Vanderbilt University

Department of

Biomedical Engineering

Senior Design 2005-2006

Fluid Filled Cervical Dilator Reported by: Group 10 George Bikakis Drew Lansdown John Moustoukas Michael Nichols Advisors: Dr. Bruce Beyer, MD Dr. Paul King, Ph.D. Submitted April 25, 2006

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Abstract:

The frequency of induced labors has increased on a global and national level for a variety

of reasons. As many as 800,00 labors per year are induced[11]. The onset of parturition

is preceded by physical and biochemical changes to the uterine cervix called cervical

ripening. A ripe cervix is essential for a safe delivery and many complications result if

the cervix is not adequately ripe, often necessitating a cesarean delivery[3]. The

induction of labor requires active cervical ripening. The goal of this project is to design a

fluid filled balloon catheter capable of safely and effectively dilating the cervix. The

device has the potential to alter and improve the standard of care in the practice of the

induction of labor on a global perspective. We began with a thorough literature search

for information on current dilation procedures and other uses of balloon catheter devices.

Using sound engineering design principles we arrived at a final catheter design consisting

of two dilation balloons and one anchor balloon. We produced professional engineering

drawings of the device in ProE, which were subsequently submitted to outside industry

for prototype production. Safety and risk analyses were performed and hazards were

reduced to minimal levels. Relevant FDA standards were considered and thoroughly

analyzed. Through this project we successfully designed a fluid filled cervical dilator up

to the prototype stage where we were met with cost restrictions. Initial patent paperwork

has been filed to protect the intellectual property of this invention. It is recommended

that the prototype be produced and that testing of the device begin as soon as possible.

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Introduction

Posterm pregnancy Pregnancy-induced hypertension Intra-amniotic infection Preterm rupture of membranes Suspected fetal jeopardy Maternal diabetes mellitus Transverse fetal lie Fetal demise Table 1. Some indications that prompt the induction of labor. [2]

The frequency of induced labors has increased on a global and national level for a

variety of reasons. Using data from the National Center for Health Statistics, Zhang et al.

reported that from 1989 to 1998, the percentage of induced labors (of all labors)

increased from 9.0% to 19.4%[1]. The fact that the percentage of induced labors has

more than doubled in the past 15 years proves that there is sufficient necessity to induce

labor instead of allowing spontaneous childbirth. The

majority of the cases where induction was chosen cite

planning by the mother and her family as the impetus,

but many safety concerns and other anticipated

complications of labor for the mother and the fetus

can also prompt the attending physician to intervene.

Some medical complications of pregnancy that would promote elective induction are

listed in Table 1[2]. The onset of parturition is preceded by physical and biochemical

changes to the uterine cervix called cervical ripening. A ripe cervix is essential for a safe

delivery and many complications result if the cervix is not adequately ripe, often

necessitating a cesarean delivery[3]. The extent of cervical ripening is described by the

Bishop score, and a Bishop score of 6, is known to result in a healthy delivery for

spontaneous and induced labors[4]. The induction of labor, thus requires active cervical

ripening.

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Figure 1. Laminaria tents used for cervical dilation. [6]

Cervical ripening is also referred to as cervical dilation because the diameter of

the cervical canal increases to allow the fetus to escape the uterus. Many different

methods of cervical dilation have been researched and implemented clinically, each with

its own respective advantages and disadvantages. Also, some patients will exhibit

different degrees of cervical dilation corresponding to different periods of their labor.

Since the dilation of the cervix does not always correspond to the term of labor,

physicians are required to make many decisions after considering the patient’s

indications. Because of these variable human factors, a cervical dilation technique

requires a process that conforms to a variety of scenarios. Many of the methods that are

used are technologically dated and provide crude solutions to the problem. The systemic

or local administration of “ripening hormones” has been shown to successfully dilate the

cervix, but with unwanted and potentially lethal effects on the mother or fetus[5].

Hormones that have been used to this end include oxytocin, estrogen, relaxin, and a

variety of prostaglandins. These hormones are

involved in the spontaneous ripening of the

cervix, but the exogenous administration of these

powerful hormones often has unpredictable

consequences, even with careful dosing[2]. In

addition, the use of hormones in labor induction is

not often available to many patients because the

exogenous hormones and gels are very expensive and many hospitals are unwilling to

present the necessary funds.

