John Webster

Professor Emeritus


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Room: 2148
Engineering Centers Building
1550 Engineering Drive
Madison, WISCO 53706

Ph: (608) 263-1574
Fax: (608) 265-9239

Primary Affiliation:
Biomedical Engineering

Profile Summary

My graduate students and I are involved in the following research.

Implantable intracranial pressure monitor:

We are working with Department of Neurological Surgery Professor Joshua Medow to develop a permanently implanted passive pressure sensor to measure intracranial pressure (ICP). At any time, the hydrocephalic patient, care taker, or physician can hold an external display device over the internal sensor coil and display the ICP and waveform to determine if the ICP has increased due to shunt obstruction which can require surgical intervention. Pressure will (1) deform the membrane and (2) move interior inductor coils closer together to (3) cause changes in resonant frequency. The external display device coil will link inductively to the internal sensor coil to measure the change in resonant frequency and convert it to pressure.

Sleep Apnea therapy device that increases dead space

Sleep apnea is a common sleeping disorder that affects over 25 million Americans. Due to the complex nature of sleep apnea and the human body, neither an effective nor comfortable treatment option for sleep apnea has been developed. We have developed a successful and novel alternative to continuous positive airway pressure (CPAP) therapy. This device incorporates the rebreathing of exhaled air to induce moderate hypercapnic conditions in systematic blood circulation. This device is composed of a comfortable silicone rubber facemask that covers the mouth and nose, and tubing that attaches to the anterior port of the mask. Qualitative and quantitative testing demonstrated the efficacy of the device to be more comfortable than CPAP, and efficient at sufficiently increasing PETCO2 levels to eliminate apneic events due to obstructive, central, and complex sleep apnea. This device counts apneas and automatically increases or decreases dead space to minimize apneas, then sends reports to the clinician.


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