Tunneling
Interestingly enough, we stumbled across a problem that isn’t particularly visible in the literature. Insulin tunneling occurs when some kink in the insulin teflon needle or scar tissue (still figuring out whether it’s real scar tissue or something else) causes insulin to pool on skin. During a recent interview, we discovered that some of the most dangerous pooling occurs when insulin pools underneath the skin (i.e. locally disburses, but doesn’t disburse throughout the entire body system). Initially, I had thought that the pooling only occurred on the outside of the skin. This second form of pooling is actually more dangerous than the first, because it is virtually impossible to remove the locally disbursed insulin, and eventually that insulin will hit the body, which might coincide with a bolus, causing a blood sugar low.
The solution we were examining was aimed at detecting insulin on the surface of the skin. However, upon thinking about it, I can’t seem to come up with a solution to the internal pooling issue. Electrodes can’t be used on the tip of the needle because the insulin would touch the electrode regardless of whether it was pooling or not as it was released by the pump. However, I might be underestimating the changes that insulin causes in the locality in which it is distributed. Additionally, the patient stated that they were unsure about which type of tunneling occurred more often. However, the patient seemed very interested in the idea of tunneling detection. For now, I believe our group will proceed with the method we had initially thought about, but internal tunneling is definitely an issue that we will need to revisit and brainstorm about to come up with possible solutions.
For reference, I’ve included a picture of internal tunneling. In the picture, the insulin can be seen, which is not always the case with tunneling. Part of the problem is that tunneling is hard to detect, but that is also what makes it an important and significant engineering challenge.
-N
BME Design 
