Catheter Design
By: Cynthia Harmon
Jarntip Pitayagulsarn
Advisor: Dr. Ted Larson
April 23, 2002
I. Abstract
Catheters are used daily in operations to help embolize and insert coils into
aneurysms tumors. These surgeries are important in slowing down the blood flow in the
arteries for future removal of the surgery. Improving the function of the catheter is
important in making these surgeries less complicated. Currently, the catheter is inserted
into the femoral artery in the leg and progressed up through the carotid artery to the head.
With a wire inside the catheters, it is directed through the artery to the aneurysm for
embolisms and coiling. The walls of the vessel are used to direct the catheter. This is
problematic creating a chance for puncture. Other problems include the back flow in the
vessel due to the tortuous vessel and maneuvering the catheter while inside the vessel.
By looking at different ideas for a more dynamic catheter, physics and sports were
observed. Examination of stitching on baseballs and footballs gave the idea of stitching
on a catheter. Three different designs were created and tested in a model. The model
created was in a 3:1 ratio of vessel to catheter. The flow rate was determined to keep a
consistent Reynolds number with that of the artery. Glycerol water was solution was
create to produce the viscosity of blood. The different stitching was tested at this rate and
a lower flow rate to understand and determine the movement of the catheter and the flow
of blood. The flow around the spiral stitching was steady. The solution easily passed by
the catheter and flowed out at a consistent rate to the Reynolds number. The straight
stitching did not all the flow out all sides, but did not change the flow rate. The cross
stitch kept the tubing at the bottom of the catheter and slowed down the flow rate. The
spiral stitching increased the flow around all sides of the tubing without affecting the
flow rate. This allows for the best maneuverability within the tube, thus being the best
design.
II. Introduction
The objective of this project is to modify the existing catheter desig, improving
the efficiency and maneuverability in the body. This includes decreasing the use of the
blood vessel walls to move the catheter along, and finding a method that increases the
flow of blood around the catheter. In order to solve this design issue, we explored the
relationship between sports and physics. We focused on particular sports where the
design of the apparatus used effects its performance,
such as sails, golfball dimples, and stitching on a
ball. Together with Dr. Larson, we decided to apply
the effect of stitches on baseballs to the catheter
design. We found that the stitches on a baseball
reduce its drag and thus causing it to curve more
and travel further. In Figure 1, we can see the
effects of spin on the ball. The top illustration
Figure 1. Effects of spin on a
baseball depicts a ball with a boundary layer separation and drag. The bottom illustration
demonstrates how the wake of the ball is defected due to the Magnus effect, which states
“A spinning musket ball creates a whirlpool of air around it in addition to the linear flow
of the air past the ball due to its motion through space. This circulating air slows the flow
of the air past the ball on the left side and speeds it up on the right side. ...when the speed
of a fluid increases, its pressure decreases” (Watts 48-9). The force in front of the ball is
turning, inducing a greater curve on the ball. Our design uses these same principles to
manipulate the catheter through the body.
The need for a catheter to move in this manner arises from the anatomy of the
carotid artery. Two main branches supply
blood to the head and neck stem from the
common carotid artery. One branch, the
external carotid artery, “begins opposite
the upper border of the thyroid cartilage”
(Henry Gray, Bartleby). As the external
carotid artery travels up the neck, its size
Figure 2. Carotid Artery begins to decrease due to the number of braches coming off the
artery. The other main branch, the internal carotid artery, starts at the common carotid
artery bifurcation and “supplies the anterior part of the brain, the eye and its appendages,
and it sends branches to the forehead and nose”
(Grey, Henry, Bartleby). The artery has a high
degree of curves as it ascends through its course.