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Figure 2. Commonly used Single Balloon Foley catheter. [9]

Mechanical dilation of the cervix is preferable because it avoids the systemic

effects of exogenous hormones, and the effects can be more accurately monitored by

physicians. When the cervix is mechanically dilated, the endogenous release of ripening

hormones is also stimulated. The mechanical dilation is coupled with the natural ripening

effect of the hormones[2]. Currently used methods of mechanical dilation of the cervix

include the use of laminaria tents, a derivative of seaweed, that is inserted in a dehydrated

state into the cervical canal and experiences expansion when it absorbs fluid[7]. (Figure

1) This method has been proven to result in a much lower percentage of fetal morbidity

and reduced necessity for cesarean intervention when compared with exogenous

hormones administration[8]. Laminaria are inexpensive and effective, but lack a

sophisticated time-dilation response that is desired by today’s obstetricians. Foley

catheters (Figure 2) have been used for the

purpose of cervical ripening but in a different

manner, but with promising results. In one study

of 190 cases, a 22- to 26- gauge Foley catheter

was inflated directly proximal to the internal

cervical os and inflated with sterile water at a

rate of 1ml/min. The balloon was found in 90 percent of the cases to be spontaneously

expelled from the cervix within 12 hours (mean = 6.1 hours) and resulted in an average

change in Bishop score of 1.5 to 5.5. spontaneous labor followed balloon expulsion for

37 percent of cases, while the remaining 63 percent required oxytocin administration to

induce labor[3]. The use of Foley catheters for dilation in this method can be problematic

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because of the inconsistency in time required for cervical dilation. The technique may

still be much more sophisticated.

Figure 3. Device in place in pregnant patient.

Bruce Beyer M.D., an Ob/Gyn at Vanderbilt University’s Medical Center,

conceived a method of cervical dilation that circumvents the problems associated with

prostaglandin-induced cervical ripening and current methods of mechanical dilation. Dr.

Beyer proposed the use of a double-balloon catheter, inserted into the cervical canal and

filled with saline at a calculated rate of dilation. An anchor balloon is positioned

proximally to the internal cervical os, and two dilating balloons, adjacent to one another,

are positioned inside the cervical canal. The anchor balloon and dilating balloons are

filled at two different rates, with the anchor balloon maintaining slightly larger diameter

than the diameter of the cervical canal, preventing ejection of the dilating balloons.

(Figure 3) A two-syringe Harvard pump is used

to fill the balloons at different rates according to

specification.

This procedure would allow physicians

to dilate the cervix at a desired rate determined

according to the patient-specific circumstances.

The degree of control offered by this practice is

unmatched by any of the above described

procedures. If the rate of dilation is 0.6-0.8 cm

per hour, then a diameter of 5 cm may be

reached in 5-7 hours. Since mechanical

perturbation of the cervical canal is known to stimulate the endogenous hormonal

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response that results in cervical ripening, forced dilation will precede natural dilation.

Saline will be used to fill the balloons because of its similarity to the physiologic

environment, protecting the body in the event of balloon rupture.

The goal of this project is to design a fluid filled balloon catheter capable of

safely and effectively dilating the cervix. The device has the potential to alter and

improve the standard of care in the practice of the induction of labor on a global

perspective. Once mass-production is achieved, this device should cost less than $100

USD, eliminating the cost of expensive prostaglandin treatments.

Methodology

Dr. Bruce Beyer, an obstetrician at Vanderbilt University, presented our design

team with the problem of an unripe cervix during labor that requires some form of

external dilation. Given the current standards of practice for this procedure, Dr. Beyer felt

as though there should be a more consistent, a more reliable, and a safer method for

dilating the cervix. He described to us a potential device constructed of a catheter that

would be inserted into the cervix, that would be held in place in the uterus, and that

would expand via a fluid to mechanically dilate the cervix. We were instructed to

research the literature, consider the feasibility of such a device, and begin to design a

model of a catheter for dilation.

The first step of our project was to conduct a literature search. Our group needed

to research the anatomy of the female reproductive system, as well as the pregnant

anatomy, so that we could understand where the device would be placed and how it

would be inserted. It was also especially important that we researched the dimensions of

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the cervix, both before and after a dilation procedure, so that we would know the

appropriate size to make the dilator. We also were interested in examining the space

available above the cervix when there is a fetus in the uterus. Other physiological

parameters that were of interest to us at this point were the pressures present in the female

reproductive system, most specifically the pressures in the cervix and in the uterus.

