Projects II Final Report: Correct Anatomy of the Arm Model

Team Maniqkan

Curtis Ackermann(1), Patrick Caren(1), and Tyler Winningham(1)

Advisors: Dr. Mansoor Nasir(1) and Dr. Nirupa Gopinath(2)

(1) Lawrence Technological University

(2) St. John Providence Hospital Simulation Lab

3 May 2017

Abstract

Quality of surgical simulation models can be defined by how well the model can mimic the anatomy and physiology directly involved in the process being simulated. If a model is significantly inaccurate, it may no longer be effective as a training or instruction tool. We found an arm model that fell out of use due to bad anatomy and began designing a method to produce similar models with correct anatomy. The simulation was an ultrasound-assisted IV and arterial line placement vascular arm model with the holes representing blood vessels being too wide in diameter and placed inaccurately in the arm. Using medical imaging on real arms, silicone materials testing, and a 3D scan of the functional patch of the existing arm model, we created a mold and silicone mixture for easy production of a model that more closely simulates the positions of two select blood vessels and how they would appear under ultrasound imaging.

Background and Motivation Background

St. John Providence asked Lawrence Tech if some of their students could help them improve their simulations in their simulation lab to provide more accurate models for students to learn and practice procedures on. Simulation has become a very important part of the learning experience for medical students and residents. Over the past 10-15 years, simulation has grown immensely. Before simulation, many student’s first experience doing a procedure was on a live patient (Dr. Gopinath, 2016). Doing a procedure for the first time, even a simple one, on a real patient would cause fear for even the bravest of students. So, simulation was invented as a way for these students to learn and practice, so when they are faced with real situations, they have a better understanding and confidence of what to do. One of these such models is called the IV and arterial line insertion vascular access ultrasound training model. The procedures conducted on this model are radial arterial line insertion and IV insertion. Arterial insertion is a technique commonly used in critical care settings (Arterial Line Placement). In this type of setting, it is important to have constant BP (blood pressure) readings especially if the patient has been given vasoactive drugs (Arterial Line Placement). The BP reading from an arterial line is more accurate and provides constant reading of BP compared to non-invasive techniques. Another bonus of arterial line placement, is the ability to draw blood whenever necessary to test the blood without further harm of the patient (Arterial Line Placement). If a standard technique is used to draw blood many times from the radial artery, the artery could rupture and bleed, or spasm and collapse from the trauma of more than a couple of pokes. Compared to a vein, the structure of arteries is much more stable, unlike the vein that can easily collapse and change shape, the artery will keep its shape making it difficult to stop bleeding. The radial artery is the most common

artery for this procedure because it is more superficial and easy to maintain compared to the other arteries in the arm (Arterial Line Placement).

One of the problems that can occur with radial line placement is the inability to locate the artery. The main cause of this is normally an excess of soft tissue typically in obese patients. If the medical practitioner is unable to locate the artery, he or she can use a live ultrasound to locate the artery. During the ultrasound, the practitioner can see exactly where the needle is going in the wrist, and sees it directly enter the radial artery. More experienced doctors can free hand this procedure, but even they will need ultrasound assistance in particularly difficult situations.

Figure 1. Current arm model from St. John Providence Sim Lab Figure 1 is a picture of the current IV and arterial insertion vascular access ultrasound training simulation model used in the St. John Providence simulation lab. As you can see in the image above, there are four main parts of this model. First, the inactive portion of the arm is simply there for looks, it gives the arm a more real look as students practice of the arm. The inactive portion is not used for training. Second is the bulb pump, this pump needs to be mechanically squeezed by either the student or someone helping them do the procedure, it is supposed to add a pulse like feel in the radial artery, but is difficult to feel, and is more pronounced in the vein compared to artery. The tubing connects the pump to the active portion of the arm. The tubing