Due to the tortuous path and the number of
branches, navigating through the various parts of
the carotid artery may present various difficulties Figure 3. Brain Aneurysms
during surgery. Other difficulties include puncture in the sidewalls from the catheter
touching, backflow, removing the catheter, and clotting the aneurysms. The carotid
artery is a necessary path for doctors, such as Dr. Larson, to take during operations
because it leads to the brain where the operations aneurysms occur. A brain aneurysm
can be defined as, “weak bulging spot on the wall of a brain artery. ‘Aneurysms pose a
risk to health from the potential for rupture and subsequent bleeding into the substance of
the brain and/or the fluid-filled spaces that surround the brain’” (Gary L. Bernardini,
M.D., Ph.D., Columbia). The cause of aneurysms include trauma, infection, or mostly
abnormalities in a vessel lining. Often, aneurysms are treated surgically by utilizing
special clips that close off the abnormality. Dr. Larson opts for embolizing material and
a special coil that is inserted in the aneurysms and blocks blood flow. To do so, a guide
wire and catheter enter through the femoral artery and moves along to the carotid artery.
The catheter is pushed along the guide wire that twists and turns up through the body.
The coil is placed on the tip of the catheter and inserted in the aneurysm “The coils slow
the blood coming into the aneurysm, and at the same time attract blood, which has a
slightly negative charge, causing clots to form and seal off the aneurysm”
(http://www.mayo.edu/comm/mcj/news/news_739.html). There are clearly a number of
complications when operating on a cerebral aneurysm making the design of the catheter a
vital aspect of the surgery.
III. Methodology
The first step in the process is building
a flow simulation model. The model consists
of a pump, a “blood vessel”, and a “catheter”.
Plastic tubing of different sizing represents the
blood vessel and the catheter in a specified
Figure 4. Model ratio of three to one diameter.
We chose three stitching designs to focus on; straight stitches, cross-stitches, and spiral
stitches. A design with no stitches is used for a control. To simulate blood, glycerol and
water are combined to create a similar viscosity of blood. The solution comprises of 28%
glycerol by mass. Note that the glycerol solution
does not mimic blood in all respects, just simply
viscosity. To pump the solution through the blood
vessel, modify a rubber stopper by drilling three
holes. The center hole contains the catheter, and the
Figure 5. Rubber Stopper two side holes are connected to the pump using a “y” tube as
you can see from Figure 4.
To determine the necessary flow rates for the simulation model the Reynolds
number was found to be 250 (Kluzynski, K).
Re  Dv / 
Equation 1. Reynold’s number
Through different literature, the Reynolds number in the carotid artery is found to be 250.
This assumes there is continuous flow in an unblocked artery. Since the diameter and
Glycerol Solution Viscosity Modeled Vessel Diameter
2.5 cp
1.59 cm
Desnity
1130.5 kg/m3
Table 1. Reynold’s number variables
density of the modeled vessel is known, the flow rate needed to maintain a Reynolds
number of 250 can be calculated according to Equation 1. The required flow rate that
results is approximately 24.9 mL/second.
The rubber stopper is placed in the tube and the other end is corked. The solution
is run into the tubing. The tube remains corked at both ends until the tube is full. The
cork without the pump and catheter is removed when the tube is full. The flow is alled to
settle for a few moments before readings are taken. The flow is continued at a steady rate
for one minute. The flow output is collected for the later calculations and the behavior of
each catheter design is tested.
IV. Results
Type
Blank
Straight
Cross
Spiral
Trial
1
2
3
Avg.
1
2
3
Avg.
1
2
3
Avg.
1
2
3
A
Flow
19.7 19.5 21.3 20.5 23.97 24.88 23.66 24.17 24.01 24.2 23.49 23.9 24.97 25.02 24.5 2
Rate
Table 2. Measurements of Flow Rates (mL/sec)
Type
Blank
Straight
Cross
Spiral
Trial 1
2
3
Avg.
1
2
3
Avg.
1
2
3
Avg.
1
2
3
Avg.
