EGRB 310

BME Practicum II

PROJECT PROPOSAL

4/5/2015

“Nasogastric Magnetic Sensing Device”

Aaron Corbin, Khade Grant, Arthik Alda

Faculty Advisor Name(s)

Dr. Jamison

Abstract

Nutrients are necessary for humans to survive. Due to various medical

problems, some patients are unable to consciously obtain nutrients by eating.

Nasogastric tubes are used to provide nutrients to the patient’s stomach.

However, navigating the nasogastric tube into the esophagus can be a

challenging task. Often the tube can be accidentally navigated into the lungs.

This can result in various adverse effects such as choking, sepsis, or even death.

Currently, magnetic nasogastric tubes are used to locate the distal end of the

tubes. However, current magnetic nasogastric tubes on the market are hard to

operate, require constant user contact, and require certification to operate the

device. The proposed solution for resolving these issues is to design a device that

incorporates a new means for applying the magnet to the nasogastric tube as

well as developing a magnetic sensing device that requires low user contact

and detects the magnet at precise location. The research requirement will

begin with researching current magnetic nasogastric tubes, the size limit of the

magnet that will not interfere with pacemakers, chemical composition of

plastics that will not harm the patient, and magnetic detecting devices.

Research pertaining to magnetic detectors will be viewed toward how to

create only proximal detection. The deliverables pertaining to this device will

include producing a magnetic sensing device capable of limited detection,

production of a plastic sheath that will be able to withstand stresses and the

various environments of the body, and the development of a final working

prototype.

Clinical Need

Nasogastric tubes are used to place nutrients and medicine in the

stomach of patients who are unable to, or have difficulty consuming them. The

nasogastric tubes are passed through the nose, then down through the

nasopharynx and esophagus, and end up in the stomach. However, when

placing nasogastric tubes in the stomach, there is a lack of feedback as to their

location. In many cases the tube is placed either too far; too short; or it goes

down the wrong path, ending up in a patient’s lung. Disregarding the use of x-

ray technology, which can be expensive and inconvenient, the status of the

tube during insertion is unclear. There is a need for a cheaper, effective, and

more convenient method to track the nasogastric tube during insertion.

Clinical Significance

Nasogastric tube insertion is a common clinical procedure that is carried

out in hospitals. Various complications arise when the nasogastric tube is not

inserted properly. Improper insertion usually results in the tube being sent into the

lungs, which can cause various adverse effects such as pneumonia or sepsis. In

a study in England conducted by the National Patient Safety Agency, the

researchers found that 11 deaths occurred due to misplaced nasogastric

feeding tubes over a two year period (NPSA, 2005). Furthermore, 210 incidents

occurred due to misplaced nasogastric feeding tubes over a two and a half

year period (NPSA, 2008). The lack of a reliable method for determining the

location of nasogastric tubes opens the door to incidents occurring during tube

insertion. Developing a method to accurately determine the location of

nasogastric tubes would prevent the majority of these incidents.

Current Solutions

In the current market there are many magnetic nasogastric tubes that are

used to locate the exact position of the tip of the nasogastric tube. However not

all of these devices provide sufficient ease of use or are of low cost to the user.

The nasogastric tube placement and monitoring system, invented by

Philip S. Rowe, uses electromagnetic waves to detect where the distal end of

the tube is located. It also provides pH and pressure detection. (Rowe, 2006)

Percutaneous Magnetic gastrostomy, invented by Fred E. Silverstein,

contains a needle tipped magnet attach to the distal end of the nasogastric

tube with a plurality of magnetic sensors. The device displays where the magnet

is located as well as the possible paths the tube can take. (Silverstein, 2008)

Lucent TubeSite system contains a weighted magnetic chamber that is

placed on the distal end of the nasogastric tube, a handheld detector, and a

display mechanism called “TubeSite Display” which displays the current location

of the tube. However, this device requires constant contact with the user to

display the location of the tube. In addition, this device cost more than our

proposed solution. (Intelligent Design and Development, 2004)

Proposed Solution

To create ease in locating the end of a NG tube, Team Iota has created a

product design which consists of a detachable thin plastic coating containing a

magnetic strip and two small detectors that will be placed on the patients neck

(one portraying the trachea area and the other the esophagus). In regards to

current solutions, this device will be easier to use and will provide more accurate

depiction of the NG tube’s location. Moreover, this solution will be low cost

compared to its current counterparts, which use fluorescence, x-rays, and other

expensive detection devices in conjunction with the magnetic sensor.