It was also necessary to search the literature to ensure that there was no device of

this type already in use. We were able to ascertain that previous attempts to dilate the

cervix by placing a balloon above the internal cervical os, in the uterus. This balloon was

used in previous studies to apply downwards pressure on the cervix to bring about

dilation in this fashion. Through our literature review, however, this method was the

closest that we could find to our device. No previously conducted had attempted to place

catheter balloons into the cervical canal.

As we researched the literature, we often read about Foley catheters and their uses

in numerous medical procedures. These catheters are used for urinary catheterization, and

they have an inflatable balloon at their end. We decided through this research that our

device should approximate a Foley catheter, but it would need to have larger balloon

diameters than those that are used for procedures in the bladder.

At this point, we began to brainstorm about designs for our device. We knew that

the device would need an anchor balloon that would be inflated quickly and would rest

on the top of the cervix, in such a fashion as the dilation procedures that we saw in the

literature. This balloon would need to inflate to a minimum of the dilation diameter, and

it would need to be filled immediately following the insertion of the device into the

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catheter. We produced a quality function deployment (QFD) diagram in order to better

organize our ideas and design requirements. We also completed Innovation Workbench.

The dilation process would be accomplished by a balloon directly below the

anchor balloon. This balloon would be placed into the cervical canal, and it would inflate

at a slow rate with a separate feed from the anchor balloon. It would need to be capable

of expanding to a minimum of the dilation diameter. Both balloons would need to be

constructed of a firm material so as to be able to expand to the necessary large diameters,

and they would need to be made of non-toxic and hypoallergenic material so as to not

cause further complications upon insertion.

So, we decided that our device would be constructed of a balloon-tip catheter. The

catheter would need to have two separate feeds, one for the anchor balloon and one for

the dilation balloon. The balloons would be filled with saline so that, in the extreme case

of rupture or balloon leakage, the patient should suffer no adverse side effects. The

presence of saline in the uterus, we saw in the literature review, has no damaging effects

on the fetus, so this fluid is safe to use as or source of dilation.

We also realized that we would need a source of pressure to drive the fluid into

the anchor and dilation balloons. Our original idea for a pressure source was to use a

Harvard pump. This sophisticated pump is equipped to operate two inlet streams at

different flow rates. This pump seemed like an ideal solution to the pressure source issue,

but the downside of it is its price, about $5000. We concluded that we should consider

other options for the pressure source to see if we could find another method that would be

as reliable as the Harvard pump and could be slightly more cost-effective.

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For alternatives to a costly pump, we decided that we could use a standard bag of

saline that is compressed with a pressure source to provide fluid to the catheter system.

We decided that we could use a pressure cuff like that is used in blood pressure

measurements to squeeze the bag to provide fluid to the device. We explored the

possibility of using a device, such as the Hokanson E20 rapid cuff inflator. This device

could be set to a specific pressure and squeeze the bag of saline at this pressure. We had

planned to explore a simpler model of a cuff inflator, since we did not require the rapid

inflation capabilities found in this product. Our next step, however, was to get another

perspective on our project.

To get input from a knowledgeable outside source, our group scheduled a meeting

with Dr. Roselli of the biomedical engineering department. Dr. Roselli is an expert in the

fields of biomechanics and of physiological transport phenomenon, and we believed that

gaining feedback from a knowledgeable outside source would help us view the problem

from perhaps more angles than we were considering.

The first recommendation that Dr. Roselli had was to return to the Harvard pump

as our pressure source. He agreed that the cost is high and that we could find some

solution at a lower cost, but the safest and most reliable option would be to use this

pump. Also, each pump could be used for many dilation procedures, so this cost would

just be a one-time purchase. Additionally, the Harvard pump is a common medical

device, so hospitals could already have them in their possession.

Dr. Roselli also pointed out that there may need to be a small amount of dilation

prior to insertion of the catheter device. With two catheters and the deflated size of the

balloons, the device could approach 0.5 to 1 cm in diameter. It would also be easier for

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the balloons to inflate if the supply catheters had a larger diameter, allowing for better

flow. The physician using our device would simply have to dilate the cervix to a starting

diameter, then insert the device and

continue the dilation procedure by

inflating the balloons.

At this point, we also began

considering using two balloons for

the dilation process, instead of one.

Two balloons would provide for a

better force distribution than one,

and two balloons would be able to

more closely resemble a cylinder

during the dilation process. The

overall length of the dilation

segment would not change, and the

balloons would be supplied by the

same feed, but the two structures

would offer more stability and

reliability in the dilation process.

