Senior Capstone - Nasogastruc Intubation Training

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Nasogastric Intubation
This document is the confidential property of
(name of team) and may not be reproduced
without prior written consent
Approved by: Signature: Date:
Konrad Wolfmeyer 12/12/2016
Fenil Patel 12/12/2016
Cameron Locker 12/12/2016

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TABLE OF CONTENTS
Section 1: EXECUTIVE SUMMARY 4
Section 2: PROBLEM STATEMENT AND CLINICAL NEED STATEMENT 5
2.1 Description of the team’s understanding of the problem 5
The current training simulators do not meet the needs of the nursing staff of the Purdue School of nursing. A new
training simulation must be developed that will meet those needs. There is room for improvement in the
cost and functionality category of the existing solutions in the market. 5
2.2 Problem Statement 5
2.3 Clinical Need Statement 5
Section 3: PROBLEM DESCRIPTION 6
3.1 Summary of Clinical Problem 6
3.2 Summary of Current Solution Landscape 6
3.3 Assessment of Emerging Technology 7
3.4 Gap Analysis 8
3.5 Market Analysis 9
Section 4: DESIGN SPECIFICATIONS 10
4.1 Target Customer and Rationale 10
4.2 Summary Table of Design Specifications 10
Section 5: SOLUTION STATEMENT 12
5.1 Overall Solution Statement 12
Drawing(s) of Prototype Solution 12
5.2 Functional Block/Subcomponent Design 13
i) Physical Model – Cameron Locker 14
ii) Electrical System – Fenil Patel 15
iii) Tubing and Fluid System – Konrad Wolfmeyer 16
5.3 Solution Innovation 19
Section 6: FAILURE MODES AND EFFECTS ANALYSIS (FMEA) 20
Section 7: Verification and Validation of Design 23
7.1 Design Verification Plans for Subcomponents 23
i) Physical Model Testing Plans – Cameron Locker 23

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ii) Electrical System Testing Plans – Fenil Patel 23
iii) Tubing and Fluid Testing Plans – Konrad Wolfmeyer 24
Lastly, the model should be as anatomically realistic as possible to give the medical professionals the best
training possible. Any dimensions of the parts should be close to anatomical dimensions. If the dimensions
are significantly different from anatomical dimensions, the reason should be properly justified and
documented. 24
7.2 Design Verification Subcomponent Testing Results 25
i) Physical System Testing Results – Cameron Locker 25
ii) Electrical System Testing Results – Fenil Patel 25
iii) Tubing and Fluid System Testing Results – Konrad Wolfmeyer 26
After performing verification testing for the tubing and fluid subcomponent, a better system was developed that
met all of its needs. The obstructions due to the sensors were limited to under 10% which means the sensors
shouldn’t cause significant resistance when placing an NG tube. The stomach was also testing to be water
resistant which means that the stomach will be able to hold fluid for when aspiration training is done.
Lastly, iterations of the system were completed after getting feedback from nurses to develop a more
realistic product. When this product is developed beyond senior design, more testing and iterations will be
done to make it even better and meet even more needs of the nursing school. The main need that will be
investigated is into how the esophagus can be made to contract and relax during swallowing during the
procedure. 27
7.3 Design Verification Plans for Final Prototype 28
7.4 Design Verification Final Prototype Testing Results 29
7.5 Design Validation Plans and Testing Results for Final Prototype 31
The feedback from those at the nursing school was overall very positive. The general consensus was that the
Nasogastric Intubation Dummy is a good tool for training users on the procedure. Most went so far as to
say that the solution was better than what is currently used at the school. This meets what was needed to
be validated. Some improvements were suggested to make the solution more realistic. During the
procedure, it is expected to tilt the head back and tell the patient to swallow, this is an interesting idea that
could really improve the quality of the design if implemented properly. Another suggestion is to add
contracting elements to the fluid system. The walls track leading to the stomach contract and add
resistance to the placement. 32
7.6 Discussion Relating Final Prototype Results to Literature, Design Specifications, and Customer Needs 32
Section 8: Project planning 32
8.1 Project Schedule 33
i) Physical Model Budget Justification – Cameron Locker 35
ii) Electrical System Budget Justification – Fenil Patel 35
iii) Tubing and Fluid System Budget Justification – Konrad Wolfmeyer 36
REFERENCES 37

