HHS Public Access Author manuscript Author Manuscript
Sens Actuators A Phys. Author manuscript; available in PMC 2016 October 01. Published in final edited form as: Sens Actuators A Phys. 2015 October 1; 234: 223–231. doi:10.1016/j.sna.2015.08.023.
Demonstration that a new flow sensor can operate in the clinical range for cerebrospinal fluid flow Rahul Raja,1, Shanmugamurthy Lakshmanana,2, David Apigoa, Alokik Kanwala, Sheng Liua, Thomas Russella, Joseph R. Madsenb, Gordon A. Thomasa, and Reginald C. Farrowa,*
3,
Author Manuscript
a
New Jersey Institute of Technology, Department of Physics, Newark, NJ 07102, USA
b
Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
Abstract
Author Manuscript
A flow sensor has been fabricated and tested that is capable of measuring the slow flow characteristic of the cerebrospinal fluid in the range from less than 4 mL/h to above 100 mL/h. This sensor is suitable for long-term implantation because it uses a wireless external spectrometer to measure passive subcutaneous components. The sensors are pressure-sensitive capacitors, in the range of 5 pF with an air gap at atmospheric pressure. Each capacitor is in series with an inductor to provide a resonant frequency that varies with flow rate. At constant flow, the system is steady with drift
Sens Actuators A Phys. Author manuscript; available in PMC 2016 October 01. Published in final edited form as: Sens Actuators A Phys. 2015 October 1; 234: 223–231. doi:10.1016/j.sna.2015.08.023.
Demonstration that a new flow sensor can operate in the clinical range for cerebrospinal fluid flow Rahul Raja,1, Shanmugamurthy Lakshmanana,2, David Apigoa, Alokik Kanwala, Sheng Liua, Thomas Russella, Joseph R. Madsenb, Gordon A. Thomasa, and Reginald C. Farrowa,*
3,
Author Manuscript
a
New Jersey Institute of Technology, Department of Physics, Newark, NJ 07102, USA
b
Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
Abstract
Author Manuscript
A flow sensor has been fabricated and tested that is capable of measuring the slow flow characteristic of the cerebrospinal fluid in the range from less than 4 mL/h to above 100 mL/h. This sensor is suitable for long-term implantation because it uses a wireless external spectrometer to measure passive subcutaneous components. The sensors are pressure-sensitive capacitors, in the range of 5 pF with an air gap at atmospheric pressure. Each capacitor is in series with an inductor to provide a resonant frequency that varies with flow rate. At constant flow, the system is steady with drift