is held to the inactive portion by some sort of epoxy or glue and only protrudes a short distance into the active portion of the arm. Last, the active portion, or patch as we call it, is a softer material that feels like silicone with a small amount of slacker added. This is the part of the model that arterial line insertion and IV insertion are practiced on. The red box symbolizes the area that the procedure is typically done, because at that location of the body the artery is more superficial and easy to locate (Dr. Gopinath, 2016). The company that creates this product is called Phantom, they specialize in creating ultrasound compatible models and their material has a self healing ability. Dr. Gopinath said the patch will last about 200 pokes. She also mentioned that 10-20 pokes are done in one sitting and then the patch needs to “heal” for 2-3 days before more practice can be conducted. Problem Identification

After Dr. Gopinath explained the purpose of this model, she pointed out a few problems that are currently in the model. First and foremost the anatomy of the patch is wrong. The location on the patch of the radial artery is located more towards the middle of the patch and the vein is located much more towards the thumb side of the arm. They should be very close to each other and both towards the thumb side of the arm. The patch also needs to be ultrasound compatible for our model because one of the most important aspects of this model is the ability to practice ultrasound guided arterial line insertion. Last, the cost of the replacement patch is $675, so a cheaper and easily reproducible patch is highly desired for this project (Dr. Gopinath, 2016). Overall, we want to make an anatomically accurate model with a radial artery and vein, that is ultrasound compatible, and is easily reproducible. Market Analysis

The market for simulation is mainly medical schools and teaching hospitals that benefit from simulation by training their students before they enter the field. It is important that the students understand exactly and have experience in performing the required procedures for their job. The confidence gained by practicing on models helps them think and relax when it comes time to perform on patients.

The stakeholders are students, residents, and doctors. Students and residents are still learning, and practicing on models gives them a better understanding on how to perform procedures. Doctors may want to brush up on procedures, or try new more advanced techniques on models before practicing them on patients. This is why the market is so good for simulation, the ability for students to practice before going into the field gives them confidence and the know how that cannot be done simply by talking about doing a procedure. There is a report by MarkestandMarkets that estimates a 15% growth to 2.7 billion dollars by 2021.

There was also a survey given out by the Association of American Medical Colleges to teaching hospitals and medical schools regarding their usage of medical simulation for training their students. There results were 96% of medical schools and 70% of teaching hospitals use

simulation as part of their curriculum in training students. This is a very large percentage and shows that the simulation market is much desired in the medical field.

Figure 2. Simulation model use survey among medical students

Figure 2 represents the percentage of students in medical schools and teaching hospitals that are exposed to simulation models during their time learning at these institutions. As shown, the majority of medical students use training models throughout their stay at medical school, and by the end of their time at teaching hospitals, over 50% of students are using medical simulation (Medical Simulation).

Before simulation, cadaver labs were the gold standard for procedure training. There are issues associated with cadaver compared to simulation usage. First, cadaver labs and upkeep are very expensive. There are also issues with disease transfer from the cadaver if it is not preserved or cleaned properly. Cadavers also can only be used a few times before a new one must be purchased. There is not a large supply of cadavers because they can only use donors for training. Simulation allows for multiple uses at a much lower price. There are also no ethical dilemmas associated with simulation use.

Design 1 - Anatomical Accuracy

Anatomical accuracy was the biggest failing of the existing model and is the top priority for our model. A wide literature search was done to identify which vein was which in the forearm. Using an MRI scan of one of our member’s arms, who had similar size and proportions to the current full at model, we tracked the location of the cephalic vein and radial artery along 5 points in the arm, at where the beginning and the end of the patch would represent on the model, and three slices in between at regular intervals. By measuring the distance from the vessels to the surface of the arm and the angle between the two vessels, we found locational coordinates to

represent the positions of the vessels. We also viewed an ultrasound of the same member’s arm at those coordinates and adjusted the coordinates so that the vessels would appear similarly under ultrasound. Material limits of the silicone required a certain distance from a vessel to the surface or another vessel as not to risk breaking while liquid is running through, so a minimum distance constraint of 4 millimeters was applied to the coordinates.

