of the fluid past the sensing element show an optimal hinge length of the flexible flaps, as well as a significant increase in sensitivity with reduction of the by-pass gap to ∼50 µm. The effect of electro-magnetic interference and other sources of low-frequency noise (drift) has also been investigated. The results from the study are used to derive a set of design rules that may lead to the successful development of a smart catheter. [2014-0148] Index Terms-Liquid flow sensor, GMR sensor, smart catheter, ventriculoperitoneal (VP) shunt.

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“…Instead of flow measurements, the device measured changes in intra-cranial pressure (ICP). Efforts in the early 1980s were aimed at producing a batteryless prototype [8], however without demonstration of a functioning unit. More recent efforts showcased prototypes relying on calorimetric principles to measure flow rate using external power sources and readers.…”

Section: Introductionmentioning

confidence: 99%

Optimization and Long-Term Stability of Micro Flow Sensors for Smart VP Shunts

Edes

Enikov²,

Skoch

et al. 2020

IEEE Sensors J.

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This paper reports on a systematic study of the flow sensitivity and resolution of micro-flow sensors intended for use in implantable ventricular-peritoneal shunts. The flow sensors utilize ferromagnetic flaps (transducers) whose deflection is detected by ultra-sensitive MTJ sensors (20mV/V/Oe). A working range of 0-40 ml/h was demonstrated at a maximum uncertainty of 4% RMS and a resolution of 0.4 ml/h. Earlier studies on this sensor unveiled significant low-frequency noise (drift) limiting the sensitivity to 1.4 ml/hr. The present study identifies thermal noise as the main source of low-frequency drift. Using thermal compensation it was found that the drift can be reduced below 2 ml per 24-hr. Combining an array of four transducers operating in series, it has been demonstrated that a sensitivity can be increased 10.9 fold. Furthermore, the report examines the long-term structural stability of the sensors and produces a corrosion report suggesting a lifespan of 15 to 55 years.

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Batteryless on-demand-sampling active radiosonde for intracranial pressure measurement

Cited by 7 publications

References 17 publications

Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement

Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement

Application of GMR Sensors to Liquid Flow Sensing

Optimization and Long-Term Stability of Micro Flow Sensors for Smart VP Shunts

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