Manufacturing Process for Infection-preventing Catheter

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Sponsors University of Idaho
Team Name Manity
Duration Fall 2020 - Spring 2021
Faculty Advisor Dr. Michael Maughan
Mentor Anas Nawafleh
Client George Tanner and John Crepeau
Team Members
  • Niklas Gillihan
  • Tyler Haglund
  • Matt Hodgson

Every year hundreds of thousands of urinary catheters are utilized in hospitals. Over time bacteria builds up in the urethra potentially causing a catheter associated urinary tract infection (CAUTI). CAUTIs cause over thirteen thousand deaths a year in the U.S. and cost hospitals in excess of $400 million dollars. In a past capstone project, U of I students designed a revolutionary catheter that can greatly reduce or eliminate the risk of a CAUTI. Team Manity’s goal is to create a manufacturing process and designing a fluid catching device for the catheter. Our work will move this catheter into the market where it can save lives and money.

Problem Definition[edit | edit source]

In the US thousands of people are hospitalized each year with the need to have a urinary catheter inserted. Worldwide the urinary catheter market is worth 3.4 billion USD and will increase by an estimated 5.5% per year. In the US the market is evaluated at roughly 1/3 of the global market with nearly 250 million USD reserved for Foley/indwelling urinary catheters. This has increased the prevalence of catheter associated urinary tract infections or CAUTIs in hospital patients. This creates an added cost of 400 million USD for US hospitals having to pay to fix the CAUTI and settlements. The above information has created a niche market for a new product that could greatly decrease or eliminate all hospital and home CAUTIs.

Creating a catheter device that operates like a Foley catheter but can decrease the prevalence of bacteria over long periods of time would be beneficial for hospitals. This could dramatically reduce their costs paying for catheter associated UTIs and possible settlements.

Background[edit | edit source]

The use of indwelling urinary catheters is increasing rapidly. This has a lot to do with advanced care techniques and an ever-increasing population age. Roughly, 23% of all patients in hospitals will need a urinary catheter for some period of time. The length of time these catheters remain in place greatly increases the chance of a UTI. These UTIs start when bacteria enter the urethra and makes it's way up the urinary tract, possibly infecting the bladder, ureters and kidneys. These types of infections are extremely prevalent when a catheter is used and very dangerous. This leads to them being the number one nosocomial infection. Nosocomial meaning infections contracted in hospitals. The problem is compounded with the fact that UTI bacteria is the most common to be anti-biotic resistant.

Catheter associated urinary tract infections cause in excess of 13,000 UTI cases per year. This leads to costs of $400 million dollars USD per year. This problem is going to be compounded with the COVID-19 pandemic. As more people are being placed on ventilators or other forms of long-term care catheters will be used more frequently.

Currently, there are 4 main options for indwelling urinary catheters. The first option is a very simple design, this option is a straight catheter that only drains the bladder. These catheters are used for one tie and then thrown away. Typically made of plastic they are not meant for long-term use. 2-way catheters are the most common types of catheters. This catheter has 2 channels, one to drain the urine from the bladder and the other is for the balloon to be filled with saline. Filling the balloon with saline will block off the urethra forcing the urine down the catheter tube. Lastly are 3 and 4-way catheters which are very similar. These include the two channels but have a 3 channel that is used to irrigate the bladder. This allows saline to flush blood clots or other internal debris out of the bladder. The four-way catheter has a specific channel to allow for the irrigation of wound sites in the bladder. This allows for a clean wound site reducing the risk of infection.

Deliverables[edit | edit source]

The desired function of the catheter is to eliminate the risk of CAUTIs (catheter associated urinary tract infections) in patients that require long term catheterization. That risk will be eliminated by flushing the urethra with a saline fluid, using the catheters’ unique design. A flushing fluid catching device will capture the flushed fluid and deposit it into a container to eliminate messes. This catheter will be able to remain inserted for extended periods of time with a much lower risk of the patient contracting a UTI. Also, the desired function of the manufacturing process is to produce quality parts within tolerances at a fast pace. The manufacturing process will need to be safe and cost effective. This will enable the team to produce enough catheters to start the testing phase of the product.

