{"id":300,"date":"2017-07-04T21:55:24","date_gmt":"2017-07-04T20:55:24","guid":{"rendered":"http:\/\/eoghan.me.uk\/notes\/?p=300"},"modified":"2023-01-04T13:14:14","modified_gmt":"2023-01-04T13:14:14","slug":"blood-pressure","status":"publish","type":"post","link":"https:\/\/eoghan.me.uk\/notes\/2017\/07\/04\/blood-pressure\/","title":{"rendered":"Doppler Blood Pressure Simulator"},"content":{"rendered":"

In collaboration with the Clinical Skills Team, the Digital Education Unit at the Royal (Dick) School of Veterinary Studies at the University of Edinburgh have developed a Doppler flow measurement simulator to teach the measurement of systolic blood pressure.<\/p>\n

Idea and testing by Rob Ward and Caroline Mosley, construction and coding by Eoghan Clarkson.<\/p>\n

\"Assembled<\/a>
The assembled simulator<\/figcaption><\/figure>\n
\"Raspberry<\/a>
Raspberry Pi wired up<\/figcaption><\/figure>\n
<\/div>\n


\n\"Creative<\/a>
\nThis work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License<\/a>.<\/center>
\n<\/p>\n

The idea<\/h2>\n

Doppler flow measurement is a cheap technique for non-invasive measurement of systolic blood pressure commonly used in small animal practices, and as such is a skill we require our students to master. The technique can be practised on live animals or students themselves, but at Edinburgh we are reducing our use of live animals and have safety concerns about self-experimentation. Also, practising on a live subject does not produce consistent and repeatable results that can be later checked for accuracy. As a result of collaboration between our Clinical Skills Team and Digital Education Unit, we created a prototype Doppler flow measurement simulator using a Raspberry Pi and Arduino together (low-cost computers, about the size of a credit card, which can be extended by adding environmental sensors). This prototype was later refined to require only the Raspberry Pi, and both versions have since been used by students during Clinical Skills practicals.<\/p>\n

The plan<\/h2>\n

Rob and Caroline’s idea was to use a Raspberry Pi to simulate Doppler flow measurement in small animals.<\/p>\n

    \n
  1. A ‘Doppler probe’ would be placed on a dummy of a canine forelimb.<\/li>\n
  2. When in the correct position to take measurements, the sound of blood flowing forward and back would be played through a speaker.<\/li>\n
  3. The student would inflate a cuff using a sphygmomanometer, until the blood flow sound stops.<\/li>\n
  4. They then deflate the cuff until they hear the sound of blood flowing forward, but not back, and note the systolic blood pressure.<\/li>\n
  5. They continue to deflate the cuff until they hear the sound of blood flowing forward and back again, and note the diastolic blood pressure.<\/li>\n<\/ol>\n

    The original idea was that one blood pressure reading would be programmed into the Raspberry Pi.<\/p>\n

    Optional extension<\/h3>\n

    A further idea we had was that a rotary switch could be added, which would allow students to select a number of different blood pressures to try measuring.<\/p>\n

    NOTE: As an emergency measure, if the probe doesn’t seem to work and the blood pressure can’t be heard when placing it, then setting the rotary switch to position ’10’ will ignore the need to place the probe in the correct position, and will cause the blood pressure sound to be heard regardless.<\/p>\n

    The parts<\/h2>\n

    Standard electronic parts:<\/p>\n