Obesity and diabetes are two of America’s leading killers, yet patients suffering from one or both of these diseases have limited treatment options due to physiological, economic, or other constraints. Currently, the Center for Disease Control estimates that 78.6 million Americans, just over one-third of the population, are obese, as defined by having a body mass index (BMI) above 30. Each year, obesity costs the United States a total of $153.38 billion in direct costs and obesity related productivity loss. Similarly, 29.1 million Americans have Type II Diabetes, with 1.7 million new cases diagnosed each year. Diabetes costs the United States a total of $245 billion annually. Overweight (BMI >25) and Obesity (BMI > 30) increases the risk of developing Type II Diabetes, and these diseases present simultaneously in just under 25 million Americans..

Weight loss surgery offers the morbidly obese population (BMI > 40) a solution to lose weight and even reverse Type II Diabetes in some cases. However, this procedure is not without risks and is available to a small subset of the population. Only patients between 18 and 65 years old with a BMI above 40 qualify for this operation, and of the qualifying population, less than 1% actually undergo surgery. During this operation, shown in the figure, a surgeon removes a significant portion of the stomach and attaches the remainder of the stomach directly to the jejunum. The average cost of this procedure is $25,000, making it financially unfavorable, especially for patients without adequate health insurance coverage. However, bypassing the foregut without removal of the stomach or portion of the small intestine can also result in the reversal of Type II Diabetes. Our goal is to create a safe, inexpensive device used to run a feeding tube from the nasal cavity into the duodenum or jejunum. This will allow for a safer alternative to surgery that would help patients suffering from obesity and diabetes.

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Our design will utilize a traditional feeding tube – no element of this will be changed. The novelty of our device comes from its placement system, which will be comprised of a removable insert. The removable insert will contain a variety of elements, including an imaging system and physiological sensors.

One of our main focuses over the last few weeks has been identifying an imaging modality that would be most appropriate for placement of a feeding tube in the intestines. Technologies that were considered include radiofrequency triangulation, ultrasound, X-ray/CT, an endoscopic camera, and an MRI. Each of these systems have their own advantages and disadvantages.

X-ray/CT and MRI imaging were immediately thrown out due to major drawbacks that each system had. X-ray imaging exposes the patient to a great deal of radiation, and therefore was eliminated due to its inherent danger. MRI imaging was deemed to not be an appropriate technology due to its lack of efficiency for placement purposes.

Radiofrequency was determined to be a possible option because it is a relatively inexpensive technology and is easy to setup and use. However, there are a few drawbacks to this technology. The major problem is that it only gives the relative placement of the tube, not an absolute placement. In addition, our sponsor specifically mentioned that he did not like an existing system using RF technology and would prefer if we avoided it in our device. For these reasons, we eliminated RF technology as a possible solution.

An endoscopic camera was another possible imaging technology. While use of a camera can make the overall design a little more expensive and can be a little more difficult to train the health care provider how to use, this system provides the user with an absolute position of the end of the feeding tube. In addition, it allows the user to see the internal anatomy – if there are any unusual areas or any complications arise, visualization of the inside of the patient would be very useful.

Another technology being considered is ultrasound imaging. While this modality is also a little more expensive, it is easy to setup and gives an absolute position of the tube within the GI tract. In addition, while traditional ultrasound imaging may not provide the best resolution, this can be dramatically increased through the use of a piezoelectric material as a contrast agent.

In the coming weeks, we will present these ideas to our senior design sponsor. After comparing the strengths and weaknesses of the endoscopic camera and ultrasound technology, we will decide which technology to use, if not both.

Another very important element of our device is the use of physiological sensors in conjunction with the imaging modalities to confirm accurate placement of the feeding tube. The two main sensors that will be used are a pH sensor and a motility sensor. A pH sensor will allow the user to distinguish between the GI tract and non-GI structures, as well as differences between the stomach, duodenum, and jejunum. This element is also very small and cheap to install. The motility sensor will also enable the user to identify which part of the GI system the tube is in. This was an element that was recently suggested by our sponsor, and while we are not exactly sure how to construct and incorporate this now, it will be one of our main focuses in the coming weeks.

When considering the design of our device, it was crucial to look at competing devices, and what aspects of them were good and bad. As of now, we have determined that the only major competitor in this field is Cortrak, which has a monopoly on the feeding tube placement field. Cortrak has two main systems – one placed by X-ray fluoroscopy and one placed by RF triangulation.

The fluoroscopy system uses traditional X-ray fluoroscopy to determine if the naso-duodenal feeding tube is accurately placed. Radioactive isotopes are injected into the tip of the tube. While this illuminates the tube, these harmful isotopes also radiate to nearby structures in the GI tract. After placement of the tube, the patient is taken to X-ray. In the resulting image, the tip of the tube lights up brightly, revealing the placement of the end of the feeding tube. The most beneficial aspect of this system is that it provides an extremely accurate and precise location of the tip of the feeding tube. However, the X-ray process is extremely time-consuming, as the placement of the tube often must be attempted several times before it is located in the correct position. As a result of this, the patient is often required to attend many doctor’s visits before accurate placement is achieved. In addition, the series of X-rays exposes the patient to a relatively high amount of radiation, in addition to exposure to the radioactive fluoroscopic isotope.

The second Cortrak system utilizes radiofrequency triangulation of a signal emanating from the tip of the feeding tube. In this system, a receiving device is placed on the patient’s xiphoid process. This device has contains three receivers, which calculate the position of the tube based on the time that it takes for RF pings to reach the three receivers. The device then provides two graphs of tube’s position – one in the sagittal plane and one in the coronal plane. While this device provides the location of the tube without exposing the patient to undue radiation, it has many drawbacks as well. The two graphs that are provided can be extremely difficult to read and comprehend at the same time, especially for an inexperienced user. These graphs also only provide a relative position of the tube, not an absolute position. This is fine if the patient has normal GI anatomy; however, if the patient does not, the bends and curves of the GI system will be out of place compared to what is expected.

Our product will differ from others on the market because we will be using a different imaging technique and including physiological sensors to verify placement of the tube. We have narrowed the potential imaging techniques to either ultrasound or a camera placed at the tip of the tube. If we employ ultrasound imaging, we will coat the tip of the tube with a material that can be viewed in ultrasound. This could include traditional metals such as titanium, CoCr alloys, or stainless steel. We could also improve visualization of the tip by using Piezoelectric materials such as PZT-5 ceramic or PVDF piezopolymer. The physiological sensors would also be placed on the tip of the tube and would measure pH as well as gastric motility. Different regions of the gastrointestinal tract propel food at different rates, so measuring motility in conjunction with pH would verify the tip’s placement along the GI tract.

We will be meeting with Dr. Abumrad next on November 10th and once per week thereafter. During our most recent meeting, Dr. Abumrad suggested motility sensors that could distinguish between the different sections of the gastrointestinal tract and recommended a few research articles relevant to our design. At this meeting we will be discussing these articles in addition to implementation of motility sensors and any other specific needs. We also intend to discuss funding and how to test future prototypes. Because our design will be used in human patients, we will also address a potential need for an Institutional Review Board.

In addition to our meetings with our sponsor, we intend to meet with other professionals whose advice may influence our choice of imaging technique and implementation of sensors. We will be consulting Dr. Cynthia Pascal, Katie Lansance, and Leland Husband for their advice for potential approaches and recommended imaging techniques. Additionally, we will be consulting Dr. Grissom about the motility and pH sensors we intend to include in our design.