Flow
5.2 6.19 6.10 5.83 9.32 8.47 9.72 9.17 6.03 6.25 6.48 5.92 9.22 9.06 9.05 9.11
Rate
Table 3.Measurements of Flow Rates (mL/sec)
Table 2 above, shows the catheters were able to stay around 24.9 mL/sec when
experimenting under a similar environment
Measuremets of Flow Rates
to the carotid artery. The lower flow rates,
2000
1500
Flow Rate
1000
(mL/s)
500
0
no
stitching
Trial 1
Trial 2
though, varied between about 5-9 mL/sec as
Trial 3
cross
stitches
Average
seen in Table 2. Figure 5 and Figure 6
represent how the spiral stitches resulted in
Figure 6. Measurement of Flow Rates (mL/sec) the best performance. In the trial with a
normal flow rate in the carotid artery, the spiral stitches resulted in the highest flow
rate. In the second set of trials with the
Measurements of Low Flow Rates
lower flow rate, the spiral stitches had the
600
Flow 400
Rates
(mL/s) 200
Trial 1
Trial 2
Trial 3
0
No
Stitches
Cross
Stitches
Average
second highest flow rate. This
demonstrates that even with impedance,
the flow rate could remain at a value
Figure 6. Measurement of Lower Flow Rates (mL/sec) of that of the carotid artery.
Our design targets doctors in the radiology or neuroradiology field who operate
on cerebral aneurysms. The few doctors at Vanderbilt University Medical Center who
specialize in this perform a total of approximately 120 operations a year. This number
may seem low when considering the large size of the university hospital, but we must
take into account special techniques are required to execute this comprehensive process.
Estimating a rate of $15/hr for labor costs, we would have collected about $2500 for our
work and supplies. Supplying the entire Vanderbilt University Medical Center would
return profits of $300,000. However, this only represents the cost of the modeled
catheter. The price of a real microcatheter in this instance would be on the order of
hundreds of dollars. Also, the life cycle of a microcatheter is only one use, making it
necessary to purchase a new microcatheter for each operation. Therefore, if the
Vanderbilt Medical Center were to purchase this designed catheter, the profits would
dramatically increase from the above estimate of $300,000.
Before our microcatheter can be marketed, it would be necessary to obtain
approval of the design. This may pose some difficulties because it may not be possible to
test some of the key issues on humans. Most notably, a durable biocompatible stitching
material needs to be chosen. With some detailed research, a few different materials may
be options, but they must certainly be biocompatible with the body before being tested.
Another key issue is that the stitches may get caught on the walls of the blood vessel,
especially when being removed from the body. A guaranteed, safe method of testing this
issue does not exist. The design may have to be tested on animals prior to being tested on
humans. If these main issues were addressed, the risk factors stemming from the design
would substantially decrease. This would then ideally result in increased marketing of
the product and thus increased profits.
Risk reduction is very important in a procedure, as death is a possibility. Death
can occur from an air bubble, a clot in the vessel, and much more. The procedure needs
to be done carefully and slowly to avoid problems. Changing the design can cause
clotting, along with changing the results of a surgery. The surgery length can be altered
do to the operation. The procedure needs to be done slowly and with care to avoid any of
the problems that have occurred in the past. These include such ideas as avoiding the
wall of the artery. Other factors that affect the catheter are the material used for the
stitching. By using a smooth biocompatible material, the stitching will not catch on the
walls of the artery. Additional problems include the material used for the catheter to
avoid risks of non-compatible material. Design changes enable the catheter to move
easier with less risk to the person having the operation.
V. Conclusion
The spiral stitches returned the most effective results. As mentioned above, it
returned the highest flow rates when simulating the carotid artery. One reason for this is
that the spiral stitching floated in the middle of the “blood vessel.” This allows the most
flow around the catheter similar to the effects of stitching on a baseball. Allowing flow
around the catheter allows for a result of flow similar to that without the catheter.