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SECTION 1: EXECUTIVE SUMMARY
Nasogastric intubation is a procedure to administer or aspirate contents to and from the stomach. There
are a number of potentially fatal mistakes that can be made while preforming the procedure. Mistakes
like placing the tube into the patient’s frontal head section causing pain or damage done to the lining of
the esophagus. There is a need for device to provide a realistic training simulation in order to properly
train medical personnel in this procedure. The device needs to be able to provide real-time feedback, be
anatomically accurate, and cost effective. Another task the device needs to accomplish is to aspirate and
administer dungs. The goal is to reduce the number of potentially harmful errors by educating and
providing better training. There are a few solutions that currently strive to meet the goal of nasogastric
intubation training. The Leardal SimMan is a fully integrated system of electronics and body. With a
realistic torso and an adjustable physiology, it is a very complex machine. However, it is very extremely
expensive and not suited to the budget of smaller nursing schools and hospitals. There is also a simulator
for the company 3-D med that allows the user to aspirate and administer fluids virtually without a dummy.
The device is almost twice as expensive as the Leardal SimMan. The solutions on the market have a wide
variety of functions but have a critical flaw in the fact that they are very expensive.
The Nasogastric Intubation Dummy (NID) is the culmination of many efforts to meet these needs. A fully
integrated system consisting of the physical model, the fluid tubing, and the electrical components. The
physical model consists of a head, nasal cavity, and body. The head is a mannequin head that’s been
hollowed out and the nose removed. The nasal cavity is a 3D printed box that has a cavity anatomically
similar to an actual nasal cavity. The body is a simple plastic box but it meets a couple of important needs.
It allows the uses ease of access into the dummy as well as providing ample space for the other
components. The fluid and tubing subcomponent is made up of the trachea, esophagus, stomach, and the
electrical sensor infrastructure. Plastic tubing was used to do the bending nature of the material. The
trachea, much like the nasal cavity, was 3D printed to be anatomically similar to that of split between
trachea and esophagus. The stomach was design to hold fluid and be replaced. This is a key feature wanted
by those in the Nursing school. The electrical system includes the infrared sensors and the internal
programming. The sensors placed throughout the system relay that they have been tripped to the
microprocessor and displayed using an interactive software. Sounds were also coded in to audibly cue
when the user has reached certain parts of the body.
To test the system, it was important to look at two things. The delay between the computer and the device
and the response from the nurses trying the device. The delay was calculated by measuring the time it
took for the computer to display that a sensor has been tripped after passing the light sensor. After
running a number of test it was shown that sensor 6, the one that leads to the stomach, only reported
within the desired timeframe about 40% of the time. This is an area for improvement. The feedback from
the nurses is imperative to improving the device and after testing our most recent iteration, it was
incredibly positive. That the device was much better than what they currently use. Most even agreed that
it could be used to train nurses on the procedure. One of the suggested improvements for the solution
was to simulate sphincter action. To have opening and closing valves within the solution. Taking the
feedback from the nurses there are some things the solution could improve on. To continue to make the
simulation as anatomically accurate as possible. Even adding more mechanical action to the simulation in
the form of valves. Even as the simulation currently stands, with the positive feedback from the nurses,
the device can be marketed to nurses and doctors with the intent to improving training on nasogastric
intubation.

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SECTION 2: PROBLEM STATEMENT AND CLINICAL NEED STATEMENT
2.1 Description of the team’s understanding of the problem
The current training simulators do not meet the needs of the nursing staff of the Purdue School of
nursing. A new training simulation must be developed that will meet those needs. There is room for
improvement in the cost and functionality category of the existing solutions in the market.
2.2 Problem Statement
Tube feeding is a very common procedure to administer basic nutrients and drugs into a person. In Britain,
there were 210 incidents reported related to nasogastric tube placement [1]. This method is mainly used
on babies and younger patients who have diseases like Down’s syndrome that can cause heart failure at
any moment and risk choking. During the procedure, the doctor will place a tube through the patient's
nose and into the stomach. A number of problems can occur during this procedure. These include:
placement of the tube into the patient's brain, damage to the lining of the esophagus causing infection,
and placement into the lungs causing sepsis. All of these are caused by improper technique and experience
with the procedure. One of the most imminent problems in medical and nursing school is how medical
simulators do not accurately mimic real life conditions. This problem includes the accurate modelling of
Nasogastric intubation for training purposes. Some problems with the existing models include not being
able to insert the tube further than 5 centimeters into the model due to existing mechanical parts. Other
problems include the incorrect sense of success for an accurately performed procedure. There is no way
to quantify the chance of success or failure to better train nurses and doctors.
2.3 Clinical Need Statement
There is a need for a way to provide a realistic simulation of nasogastric intubation to properly train
medical personnel for the real world. The simulation should monitor where the tube would go in an actual
human body. This would help improve the skill of the nurses by notifying them when they have incorrectly
placed the tube in the dummy. It should also produce obstructions. Not only will this more accurately
simulate real life procedures, it will also make the training more in-depth and challenging. and provide
real time feedback to the progress of intubation. Another key need is for the solution to be as anatomically
similar to its real life counterpart as possible. The nasal cavity as well as the trachea esophagus split are
important area for this. The nasal cavity has a certain unique geometry that can make it difficult to
perform the procedure. If the tube enters the trachea, then the patient will begin to cough. The procedure
will have to restarted and this wastes time and money. Making it more life-like also include items like the
ability to aspirate fluid. This means that, like in the actual procedure, fluid can be removed or replaced in
the simulation. The PH of the patients’ stomach contents can also be tested by fluid removal. This will add
to the overall realness of the solution thus providing a stronger learning tool for the user. In the future it
could be able to be incorporated into existing models or simulators, therefore providing a relatively cheap
and easy transition from the current simulator to the solution. Most importantly, it should be an effective
learning tool to better prepare nurses and doctors to preform nasogastric intubation.