Specifications[edit | edit source]

For this project we have multiple specifications and criteria that we are working with. Some of these are from the start of the overall project others are built off of the previous capstone's work. Some of these specifications include:

  • Including the time to carefully anchor the catheter within the bladder, insertion should take no more than 45 seconds.
  • The flow rate must be no less than 4 mL/s. This will be the minimum requirement for all different sizes of catheters.
  • For the design process and proof of design we will be focusing on 18 Fr. After proof of design the catheter will be scalable to the any size in the size range of catheters from 8 Fr to 36 Fr.
  • The catheter shall be available in lengths ranging from 6-16 inches.
  • Must be functionally stable inside the body for long periods of time.
  • The process to make a single part should be less than 2 minutes.
  • For initial prototype production, the manufacturing of the catheters must be able to take place within a small facility.
  • The manufacturing process will be compliant with FDA standards for catheter production. The manufacturing will take place within a sterile environment along with autoclaving (or some other form of sterilization) the units prior to packaging. The materials should be approved by the FDA and the design will need to be tested before approval.
  • Value Proposition Statement[edit | edit source]

    Every year hundreds of thousands of urinary catheters are utilized in hospitals. Over time bacteria builds up in the urethra potentially causing a catheter associated urinary tract infection (CAUTI). CAUTIs cause over thirteen thousand deaths a year in the U.S. and cost hospitals in excess of $400 million dollars. In a past capstone project, U of I students designed a revolutionary catheter that can greatly reduce or eliminate the risk of a CAUTI. Team Manity’s goal is to create a manufacturing process and designing a fluid catching device for the catheter. Our work will move this catheter into the market where it can save lives and money.

    Design Considerations[edit | edit source]

    There were multiple ideas that first lead us to the idea of choosing a cup design. The first idea that we had and concept we had was to incorporate a sleeve into the catheter tube that could be pulled up over the genitalia. The thing that we wanted to accomplish with this was to have something that could just be attached to the catheter tube and pulled up when it needed to be used. The idea was to then have it be able to drain into the urine bag that patients already used. However, it turned out that this would require us to manipulate and change the drainage bag. This something the team did not want to get into as it would cause a lot of money and time to be spent designing a new bag. We wanted to keep everything as simple as we could. The next problem we realized is that it would not be ideal for female anatomy. It may work very well for a male anatomy but was not feasible for female anatomy. This is something that also made us think about a universal design that would fit both anatomies, while not changing the drainage bag or drainage tube. Another idea the team had for the fluid flushing catching device was to utilize a bedpan. This thinking behind this is that they are cheap and readily available in a hospital setting. We eventually moved away from this idea due to the client wanting a new product that could be utilized by nurses to increase ease of use and efficiency. The team finally decided on trying a cup design. This idea came from the original idea of using an existing product like a bedpan but to increase the ease of use we aimed to manipulate a sports cup. We knew that this was the most universally sound shape and would give us the best chance at fitting both male and female anatomy the best. The first thing that the team did was go out and buy a regular sports cup. We made a tapered slot in the top of the cup for the catheter tube to fit through. At the bottom of the cup, we drilled a small hole that the drainage bag tube could fit into. The thing that we thought was beneficial about this design was the fact that we could drain the flushing fluid into the same drainage bag that the urine goes in. We conducted test and found out that this design worked very well. Not only for the male anatomy but the female anatomy as well. However, we soon realized that this would mean that we would have to incorporate a special port for which the drainage tube could go into at the bottom of the cup. This would lead to a harder manufacturing process for the cup and more expensive product. The team wanted to keep the price of the device as cheap as possible as well as the manufacturing process. However, we knew that the shape of the cup was the perfect shape since it fit both anatomies well. We needed to keep the shape but find out how to get rid of the drainage port or at least change it.
    Here is our first prototype for a cup design using SolidWorks.
    After reviewing the design we developed our second prototype also in SolidWorks, shown above.