(a)

Next, we drew our first

sketches of the potential device.

This initial sketch is shown in

Figure 1. As specified by this drawing, the device would have two dilating balloons and

(b) Figure 1. First sketch of undilated and dilated balloon catheter. A side view of the two dilating balloons and anchor balloon is provided in Figure 1 (a), while Figure 1(b) provides a cross-sectional view of the catheters that provide the input feed to the two balloons.

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one anchor balloon. All dimensions of the device are specified in this initial drawing, and

all measurements are a result of the research that our team did into the average

dimensions of the female anatomy. We finalized our design to be what is shown in the

first sketch. The device has one catheter within another, with the inner one supplying the

anchor balloon. The outer catheter stops at the end of the dilation balloon system and

provides the saline for the dilators. There is a separate feed for each catheter so that the

flow rates can be controlled independent of each other using the Harvard pump.

In regards to the size of our device, we decided to make one device at a specified

size for this project. If this device ever reaches a stage of widespread clinical use, it

would be better for the dilator to be produced in varying sizes for patients with different

cervical lengths. For a prototype though, we reasoned that it is most pressing to simply

demonstrate the viability of our device, and any customizations in the size of it will be

made at a later date.

We also hoped to make a device where the dilation procedure would occur

automatically, leaving the physician free during the process. To simplify the problem,

and to ensure that the overall concept was feasible before making unnecessary additions,

we decided to design for a manually inflated dilator. Even for clinical trials, it would be

fine for the device to be manually operated, since a trained expert should be present

during the testing of any new medical device. After confirmation of a working dilation

process via balloon catheters, the device should be automated, but this step was

postponed until later.

With our device designed in the initial sketch, our next step was to approach

catheter companies about manufacturing a prototype of the dilator. We chose to pursue an

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outside manufacturing firm for the production of a prototype rather than attempting to

make one ourselves because the necessary materials and equipment are not readily

available to us. We began searching the websites of medical device companies to find

several that appeared to have the capabilities to produce our device. Two companies that

we found at this point were Bard Medical Division and Utah Medical Products, Inc. Bard

makes many catheter products, and Utah Medical already produces other devices for

obstetric processes.

In order to professionally approach any outside company, we needed actual

engineering drawings of our device. Out of availability, we chose to use ProE to make the

drawings. Since we had no background or training with this program, it took a great deal

of time to understand the workings of ProE and produce our drawings. The drawings of

the dilator were made with various views, and they were drawn to our specific

dimensions.

At this point, we decided that we should build a mock-up prototype to help

visualize the dilation process. This model was constructed with plastic tubing

representing the catheters and regular balloons representing the dilation balloons. The

Harvard pump was simulated with balloon pumps, and the catheter inputs were modeled

with balloon stems. The prototype was assembled with superglue to attach the balloons

and caulking to seal points of possible leakage.

With the drawings completed, the next step was to make contact with outside

companies to get a prototype produced. We first attempted to correspond with Bard

Medical Division, but we received no response to our initial inquiry. We chose to then try

talking to Utah Medical, and they were very receptive to helping us with the production

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of our device. In order to not compromise our intellectual property of this device, we

initially told them limited details just to gauge the feasibility of their company

constructing a prototype. At this point, Dr. King also alerted us to Interface USA, Inc, a

company that specializes in catheter production. We decided that this company held more

promise than Utah Med since their website claimed to be able to do what we needed.

We had simultaneously been speaking to Mr. Bill Eads at the Office of

Technology Transfer (OTT). It was necessary for us to obtain a confidentiality agreement

to send to an outside company prior to disclosing any specific parameters of our device.

OTT requires that all inventions be disclosed to Vanderbilt before a confidentiality

agreement can be drafted, so we completed the invention disclosure process.

Results:

In order to evaluate the needs of the potential customers in relation to the

technological requirements of this device, a quality function deployment diagram (QFD)

was produced. The QFD is shown in Appendix A. This diagram helped to visualize the

most important design aspects of the project and make sure that we keep these points in

the forefront of our design process. From this diagram, we realized that the most

important part of our project was to design a balloon catheter device to replace the

current methods used for cervical dilation. One recurring theme stemming from the QFD

was that of safety for the patient, so it was of utmost importance to continually evaluate

the safety aspects of the dilator. Also, the diagram shows that the cost of the device

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(a)

should be less important than its function and safety. The results from Innovation

Workbench can be seen in Appendix B; it helped us with our problem formulation and in

our understanding of the design constraints.