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SECTION 3: PROBLEM DESCRIPTION
3.1 Summary of Clinical Problem
Esophagus is a long tube connecting the throat to the stomach. It is roughly 8 cm long in a healthy adult
and lined with tissue called mucosa. The normal function of the esophagus is to take food and water from
the mouth and transport it to the stomach. It achieves this by muscles that constantly perform peristalsis
when stimulated. There are two different muscles groups in the esophagus; the upper esophageal and
the lower esophageal sphincter. The Upper Esophageal Sphincter (UES) contribute to the conscious
motion of breathing, eating, belching and vomiting. The Lower Esophageal Sphincter (LES) contribute to
preventing any stomach acid or food to re-enter the esophagus. Both of these need to work in
coordination with the other to function properly [2]. There are extenuating circumstances when overdose
of drug could cause severe fatalities and aspirating the stomach or administering activated charcoal is the
only methods to reduce the harmful effect of the drug on the body. All of these factors and more
contribute to the growing use of nasogastric tube to administer drugs and nutrients and aspirate stomach
content [3].
Patients in certain situations are also administered many different drugs and nutrients by using NG tubes.
Many patients who are in a coma or have esophagus cancer require NG tube to keep them functioning
well. Patients that are not able to use the esophagus to their bare minimum capacity start to become
under nourished and can cause many different complications with not being able to take in enough
vitamins and minerals necessary. Some patients in a comatose condition could be put at risk of more
severe complications if drugs and nutrients aren’t administered properly to them. Half a million
nasogastric tubes are misplaced every year, leading to death and can cost health care providers millions
of dollars [1]. These misplaced tubes are typically misguided into the lungs because of the closeness of
the esophagus and trachea entrances. The lack of proper training for nurses and healthcare professionals
is the main determinant of tis improper placement of nasogastric tubes. These complications from
misplacement can be severe ranging from simple coughs to drowning a patient. It’s difficult to monitor
this and can occur in any hospital that uses nasogastric tubes as a source of aspirating or administering
drugs to a patient. Between 2001 and 2011, there was more than $10 million paid to resolve lawsuits filed
for injuries and death due to NG tube placement in Chicago alone [1]. This high cost and risk can easily be
minimized if there was a better training simulation on the market. Asking the nurses at Purdue, it became
clear that they almost had no idea how to place an NG tube when they first had to on an actual patient;
attributing that to the lack of experience they had in the classroom. Testimony from nursing instructors
claimed that current training simulators cost too much for how little they actually teach the students.
3.2 Summary of Current Solution Landscape
There is a relatively crowded market with many different solutions that can assist in training healthcare
professionals on placing nasogastric tubes.
Table 3.1: Table of existing solutions
Product/Solution Ability to
aspirate/administer
drugs into stomach
Provides real time
feedback
Cost ($)
SimMan X X 1350

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3-DMed ✔ ✔ 2380
Laerdal NG Tube and
Trach Care Trainer
✔ ✔ 1350
3B Scientific ✔ ✔ 1010
SimMan is a simulation model that uses a life size dummy to train nurses in many different medical
procedures. One of the procedures fitted into the SimMan is the ability to insert a nasogastric tube into
the dummy and practice this method. There are many drawbacks from using this solution to practice the
method. One of the most eminent drawback is that there is no sense of success provided by the dummy
if the tube has been placed accurately in the correct location. The other drawback of using this dummy is
that there is no way to administer or aspirate drugs to and from the dummy. The SimMan also cost roughly
$1,350 which is a very expensive solution to a very simple training procedure [4].
3-DMed nasogastric tube feeding simulator is another solution that can be used to treat caregivers in the
nasogastric tube feeding method. This solution is able to aspirate and administer drug into the dummy
and also provide a sense of success by having a semitransparent body. However, the main drawback of
using this dummy is the cost associated with it. The Nasogastric Tube Feeding simulator is $2,380. This is
the most expensive solution in the market compared to the SimMan [5].
Laerdal NG tube and Trach Care trainer is another solution that is very similar to the 3-DMed simulator.
They have the same qualities, however the Laerdal simulator is cheaper than the 3-DMed and can perform
the same functions [6].
The last and probably the best existing solution is the 3B Scientific. One very attractive feature of this
solution is that the manufacturers added replaceable parts that could be changed out if needed, or simply
added for a different function. Some of these additional replaceable items include lubricants and trachea
tube. This would provide the user with a longer lasting solution that works perfectly fine after some wear
and tear. However, the price of the product is still unattractive [7].
3.3 Assessment of Emerging Technology
One of the most recent technologies that has come into the market is the use of virtual reality for nurse
intubation training. This works by providing the nurses with a 3D model that accurately mimics the
conditions inside the nasal cavity and neck of a human being. Using this model, developers can extrapolate
the use of this device to train medical professionals. There is also an additional feature that provides the
user with a haptic feedback feeling, very similar to the one received when placing an NG tube. This could
make the model more realistic thus giving a better quality of training to healthcare professionals. There
are many peer review articles released about this technology, however no substantial progress has been
done to make this technology feasible in a clinical setting [8].