    We finally decided that the easiest thing would be to take the drainage hole out completely. We decided that if we were able to make the fluid catching device out of an absorbent material it may solve our problem. Instead of draining the fluid into the urine bag, we could simply absorb it through the cup and just throw the cup away after the patient used it. So, we created a 3D model in SolidWorks of our first prototype of this design as seen in the first image to the right. After creating the first prototype the next thing was to test it on actual patients. We got 3 volunteers to conduct tests on about how the geometry fit their anatomy while they were standing up, sitting down, and laying down. The test showed that the cup was too big, and the walls were poking into the patients. This resulted in a very uncomfortable feeling when the patients used our prototype. We knew instantly that the geometry and size of the cup had to be changed, and it needed to be changed drastically. We originally thought the bigger the better however, that was not the case. This idea was somewhat dated in our conceptualization of the problem because once we move to an absorbent material this negated the need for the cup to physically hold a large amount of liquid. We then worked on figuring out how big we needed to make the cup for an ideal size.

    The team also had to decide on what material to make the cup out of. We wanted something that had a lot of added benefits but wouldn’t drastically change the cost. The manufacturing process for the material would also have to be easy and not add a lot of extra work. We first thought of using silicone since that is what the catheters are made from. This would allow for them to be made within the same facility. However, the cost of silicone is very high, and this would make the product a multi-use product. Which means that the cup would have to be sterilized after each use, and this would cause nurses and hospitals extra time and money. We then thought about making them out of a plastic and just putting a small absorbent padding into the cup such as a puppy-pad. However, after thinking about it we decided not to use anything plastic because it wasn’t sustainable. The team didn’t want to use anything that would cause harm to the earth and ecosystem and couldn’t be recycled easily. This is what lead the team to their final concept selection.

    Concept Selection
    This is the final cup prototype, this may be altered for manufacturing

    The team went through multiple prototypes trying to get the size right. There were many different shapes and sizes considered. However, the team finally decided on the prototype seen to the right. As you can see the walls are much smaller and this allows for it to lay comfortably underneath the body. It also has just a slight raise in the back walls just in case it needed to hold any liquid it could. We didn’t want the cup to have to hold liquid because we didn’t want to have nurses to have the possibility of spilling the biohazard. This would cause a huge liability for the nurses and patients saftey if they had to walk a cup with biohazard over to the trash can. This is why we decided to create the cup out of an abosrbant material. This would decrease the chance of spilling the biohazard, and ensure the saftey of patients and nurses.

    The team decided to make it out of molded pulp. They decided to do this due to the many benefits and absorbant properties that molded pulp provided. For example moldeld pulp is, cheap, biodegradeable, recyclable, semi-absorbant, stackable, and offers a long term price gurantee. The team conducted many tests on the molded pulp’s absorbancy. The team was very surprised with how much liquid it could hold. The team wanted the cup to hold at least 20 ml of water because we knew that was how much flushing fluid would come from the catheter. We conducted many absorbtion test and the results are found in appendix G.6. From these test we found out that it could absorb more than 40 ml of liquid before the cup would loose its shape. We then found out that if we waxed the outside of the cup that it could hold way more liquid. With the wax coat it was holding around 60 ml of liquid. This test provided all of the data we needed to go with this design. The final cup prototype made out of molded pulp can be seen below.

    Here is a rough final prototype that was created by the team. This is the final cup design made out of molded pulp.

    Manufacturing Plan[edit | edit source]

    Throughout the project one of our main deliverables and goals was to develop a manufacturing plan for both products. For the catheter we aim to stick to industry standards for catheter manufacturing. This allows for a shorter timeline to get the product to the market and will be easier to do so. We are looking to create the catheters through extrusion or injection molding. The shaft piece of the catheter will be paired with the three channels which will be separately molded and pieced together later. AS previously mentioned this is currently what occurs in the industry and is what we propose for this product. Throughout the process the molding will occur within the necessary FDA clean room standards. This methods allows us to scale up the size of the catheter from 8Fr to 36Fr and the shaft of the catheter can be extruded to be many different lengths.

