Update #2
Order for Spring Prototyping
We have successfully research and complied a list of items to be ordered for our project. These will cover the main desired functions of the sleeve: to prevent edema and monitor skin perfusion actively.
Edema Prevention
To actively attempt to prevent edema post operation, we plan to implement mechanically inflatable air bags, much like what is found in a blood pressure cuff. However, these must be slight different, since they will need to provide uniform pressure in three directions and remain in constant balance despite pressure adjustments. Therefore, we have ordered two inflatable cuffs to experiment with orientation and use.
Item Link: https://www.amazon.com/Reusable-Ice-Pack-Knee-Compression/dp/B072VQPG63/ref=sr_1_33_sspa?keywords=air+bladders&qid=1577731004&s=hpc&sr=1-33-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExWUJZUEJTQU1ZQzEzJmVuY3J5cHRlZElkPUEwMDYxMDczMVNDOVJHUTNPNks0UyZlbmNyeXB0ZWRBZElkPUEwNjc4ODgxMjA1V1A3REtPVk9ETyZ3aWRnZXROYW1lPXNwX2J0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
Item Link: https://www.amazon.com/Blood-Pressure-Monitor-Upper-Arm/dp/B07D6LWQB2/ref=sr_1_2_sspa?keywords=blood+pressure+cuff+pump&qid=1578436190&s=hpc&sr=1-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFTMVI2SEpIWlU0TlQmZW5jcnlwdGVkSWQ9QTA5NDM5NjcyOFBVTkZNUU1PUUJIJmVuY3J5cHRlZEFkSWQ9QTA5OTkwNzkyVEdHODZNSVE0WTNBJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
We plan to measure the local pressure from the cuffs using pressure sensors, which could either act automatically to adjust the pressure, or notify an interface for the patient to create manual adjustments.
Item Link:https://www.adafruit.com/product/1075?gclid=EAIaIQobChMI0_zg7dTZ5gIVxcDACh2jOQ7sEAQYASABEgLpsvD_BwE
Skin Perfusion
To measure skin perfusion, we envisioned being able to utilize TcPO2 sensors placed directly on the skin, but those require expensive and elaborate medical equipment. Therefore, we will be creating our own leg pulse oximeter, using the circuit located in the more common finger pulse oximeter.
Item Link: https://www.amazon.com/Deluxe-SM-110-Display-Finger-Oximeter/dp/B003TJH3LI/ref=sr_1_1?keywords=transcutaneous+oxygen+sensor&qid=1578418309&sr=8-1
Finger pulse oximeters measure oxidation by transmitting a red laser through the skin and recording the amount that passes through. This works well on the finger due to its smaller size, but could have issues transmitting through the leg. Therefore, we are also ordering a reflectance sensor, which operates with a very similar mechanism, but with laser reflected back. This method is less impacted by limb volume or size, and can be compared to our transmittance signal.
Item Link: https://www.concordhealthsupply.com/Nonin-8000r-3ft-Forehead-Infrared-Sensor-p/non-8000r.htm?gclid=Cj0KCQiA9dDwBRC9ARIsABbedBOYPkOADogMydHR-wkJHR0SxLtqABnaIO6H4bAyCJQgdG4ld2RagpwaAhFcEALw_wcB&click=71
Limb Volume
To understand the success of this medical device, we are observing limb volume to allow for a more well rounded idea of the wound healing process and extent of edema. One way we will potentially be able to do so is with bioimpedance, through sending micro currents through the leg to measure volume.
Item Link: https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/EVAL-AD5933.html#eb-overview
The other effective method is through using soft potentiometers, which could flexibly measure the circumference of the leg, and help assess necessary pressure changes.
Item Link: https://www.adafruit.com/product/2273