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Figure 3.1: This figure shows the nasogastric system model of the virtual reality technology currently
under development [8].
3.4 Gap Analysis
Table 3.2: Existing and Emerging Solutions Gap Matrix
Existing and
Emerging Solution Brief Description Cost
Provides
Real Time
Feedback
Able to
Aspirate
Stomach
Contents
Realistic
Feedback
SimMan A simple dummy that is used for
many different training
simulations
-- +/- -- -
3D-Med A semi-transparent dummy for NG
tube placement specifically
--- ++ ++ -
Laerdal NG Tube and
Trach Care Trainer
A semi-transparent dummy for NG
tube placement specifically
-- ++ ++ -
3B Scientific Dummy torso with removable
parts that can be added or taken
out for different training functions
+/- ++ - -
Virtual Reality
Simulation
Virtual reality model of
nasogastric intubation instead of a
physical model
+/- ++ --- +
After assessing all of the existing and emerging solutions on the market a clear gap was seen. As shown
by the Pugh matrix, there is a gap for a solution with a low cost and but high efficacy for realistic training.
There is a need for a solution that can provide a combination of real time feedback, realistic feedback and

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ability to aspirate the stomach while maintaining a low cost. All the existing solutions in the market have
some of the design specifications that were taken into consideration but more features would allow the
user to experience a more well-rounded training technique. Specifically, a lower cost and realistic
feedback seems to be the two largest needs in the gap.
3.5 Market Analysis
Market Size: With more than 18,705 total medical school graduates in 2015 [9] and 80,767 nursing
school students in the United States [10] the market for who will use our solution is considerably large.
There is also potential for growth in the market because the solution could expand from just being used
in classroom settings to also being used in hospitals for practice of nasogastric intubation.
Market Costs: Most medical schools will have at least one of the dummy models that were listed in the
current solution table; the cheapest being $1,350. Since most schools will have multiple models on hand
for training many people at one time, the cost could get pretty large. If a school had 10 models of $1,350,
the cost could end up reaching $13,500 all for ineffective training. As mentioned, a majority of that money
would go to waste because it would still not properly train the individuals; the costs go beyond just money
Solution Costs: Our target cost is about $150 because we plan to either use materials available to us or
materials that are relatively cheap. The main cost of this product will be the electrical parts since reliable
working electrical components are essential for the product to effectively work, thus meeting the design
requirements. With further iterations of the design and more research, there is a possibility to lower
that cost more while still maintaining its efficacy. Lastly, the design could eventually become one that
could be implemented into already existing dummies, lowering the cost and saving the schools even
more money.

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SECTION 4: DESIGN SPECIFICATIONS
4.1 Target Customer and Rationale
The main target customers for NID, the new product, are aspiring medical professionals who would use
this device to further their training in the nasogastric intubation procedure. This device would be used in
hospitals and nursing schools after introduction in the market. The main factor when considering the
development of the product is the cost of the solution. Most of the training dummies are heavily
overpriced and a cheap but reliable solution would be the most efficacious way to introduce the product
into the market. To avoid improper training by developing an inaccurate anatomy of the nasogastric tube
and nasal cavity, the product would be approved by the Liaison Committee of Medical Education before
release into the market.
4.2 Summary Table of Design Specifications
Table 4.1: Summary of the design specifications
Design Needs Design Specification Originated from
Ethical
considerations or
Hazard analysis
Weight
Real Time Monitoring Requirement for an indicator to check the
location of the tube during procedure
Ethical 5
Simulate Obstructions Must be able to accurately mimic any
complication typically seen when placing an NG
tube
Ethical 3
Realistic Feedback Solution should make realistic audio sounds
(coughs and gurgles) that would typically be
heard at different points of a procedure
Ethical 4
Cost Less Than
Competitors
Cost less than $1,350 [11] Ethical 2
Able to Aspirate and
Administer Drugs
Solution must be able to draw fluid as well as
add drugs or fluid into the stomach
Ethical 3
Model is to Scale of
an Actual Adult
Human
Esophagus: 25 cm +/- 2 cm [12]
Nasal Cavity uses literature modeling
Hazard Analysis 4
Removable Parts Solution must have parts that can be removed
for cleaning
Ethical 2
The device should be able to provide the user with a real time monitoring system on where exactly the
tip of the nasogastric tube is during the whole procedure. Mains checkpoint areas should be the back of
the nasal cavity, neck, trachea entrance and stomach entrance. This would prove to be very helpful for
the user since the existing system has no way of monitoring the exact whereabouts of the feeding tube
inside the dummy. By. accurately monitoring the progress of the tube inside the dummy, the instructor
would be able to help the student adjust their technique.
Since the device is going to be used strictly for training purposes, to make it more realistic there would
need to be anomalies or obstructions that would mimic a real human esophagus tract. Hence, adding a