Therefore, the catheter can increase the speed of insertion because the flow rate is not
inhibited as before. The cross stitches remained near the bottom of the model allowing
flow mainly around the top. However, this placed the catheter around the wall of the
artery. Creating a similar problem of tearing the vessel as in the old design. In contrast,
the cross stitches stayed close to the bottom, letting flow only around the top of the
catheter. If the straight stitches or cross stitches were actually used, we believe that they
would need to use the vessel walls to move along through the body. Consequently, they
could scrape or puncture the lining of the artery. The spiral stitching would make the
most improvements to the current design. By floating in the middle of the vessel, it
would not move along the vessel walls. Instead, the steady flow around the catheter
would allow it to travel along the artery with fluid pressure helping it move. One
speculation at the start of the project includes the curving and twisting of the catheter
within the vessel once stitches were added on. At both the normal and low flow rates, we
did not observe any such motion of the catheter. More improvements would have to be
made to the design in order for this to take place.
VI. Recommendations
There is a great deal of further research that can take place on this design. The
next step would involve a model that added the curves of the carotid artery. Our model
simply used a straight tube to experiments. If curves were included in the model, the
motion of the catheter around the turn could then be observed. Another aspect that can
be further examined is pulsatile flow. We prepared our model to show only continuous
flow. Pulsatile flow may alter the behavior of some of the catheters within the vessel.
Also, different types of spiral stitches may be included in the experiments. For instance,
our spiral stitch consists of straight stitches. An additional design could utilize spiral
designs made of cross stitches. Other procedures that need to be examined is the removal
of the catheter to assure no catching on the walls occurs. The last example is the need for
biocompatible material. The material for both the stitching and the vessel need to be
biocompatible to avoid clotting and infection.
VII. Appendix 1
Ideation Workbench- Ideation Process
Innovation Situation Questionnaire
1. Brief description of the problem
Catheter tips are designed as a wire inserted in a tube. The catheter chosen is a matter
of trial and error. The size, shape, strength, and durability of the catheter are chosen
by the artery it will be inserted into. Choosing the correct catheter is not the only
difficult part of the process. The catheter is then inserted a distance away from the
problem. It is lead up the blood vessel to the desired location. The catheter is directed
by the wire and the walls of the blood vessel. Not only is this a dangerous process, but
it is damaging to the walls of the vessel. By creating a catheter that does not use the
walls of the vessel, the procedure will be more effective.
2. Information about the system
2.1 System name
Catheter Tips
2.2 System structure
-wire
-tubing
-varying sizes and shapes
2.3 Functioning of the system
The system will use blood flow to conduct itself through vessels without touching
the walls of the vessel
2.4 System environment
-circulation of the human body
-blood/ blood flow
-blood vessels
-brain
3. Information about the problem situation
3.1 Problem that should be resolved
Currently catheters use the wall of the vessels and a wire to guide the tubing. This is
dangerous, slow, and tedious.
3.2 Mechanism causing the problem
The current technology and lack of new inventions create a situation not easy to
control. The wire and tubing are a complicated method for guiding the catheter
through the turns of the vessels.
3.3 Undesired consequences of unresolved problem
-process takes too long
-could damage the vessels
-if vessel is punctured, patient could die
3.4 History of the problem
Catheters do not supply much in the way of moving through the vessels. Currently,
trial and error are used to determine the type of catheter to thread through the body.
This seems medieval and outdated.
3.5 Other systems in which a similar problem exists
-the heart
-the brain
-any system that has an aneurysm
-any place containing tumor
3.6 Other problems to be solved
-blood clots
-abnormal blood vessels
-tumors
4. Ideal vision of solution
A catheter that uses blood flow to maneuver without the walls. This product should
also be aerodynamic.
5. Available resources
-current catheters
-books
-blood flow
-arteries
-journals
6. Allowable changes to the system
-anything seen fit
-must be biocompatible
-fits in vessel
7. Criteria for selecting solution concepts
-safety
-ease of use
-best fit for given vessel
-safe
-cost efficient
8. Company business environment
The Vanderbilt University Medical center is the business environment for this product.