Figure 3. Example of arm patch slice with coordinates applied.

Figure 4. 3D model with all 5 coordinate-applied slices

All 5 slices of the arm’s coordinates were applied to a model of the mold in 3-Matic and adjusted to the mold’s irregular surface based on X: distance from radial side of patch, and Y: distance from top surface of patch. We applied two curves between the 5 slices and sweep-lofted across these points to create a model to represent the shape of vessels based on these positions to visually verify that these positions were correct. After verifying we lofted the ends of the 3D vessels to create holes and notches that would hold and guide the steel rods that form the openings for the vessels in the final model.

Figure 5. 3D modeled vessels for verification and guiding hole placement

We bent the steel rods into the exact positions of the coordinates by physically measuring the position using the same X,Y coordinate system that was used to create the 3D representation. Steel rods were also bent carefully so that they could be easily removed without damaging silicone or misshaping the rods on repeated reuse.

Figure 6. Final model with steel rods that create the holes in the silicone on removal to form the

blood vessels 2 - Easily Reproducible

One request we had from Dr. Gopinath was that the new patch that we developed would be able to be reproducible. Our idea we that in order to do this we needed to develop some kind of mold that could be provided where the silicone could be poured to make new patches.

We started off by taking a 3D scan of the current arm model patch so we had a model with the exact dimensions and curvature on all 6 sides that could be replicated and represented in some kind of computed aided design software such as AutoCAD or SolidWorks. Below are

images of 3D scans taken of the current arm model from the NextEngine Tabletop 3D scanner that is located in the Lawrence Tech Biosensors Lab.

Figure 7. 3D scanned images of the current arm model

In the 3D scans, an STL file was generated. From the STL file we then… We imported

the STL file into 3-Matic Research 10.0 and aligned the top of an extruded box with the bottom of the arm patch. We used Boolean Subtraction to make the box into a mold before treating the model using push-pull and smoothing operations to make for a more easily molded “top” surface for the model.

The next thing we needed to look at was the surface modification post-3D print. One of the characteristics of the patch that we wanted to incorporate into our design is a smooth finish of the surface of the patch. We want the patch to be as human like as possible to simulate human tissue. Since our design involves pouring silicone into a 3D mold and the top surface is actually the bottom of the 3D print, there would be roughness if no surface modifications were done. 3D printing inherently has striations from the layer by layer deposition of the plastic. In order to remove these striations we attempted various surface modifications into our design.

The first method that we tried was using a dremel tool to sand the 3D print. We used a sanding bit for the dremel to try to smooth out the surface of our final product. We quickly discovered that this bit was too aggressive and actually made the surface more rough. We believe that this was due to the high rpm of the tool. The plastic seemed to melt under the intense heat caused by friction and created a more rough surface.

The second method that we tried was using 120 grit sandpaper to sand the surface by hand. Although this method did seem to work, it took hours to see any progress. Another problem with this method was the difficulty associated with trying to smooth out the edges of the mold. We could not get the sandpaper to fully sand the corners of the mold.

The final solution that we ended up using was applying XTC-3D by Smooth-On. This is a resin that is meant to be applied to the surface of 3D printed materials to fill in the striations and impurities that comes with 3D printing. There is a part A and part B to this solution that needed to be mixed with a 2:1 ration of part A to part B by volume. We used a centrifuge tube with labeled volumes to get correct volumes of each part of the resin. After mixing part A and B, we used a half inch paint brush to apply the resin to the 3D print. Two layers was the correct amount to fill in all of the striations in our 3D mold. The product is shown below and a before and after picture.

