Francis Felice: Arterial Details BACK

Published by AFAR

After a week of trying different techniques to make our protocol work, I finally collected some usable data today. For my project, I'm using a doppler probe to monitor blood flow in the radial artery; this is a technique that has been successfully applied to mouse models with the equipment I am using, but the technique has been untested in humans, so my mentor and I were becoming skeptical when we weren't getting analyzable results. However, with some trial and error, as well as some irritated skin from having to push the probe pretty deep into my arm to get a signal, I've traced the radial artery up my arm so that I will be able to obtain data from a proximal and distal point of the artery.

The first step, which also happened to be the longest step, was to make sure I could get any kind of consistent doppler signal from my radial artery using equipment that was built for rodents. This was predominantly an effort of trial and error, because even though I could readily palpate my distal radial artery, I couldn't find the blood flow with the probe. As a result, I ended up having to try a lower frequency probe, which gave me a lower quality signal, as well as different angles and depths to finally get a signal from the distal radial artery, but this data was not sharp enough for me to perform any meaningful analysis. Furthermore, at this point, I was only able to get a signal at the distal radial artery and I needed to get signals from two distant points along the radial artery for our experiments.

So the next step was to start using the higher frequency probe to see if I could obtain higher quality data from the distal radial artery. Once I was able to consistently find the distal radial artery with the higher frequency probe, I endeavored to find a more proximal portion of the radial artery with the higher frequency probe. This proved difficult, because while I could readily palpate my distal radial pulse, I had a much more difficult time palpating my proximal radial pulse, so I had a difficult time determining where the probe should be placed to have any chance of finding the artery. So I spent time trying to palpate a proximal portion of the radial artery with the hopes of finding a landmark I could use to find the artery on other people. This caused some more pain from probing deep into the arm to try to find the artery, but after some time, I was able to find the proximal radial artery consistently and since it essentially runs along with the distal cephalic vein, I was able to use the cephalic vein as a landmark to find the artery in other people.

Once I was able to find both sections of the artery consistently, my goal was to get a signal that was clean enough to analyze with our software. This took some more time and pain, but I'm now able to get clean signals from both proximal and distal sections of the radial artery independently. Since my protocol requires that I capture signals from both locations simultaneously, my next step is to determine how to capture both signals consistently and in a way that can be applied to other people. So this turned out to be a good week with success following initial frustration. As I have experienced during previous research opportunities, I cannot expect everything to go smoothly and this experience has been no different so far, but that's part of the challenge.

Francis Felice
Baylor College of Medicine

 

"Diary of an MSTAR Student" follows scholars in the 2011 Medical Student Training in Aging Research (MSTAR) Program, highlighting their summer experiences. As they continue their path of research, training and clinical practice, read their daily thoughts at www.afar.org/mstarblog. New diary entries are posted every day, so check back soon.