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trachea passage would make the system more realistic and complex. Also proper resistance trains the
user how to maneuver the tube, similarly to what would be felt in a patient. To meet this, the product
should accommodate the actual dimensions of the human nasal cavity, entrance to trachea and
esophagus; the esophagus in an average adult human is 25cm long [13].
Current solutions do not have any method to provide the user with real time feedback. Some of the
realistic feedback would include coughing sounds when the tube enters the trachea and gurgling sounds
when the tube enters the stomach. These would better help the user understand the geometry of the
esophageal tract and to hone their skills in performing this procedure. Another very important feature
that the existing system lacks is the sense of success. The users do not have any way to tell if they have
performed the procedure correctly by inserting the tube in the stomach. Again this can be achieved using
the audio feedback. This real time feedback system would help the nurses know what mistakes they are
doing and improve upon them while training by accurately displaying if they have placed the tube in the
stomach or slipped into the trachea.
Existing devices that attempt to train nurses in nasogastric tube intubation sell for about $1350 [11]. The
price is a major drawback and ward off target customers from buying it when considering the ineffective
training they provide. NIDS must be cheaper than other products in the market to make it more attractive
to the target customers. This will also allow more hospitals and nursing schools to purchase the device
and provide efficient training for a routine procedure.

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SECTION 5: SOLUTION STATEMENT
5.1 Overall Solution Statement
The solution will have four different subcomponents that will be combined to create a nasogastric
intubation simulation training device. These subcomponents are the physical model, fluid systems,
graphical user interface and electrical systems. Current simulation models are not capable of a realistic
model combining a physical and electrical interface at a relatively cheap price. A custom trachea and
esophagus will be integrated into a mannequin and they will be lined with sensors that will inform the
user if the tube is positioned in the esophagus instead of the trachea. There will be a removable stomach
at the end of the esophagus that can hold a certain amount of liquid to practice drug administration or
aspiration of the stomach. The stomach would need to be removable so it can be cleaned out. A sensor
will also be placed at the beginning of the stomach which will tell the user when the nasogastric tube has
entered the stomach and it is safe to aspirate or administer the necessary drugs. Sound cues will also be
added to the solution, including coughs and gastric gurgles, which will inform the user various different
information. When placing a nasogastric tube, respiratory aspiration of gastric fluids is a concern. This is
when gastric fluid gets into the lungs which will cause a variety of complications. In order to properly train
the users on preventing that, we will include a prevention program that will tell the user if respiratory
aspiration has occurred or not. Lastly, the sensors and graphical user interface program will be able to
give the user realistic feedback and a sense of success of failure.
For the final iteration, each sub component has evolved due to user feedback. The nasal cavity and
the trachea esophagus split has been updated to more accurately reflect the anatomical geometry. The
electrical system has been updated to include more sensors as well as a stronger algorithm for the sensors.
The program will now tell the user when to begin the test and report where the tube is in the model. It
will also play a coughing noise and display a warning sound when the tube enters the trachea. There will
also be a gurgling sound when the tube enters the stomach.
Drawing(s) of Prototype Solution
The final iteration of the dummy is shown in the fig. 5.3. It incorporates all the different subcomponents
into the dummy after they were perfected individually with repeated iteration. The fluids and tubing was
first attached to the sensors with the nasal cavity and then introduced into the dummy with the trachea
and esophagus complexities. This design was then validated by different healthcare professionals and
their feedback was recorded when training on this dummy. It is worth noting that this iteraiton is of a
patient sitting upright instead of laying down like the previous one. This was due to feedback form the
nursing school.

