PROJECT GOAL

Develop low-cost prototype to measure blood pressure for pre-eclampsia and eclampsia patients. 

Role: Design researcher
Project Type: Product design
Team: Jason Lam, Adam Burdo, Gaurang Alat, and Michael McBurney
Contribution: Research Plan, usability test moderation, field observation, and design prototype
Deliverable: Design prototype

BACKGROUND

Preeclampsia is a health disorder diagnosed in pregnant women that can lead to eclampsia, the onset of seizures, and possible death. It is the second largest contributor to maternal mortality worldwide and the leading cause of maternal death in the Komfo Anokye Teaching Hospital (KATH) in Kumasi, Ghana. Eclampsia is the occurrence of grand mal seizures before, during, or after delivery that cannot be contributed to other causes. The mechanisms of this are relatively unknown; the only known treatment for preeclampsia and eclampsia is delivery of the baby and placenta. Thus, accurate and early diagnosis of this disorder is imperative for appropriate management. This disorder is largely characterized by high blood pressure (BP) (>90/140 mmHg) and excessive protein in the urine (>300 mg/24 hours). For the purposes of early detection, periodic measurements of BP provides a more timely diagnosis.

The present issue is that the BP measurement devices and methods used in KATH do not fulfill the requirements necessary to effectively detect preeclampsia: either lacking accuracy, safety of use, or requires extensive training and time to be operated successfully. In addition, most devices that fulfill these conditions cost far too much to be implemented in KATH. Thus, we were tasked with creating a suitable replacement for these current methods. This device must be able to reliably and accurately measure BP every 30 minutes to 4 hours, depending on the measurement schedule prescribed by the medical staff. 

Our current design utilizes the auscultatory method of BP measurement: listening for the turbulent flow of blood through a restricted artery. Our device contains both manual and automatic components, differing slightly from commercially used products as well as traditional cuff and stethoscope methods. Thus, usability tests (UTs) were performed to identify how these new features seen in our device impacted a user’s ability to interact successfully with the device. Our tests included several different device components and subcomponents as well as overall considerations for a fully-functional device. From this, we gained insight into the usability of the device to guide future changes to this initial design.

PROCESS

background research

For our first step, we began with a literature review to see better understand the problem. We went through articles to better understand preeclampsia, Ghana, hospital systems, and blood pressure devices. Afterwards, we conducted a task analysis and went through the engineering specifications to get a better idea of how the products works. We also went through some of the surveys, observational data, and interviews from previous teams to create personas of our users.

Hypothesis testing

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After our research, we conducted a competitive analysis to understand what products are available. Through our research, we had 3 proposed changes: form factor, sound output, and display. The key unknowns facing our prototypes were: 1) What was the specific case where our device would be used (lighting, sound, position) 2) How were nurses trained in using BP devices 3) How were devices maintained 4) How patients felt during getting tested

After some formative usability tests to refine some of the proposed concepts, I went to Ghana to talk with our end users and better understand the context for which we are designing. I brought some basic prototypes to get feedback on the different aspects. In total, I spoke with 8 nurses and 3 doctors over the course of 3 days. With a better understanding of our end users and the environment they worked in, we refined our prototype.

usability testing

In our final stage, we wanted to prepare a robust prototype that could be tested in more clinical trials. We began with conducting a risk analysis to better understand some pros and cons for each of the different prototypes we proposed. Afterwards, we refined the prototype and tested it with professionals nurses. During the usability tests, we recorded speed, accuracy, and ease of use.

results

Our prototype is currenting in use and future teams are refining the concept with end users. We discovered some issues witht the basic form factor, such as trouble handling the pump and decompression unit. However, our main goal for this project was to determine if a semi automatic BP device could save time, while remainging durable.