    Catheter Manufacturing

    The manufacturing process for the catheter will be injection molding and/or extrusion. Injection molding is the cheapest and easiest way to manufacture medical grade silicone catheters. This manufacturing process is already approved by the FDA, which is a large hurdle to get over when producing a medical device. Using injection molding and extrusion for the catheter will provide the precision necessary to make quality spiral ridges on the catheter. It will also produce quality functional channels inside the catheter.

    Cup Manufacturing

    The manufacturing process for the FFCD will be Type 1 Molded Pulp. Molded pulp is a material made from recycled paper products, such as cardboard or newspaper. It is used in a wide variety of applications, from egg cartons to electronics packaging. We chose this manufacturing process for the Flushing Fluid Catching Device because it aids our design in meeting our criteria. It is cheap​, environmentally friendly, sturdy, and very importantly, absorbent. Its price will be stable in the long run, and it also is easily stackable, which gives it reduced shipping costs. This manufacturing process is highly customizable, so it will be a simple thing to produce our cup. The cup will be made using Type 1 molded pulp, which is the thickest variety. It is durable enough to hold products that weigh anywhere from 10lbs to over 100.

    Catheter and Cup Price[edit | edit source]

    Cup Price per Unit

    After contacting multiple manufacturers there is a more concrete price point to produce the cups. As mentioned above we will be producing the cups using a Type 1 molded pulp product that can withstand 10 to 100 pounds. To start the production for this product there will be a design process that will cost about $500. After this the prototyping for the production parts can cost anywhere from $500-1,000. For the first 500 units from this specific supplier it will cost $1 per unit. This is not taking into account the designing time only the prototyping costs. After the first 500 units the price can drop considerably down to $0.02-0.1. This price per unit is reasonable for a one time use product that may not be needed everyday.

    Catheter Price per Unit

    Two way Foley catheters made from latex range from $6-10. Our goal for a price target is to remain competitive with this price point. We are looking at large initial costs to get a mold machined and prototyped. After the initial investments we are also looking at higher costs for the high grade medical silicone. The MED 5870 silicone will be expensive compared to other catheter products because of its longevity, being able to stay implanted for over 28 days. The silicone will cost roughly $150 per kilogram but this cost can be reduced considerably by purchasing in bulk later on. The mold has a wide price range starting near $20,000 but the cost per catheter associated to the mold and the manufacturers can be well below $1, closer to $0.50. The cost for the silicone will be near $4 each, so in total one unit will cost $4-6 per unit. There is a slim profit margin for the product but this can be expanded if the redesigned catheter has a slightly higher mark up. The added benefits the redesigned catheters offers can make it competitive on the market.

    Final Design[edit | edit source]

    For our final design we will not be changing the catheter from the previous year capstone. The only change to the catheter will on size based on the size of French gauge and the overall length. The catheter will be similar to industry standard for a 2-way Foley catheter but will feature a revolutionary spiral pattern on the outside of the catheter. The spiral paired with a third port will allow for the space between the wall of the catheter and the urethra to be flushed with saline, reducing the chance to contact a catheter associated UTI.

    Our final design for the fluid catching device will be the one shown here. This was our third prototype and will provide the most effective results in regard to comfort and function. This design will feature a low profile on the backside of the cup to remain comfortable. We kept just a small wall on the back side for it to still be able to hold liquid and any absorbent material needed. The front of the cup is largely unchanged except for the overall height, it still features the taped channel for the catheter and acts as a barrier for splashing. The sides were also reduced for comfort, but remain higher than the back of the cup for splashing and absorbent material to be pushed more towards the front. This will allow for all of the material to be contained within the cup and will not create any messes when used correctly.

    For the manufacturing of the cup we have concluded that molded pulp will be the best option. Molded pulp is a very cheap way to produce materials like egg cartons or packaging materials. It is made from recycled materials, is biodegradable and will still maintain the function we need. We have been in contact with manufacturers and to work with certain manufacturers our cup design may be slightly altered to fit their machines.

    Team Members[edit | edit source]

    Nik Gillihan

    Major: Mechanical Engineering

    Tyler Haglund

    Major: Biological Engineering

    Matt Hodgson

    Major: Mechanical Engineering

    Sources and Works Cited[edit | edit source]