The difference a medical device can make - an engineer's view


Posted on 8 June 2017 (Permalink)

John Lennon famously said, “Life is what happens while you are busy making other plans”. And so it did. I had planned a week of developing ideas, gathering data for a project, business meetings and so on. Then life struck. With a bladder that felt like the size of a football, I was rushed to the local medical centre, where a urinary catheter was inserted to my great relief. Everything was put on hold. However, as an engineer with an interest in equipment which helps people manage, or recover from, an illness, the situation was one I had to explore further.

The purpose of a medical device is to “diagnose, prevent, or treat a disease or other conditions, and does not achieve its purposes through chemical action within or on the body.” They can range from disposable gloves through to Robotic Surgeons. The market for medical devices is projected to be a market worth $398 billion globally by 2017. The urinary catheter market is estimated to be worth $2.37 billion by 2020; big business!

The urinary catheter has been around for 3500 years. The earliest ones consisted of bronze tubes, reeds, straws and curled-up palm leaves (ouch!). The device has evolved throughout the centuries to the one that I used with all of its parts made from soft plastic. There must be many design challenges and off the top of my head they would include: minimise infection, no leakage, minimal pain during installation and extraction and ease of use, for example when changing the bags. The actual list I am sure will be significantly longer.

Using the catheter requires some basic plumbing skills that most of us who connect garden hose pipes can easily master. The valves used on the bags are an example of keeping it simple, with an intuitive way of switching it off and on. Also, through trial and error with a series of bands, I managed to strap bag and pipe onto my leg in such a way that I could walk normally.

For my own interest, I started to gather data on how much I was drinking and volumes when emptying my bag - inputs and outputs in engineering terminology - which produced a fascinating insight into how my body was working. Given the problem that the catheter is managing - emptying urine from my body - and the constraints of everyday use, the one I used worked well.

It is interesting how the world changes for the user of a medical device. In my case, public toilets were key points of reference when out shopping. I developed a mental map of where and when the toilets were open. Of course, planning is critical to cover all eventualities when out and about, especially when drinking too much! Another aspect that I didn’t fully appreciate was the reaction of others when using disabled toilets; because I ‘looked normal’, the waiting queue outside the toilet would glance disapprovingly.

One final point. The district nurses gave me great practical advice based on their experience of helping other people managing their catheters. For any medical device designer, getting feedback from the people who are using it is an invaluable source of information for revisions to the design. In general, the users of medical devices can very often find better solutions to the problems of using it, even if it involves Duct Tape! ‚ÄčA big thanks goes to the doctors, nurse practitioners, district nurses and the people in the dispensary for their professionalism and kindness during my urinary problem. 

Next time I am sitting in the waiting room of my medical centre, probably listening to some John Lennon classics, I will be reflecting on the many people, over the centuries, who developed the urinary catheter and how the current version saved me from torturous pain.