Figure 8. XTC-3D by Smooth-On used to coat the surface for a smooth finish

Figure 9. Before(left) and after(right) image of the surface conditions from the 3D print

3 - Human-like Tissue Material Properties

One key characteristic that simulation models have and focus on is the material properties. If you are going to create a model that medical professionals are going to use then they must have similar properties such as feel, resistance, and stiffness. The main material component that was selected was silicone. Silicone comes in a part A and part B set up where they are mixed by equal volume and masses. Some components we took into consideration to add into the silicone mixture was both slacker and cellulose. The reason for investigating slacker is because it leads to different properties such as the stiffness and tackiness of the solution after it

cures. The reason for investigating cellulose is that according to one literature source said that the cellulose could have a positive impact on the ultrasound properties of the solution.

Besides the material properties of the silicone solution that we looked at also included the different shapes the silicone was able to cure in, the tubing subsystems, and removal of materials embedded in the silicone. The different tubing subsystems that we investigated included steel, brass, a coated steel, and two types of rubber. The shapes we looked at varied from different thickness focusing on various heights and widths. 4 - Automated Flow

A complaint that we wanted to address from the current patch model is the pump design. Currently, a bulb pump is used to push fluid through the arm model. We incorporated a peristaltic pump into our system, so one simply needs to flip a switch and will get constant fluid flow. A peristaltic pump is best for this design because it provides a specific flow rate, and can produce a pulse if large enough and rotates slowly. Unfortunately, since price was a concern , a small peristaltic pump was incorporated. This pump can work up to 12V. The more voltage applied, the faster the flow rate.

An experiment was conducted to see how high the flow rate could get at 12V. This experiment was conducted by weighing water as it flowed from the pump for one minute under different voltages. Since water is 1g/ml we were able to convert grams to ml very easily. Since this pump is relatively small, a pulse is very difficult to feel, but it does allow for constant fluid flow of up to 70ml/min which is satisfactory for our needs. Normal flow rate is 100-300ml/min in the radial artery. Another benefit of peristaltic pumps is the pump never comes into contact with the fluid. Because of this feature, the pump can last a long time, and only the tubing will need to be replaced in the future. Below is a picture of the pump that is in our model.

Figure 10. 12V peristaltic pump that we used for our project. 5 - Ultrasound Compatible Design

The last design parameter to be looked at was an ultrasound compatible design and capability as simulation labs do practice ultrasound guided procedures. Ultrasound guided

procedures occur when a patient may have vessels that are difficult to find due to old age or large figures. In literature we found one source that had used cellulose in their study and the reasoning behind doing so was that the cellulose nanoparticles had increased the ultrasound capability. In this study, we found cellulose to have no positive impact on the silicone situation and thus decided to not use it. The silicone solution without the cellulose showed results of being ultrasound compatible to the extent that we needed.

Testing 1 - Anatomical Accuracy To test for anatomical accuracy, after we went about the whole development and production phase and having our patch cured we needed to have a comparison for our patch. We did this by comparing our new patch to the current arm model patch at Providence and also compare to a human anatomy model (Curtis’ arm). We took ultrasound images of each model at different slice locations. One important thing to note is that the vein and arteries move in multiple directions as you move from the elbow down to the wrist so multiple cross sections slices had to be taken this. We did this by choosing one central location on the patch, one location towards the elbow, and one location towards the wrist. The images below show the exact location of each ultrasound image slice that was taken on the models and human subject.

Figure 11. Slice locations that ultrasound images were taken to compare the models to

human anatomy.

Figure 12. A comparative image showing the ultrasound images taken from the current

arm model, Curtis’ forearm scan, and the new arm model patch.

