UCLA

There has been a push to modernize the technology used in patient monitoring. One area that is being investigated is the use of in situ sensors for real time, continuous vital signs monitoring, particularly to measure pressure. We developed two sensors fulfilling different roles. One is fully implantable and wireless for long term urological pressure monitoring using conventional MEMS technology. This sensor required the use of a battery-powered wireless transmitter. The second sensor utilizes an entirely new method of pressure sensing designed to be easily scaled down in size while being extremely cost effective. By using an electrolyte solution-filled elastic tube, the sensor does not require further packaging; also the materials used are easily obtainable commercially, so no custom components are required even when downsizing. Although initially designed and tested as a wired sensor, the new catheter sensor was designed to be integrated with wireless capability later--to create a truly minimally invasive long term pressure monitor. Both pressure sensing systems were developed by fabricating a pressure sensitive catheter lead, designing the electronics required to amplify and filter the sensor signal, programming the software client that received, stored, graphed, and interpreted the data. Furthermore, both sensors were subjected to extensive in vitro testing to characterize sensor performance and lifetime, as well as simulate an in vivo environment. Both sensors required the investigation of robust packaging techniques to ensure functionality and survivability while implanted. Last, both sensors demonstrated their potential use as a pressure monitor in animal studies: within the bladder for the wireless implantable sensor and as an intravascular sensor for the new conductometric design.