This project was to build a hemodynamic patient monitor similar to the Schiller PB1000 which is what Merge/Camtronics used as their patient monitor front end. Basically it is a patient monitor that acquired all vital signs, waveforms and parameters: 12 lead ECG, 4 invasive pressures, 2 temps, SPO2, and EtCO2, just like a standard patient monitor. What was unusual about this project is that the requirement was to use open source hardware. This meant that we could just build an isolated daughter board to acquire and digitize the signals and then pass off to the processor, which was originally a Raspberry Pi, but then was superceded by a Beagle Bone Black (BBB) as it has a bit more horsepower. This, in essence, was building a physiological monitoring “cape”.
I chose the Analog Devices ADAS 1000 chip-set for ECG. This gave a compact solution for 500 sps 12 lead ECG and provided all of the housekeeping tasks such as lead-fail detection and respiratory waveform output. The system used standard YSI compatible thermister temperature probe inputs, and modules for non-invasive blood pressure (CAS Medical), SPO2 (Covidien/Nellcor), and even EtCO2 (Covidien). All of the connectors were being sourced from Bernd Richter. The hardest part was creating the relationships with these large companies to create this tiny project.