A description of the product is detailed below:

The plastic coating or sheath of the device would be placed on the NG

tube. The magnetic strip would be detected by magnetic sensing devices

placed outside the body over specific anatomic locations. These sensing

devices would flash lights after detecting the magnet as it passes in a close

enough proximity. The device has stationary magnetic sensing devices, which

allow it to fulfil the ease of use, human factors, and misuse potential

specifications. The stationary sensing devices also enable this product to be

precise since it does not require the user to search for the magnet and attempt

to manually determine the location of the magnet. Searching for the magnet

can be difficult and allows room for error.

The product allows the nurse to easily locate the magnetic nasogastric

tube (MNGT). If it approaches the trachea, the detector that is placed over the

location of the trachea flashes, warning the user that the MNGT is heading in the

wrong path. In addition due to the hands free use of the magnetic sensing

device, the user can focus more upon navigating the tube. The magnet along

with its plastic coating can be fitted to any size nasogastric tube, however the

length of the device will vary. The total cost of the device will be less than 50

dollars, a magnetic strip costs $1, a plastic tube will cost $10, and magnetic

detectors can go as low as $30. In case of product failure the nurse would simply

remove the plastic covering from the NG tube, replace the batteries of the

magnetic detectors and/or get a new magnetic detector.

The final product will be made out of a tough malleable sterilizable

plastic, making it durable. The final device will be reusable, up to a certain

amount of uses. Product manufacturing will be simple and cheap, as these

devices can be made in a factory with a specific mold for the plastic covering

and a furnace to melt the plastic into the mold. In addition the magnetic

detector will be made by hand, possibly by an assembly line of people. The

commercial potential of this product will be very high, as this will be a MNGT that

can be used by any healthcare provider that interacts directly with the patient.

The novelty of this idea discerns this product from other products that are

already out on market. The design, placement of the magnet, and how the

magnetic device is incorporated allows easy use for nurses, and is different from

what is already on the market. The low cost of this device, its reusability,

durability and low manufacturing cost also produces a low cost device that will

be easier to sell to health related facilities.

The deliverables for this product are as follows:

1. Magnetic detector: A detector that will only sense the magnetic in

a very narrow vicinity, as to provide accuracy in the detection of its location.

These detectors will light up once the detector has detected the magnet.

2. Coating/Sheath: A sheath which contains the cap containing the

magnetic strip must be made such that it can withstand the highly acidic

environment of the stomach and the stresses that it will experience in the body.

Repeated testing with using chemicals such as HCl and other acids will be used

to test the durability of the sheath. In addition, failure testing will be subjected on

the tube to obtain results that will help the team decide whether or not to

modify the composition of the sheath. The chemical composition of the sheath

will determine its durability.

3. Final Prototype: A final prototype will be designed after many

rigorous tests. This will become the product that we base our presentation,

animation, and future products on.

Significant Factors

The significant factor for the magnetic nasogastric tube design is the

magnetic sensor’s ability to detect magnets in a very close proximity. The ability

of the sensor to detect magnets only at a close range will give it high accuracy

in determining where the magnet is precisely located. However, the sensor

cannot detect the distal end of a tube if the magnet is not placed properly on

the end of the tube. Careful consideration will be put into developing a cap

that contains the magnet such that the magnetic cap is firmly attached to the

end of the tube. Sterilization will also affect the ability to reuse the device.

Therefore a sterilization technique will be chosen that properly cleans the device

with limited damage to its material composition. The composition of the sheath

must also be resistant to degradation from the acidic stomach environment. The

thickness of the sheath also has to be kept to a minimum in order to allow

mobility of the tube and to prevent any friction that may caused by the

interaction of the sheath with the upper digestive tract or upper airway. Lastly

the magnet chosen for the device will have to be small enough such that it

would not interfere with pacemakers.

Resources Required

Based on research of nasogastric tubes a suitable coating and or sheath

will be developed from the tools supplied by VCU, sigma-aldrich, vector, and

other laboratories. The sheath will be tested in the machine shop of VCU’s West

Engineering Hall and the chemistry labs of Oliver Hall; where failure testing and

chemical testing will proceed. The chemical aspect of the sheath will make sure

that the plastic does not decompose into anything harmful, in addition to

determining the degradation characteristics of such plastic. The magnetic will

be ordered off line from amazon. Tools such as a knife and blow torch, offered

at VCU’s West Engineering Hall, will be used to insert the magnet inside the cap.

The cap will be then attached to the sheath by melting the ends of both the

sheath and cap.

The sensor will be made from materials bought from Leviton. Prior

knowledge of programming and electrical engineering will provide the

necessities to make the device operable. Team Iota will use the facilities of VCU

East Engineering Hall to build the circuits and code for the sensor, with help from

Dr. Fei and Dr.Bai.