9. Project data
Name-Catheter Tips
Objective-Design new catheter tips for easier use
Timeline-as seen in proposal
Team-Jarntip Pitayagulsarn
Cynthia Harmon
Advisors-Ted Larson
Paul King
Contact Information
jarntip.pitayagulsarn@vanderbilt.edu
cynthia.t.harmon@vanderbilt.edu
Problem Formulation
1. Build the Diagram
2. Directions for Innovation
12/17/01 1:16:40 PM Diagram1
» 1. Find a way to eliminate, reduce, or prevent [the] (problem with vasculature) in
order to avoid [the] (abnormal blood vessel growth).
2. Find a way to eliminate, reduce, or prevent [the] (abnormal blood vessel growth) in
order to avoid [the] (injury and death), under the conditions of [the] (problem with
vasculature).
3. Find a way to eliminate, reduce, or prevent [the] (injury and death) under the
conditions of [the] (abnormal blood vessel growth).
» 4. Find an alternative way to obtain [the] (catheter procedure) that offers the
following: provides or enhances [the] (embolization), eliminates, reduces, or prevents
[the] (injury and death), does not cause [the] (slow, tedious dangerous process).
» 5. Try to resolve the following contradiction: The useful factor [the] (catheter
procedure) should be in place in order to provide or enhance [the] (embolization),
eliminate, reduce, or prevent [the] (injury and death), and should not exist in order to
avoid [the] (slow, tedious dangerous process).
6. Find an alternative way to obtain [the] (embolization) that offers the following:
provides or enhances [the] (blockage of blood flow), does not require [the] (catheter
procedure).
7. Find an alternative way to obtain [the] (blockage of blood flow) that does not require
[the] (embolization).
» 8. Consider transitioning to the next generation of the system that will provide [the]
(blockage of blood flow) in a more effective way and/or will be free of existing
problems.
» 9. Find a way to eliminate, reduce, or prevent [the] (slow, tedious dangerous process)
under the conditions of [the] (catheter procedure).
Prioritize Directions
1. Directions selected for further consideration
1. Find a way to eliminate, reduce, or prevent [the] (problem with vasculature) in
order to avoid [the] (abnormal blood vessel growth).
1.1. Isolate the system or its part from the harmful effect of [the] (problem with
vasculature).
1.2. Counteract the harmful effect of [the] (problem with vasculature).
1.3. Impact on the harmful action of [the] (problem with vasculature).
1.4. Reduce sensitivity of the system or its part to the harmful effect of [the]
(problem with vasculature).
1.5. Eliminate the cause of the undesired action of [the] (problem with vasculature).
1.6. Reduce the harmful results produced by [the] (problem with vasculature).
1.7. Apply universal Operators to reduce the undesired factor (problem with
vasculature).
1.8. Consider resources to reduce the undesired factor (problem with vasculature).
1.9. Try to benefit from the undesired factor (problem with vasculature).
4. Find an alternative way to obtain [the] (catheter procedure) that offers the
following: provides or enhances [the] (embolization), eliminates, reduces, or prevents
[the] (injury and death), does not cause [the] (slow, tedious dangerous process).
4.1. Improve the useful factor (catheter procedure).
4.2. Obtain the useful result without the use of [the] (catheter procedure).
4.3. Increase effectiveness of the useful action of [the] (catheter procedure).
4.4. Synthesize the new system to provide [the] (catheter procedure).
4.5. Apply universal Operators to provide the useful factor (catheter procedure).
4.6. Consider resources to provide the useful factor (catheter procedure).
5. Try to resolve the following contradiction: The useful factor [the] (catheter
procedure) should be in place in order to provide or enhance [the] (embolization),
eliminate, reduce, or prevent [the] (injury and death), and should not exist in order to
avoid [the] (slow, tedious dangerous process).
5.1. Apply separation principles to satisfy contradictory requirements related to [the]
(catheter procedure).
