Pressure Sores and Electronic Monitoring

There are many cool ideas in medicine… and many go unfunded, and unimplemented. Having been down the path with the FDA a few times in the past, its a pita for the small entity. When one should be working on engineering, one ends up filling out 2″ thick documents for the FDA, most of which is repetive in nature, just in slightly different formats, or + this or – that. It can be pretty frustrating. However, once one has done it a few times, it does become less burdensome.

In 1997, we came up with the cool idea of monitoring a bed ridden patients thermal profile. By looking for hot spots, it was possible to predict potential areas for skin breakdown, resulting in pressure sores. The idea was to alert nursing staff to a potential problem before it developed, thus saving a substantial amount of nursing resources. Eg, its a lot easier to be proactive to prevent a bed sore, than it is to treat an open wound after the fact.

The normal course of action for prevention, is manually moving the patient. This is typically done on a time schedule, ranging from 4-6 hours, and due to staffing shortages, it might even be longer for larger patients, if multiple people are not available to help.

A monitoring system, could be use to alert staff that patient A is getting into trouble, such that they could be put on a shorter duration rotation schedule. Patient B otoh, may be doing fine, and instead of a 4 hour cycle, might appreciate not being woken in the middle of the night every 4 hours instead of 6.

The idea is pretty simple. A mattress pad with interwoven scannable temperature sensors. The actual implementation would be fairly easy to accomplish with spun chromel, and spun alumel alloys, by simply adding them to the interlayment of the mattress pad, with chromel on the top side in a horizontal direction, and alumel on the bottom in a vertical direction. The net effect, is that where the lines cross, a thermocouple junction is created. Thus by adding a pvc insulation, combined with a junction creation process not unlike selective fuse blowingb in the proms of old, its fairly simple to manufacture. (Please note the ambiguity here). The idea is free, the implementation I do not give away completely!

Then its a simple matter of creating an IO block to the mattress pad, and an multiplexed data collector, and some prediction algorityms, and you are in business.

Thus a monitoring mattress pad is born, and its a whole lot less expensive than a Hill Rom sleep surface with autorotation. Don’t get me wrong, the Hill Rom idea is a great one, its just out of reach for the average nursing home.
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