(b) Figure 2. Two drawings of cervical dilator. Figure 2 (a) shows a side-view of the inflated device. Figure 2 (b) is the dilator with the dimensions of the inflated dilation balloons, given in millimeters.

Precise drawings of the fluid-filled catheter were created in the computer software

program Pro-E. This engineering design program allows for a three-dimensional

rendering of an object, so it was possible to view the dilator from all angles after it was

drawn. This program also allowed for the drawing of our device with specified

dimensions. It was absolutely necessary that the drawings have our specific parameters so

that they could be sent to a contractor for production of a prototype. These drawings are

displayed in Figure 2 and in Figure 3.

Figure 2 shows two side views of the cervical dilator in the inflated state. Figure

2 (a) displays the three-dimensionally rendered view of the device. The size of the

dilation balloons in relation to the anchor can be seen here, and the narrow spacing

between the dilation system and anchor balloon is also readily apparent. Figure 2 (b)

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presents a side view of the device with appropriate dimensions noted in millimeters. The

length of the dilation system compared to that of the anchor balloon can be seen here.

In Figure 3 (a), there is a cross-sectional view of the catheter, with the two tubes

inside. This drawing shows how one tube is present inside of the other, with the feed for

the anchor balloon being the inner tube. Figure 3 (b) gives a top view of the device in the

inflated state. The diameter of the anchor balloon is once again apparent in this figure.

For both drawings in Figure 3, the dimensions are given in millimeters.

In order to demonstrate the functioning of our device, a mock-up prototype was

successfully created. This model demonstrated the workings of the multiple balloons and

the inputs to the catheters. The model also helped the audience in our visual presentations

comprehend the functionality of the device because the concept of balloon catheters is

not immediately relevant to all who have not had specific, prior exposure to the field.

The invention disclosure process was successfully completed with the Office of

(a) (b) Figure 3. Two drawings of a top view of the cervical dilator. Figure 3 (a) shows a cross-section of the catheter with dimensions of the two catheters. Figure 3 (b) shows the inflated anchor and top dilation balloons, with the anchor balloon in light grey and the dilating balloon in darker grey. All dimensions are given in millimeters.

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Technology Transfer. The cervical dilator was registered under Case Number VU0689.

Following the disclosure of our device, a confidentiality agreement was obtained and

signed by all necessary parties. The confidentiality agreement is attached in Appendix C.

One final step to ensure the protection of our intellectual property was to file initial patent

paperwork, which was also done our behalf by the Office of Technology Transfer.

Three catheter-production companies were contacted, and we pursue the reception

of a quote from one biomedical company. The feasibility of producing this device was

proven because the company, Interface USA, said that they would easily be able to make

this device. A prototype was not made at this point, however, because of the exorbitant

cost of production.

Economic/Market Analysis Table 2 shows the costs received from Interface USA to produce the cervical

dilator prototype. The expensive price is because molds for balloons of this size do not

exist, and also the catheter stem would

need to be produced to specifications.

There is a fixed cost of $27,000 for

producing this device. This cost will

change only slightly with changes in the volume of production. Once the molds are

created, the subsequent balloon catheters will cost much less. With approximately

400,000 labors each year requiring a cervical ripening agent, the demand for the device

could theoretically be extremely high. If just 50,000 catheter dilators can be

manufactured at a cost of $30 per unit, the total cost of manufacturing will be $1,500,000

Table 2. Itemized projected cost of device production Item Quantity Cost Balloon Molds 2 $6000/mold Labor 5 days $1200/day Catheter mold 1 $6000/mold Production Costs 1 $3000 Total $27,000

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+ $27,000 = $1,527,000. If we can sell the dilators for $100 each, total revenues will be

$5,000,000. This translates to $3,473,000 of profits. This hypothetical scenario

demonstrates that the device can definitely be profitable while maintaining affordability

for patients. Our device is very specific and requires expensive manufacturing

equipment, so we could possibly also profit from this idea by marketing and selling the

design, and accompanying rights, to a medical company such as Interface USA, who has

the expensive manufacturing equipment and a strong presence in the marketplace.

Risk and Safely Analysis

Hazard and risk analysis using DesignSafe®, attached as Appendix D, helped us

identify potential risks associated with our device. Puncture, reaction with chemicals,

fluid leakage, and possible excessive force were our main safety concerns. Through the

use of hypoallergenic materials as well as designing the balloons to expand further than

would be required for cervical ripening we minimized the effects of these hazards to an

acceptable level.