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Figure 5.3: Final working prototype of the product
5.2 Functional Block/Subcomponent Design
Figure 5.4: Nasogastric tube training model flow chart

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Table 5.1: Subcomponent design table
Subcomponent Title Technical Description Contributing
discipline/skill
set
Design Specification
Addressed
Physical Model 25in x 18in [5] torso with a
plastic mannequin head
hollowed out and cut to scale.
Comes with abdominal opening.
machine skills,
mechanical
engineering.
removable parts, to
scale model
Electrical System Infrared sensors on the inside
of the modeled esophagus and
stomach that will indicate
where the tube is in the model,
Electrical
engineering
real time monitoring,
sense of success or
failure, realistic
feedback
Tubing and Fluid
System
A 25 cm esophagus with a 9-
liter removable stomach. A
short trachea tube will also be
included with the system to
detect if gastric fluids have
entered the respiratory tract at
all.
Fluid dynamics,
mechanical
engineering
to scale model,
removable parts, able
to aspirate and
administer drugs
i) Physical Model – Cameron Locker
This subsection is going to focus on the body of the dummy, the head, and any moving parts within the
dummy. The dimensions of the body are based on average human schematics [5] as well as the head
using skin like plastic. The head will be hollowed out to provide realistic feel as the tube is inserted.
There will be an abdominal door that allows access to the parts of the model. This will allow the user to
replace or wash the stomach.
Figure 5.5. This will the nasal cavity model that would be used to accurately 3D print the nasal cavity and
remodel a deviated septum.

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Figure 5.6. This would be the make do mannequin that would be used for all purposes of training.
ii) Electrical System – Fenil Patel
Method 1 – Passive Infrared sensors [September 30, 2016]
This subsection deal with everything electrical in the projects. There are going to be passive infra-red
sensors placed along the lines of the esophagus to detect if there is any motion in the tube and give
feedback to the user to determine the accurate position of the tube at that point of time. There is going
to be an analog front end to the system that would amplify signals obtained from the sensor and convert
them into digital signals that would be sent to a mini processor to decode.
Another important part of this subsection is the configuration of the mini processor with a wireless
adapter to transmit signals wirelessly to a mobile device. -The mobile device would be the front end of
the device and all the electronics would be controlled from here.

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Figure 5.7: This figure shows the arrangement of PIR sensors with the attachment to the micro controller.
The second part of the electrical system is the python code that would be used to control the sensors
and detect every signal within the dummy.
Iteration 1 – using a 'yes' or 'no' signal output [October 7. 2016]
The first code written is provided in detail in the appendix of the document for section 5 electrical
subsystem. In brief this code detected a signal for every trigger giving a signal greater than 0 for every
detection and 0 in its default state. This was a digital method used to track changes in the conductance of
the sensors. However, the first iteration had a lot of false positive and this was changed in the following
iterations.
Iteration 2 – Peak finder function integrated with a 'yes' or 'no' function [November
18, 2016]
This iteration proved to be the most efficient in reducing the number of false positives. This was achieved
by using the peak finder function and not permitting sensors further in the esophagus to be triggered
before the ones above. Another important change made to the sensors was to set their initial state to
false, hence calibrating sensors to a non-trigger state. Previous iterations did not attempt to reset the
sensors after every trial, however this was adjusted in the following iteration. The detailed code can be
found in section 5 of the appendix, labelled under electrical subsystems. Some internal features were also
added such as addition of sound in the dummy for both the trachea and the stomach sensors.
iii) Tubing and Fluid System – Konrad Wolfmeyer
This subcomponent includes the tubes inside the dummy that will be used for the esophagus, the
removable stomach and the respiratory aspiration training. Adult esophagus’ are about 25 cm in length
so the tube will have to meet that desired length; the esophagus also has an inner diameter of 2 cm [14].

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The trachea’s length will not be anatomically accurate because all that is needed is enough room to tell
the user if the tube went into the trachea versus the esophagus. This can be done with a length of a few
inches. Unlike the esophagus, the trachea has a slightly larger inner diameter, 2.5 cm, so that will have to
be taken into consideration [14]. The capacity of the stomach can expand to .9 liters so it was determined
that the removable stomach should also be that size [15]. However, if the size of the stomach seems to
be too large, it may be decreased. It will also have to be water resistant or waterproof since it will be
holding liquid when aspiration training is done. Lastly, sensor boxes will be placed along the system to
hold the sensors that will be monitoring the NG tube progress.
The following physical models below would be used for various different functions in the dummy. Some
of these functions include placing the sensors, separating different parts of the neck and having a
stomach pouch.
The following sketch was drawn to design an anatomically correct model of the nasogastric system. This
sketch was then used for Autodesk Inventor modeling and eventually the different parts were 3D
printed.
Figure 5.8: Full system sketch of the tubing and fluid system subcomponent

