Week 4: Prototyping

This past week we had a very focused objective of completing a prototype to get patient and doctor feedback on Friday. The prototype was mostly designed by last year’s GMI cohort, so our main task was to make it out of locally available materials. You may be thinking, like I was, that a full week with 9 people just to build a prototype seems like plenty of time. Nevertheless, we were working until 9PM the night before. Here’s how it went:


Project Background

Your kidneys filter your blood and remove waste. When your kidneys fail, that waste still needs to be removed or you will die. There are two methods in which waste is removed from the blood in patients with kidney failure: hemodialysis and peritoneal dialysis. In hemodialysis, blood is removed from the patient, cleaned by pumping it through an external filter, and returned to the patient. This procedure lasts 4-6 hours and must be done around 3 times per week, but is expensive and only used in wealthier parts of the world. Peritoneal dialysis starts by filling the patient’s peritoneal cavity, an empty cavity in the abdomen, with a fluid called dialysate. The natural lining of the cavity allows waste to pass into dialysate, where it is held until the cavity is drained. While the procedure varies, it usually lasts 30 minutes and must be completed 4-5 times per day. Peritoneal dialysis is much cheaper than hemodialysis, and is used when hemodialysis is too expensive, including here in Costa Rica.

Because the peritoneal cavity must be filled and drained through a catheter, this procedure must be conducted in a sterile environment to prevent infection. Therefore, those whose homes are not sterile enough must be at a hospital 6 days per week, morning to night, to conduct this procedure. This puts a significant monetary burden on the healthcare system, not to mention on the personal and family lives of the patients.

The prototype we worked on this past week was a small room that could be rented to patients by the healthcare system of Costa Rica (the “Caja”) to enable the patients to conduct dialysis in their own homes. The room should be able to maintain a sterile environment, and have all the elements needed to conduct this procedure. Last year’s GMI cohort designed and constructed a prototype in Houston, but our task was to build it out of materials available here in Costa Rica and get feedback from actual patients and physicians in the Liberia hospital.


Work done up to this week

As mentioned previously, last year’s cohort actually designed the room out of materials available to them in Houston, so we had a blueprint to work off of going into this week. On last Thursday, we travelled to the Liberia hospital to observe the dialysis procedure being conducted to gather any extra insights we could before building the prototype.

Last Friday morning, we travelled to Invenio, a private University in Costa Rica we partnered with to complete the prototype. There, we discussed the original design and our concerns moving forward. Primarily, this looked like how we were going to frame and transport the panels of the room. There was talk of both fully framing every panel or only fully framing some, and slipping in the remaining panels to the existing framing. Unfortunately, they did not speak much English and we did not speak much Spanish, so we were fairly limited to our communication through Dr Richardson. Therefore, at the end of our meeting with Invenio, we as the Rice students decided to fully frame every panel, but, as we learned later, accidentally failed to communicate that to the Invenio staff.

Friday afternoon we split into three teams and planned out the week as best we could. I was placed on the Build team, which was responsible for the final design of room based on the materials we could find and for constructing the room. The other teams were Materials, who were responsible for finding the best materials available to use for our design, and Testing, who would ensure we had everything we needed on Friday to get good and reliable feedback. Because I was on the build team, most of my thoughts will be from the design and fabrication perspectives.

Over the weekend, we found out that our partners at Invenio had already gotten started framing some of the panels. In our meeting with Invenio, we had not yet wanted to commit to a material for the panels and frames, and so we were a little frustrated with their commitment to these materials. In hindsight, though, their eagerness to get started may have saved us from not finishing our prototype. They likely knew how long it would take to complete the room and realized we needed to go ahead and commit to some materials to complete it on time. Nevertheless, miscommunication and differences in expectations are always frustrating to encounter.



Our goal for Monday was to meet with the Invenio staff in the morning to better define each group’s role in the process. We wanted to maintain as much control over the final design and materials selection process to make sure we still had an educational experience and that it was done properly. What I imagined to be a formal meeting turned into an informal 10-minute conversation between Dr Richardson and the head shop guy we were working with, Ronald. I think what came of that conversation was that we were to show them our ideas of what we wanted to make, and they would do their best to make it with the equipment they had available. However, since they had already gotten started on the framing themselves, they maintained most creative control on that aspect of the design.

Here I will also pause to mention that we decided early on that we needed to redesign the sink from the old design. It was in a somewhat awkward position in the room, it wasn’t structurally stable, and was smaller than we thought was appropriate. Therefore, a large portion of the build team’s focus was on the design of the sink.

For the rest of the day Monday, my team helped fabricate wall panels and worked on making some design decisions.



Tuesday was a hoot! The Materials and Testing team needed to do some work in Liberia (about 45 min from Invenio), so the build team camped out at a McDonalds to try to finalize our design before lunch, where we were supposed to present it to the rest of the team. This was mainly talking about the sink design, but we also looked at pictures given to us by the materials team about what tables, chairs, plumbing, hooks, etc were available to us and made selections. There may have also been a McFlurry break along the way.