Several safety considerations have been implemented into the design of the

cervical dilator. The first of these is that the materials used will be sterile and the

balloons will be latex-free to prevent allergic reactions. The fluid used for dilation will

be saline, which will not react with the body in the case of a rupture. A non-toxic

lubricant will be needed for easy insertion. The syringe in the pump will hold only

enough saline to dilate the balloons to 5-6 cm. Also, an emergency shut off system will

be implemented if the catheter pressure does not meet the specifications. There will also

be a physician override to halt dilation in case of emergency. In addition, the balloons

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are capable of expanding much more than the diameter required for cervical ripening to

prevent rupture. The presence of air emboli will be reduced through initial washing of

the catheter in saline and by monitoring fluid pressures within the catheter. Long term

exposure effects, such as toxic shock syndrome, will need to be analyzed once human

testing begins.

Relevant FDA Standards

According to the FDA standards, the cervical dilator should be classified as a

class II device. This implies that it is not life sustaining, but it must meet detailed

performance standards. A class II device must also meet basic standards such as pre-

market notification (501(k)), registration, device listing, good manufacturing practices

(GMP), and proper record keeping[10]. In addition, the FDA may require clinical or

laboratory studies to prove safety and efficacy.

Conclusion:

We have successfully designed a fluid-filled catheter for safe, efficient cervical

dilation. Furthermore, our design meets each goal designated by our preceptor. A three-

balloon saline-filled catheter proved to be the optimal design for cervical ripening.

Tremendous costs associated with the initial production of balloon-tip catheters prevented

us from producing the device at this time; however, a prototype was developed which

sufficiently demonstrated the feasibility of our design. The potential risks to our users

and operators has been analyzed and minimized to an acceptable level through design

practices. Initial patent paperwork has been started by the Vanderbilt University Office

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of Technology Transfer and Enterprise Development. We have confidentially disclosed

our design to a balloon-tip catheter production company and they have revealed their

ability to produce catheters to our specifications should we be able to find funding for the

production

Recommendations:

Recommendations on the use and improvement of our device will likely need to

be made after production and initial testing has begun. In addition to a catheter, a

pressure source and saline reserves are necessary for cervical dilation. Our catheter could

work with several pressure sources and the optimal one will vary depending on the

specific use of the dilation catheter. For hospitals and other settings so equipped, we

recommend the use of a “Harvard” series two syringe pump. This pump allows precise

control over the balloon fill rates, and thus, the rate of dilation. The balloons can also be

filled manually with syringes, but this reduces control over the dilation rate. Syringes

pre-filled with specific volumes of saline will accompany our device. The exact volume

expelled from the syringe into the catheter balloons is left to the discretion of a physician

and will vary depending on the caliber of dilation required and personal anatomical

differences.

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References:

[1] Zhang J, Yancey MK, Henderson CE. “US National trends in labor induction1989–1998,” Journal of Reproductive Medicine, 47:120–4 (2002). [2] Rayburn WF. “Preinduction Cervical Ripening: Basis and Methods of Current Practice,” Obstetrical & Gynecological Survey, 57(10):683-692, (2002). [3] Sherman DJ, Frenkel E, Tovbin J, Arieli S, Caspi E, Bukovsky I. “Ripening of the Unfavorable Cervix With Extraamniotic Catheter Balloon: Clinical Experience and Review,” Obstetrical & Gynecological Survey, 51(10):621-627 (1996). [4] American College of Obstetricians and Gynecologists (Washington DC). “Induction of labor ACOG Practice Bulletin no. 10,” American College of Obstetricians and Gynecologists (1999). [5] Maymon R, Haimovitch L, Shulman A et al. “Third-trimester uterine rupture after prostaglandin E sub 2 use for labor induction,” Journal of Reproductive Medicine, 37:449 (1992). [6] website: http://www.healthwomen.com.tw/ch.test.menu.htm viewed on April 16th at 7:33 pm. [7] Blumenthal PD, Ramanauskas R. “Randomized trial of Dilipan and Laminaria as cervical ripening agents before induction of labor,” Obstetrical & Gynecological Survey, 75:365–71 (1991). [8] Boulvain M, Kelly A, Lohse C et al. “Mechanical methods for induction of labour (Cochrane Review),” The Cochrane Library, Issue 4 (2001). [9] website: http://www.suru.com/fole1.htm viewed on April 20th at 9:30 pm. [10] King P, Fries R. "Design of Biomedical Devices and Systems" Marcel Dekker, Inc. (2003). [11] Website: http://www.susps.org/overview/birthrates.html viewed on April 16th at 6:27 pm.