Deliverables

1. A magnetic detector that can sense a magnet in an optimum

range

2. A coating/sheath that can withstand damage from the

environments of the human body

3. A working final prototype of the design that can detect the NG

tube, will not damage nearby tissue, and can be reused multiple

times

Preliminary Work Plan

Background Research and Consultations – The goal of the project is to design

and develop a device that can determine the location of nasogastric tubes in

the body using magnetic properties so that proper placement can be ensured.

The project will begin with project due diligence along with preliminary research

on magnets, magnetic sensing devices, and various coating materials. Aaron

will focus on researching magnets and how they can be incorporated in

nasogastric tubes. In regards to the due diligence, Aaron and Khade will work

with librarian Julie Arendt to research current solutions to the problem of

determining nasogastric tube location and determine how to develop a novel

solution. Khade will conduct research on various magnetic sensing devices,

specifically on how they work and how their placement on various anatomical

locations of the body will ensure correct placement of a nasogastric tube.

Khade will be the primary contact between Dr. Jamison and the group to make

sure the project is progressing successfully. Arthik will primarily focus on

researching various coating materials for the magnet to ensure that the magnet

is not affected by the environments in the body that it might experience. Arthik

will be the contact between nurse Katie Gunter for suggestions on how to make

the design more useful to the medical community. At the end of the project due

diligence a preliminary design will be chosen.

Preliminary Device Production – After a preliminary design is chosen, materials

will be ordered for creation of the initial prototype of the design. When the

materials arrive, the initial prototype will be create. During this time, materials for

the development of the magnet and the magnetic sensing device will be

ordered. When the materials arrive, Aaron will be primarily in charge of

designing and shaping the magnet so that it fits around the end of a nasogastric

tube. Khade and Arthik will manage designing and building (or modifying from

an existing device) the magnetic sensing devices to their required size and

shape.

Preliminary Device Testing – Once the preliminary device production is

completed Khade and Aaron will test the device by using the magnetic sensing

device to detect the magnet. The sensing device will be calibrated to detect

the magnet at a certain range based on the magnitude of the magnetic force.

Coating Testing and Production – During ordering of the materials for

development of the device, various plastic coating materials will also be

ordered. After their arrival, Arthik will test the resistance of the various materials

to the environment of the stomach. The team will then choose a final plastic

coating material to be used in the final design based on the results of the tests.

Arthik and Aaron will then be primarily in charge of modifying the coating

material so that it forms a sheath around the magnet and attaches securely to

the end of the nasogastric tube.

Final Device Production and Testing – After the preliminary production and

testing of the device and coating materials the team will finalize the magnetic

nasogastric tube design. After the design is finalized, Aaron will create an

AutoCAD model of the design. During this time Arthik and Khade will begin

development of a working model. After completion of the computer model,

Aaron will order an animal cadaver on which the working model will be tested.

The team will test the working model on the animal cadaver to ensure that the

design is working.

Approach

The approach for the magnetic nasogastric tube will be taking with

regards to sterilization, manufacturability, safety, commercial potential,

reliability, sustainability, and ease of use. The manufacturing the product will

involve creating a mold for the sheath of the plastic, cap with an inserted

magnet, and magnetic sensing device, these will be created on an assembly

line process. Seeking FDA approval will demonstrate the safety, sustainability

and sterilization aspect of our product. The magnetic nasogastric tube will follow

all aspects of FDA guidelines. The technique for which the product will be

sterilized will follow regulations of the FDA, and will be further tested to seek the

best method for sterilization of the product. The sustainability will be based off of

the plastics composition and the method used to sterilize the product for

multiple reuses. Team iota will choose a sterilization technique that leaves no

residue of harmful substances on the sheath of the product. Animal testing and

human testing will lead to the increase reliability of product. Yet FDA team iota

will pursue the approval of animal and then human testing to obtain results for

the product.

Timeline

Works Cited

Intelligent Design and Development. (2004). Retrieved from Lucent Medical System:

http://www.lucentmedical.com/TPV.htm

National Patient Safety Agency. Patient safety alert: reducing the harm caused by

misplaced nasogastric feeding tubes London: NPSA, 2005

National Patient Safety Agency. Patient safety incident reports in the NHS: National

Reporting and Learning Service, quarterly data summary, issue 9 London:

NPSA, 2008

Rowe, P. S. (2006). Patent No. US20090187164 A1. United States.

Silverstein, F. E. (2008). Patent No. US20130317338 A1. United States.

Silverstein, F. E. (2008). Patent No. US8437833 B2. United States