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Figure 5.9: This is a model of the sensor attachment box used to place the sensors on the
tubes
Figure 5.10: Final iteration of the esophagus and trachea interface
The final iteration of the esophagus and trachea interface differs greatly from the first iteration, found in
Appendix A, in that the trachea branches off of the esophagus similarly to what it naturally does.
Feedback from the nursing students can be found in Section 7.2 and considered when making this final
iteration. The first iteration was not anatomically correct and would have caused unnecessary issues
when trying to get the NG into the stomach, thus not properly training the user.
Figure 5.11: Final iteration of the stomach; for a patient sitting up
When the model was first presented to the nursing school, one of their suggestions was to make a
model that would simulate the patient sitting upright. To accommodate this suggestion, the stomach
was modified from the iteration found in Appendix A. A boxed stomach was decided on so it could sit up
with no support. The team saw no reason for the stomach be round and use correct dimensions of a

19
normal stomach, mostly because the model of the stomach won’t affect training of placing an NG tube.
It is worth noting that after verification test results in Section 7.2 demonstrated a lack of water
resistance, the stomach was lined with plastic
5.3 Solution Innovation
Current models either don’t really allow the user to train with a realistic model or don’t provide any real
time feedback. The simulation proposed should monitor where the tube would travel through an actual
human body and provide feedback to the progress of the intubation procedure. Sensors and the electrical
components in our product provide a way to monitor where the nasogastric tube is in the body, as well
as give the user a sense of success if they reach the stomach or failure if they get in the trachea. This would
be done by the solution emitting sounds that would be normally be heard at various stages in the tube
placement. Also different noses, and nasal cavities, can be inserted into the model to give the user more
challenges; i.e. placing a NG tube in a patient who has a deviated septum. Lastly, the new product will
have removable parts that can be taken out and replaced for cleaning purposes. All of those combined
make a more effective way of training personnel for nasogastric intubation. This solution is different than
what is already out on the market mostly because of the electrical components. None of the current
solutions that were observed have any electrical components or interfaces. Our solution will also cost
much less than existing solutions. Lastly, we hope that eventually our solution could be implemented into
existing dummies, instead of requiring medical programs to buy new dummies, which will cut down the
cost even more. Currently the only simulation models on the market are whole separate dummies instead
of something that can be used with existing ones.

20
SECTION 6: FAILURE MODES AND EFFECTS ANALYSIS (FMEA)
FMEA Scope and Analysis
FMEA Scope
Since our solution does not directly interact with a patient, none of the potential failure modes are critical
to the safety of a person. The most critical errors could come from property damage by any mishaps when
using the device. The project requires fluid movement throughout the system as well as a comprehensive
electrical system. This leads to many potential failure modes within the system. Fluid leaking out into the
body could lead to a short circuit of the electric sensors. This will ruin the real time feedback feature by
destroying the sensors used to determine the placement of the tube. A lagging or unresponsive computer
program is also a concern because it would not allow the user to get the real time monitoring needed for
proper training. The dummy could also lose the ability to administer and aspirate drugs if the tube being
used is not able to be inserted properly or there are tears along the tube. These could cause leakage of
fluid and further destruction to the electrical component of the dummy. Another eminent cause of error
could be in the feedback taken by the microprocessor. Sensor might stop working or become inaccurate
over time due to any loose connections or water damage. This would provide incorrect feedback and not
benefit the user in training for this procedure in any way. water damage. This would defeat the whole
purpose of training the nurses to better themselves at nasogastric tube insertions. It is worth noting that
most of the failure modes seem to be connected; if one happens, it can affect a variety of other parts of
the model.
Design changes and updated failure modes will be made as the prototyping process occurs. One important
design aspect that was taken into consideration after the FMEA analysis was the addition of a self-
diagnostic tool installed in the GUI to ensure that all the sensors are working correctly and there is no
liquid damage. Another important factor taken into consideration was the addition of a surface that's
smooth and not rugged to ensure that the tube goes in smoothly once placed in the correct position.
Table 6.1: Severity, occurrence and detectability ranking system
Ranking Severity Occurrence Detectability
1 Does not affect the user's
ability to receive proper
training
Not likely to occur Immediately detectable by the
user
2 May or may not hinder the
effectiveness of the user's
training
Somewhat likely to occur Less detectable by the user
3 Slightly hinders the user's
training
More likely to occur Somewhat detectable by the
user
4 Hinders the user's ability to
receive effective training
Very likely to occur Very undetectable by the user
5 Causes the training simulation
to not be effective whatsoever
Extremely likely to occur Totally undetectable by the
user

