Lethal Injection

I killed my first patient today. As the tiny heart pumped away beneath my fingers, I felt for the bottom of the ribcage with one hand and slowly pushed in a syringe full of potassium chloride with the other. The needle punctured the skin. As I aspirated, bright red blood flowed into the syringe mixing with the clear fluid I would soon be injecting in, indicating that my syringe had properly reached the heart. I slowly injected in the fluid and almost instantly felt the heartbeat slowing down, the fingers tightened, a subtle paleness engulfing the face which was teeming with life only moments earlier. Then there was a silent stillness. His heart had stopped. I had made it stop.

Okay, so I have a slight flair for the dramatic - my 'patient' was actually a small gerbil which we had just operated on a few hours earlier, but nonetheless I administered a lethal injection to a living being and directly caused its heart to stop beating. It might have sent a chill down my back in the moment, but in the long-run I have a feeling these poor gerbils will be dying for a greater cause, for the advancement of science, for medicine, for the improvement of human life...okay before I get carried away..

...a little bit about my summer research project:

Literally everyone told us first years to enjoy the summer between our first and second year of medical school, how this is the last summer of our lives, etc. etc. And so far, I can't complain - I've been having a pretty nice summer. I'm working on cochlear implantation research in the ENT department at UNC, using a gerbil model to try and find a method of detecting potential damage caused by the cochlear implant electrode while it is being inserted in a partially-deaf gerbil. Sounds like a lot of words, but basically the ideal patients for cochlear implants are individuals who are hard of hearing high frequency sounds, which are localized at the base of the cochlea. These patients usually retain lower-frequency hearing, which are more towards the apex of the cochlea. Here are some visual aids:

What a cochlear implant looks like (on an adorable baby):

This is a general photo of the position of the cochlea within the inner ear:
And inside the cochlea, there's a tonotopic organization, with the highest frequencies of sound heard at the base of the cochlea, and the lowest near the apex:
As we get older, we naturally lose our ability to hear some of the higher frequency sounds. Even by our teen years, we can't hear some of the more higher frequencies - and we just lose more and more of that as we age. If you want to see what frequency you can still hear, here's a fun website: How well can you hear?

So, when doctors insert cochlear implants, they aim to insert the implant electrode into the cochlea far enough so as to cover all the damaged hair cells (the sensory receptors of the auditory system). If the spiral cochlea was rolled out, it would look like this photo below - contrary to what you'd think, the cochlea is actually narrower at the base and widens as it gets rolled out towards the apex:

However, there's a huge risk of damaging the existing non-damaged, normal-functioning hair cells as the electrode is slowly advanced forward causing further hearing loss than the patient originally presented with.
So in this case, once the surgery is over, the patient will have better high-frequency hearing because of the implant, but will have lost the low-frequency hearing he had before, because the implant itself damaged the hair cells at the apex of the cochlea.

Currently, there does not exist a method of detecting whether the existing lower-frequency area hair cells have been damaged during the insertion process as the surgeons are doing the cochlear implantation surgery. This research project hopes to take a huge step towards providing that technology to the surgeons so if they detect the damage they have just caused, they can either know how far to precisely advance the electrode or if they've already caused irreversible damage, they can advance the electrode all the way to the apex of the cochlea, so the patient can have full use of the implant even at the portions near the apex of the cochlear, which the surgeon just damaged via the insertion procedure.
I know it sounds a little confusing at first, but is actually a pretty cool project. We basically advance electrodes within the cochlea of noise-exposed gerbils (whose high-frequency hearing has been wiped out), and try to see whether the electrode can detect the extent of the existng damaged hair cells before the electrode passes beyond them to potentially cause damage to normal hearing hair cells.
Bottom line: I get to do surgery on gerbils. And that makes me very happy.

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= SUMMER FUN!

Long post, I know, but we're finally at the end. Hope everyone is enjoying their summers!