5.2. Apply 40 Innovation Principles to resolve contradiction between useful purpose
of (catheter procedure) and its harmful result.
8. Consider transitioning to the next generation of the system that will provide [the]
(blockage of blood flow) in a more effective way and/or will be free of existing
problems.
8.1. Improve Ideality of your system that provides [the] (blockage of blood flow).
8.2. Consider the possibility to transform the existing system that provides [the]
(blockage of blood flow) into bi- or poly-system.
8.3. Consider segmentation of the existing system that provides [the] (blockage of
blood flow).
8.4. Consider restructuring the existing system that provides [the] (blockage of
blood flow).
8.5. Increase dynamism of the existing system that provides [the] (blockage of blood
flow).
8.6. Increase controllability of the existing system that provides [the] (blockage of
blood flow).
8.7. Make the existing system that provides [the] (blockage of blood flow) and/or its
elements more universal.
9. Find a way to eliminate, reduce, or prevent [the] (slow, tedious dangerous
process) under the conditions of [the] (catheter procedure).
9.1. Isolate the system or its part from the harmful effect of [the] (slow, tedious
dangerous process).
9.2. Counteract the harmful effect of [the] (slow, tedious dangerous process).
9.3. Impact on the harmful action of [the] (slow, tedious dangerous process).
9.4. Reduce sensitivity of the system or its part to the harmful effect of [the] (slow,
tedious dangerous process).
9.5. Eliminate the cause of the undesired action of [the] (slow, tedious dangerous
process).
9.6. Reduce the harmful results produced by [the] (slow, tedious dangerous process).
9.7. Apply universal Operators to reduce the undesired factor (slow, tedious
dangerous process).
9.8. Consider resources to reduce the undesired factor (slow, tedious dangerous
process).
9.9. Try to benefit from the undesired factor (slow, tedious dangerous process).
1. Find a way to eliminate, reduce, or prevent [the] (problem with vasculature) in
order to avoid [the] (abnormal blood vessel growth).
1.1. Isolate the system or its part from the harmful effect of [the] (problem with
vasculature).
1.2. Counteract the harmful effect of [the] (problem with vasculature).
1.3. Impact on the harmful action of [the] (problem with vasculature).
1.4. Reduce sensitivity of the system or its part to the harmful effect of [the]
(problem with vasculature).
1.5. Eliminate the cause of the undesired action of [the] (problem with vasculature).
1.6. Reduce the harmful results produced by [the] (problem with vasculature).
1.7. Apply universal Operators to reduce the undesired factor (problem with
vasculature).
1.8. Consider resources to reduce the undesired factor (problem with vasculature).
1.9. Try to benefit from the undesired factor (problem with vasculature).
4. Find an alternative way to obtain [the] (catheter procedure) that offers the
following: provides or enhances [the] (embolization), eliminates, reduces, or prevents
[the] (injury and death), does not cause [the] (slow, tedious dangerous process).
4.1. Improve the useful factor (catheter procedure).
4.2. Obtain the useful result without the use of [the] (catheter procedure).
4.3. Increase effectiveness of the useful action of [the] (catheter procedure).
4.4. Synthesize the new system to provide [the] (catheter procedure).
4.5. Apply universal Operators to provide the useful factor (catheter procedure).
4.6. Consider resources to provide the useful factor (catheter procedure).
5. Try to resolve the following contradiction: The useful factor [the] (catheter
procedure) should be in place in order to provide or enhance [the] (embolization),
eliminate, reduce, or prevent [the] (injury and death), and should not exist in order to
avoid [the] (slow, tedious dangerous process).
5.1. Apply separation principles to satisfy contradictory requirements related to [the]
(catheter procedure).
5.2. Apply 40 Innovation Principles to resolve contradiction between useful purpose
of (catheter procedure) and its harmful result.