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Appendix A – Quality Function Deployment Diagram

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Appendix B – Innovation Workbench

Ideation Process Project Initiation Project name: Fluid Filled Cervical Dilator Project timeline: Finish Before May 1 Project team: John Moustoukas Drew Lansdown Michael Nichols George Bikakis Innovation Situation Questionnaire Brief description of the situation Foley Catheters - Off label usage of catheter, adequate performance, safe, convenient, reliable, controllable, predictable, Metal Rods - perforation, crude Laminaria - crude, unpredictable Prostaglandins and Drugs - side effects, unpredictable

Detailed description of the situation Ideal Solution - dilate cervix safely, no side effects, controlled rate and time, no tearing, reproducible effects, transportable, cheap?, rugged as hell,

Supersystem - System - Subsystems System name Fluid Filled Cervical Dilator - safely dilate cervix in predictable fashion System structure pressure source, balloon tip catheter, saline (fluid), Supersystems and environment cervix, vagina, female reproductive tract, other GYN tools, energy source, biological substances, saline, common hospital systems and tools Systems with similar problems Angioplasty catheters increasing diameter of occluded blood vessel lumen - need bigger, more elastic balloon; trapping a cow with balloons; may be others Input - Process - Output Functioning of the system Intended work is to dilate the cervix, expand with fluid without breaking, System inputs We cannot change the fact that saline will be used as an input. Harmful inputs are air bubbles getting into the catheter (harmful if there is a breakage). System outputs After dilation, the entering fluid becomes the output when it is removed from the catheter balloon. Cause - Problem - Effect Problem to be resolved

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The undilated cervix is too small for a baby to pass through, so we need to increase the size of the cervix. Some women have trouble dilating naturally, so, for these pateints, we will use our fluid filled device to mechanically perform the dilation more effectively than other methods. Mechanism causing the problem 1. There is a system, the fluid filled cervical dilator, for mechanically expanding the diameter of the cervix. An undesired effect of a ruptured dilator occurs under the condition of inflating the device too quickly or with too much pressure. It is necessary to find the cause of this phenomenon. 2. It is required to make the dilator rupture under the conditions of cervical dilation. 3. It is required to make a piece of the balloon of the dilatore completely tear under the conditions of the existing dilation process. 4. This same phenomenon is also found in research labs when cells are placed in hypotonic solutions causing the cells to fill with fluid to the point where their cell membranes rupture. 5. The hypothesis is the following: When the balloon fills with either too much fluid or the pressure on its walls is too high, the balloon will rupture. A simple test confirmed this hypothesis. 6. After confirming the hypothesis, we decided that we need to use a material for our balloon that will be able to easily withstand the necessary fluid volumes and the pressures that will be present when we fill the catheter with the fluid. Undesirable consequences if the problem is not resolved The undesirable consequence if the problem remains unsolved is that current dilation methods that are crude under modern standards will continue to be used. Other problems to be solved If all babies were delievered with C-sections or if all women had normally functioning cervixes, then there would be no problem. Past - Present - Future History of the problem This problem is one that has existed forever. The other solutions include the laminaria and the metal rods, but these are crude in relation to current technology. Pre-process time No. Post-process time No. Resources, constraints and limitations Available resources Saline, balloons, pressure produced by source, electrical energy, hospital resources Allowable changes to the system Completely changing the system is allowed, but it is most likely that only small changes will be made. Constraints and limitations The only restrictions are the final product of safe and reliable dilation of the cervix, and the string theory imposes minor constraints in allowing us to manipulate cervixes in other dimensions.