The above image shows the ultrasound image comparison between the current arm model patch, Curtis’ forearm scan, and our new arm model patch. Some observations to be focused on is the diameter size of the current arm model patch’s tubes and the orientation of the vein and artery. We performed these test so we had a visual representation and comparison to show if our new model patch was able to improve the anatomical accuracy of the arm model patch that is used in the simulation lab. The data collected off the images are as follows:

Figure 13. Table showing the data results from the image comparison test

Anatomical accuracy is first and foremost of our parameters for this project. From these comparisons, it is shown that our model is more accurate than the current arm model. A few observations can be made from these images. First, the diameter of the vessels in the current model is three times larger than the actual diameter of a human artery and vein in that location. Second, the orientation of the vein and artery are wrong especially when close to the wrist. In the

current patch the vein is deeper than the artery, when in fact the vein should be more superficial as shown in the human ultrasound and the new patch model. The vein and artery should also be closer together as seen in the new model and human ultrasound images.

We realize that in a live patient, the artery and vein are only 1.5mm from the surface of the skin, however, since reusability is an important consideration we wanted at least 4-5mm of silicone between the surface and the vessel to allow more uses of the simulation model. 2 - Easily Reproducible The testing for the reproducibility of the patch is simple. Two main areas we looked at focused on the time it took to reproducible and cure. To prepare the silicone solution took 45 minutes. After the solution is poured into the mold it takes a minimum of four hours to cure completely. After the silicone cures and the steel tubing system is removed, the plastic tubing has to be placed as the input points and the loop point near the wrist. After the tubing is placed, the silicone caulk has to be used to create the barrier to seal off the liquid flow system. The silicone caulk will take 24 to 36 hours to completely cure itself. 3 - Human-like Tissue Material Properties A) Silicone Ratio

The purpose of the silicone ratio is that we want to aim for a material with similar qualitative and quantitative characteristics as the previous Arm Model and human tissue such as fat, muscle, or skin. The silicone ratio can be adjusted in different ways for different feelings, strength, compression, and observations of the materials. The following test were done to investigate the silicone ratio: December 2, 2016

(1) 1A : 1B : 1 Slacker (2) 1A : 1B : 0.75 Slacker (3) 1A : 1B: 0.5 Slacker (4) 1A : 1B : 1.5 Slacker (5) 1A : 1B : 2 Slacker (6) 1A : 1B (7) 1A : 1B : 1 drop of dye (8) GE Silicone Caulk

From these samples we were able to learn a lot. The protocol was adjusted by mixing B → Slacker → A → dye. We learned that more than 1 part slacker was way too mushy and no slacker was way too stiff. The silicone caulk was unhelpful for further use because the outer surface exposed to oxygen cured and hardened, but the inner core did not. From these samples some of them never fully cured because the mixing was done incorrectly compared to our updated protocol.

December 6, 2016 (1) 1A : 1B : 1 Slacker (2) 1A : 1B : 0.75 Slacker (3) 1A : 1B : 0.5 Slacker (4) 1A : 1B

From these samples we were able to make more conclusive assumptions to aim our ratio towards. The previous results from our first attempt were inconclusive so these test narrowed it down more. One part slacker and no slacker were too mushy or too stiff respectively. January 24, 2017

(1) 1A : 1B : 1 Slacker : 1% cellulose : 2 drops of dye (2) 1A : 1B : 0.5 Slacker : 1% cellulose : 2 drops of dye (3) 1A : 1B : 1% cellulose : 2 drops of dye (4) 1A : 1B : 0.5 Slacker : 1% cellulose : 2 drops of dye (with tube) (5) 1A : 1B : 0.5 Slacker : 1% cellulose : 2 drops of dye (cylinder)

From these with the cellulose we could use the samples on the Ultrasound Machine to view images. One part slacker was too mushy and 0.5 may be too mushy as well so we are planning next test to decrease slacker and try values below 0.5 parts. The cellulose worked well in the mixture and in the mixture no problems were discovered.

Figure 14. Five samples made with varying slacker ratios.

