Non-invasive biomedical patch sensor to measure intracranial pressure

Eckerman

et al. 2018

Sensors

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Elevated intracranial fluid volume can drive intracranial pressure increases, which can potentially result in numerous neurological complications or death. This study’s focus was to develop a passive skin patch sensor for the head that would non-invasively measure cranial fluid volume shifts. The sensor consists of a single baseline component configured into a rectangular planar spiral with a self-resonant frequency response when impinged upon by external radio frequency sweeps. Fluid volume changes (10 mL increments) were detected through cranial bone using the sensor on a dry human skull model. Preliminary human tests utilized two sensors to determine feasibility of detecting fluid volume shifts in the complex environment of the human body. The correlation between fluid volume changes and shifts in the first resonance frequency using the dry human skull was classified as a second order polynomial with R2 = 0.97. During preliminary and secondary human tests, a ≈24 MHz and an average of ≈45.07 MHz shifts in the principal resonant frequency were measured respectively, corresponding to the induced cephalad bio-fluid shifts. This electromagnetic resonant sensor may provide a non-invasive method to monitor shifts in fluid volume and assist with medical scenarios including stroke, cerebral hemorrhage, concussion, or monitoring intracranial pressure.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Non-Invasive Electromagnetic Skin Patch Sensor to Measure Intracranial Fluid–Volume Shifts

Eckerman

et al. 2018

Sensors

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“…Additionally, the penetration depth of the sensor’s electromagnetic field is an important factor. We have conducted some preliminary studies with varying thickness of muscle tissue and bone and have been able to detect usable signals in depths of up to 26 cm [26] , [27] , [49] . Due to the operating principles of the sensor, the penetration depth is substrate specific.…”

Section: Discussionmentioning

confidence: 99%

“…In summary, this study presents a foundation for the development of a passive skin patch sensor, powered externally by radiofrequency (RF) waves via an antenna, to measure cardiac fluid volume changes. In our previous work, we were able to demonstrate the ability of an RF skin patch sensor to detect intracranial fluid-volume shifts, detect pulsatile blood flow in a human arm phantom, identify hemodynamic waveform features, and measure heart rate [24] – [27] . The patch sensor was designed from a single baseline component comprised of a trace of silver configured into a square planar spiral patch.…”

Section: Introductionmentioning

confidence: 99%

Passive Self Resonant Skin Patch Sensor to Monitor Cardiac Intraventricular Stroke Volume Using Electromagnetic Properties of Blood

Alruwaili

IEEE J. Transl. Eng. Health Med.

et al. 2018

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This paper focuses on the development of a passive, lightweight skin patch sensor that can measure fluid volume changes in the heart in a non-invasive, point-of-care setting. The wearable sensor is an electromagnetic, self-resonant sensor configured into a specific pattern to formulate its three passive elements (resistance, capacitance, and inductance). In an animal model, a bladder was inserted into the left ventricle (LV) of a bovine heart, and fluid was injected using a syringe to simulate stoke volume (SV). In a human study, to assess the dynamic fluid volume changes of the heart in real time, the sensor frequency response was obtained from a participant in a 30° head-up tilt (HUT), 10° HUT, supine, and 10° head-down tilt positions over time. In the animal model, an 80-mL fluid volume change in the LV resulted in a downward frequency shift of 80.16 kHz. In the human study, there was a patterned frequency shift over time which correlated with ventricular volume changes in the heart during the cardiac cycle. Statistical analysis showed a linear correlation \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{upgreek} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} }{}${R} ^{2} = 0.98$ \end{document} and 0.87 between the frequency shifts and fluid volume changes in the LV of the bovine heart and human participant, respectively. In addition, the patch sensor detected heart rate in a continuous manner with a 0.179% relative error compared to electrocardiography. These results provide promising data regarding the ability of the patch sensor to be a potential technology for SV monitoring in a non-invasive, continuous, and non-clinical setting.

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A Noninvasive, Electromagnetic, Epidermal Sensing Device for Hemodynamics Monitoring

Mohammed

IEEE Trans. Biomed. Circuits Syst.

et al. 2019