technology insights and the HEM-790ITCAN

Technology insights are not just there for the picking.  If they were easy the area would not be filled with gee-whiz and i-candy.

An article from last fall discussed the role of semiconductors in medical devices in general and the Omron HEM-790ITCAN in particular.

In thinking about medical devices it is put forward that advances therein are generally within either the “medical” bit or data collection and processing.  The former group might include micro-fluidics and the role monoclonal antibodies have played in modern immuno-assays, to name but two.  Advances within the latter group might include, for example, better sampling rates, the ability to efficiently run a given algorithm locally or the ability to interact, in real time with say patient medical history on a server attached to a LAN. Such advances in turn often result from the increased use of integrated circuits or electronics in general.

So where does the Omron HEM-790ITCAN fit?  Does the meaning of sphygmo … whatever, matter?  A better understanding of the technology behind this device and the role semiconductors play can probably be obtained by answering some basic questions.

Q: What does Omron say about the HEM-790ITCAN and how is it being marketed?
A: The device’s page on the Omron website discusses the detection of hypertension and an irregular heartbeat.  A glance at figures in the manual suggests these functionalities are available on the device itself, so there is logic and software operating on it.   It is also indicated that up to 200 readings, in total, can be stored between two patients, so there has to be memory.  This memory would have to be non-volatile to maintain this data when the device is turned off.   This might take the form of  a battery backed SRAM or maybe EEPROM.  The device page also highlights two trademarked terms “Intellisense” and “Comfit”, with the former being combined with the terms accurate and comfortable, while the latter is used to describe a cuff.  Both phrases suggest there must be advances in the cuff behind this marketing.

Q: Are there any patents around technology that might be in this device?
A: Yes.  A very basic search of issued patents in the USPTO found 16 patents assigned to Omron containing “blood pressure” in the title.  Within these are US 7,018,335 and 7,775,984 entitled “Blood Pressure and Cardiovascular Disease Risk Analyzing Program” and “Electronic Blood Pressure Monitor and Data Processing Apparatus”, respectively.  There are also numerous patents  related to a cuff.  The presence of issued US patents associated with both the cuff and the monitor support the above marketing message.

Q: What does the reverse engineering tell us in terms of the use of the implemented integrated circuits?
A: The Cypress and Toshiba ICs are shown in the board level photographs on page 55 of the article.  Otherwise  the pressure sensor, USB port, two TSOPs, what appear to be some high voltage parts and discretes are visible.  At this level the various die markings are unclear but at least one of the 8-pin TSOPs might be non-volatile memory.  There will also some software for running the various data processing algorithms stored somewhere.  Whether it is in the second TSOP or onboard one or both of the micro-controllers is unclear.  What is clear is that a system to collect, manipulate and store data is provided by the device.  Finally, it is  somewhat interesting that the two die markings have a 1999 copyright, indicating they are older designs.  In the end that is fine as not much computing power is needed for this application.

Apart from improvements within the cuff that might be slotted into the “medical” bit the role of semiconductors, including any improvements in sensitivity of the pressure sensor, provide for better data collecting and processing.  While only the surface has been scratched here there is a much more interesting story to be told when you look.