February 2, 2017 This is our latest samples that we have developed. The aim of the testing on this day was focused on small ratios of the slacker that we could qualitatively compare between one another that is the most similar to the current arm model at Providence. We also wanted to try a sample with zero cellulose in it so we could compare to find out if the cellulose is impacting of the image at all. The four samples made had the following ratios in them:

(1) 1A : 1B : 0.4 Slacker : 3 drops of dye (2) 1A : 1B : 0.3 Slacker : 1% cellulose : 3 drops of dye (3) 1A : 1B : 0.2 Slacker : 1% cellulose : 3 drops of dye (4) 1A : 1B : 0.4 Slacker : 1% cellulose : 3 drops of dye

From this data and from contact with Paul from Providence, 0.3 part slacker is what he uses in his mixture to represent muscle. A slacker value of 0.3 is most likely are desired ratio we will use, but further testing may need to be done on physical testing bases such as compression or deformation testing or qualitative testing may be enough. The use of cellulose did not make a difference in the initial testing, so more analysis needs to be done with that. B) Deformation Testing The purpose of the deformation testing is to see if we can get a more precise and quantitative measurement showing a justification of why we chose the silicone ratio that we did. Because we need a comparison value, we used the current arm model at Providence as the standard that we are aiming to achieve. This is because the simulation lab likes the feel and composition of the current model as the model has proprietary rights on it so we cannot know the exact composition.

Figure 15. First deformation testing done using 0 part to 1.2 part slacker.

The initial deformation testing was done to see if compression testing would be doable and if the testing would give us comparable stress vs strain curves. We performed loads of 9N, 23N, and 36N on solutions with 1 part A : 1 part B and the slacker varied from 0 parts to 1.2. Some variables were constrained in this experiment do to limited time and materials. After we saw that deformation testing could give us a good visual comparison to the current arm model we did more advanced testing.

Figure 16. Second deformation testing performed on only 0.3 and 0.4 slacker.

Two improvements we made from the initial deformation testing to the second set is that the area that the force was applied changed. In the initial test the samples were made in a 2oz cup to be tested with a measuring tape. In the second test the samples were made by pouring the solution in the molds that are the same size and area of the current arm model so the area the force is being applied in all three samples is identical. Besides just improving the area, in the second testing we also used calipers to measure the lengths and change in lengths. The curve that the current arm model produced was directly in between the 0.3 part slacker and 0.4 part slacker curves. Our results from the deformation testing showed the ideal silicone solution would be 1 part A : 1 part B : 0.35 park slacker. C) Life Span Testing

For this experiment, 0.4 and 0.3 part slacker patches were tested in accordance to the deformation testing. An 18 gauge needle was used to puncture the patch as is standard for arterial line placement and IV line placement. Both the vein and artery were tested in the same locations until leaking would occur. The pump was pushing water through the patch at 70ml/min while punctures were being made. The procedure was one puncture at a time and pulling liquid out of the patch to make sure the needle was in the vein/artery. The results

were 100+ punctures in both patches for the vein and artery locations. Leaking did not occur even with well over 100 punctures. However, as more punctures occurred, the resistance of the needle entering the patch became less over time. After about 40-50 punctures there was a significant decrease in resistance. Also, if the patch was allowed to “rest” for two days the resistance came back for about 20 more pokes. Instead of creating a new patch when the old one leaks, a new one should be created with there is little to no resistance when puncturing the artery/vein. Below is an image of where punctures occurred.

Figure 17: 18 gauge needle (left). 0.3 and 0.4 part slacker patches (right). Markered

locations are where punctures occurred. 4 - Automated Flow

Various voltages were placed across the pump to find values of flow rate. The pump can withstand 12V and has a fairly linear increase in flow rate as voltage increases. Below is a graph of the flow rate vs. voltage.

Figure 18. Flow rate of peristaltic pump at various voltages.

5 - Ultrasound Compatible Design A) With vs Without Cellulose During the early stages of the silicone testing we used a component called SigmaCell 50 cellulose. Cellulose is a nanoparticle white powder that, according to literature, is supposed to make silicone more ultrasound compatible because powder will add specs in the solution and this adds texture or contrast to the ultrasound images. Cellulose was added on a 1% per volume into the solution. After we went through the beginning stages of using cellulose we noticed that possibly it was having no impact on the ultrasound capability of our design. This lead us to then test to see if it was or not.

