Earlier this month, we had the opportunity to visit several hospitals to collect feedback on the PneumaShoe. After visiting Queens, Mulanjie, Thyolo, Chiradzulu, and Zomba and conducting some further research, our team quickly came to the conclusion that the calf, rather than the foot is the best place to target when attempting to prevent blood clots in bedridden patients. Because the major veins of one’s lower extremities are initially supplied by the calf, blood clots tend to originate in the calf before traveling elsewhere, making the calf a more effective target. Additionally, calf compression has been shown to be more hemodynamically effective (this includes measurements of peak velocity, refill time, and cycle volume) than foot compression and is the most widely supported form of IPCDs.

Of course, targeting the calf rather than the foot means that various technical specifications of the device must be altered. This includes the applied pressure, the duty cycle, and the cuffs themselves. While implementing these changes will greatly increase the effectiveness of the device, our team will certainly face some significant engineering challenges carrying out these modifications. However, we have a good grasp on how the device needs to be changed and how those changes should be made. In general, there are 3 major changes that need to take place in order to efficiently switch to calf compression:

1. The cuff should undergo the following modifications
   1. The cuff should be a rectangle that’s 60 x 30 cm
   2. The airbladder should be a rectangle that’s 30 x 27 cm
   3. Rather than backpack straps, the cuffs should be secured with Velcro and simple buckles
   4. The material used to make the cuffs should remain the same

(Current Foot Cuff)

1. Rather than an applied pressure of 120 mmHg, the device should achieve an applied pressure of 40 mmHg
2. The duty cycle should be altered such that
   1. The inflation time is slower (5-10 seconds)
   2. The deflation time is slower (5-10 seconds)
   3. The cuff stays inflated for a period of time (“hold time” of 5 seconds)
   4. There’s less time between each cycle
   5. Both the left and the right cuff inflate and deflate in sync rather than inflating and deflating on alternating cycles

(Current Duty Cycle)

While modifying the cuffs is a relatively straightforward task, modifying the applied pressure and the duty cycle will be slightly trickier tasks. As of right now, there is no way to control how fast the air flows out of the air tank and into the cuffs. Slowing down the inflation and deflation of the cuffs will require intense modification of the software that controls the device. Essentially, because the valve that allows air to be released into the cuffs is controlled by a digital signal, we’ll have to use pulse width modulation to get analog results with digital means.

Additionally, because the right and left cuffs must inflate and deflate in sync, the airflow system must be modified such that air can flow into both cuffs at the same time. This may require using a larger pump so that both air tanks can be filled with air simultaneously. Alternatively, we could modify the airflow stream such that both cuffs are filled with air from the same air tank. However, this may not be ideal, as it requires a larger air tank and an air pump with a higher flowrate.

I’m sure our team will have a great time figuring out the best way to solve these issues in the upcoming weeks!

It’s been a little over a week since we landed in Malawi and thus far the trip has been great! Our first week of work at the Polytechnic was mainly dedicated to helping us understand the technologies that we will be working with (this includes oxygen concentrators, CPAP machines, and radiant warmers) and learning about various things that might help us with our projects this summer. So far, we’ve learned about laser cutting, Arduino programming, sensors, 3D printing, and soldering.

(LED Arduino Project!)

(Key chain produced on the lasercutter!)

Hopefully all these new tools will help us get a jump start on our projects! Speaking of which, we just received our project assignments. I will be working on the PneumaShoe, a low-cost pneumatic compression device designed to prevent blood clots in bedridden patients. Over the next few weeks, our team will be collecting feedback from several hospitals and using this feedback to build a new and improved prototype.

Luckily, this week hasn’t been all work and no play. This weekend, we had the opportunity to celebrate the 23^rd birthday of a fellow intern. The combination of Malawian birthday traditions and American birthday traditions made for a memorable night! The fun continued on Sunday when we climbed to the top of Michiru. The journey was difficult, but in the end, it was definitely worth it. I’m very excited to see what new adventures and challenges await us in the upcoming weeks!

It’s currently 5:32 PM (BST) and although we have not yet reached Malawi, we have done our fair share of traveling. Over the last few days, I’ve traveled from Chicago to Houston for Houston to London from London to Johannesburg and the final leg of the trip will take me to Blantyre, Malawi.

So far, the London stop has been the most exciting. With a 12 hour layover, we had plenty of time to experience many of the sites that London has to offer. We saw Big Ben, watched the changing of the guard, and had a lovely lunch in the park. While our stop in Johannesburg has not been as action packed, we did manage to step outside the airport for a few minutes (now we can officially say that we’ve been to Johannesburg!). It may be a good thing that we’re not going on another excursion because the downtown has given me the opportunity to reflect on all of the things that we have done and all of the things still to come.

While we’ve only been traveling for 3 days, our journey started weeks ago.  Over the last few we have put a countless number of hours into trip preparation. We collected valuable advice from last year’s interns, we prepared several technologies to be taken to Malawi (including a breast cancer model, dosing clips, and an ostomy training model), and we brushed up on our Chichewa. Because of all this preparation, it would be easy to believe that I am fully prepared for what’s to come. However, one of the most valuable pieces of advice we received from the previous interns is that our experience may be completely different from their experience and we should learn to expect the unexpected. As we travel through countless airports and through the streets of London, I can’t but feel more and more excited about many memories, progress, and (hopefully!) friends that will be made in the coming weeks. I do not expect the journey to be easy, but I am certain that it will be worthwhile.