8. Consider transitioning to the next generation of the system that will provide [the]
(blockage of blood flow) in a more effective way and/or will be free of existing
problems.
8.1. Improve Ideality of your system that provides [the] (blockage of blood flow).
8.2. Consider the possibility to transform the existing system that provides [the]
(blockage of blood flow) into bi- or poly-system.
8.3. Consider segmentation of the existing system that provides [the] (blockage of
blood flow).
8.4. Consider restructuring the existing system that provides [the] (blockage of
blood flow).
8.5. Increase dynamism of the existing system that provides [the] (blockage of blood
flow).
8.6. Increase controllability of the existing system that provides [the] (blockage of
blood flow).
8.7. Make the existing system that provides [the] (blockage of blood flow) and/or its
elements more universal.
9. Find a way to eliminate, reduce, or prevent [the] (slow, tedious dangerous
process) under the conditions of [the] (catheter procedure).
9.1. Isolate the system or its part from the harmful effect of [the] (slow, tedious
dangerous process).
9.2. Counteract the harmful effect of [the] (slow, tedious dangerous process).
9.3. Impact on the harmful action of [the] (slow, tedious dangerous process).
9.4. Reduce sensitivity of the system or its part to the harmful effect of [the] (slow,
tedious dangerous process).
9.5. Eliminate the cause of the undesired action of [the] (slow, tedious dangerous
process).
9.6. Reduce the harmful results produced by [the] (slow, tedious dangerous process).
9.7. Apply universal Operators to reduce the undesired factor (slow, tedious
dangerous process).
9.8. Consider resources to reduce the undesired factor (slow, tedious dangerous
process).
9.9. Try to benefit from the undesired factor (slow, tedious dangerous process).
Prioritize Directions
1. Directions selected for further consideration
First priority- determine a design that is not detrimental to the patient.
Long-term-design a catheter to be used in ALL future catheter procedures
out-of-scoop-preventing blood clots, allowing perfect maneuverability, being
biocompatable.
other-design a working catheter that works in all procedures.
2. List and categorize all preliminary ideas
-wings on an airplane
-dimples on a golfball
-sails on a boat
-a parachute
-the curve of a frisbee
-stitching on a ball
Develop Concepts
1. Combine ideas into Concepts
The stitching on the softball will allow for the for the flow around the catheter while
helping the catheter move throughout the entire carotid artery. Simplifying the project
we chose three specific designs, the straight stitching, the cross stitches, and the spiral
stitching.
2. Apply Lines of Evolution to further improve Concepts
We could combine the wings on the airplane, sails on a boat and a parachute to create
a catheter design that flows through the vessel.
We could use the dimples on the golfball to control the flight.
We could use the curve in a frisbee and apply it to the curve of a catheter to help it fly.
We could make a very simple design where we include the control of the flight and
applying the curve of a baseball with the reduction of the drag increase the distance of
flight.
Evaluate Results
1. Meet criteria for evaluating Concepts
The criteria that were never tested was the maneuverability of the catheter. Therefore,
the ability to go around a corner is never observed.
2. Reveal and prevent potential failures
It is necessary to produce all possible undesired effects or failures that
can occur during the implementation of this concept, such as blood clots and
moving
the catheter around the carotid artery.
Our design has succeeded in allowing flow completely around the catheter. The
catheter design does not test the movement around the corners, the blood clotting, or
removal.
3. Plan the implementation
The design has been completed as of April 18, 2002. Biomaterials need to be examined
and effects of all elements within the catheter controled. This could all be completed by
September of 2002.
References
http://www.npl.uiuc.edu/~a-nathan/pob/honors-talk-00/index.htm
http://www.bartleby.com/107/143.html
http://www.bartleby.com/107/144.html
http://www.bartleby.com/107/146.html
http://www.tmc.edu/thi/carotida.html
http://www.columbia.edu/~mdt1/cerebfaq.txt
http://www.wfubmc.edu/interneuro/aneurysmdes.html
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