Figure 19. Two ultrasound images take. The one to the left has cellulose and the one to the right

does not have cellulose.

Figure 20. (Left) US image showing sample with and without cellulose directly next to each other. (Center) Sample without cellulose and tube running through it. (Right) Sample with

cellulose and tube running through it.

If you look at the ultrasound images from the samples taken with and without cellulose, then you can see that cellulose did not have a positive impact on our solution. It could be argued that cellulose even damage/skewed the images and limited the depth of the image. For the purpose of this study, our results for using cellulose to achieve ultrasound capability were inconclusive and we decided we would not use cellulose in our silicone solution B) Vacuum vs No Vacuum

One of our initial concerns was the ultrasound imaging. At the start of this project, the silicone mixture was not placed in a vacuum during cure time. The silicone was simply mixed and poured into various molds. It was soon realized that ultrasound was not able to penetrate very deep into the silicone. It could only show about 1cm deep. The air left in the silicone blocked the ultrasound from penetrating. Since the density of air is so low, the ultrasound is not able to go through and return to the transducer causing low penetration. When silicone is placed in a vacuum, it pulls the air out of the solution leaving a homogenous piece of silicone that the ultrasound can read much deeper to about 2cm. Below is an image of non vacuumed and vacuumed silicone.

Figure 21. Left side is non vacuumed. Right side is vacuumed. The ultrasound image is much clearer on the vacuumed silicone solution.

Conclusion and Future Work

The molds underwent multiple prototypes to increase ease of use and add more qualities like the holes for guiding the steel rods that form the openings in the silicone that act as the blood vessels.

Figure 22. Three different models. The old prototype (left) had problems with usability caused by its two-part design. The second prototype (middle) incorporated an open-mouth design. The

final product incorporated the bent steel rods that form openings for the “blood vessels.”

We have a few choices for elaborating on this project. We could use silicones of varying stiffness to simulate different density soft tissues separately. We could also physically place harder tissues like bones into the mold. Alternatively, we could apply the same methods used in this project to different simulations for different parts of the body, enhancing simulation models whose utilities are hurt by poor anatomy.

Project Timeline

Key Dates

- Late January: 3D Scan complete - Late February: Prototype 1 3D print complete - Mid March: Prototype 2 3D print complete - Late March: Dicom files obtained - Late April: Prototype 3/Final Product 3D print complete - Late April: Full system running with our patch, tubing, bag, and pump

Team Structure

- Silicone Ratio = Tyler and Curtis - Silicone Testing = Tyler and Curtis - Material Properties (cellulose and deformation testing) = Tyler - Material Properties (tubing system) = Tyler - Material Properties (puncture testing and adhesives) = Curtis - Ultrasound Compatibility and Use of Machine = Tyler and Curtis - 3D Scanning = Tyler - CAD Work = Patrick - 3D Print = Patrick - 3D Print surface modifications and vacuum silicone = Curtis - Testing Pump and Flow Rate = Curtis - LESA Application and Presentation = Tyler - Full System run through = Tyler and Curtis - Reports and Updates = All

Budget

Component  Price/Unit 

Silicone  $367.44 

Slacker  $77.72 

Cellulose  $50.80 

Tubing  $6.66 

3D Printing Materials  $157.00 

Peristaltic Pump  $24.95 

Tubing Connectors  $42.33 

Power Supply  $19.90 

Miscellaneous  $25 

Total  $771.80 

Acknowledgements

- We would like to thank the Kerns Foundation LEGENDS of Entrepreneurial Student Awards(LESA for the generous support of this project.