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Criteria for selecting solution concepts The durability of the product is one criteria for selecting solution concepts. Also, the appearance is one consideration that is minor. The cost will need to be low if the device is to be used in common practice. The technical characteristics are that the device should safely perfomr the dilation and not rupture. The desired timetable is the product should be complete by May of 2006. Problem Formulation and Brainstorming Fluid Filled Cervical Dilator 11/30/2005 4:46:39 PM. Find an alternative way to obtain Dilate Cervix to 5 - 10 cm that does not require Control rate of dilation, Control extent of dilation and Dilate cervix safely with respect to mother and fetus. Find an alternative way to obtain Control rate of dilation that offers the following: provides or enhances Dilate Cervix to 5 - 10 cm eliminates, reduces, or prevents Balloon breaking under pressure does not require Control extent of dilation and Dilate cervix safely with respect to mother and fetus. Find an alternative way to obtain Control extent of dilation that offers the following: provides or enhances Dilate Cervix to 5 - 10 cm and Control rate of dilation eliminates, reduces, or prevents Rupture cervical canal and Balloon breaking under pressure does not require Dilate cervix safely with respect to mother and fetus. Find a way to eliminate, reduce, or prevent Balloon breaking under pressure. Find a way to eliminate, reduce, or prevent Catheter dislodges from cervical canal. Find a way to eliminate, reduce, or prevent Balloon contacts and disturbs fetus. Find a way to eliminate, reduce, or prevent Rupture cervical canal. Find an alternative way to obtain Control Achoring of catheter that offers the following: eliminates, reduces, or prevents Catheter dislodges from cervical canal and Balloon contacts and disturbs fetus does not require Dilate cervix safely with respect to mother and fetus. Find an alternative way to obtain Dilate cervix safely with respect to mother and fetus that provides or enhances Control Achoring of catheter, Control extent of dilation, Dilate Cervix to 5 - 10 cm and Control rate of dilation.

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Dilate Cervix to 5- 10 cmControl rate ofdilationControl extent ofdilationBalloon breakingunder pressureCatheterdislodges fromcervical canalBalloon contactsand disturbs fetusRupture cervicalcanalControl Achoringof catheterDilate cervixsafely withrespect to mother

Develop Concepts Evaluate Results

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Appendix C – Confidentiality Agreement between Our Group and Interface USA

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Appendix D – DesignSafe 1/1/2001 patient All Tasks mechanical stabbing / puncture1/1/2002 patient All Tasks mechanical break up during operation1/1/2003 patient All Tasks ergonomics / human factors excessive force / exertion1/1/2004 patient All Tasks ergonomics / human factors duration1/1/2005 patient All Tasks noise / vibration fatigue / material strength1/1/2006 patient All Tasks confined spaces confined spaces1/1/2007 patient All Tasks chemical reaction to / with chemicals1/1/2008 patient All Tasks fluid / pressure fluid leakage / ejection2/1/2001 operator normal operation mechanical pinch point2/1/2002 operator normal operation ergonomics / human factors lifting / bending / twisting2/1/2003 operator normal operation chemical reaction to / with chemicals2/1/2004 operator normal operation fluid / pressure fluid leakage / ejection2/2/2001 operator load / unload materials mechanical pinch point2/2/2002 operator load / unload materials chemical reaction to / with chemicals2/3/2001 operator sort / inspect parts mechanical pinch point2/3/2002 operator sort / inspect parts mechanical stabbing / puncture2/4/2001 operator position / fasten parts andmechanical cutting / severing2/4/2002 operator position / fasten parts andmechanical pinch point2/4/2003 operator position / fasten parts andmechanical stabbing / puncture2/4/2004 operator position / fasten parts andchemical reaction to / with chemicals2/5/2001 operator lubrication chemical reaction to / with chemicals3/1/2001 set-up person set-up or changeover mechanical cutting / severing3/1/2002 set-up person set-up or changeover mechanical pinch point3/1/2003 set-up person set-up or changeover mechanical stabbing / puncture3/1/2004 set-up person set-up or changeover ergonomics / human factors repetition3/1/2005 set-up person set-up or changeover chemical reaction to / with chemicals3/1/2006 set-up person set-up or changeover fluid / pressure fluid leakage / ejection3/2/2001 set-up person lubrication chemical reaction to / with chemicals3/2/2002 set-up person lubrication fluid / pressure fluid leakage / ejection4/1/2001 temporary / stand-in operatornormal operation mechanical cutting / severing4/1/2002 temporary / stand-in operatornormal operation mechanical pinch point4/1/2003 temporary / stand-in operatornormal operation mechanical stabbing / puncture4/1/2004 temporary / stand-in operatornormal operation chemical reaction to / with chemicals4/1/2005 temporary / stand-in operatornormal operation fluid / pressure fluid leakage / ejection5/1/2001 materials handler All Tasks mechanical cutting / severing5/1/2002 materials handler All Tasks mechanical pinch point5/1/2003 materials handler All Tasks mechanical stabbing / puncture5/1/2004 materials handler All Tasks chemical reaction to / with chemicals5/1/2005 materials handler All Tasks fluid / pressure fluid leakage / ejection