At lunch, the testing team shared what they had learned in their conversations with nurses and physicians at the hospital that morning, which caused us to pivot slightly on our design of the sink. This was the final design:

Our final trough sink design. CAD work done by Callie.

We decided to make our own trough-like sink for several reasons. The patients are required to wash their hands up their elbows, so a large area would be ideal to catch as much dripping as possible. The room is fairly small (4’x6’), so we felt foot space was at a premium. The trough design allowed us to fully support the sink by anchoring it to the wall frames and removed the need for supporting legs, adding leg room when sitting in the chair. Lastly, in the long run, a simple trough-style sink made from sheet metal should be cheaper than a typical sink. One limitation was that we would have to make it our self, which could be a problem with our deadline approaching, but we thought it was doable.

Tuesday evening, we returned to Invenio with the goal of finishing the frame of the room by the end of the day. We started working right away on one of the panels, so Dr Richardson left with the materials team to look at another hardware store. After finishing our first panel of the day, there was only one left to have all the panels we needed. Things seemed to slow down though. The Invenio guys were taking some measurements, then leaving for bits of a time. After a while, the guys started putting what panels we had together and pointing to where the last panel would go. However, they were planning on not fully framing the last panel, but just slipping it in to the existing framing. Knowing that we needed the extra framing of the fully framed panel to mount the sink, I began trying to explain this mix up. I thought they knew we wanted to have fully framed panels and decided not to do it for some other reason. They began to try to brainstorm how we might add support for the sink without fully framing the panel, but couldn’t come up with a good solution. After a while, Ronald said we could just fully frame the panel, but it would cost more. I then concluded that Invenio decided not to do the fully framed panels for cost limitations. With the question of cost being raised, I didn’t feel qualified to make any decisions, so we had to wait until Dr Richardson returned, which was around 4:30.

When Dr Richardson arrived, he quickly resolved the problem. We proceeded with the fully-framed-panel option like it was no problem. It was here that I realized we never actually told them we wanted to proceed with that design. We decided we needed to finish the frame before we left for the day, so we unable to leave until 7:00 or so. It was frustrating that we made slow progress that day, but at least we left with a completed frame.



Dr Richardson had commitments Wednesday morning and evening, so we had a shortened day at Invenio. Our goal was to finish as much of our sink as possible, knowing we had to finish the entire room by Thursday. After a quick pow-wow, we drew out the pattern on the sheet metal and began using Invenio’s tools to fabricate the sink. The shop guys were teaching classes all day, so Dr Richardson was allowed to use their tools. We were restrained to a skill saw to cut the material, and a manual die to bend the metal, both of which slowed us down significantly. We were unable to finish cutting out sink by the time we needed to leave Wednesday.

Additionally, we talked to, as we called him, “Invenio’s door and roof guy,” who was going to get us some better framing for the roof and door of our room.



Thursday was probably the most painful out of all the days. The morning was productive, finishing cutting and bending the sink pieces. But after lunch, everything seemed to slow down. We wanted to wait until we put the sink into the room before we started making most of the cuts for the water drainage. However, while we were finishing up the sink, we decided to change how we would drain the water, so the materials team needed to make one more trip to the store. We got the frames for the door and roof later than we expected, so we were not able to put those on until late in the day. One thing added to another, and we were unable to completely finish the frame until about 7:30. After completing the room, we disassembled it and loaded it onto the truck for transport, leaving Invenio around 9:00.

The prototype loaded up onto the truck.



We had a few hiccups getting into the hospital and assembling the room there, so we were only able to get feedback for about an hour and a half. However, we had a very positive response, and we had to really prod to get some constructive criticism. They commented about the sink, lighting in the room, chair and table height, and several other features.

The Hospital Liberia staff that reviewed our prototype

Overall, Friday was exciting because we got to see some of the people that would be able to benefit from our work. They were excited because if they could use our product, it would mean they could spend more time at home with their families. I would have loved to have been able to speak better Spanish to be able to talk with them some and here more of their stories. I was reminded Friday why I’m studying biomedical engineering.

After packing up at the hospital and getting back to our rooms, I accidentally took a 4-hour nap, missing dinner, which was probably one of the longest naps I’ve ever taken. You could say it was an exhausting week.


Lessons Learned

  • Good communication between two designers is hard. Good communication between multiple designers who speak different languages is harder. When working on joint projects, ensure your ideas are presented clearly, and do your best to avoid confusions.
  • Gained a new appreciation for hydraulic-powered machinery (as opposed to manual ones that sometimes jam and take 10 min to unjam)
  • Peritoneal dialysis kinda sucks, but we can make it less sucky
  • Building-as-you-go rather than doing all the design followed by all the building has its advantages


Adventures over the weekend

Saturday, we traveled back to San Jose to begin phase 3 of our trip. Taking the opportunity for a little fun, we stopped at a zipline place near Monte Verde. We flew over vast canopies for about 2 hours, and I was even peer-pressured into doing the MEGA Tarzan swing, a swing with about 3 seconds of free fall. It was an incredible way to end the week.

Flying over the canopies of Costa Rica. Looking back, maybe the harness should have been a little tighter…

This entry was posted in Uncategorized. Bookmark the permalink.

Comments are closed.