- We would like to thank Dr. Nasir for his help along the way. - We would like to thank the MRI Technologist Team at St. John’s Providence Southfield

for providing us with DICOM files of an MRI scan on our team member Curtis.

Appendix Deformation Test Raw Data

Figure 23. Raw data for the initial deformation and Figure X on the deformation testing section

of the report

Figure 24. Raw data for the improved deformation testing comparing only 0.3 slacker and 0.4

slacker to the current arm model

Procedure for developing silicone solution to patch in arm (1 A : 1 B : 0.35 slacker) i) Mix all parts (part A, part B, and slacker) thoroughly before adding anything together. The substances have ingredients that can ‘rest’ so you want to mix before using. Recommended time is 2 to 3 minutes. ii) Put a nanofiber cloth and bowl/tupperware on the measuring scale and zero the scale out. Use a bowl that is capable of holding 651g of silicone solution. iii) Pour 277g of Part B into the bowl. Zero out scale after weight is confirmed. iv) Pour 97g of Slacker into the bow. Zero out scale after weight is confirmed. v) Mix the solution together for a minimum of 2 minutes. vi) After solution is thoroughly mixed, pour 277g of Part A into solution. Zero out scale after weight is confirmed. Add 4 drops of dye to mixture. vii) Mix the solution together for a minimum of 3 minutes. viii) After solution is thoroughly mixed, pour the solution into 4 large petri dishes evenly and seal the dishes. ix) Place the 4 large petri dishes filled with the solution into a small vacuum for 12 minutes. x) After 12 minutes, remove the dishes from the vacuum and pop any air bubbles that may be visible on the surface. xi) With the steel wires in place and caulk or electric tape to seal off the gaps in the 3D printed mold, pour the first petri dish into the mold. If air bubbles appear in the mold after pouring, use a toothpick and pop them.

xii) Pour all four dishes or until the mold is filled to the brim. Make sure to pop the air bubbles after pouring in each dish. xiii) After the silicone solution has been poured, let cure for a minimum of 4 hours. ixv) After the silicone has cured, remove the steel wires from the mold. xv) Remove the silicone patch from the mold. xvi) Place plastic tubing at the entrance and exit points of the silicone patch. Also, place a small plastic tubing loop at the bottom of the silicone patch for the liquid to be able to loop around in the patch. xvii) At all four hole locations, use silicone caulk to seal off the tubing system so leaking is not possible. After caulk has been applied, let rest and cure for a minimum of 24 hours. xviii) After the caulk has fully cured, attach the patch through the arm model to the full system including the peristaltic pump, power supply, and liquid filled bag. ixx) After full system has been constructed, turn pump on and the patch is ready for use. Procedure for Ultrasound Machine use and gathering of images

1) Turn on ultrasound machine with power button located on the left side of the key area 2) Create a new patient by going to the patient tab on the lower screen of the ultrasound

a) Press new patient located on the upper screen on the left column b) Enter a patient ID and a first and last name c) Click register on the left column of upper screen d) Below a row saying Vascular under category should appear

3) Click scan on lower screen a) Make sure cross beam is highlighted green b) While scanning human tissue use a gain of around 35-40 and around 70 for simulation

material (this can be changed by turning the “B” dial) c) A frequency of 14MHz can be used for human tissue, but 9MHz for simulation d) Place gel generously on skin or simulation material and begin scanning with the

transducer e) When an image is found that you want to save click freeze on lower right hand of the

keyboard f) Click P1 to save the image to the current active patient g) Click Freeze again to unfreeze the screen

4) Once you are done gathering images go back to the patient screen a) Click “Data Transfer” on top left of upper screen b) Click “Store All” on top of Unsaved Exam Data c) Select “MPEGvue” under task list d) Insert USB into the first slot on the lower part of the ultrasound machine e) Under “To:” tab on lower left hand of the screen click the device in slot 1

f) Highlight the patient that you want to transfer g) Click “Transfer” h) Unplug USB