21
FMEA Table
Process/Step/
Input/output
Potential
Failure Mode
Potential Failure
Effect
S Potential
Causes
O Current
Controls
D RPN Recommended Mitigation
Tube insertion The NG tube
not able to
effectively
move
through
model
Simulation won’t
model the
movement of tube
in the
esophagus/stomach
4 Blockages in
the modelled
esophagus
2 Lubrication
of the tube
or
esophagus
model
2 16 Limit the amount of
blockages or spaces
created by the sensors in
the esophagus model.
Have a smooth compared
to rough and with edges
surface so that the tube
would move without
bending in the dummy.
Incorrect
feedback
Laggy,
unresponsive
GUI. Sensors
not
recording
the location
of the tube.
Unable to
determine the
location of the
tube. No validation
of procedure.
3 Programming
error, short
circuit of
sensors.
1 Program
review,
compiler
checks for
errors.
5 15 Reviewing code by other
teammates to avoid
errors, consistent testing
of program.
Fluid Movement Fluid would
not move
smoothly
along the
model and
from the
stomach.
Unable to aspirate
or administer drug
correctly to the
stomach of the
dummy.
3 Blockages
along the
tube from
fluid buildup
and adhesion
of liquid to
build by
coagulase.
Another
cause could
be the
bending of
the tube
inside the
dummy.
1 Regular
cleaning of
the
stomach if
it is
reused.
4 12 Cleaning the stomach out
after multiple uses to
make sure that the
liquids will consistently
be able to flow properly.
Also, replace the NG
tubes being placed for
training.
Rips and tears in
the tubing after
use overtime
Wear and
tear of the
tube that is
used to
aspirate the
fluid.
Liquid could
leak out
when the
tube is worn
out.
Incorrect amount of
drug administered
and incorrect
amount of fluid
aspirated.
Could possible lead
to.
4 Caused by
overuse of
the same
tube for a
long period
of time.
Wear out of
lubrication.
2 Replace
faulty
tubes and
continually
perform
quality
control on
the
system.
3 24 Monitor the condition of
the tubes and model
after every use,
documenting anything of
significance.
S =severity; O=occurrence; D=Detectability; RPN=Risk Priority Number=SOD

22
RPN Tier system:
1-10 manageable
11-20 difficult
20+ very challenging
Based on our FMEA analysis chart, the circuit failure in our project is the easiest to overcome. Despite its
extreme severity, it is easy to discover as well as unlikely to occur. Other failures that are much less severe,
like the tubing in the stomach not function properly, are much harder to detect and are more likely to
occur. Thus the tubing failure has a much higher Risk Priority Number than the circuit failure.

23
SECTION 7: VERIFICATION AND VALIDATION OF DESIGN
7.1 Design Verification Plans for Subcomponents
i) Physical Model Testing Plans – Cameron Locker
To verify the size of the body, all other subcomponents must fit within. After testing other
subcomponents, the body will be opened and subcomponents like the stomach will be removed for
cleaning. The nose and head will be tested by inserting a standard nasogastric tube through each nostril.
This will test the geometry of the nose. The head will be a hard acrylic plastic. The nose of the head will
be removed and replaced with a 3D printed nose according to the standard geometry paper [16]. The
mannequin head acquired is hallow and the base has been expanded to fit the size of the human hand.
As our device does not directly interact with the user, and is only meant for training doctors and nurses,
there are no federal regulations pertaining to the use of this device.
ii) Electrical System Testing Plans – Fenil Patel
Two different tests will be performed to assess the overall function of the system.
Testing protocol 1 – Individual sensor testing
1. Attach individual sensors to the electronic component, specifically the microprocessor GPIO Port
2 [Pin 3].
2. Attach Sensor power to Pin 2 and GND to Pin 6
3. Boot up microprocessor and run file sensortest.py. This file would enable the GPIO port on the
microprocessor to obtain signals from the sensor. Hence, the GPIO ports would be able to display
when the senor is triggered and when it isn't triggered.
4. Place obstructions before the sensor and detect if there is a message displayed on the screen.
"Motion detected" would be displayed if there is an object in front of the sensor and "No motion
detected" would be displayed when there are no obstructions in front of the sensor.
5. The number of false positives would be recorded in order to make sure that the sensor is being
triggered only when there is a stimulus and all the false triggers are mitigated.
Testing protocol 2 - Sensors testing and assembly
1. Attach the circuit shown in the diagram below.

24
2. Once the circuit is attached, boot up the raspberry pi and run fullsystemtest.py. This script would
calibrate all the GPIO ports and sensors in order to obtain signals as a whole system.
3. After this is running, place all the sensors in one line and then pass an obstruction such as a tube
horizontally in front of the sensors. This would be able to stimulate a trigger for the sensors.
4. The software should be able to accurately tell you the sensors that have been triggered and those
that haven't by displaying an interactive chart and marking the ones that have triggered after the
obstructions.
5. Record the number of false positives and false negative to improve python code for the sensor
and change the sensitivity and delay for each of the sensors.
The first test that is performed is used to make sure that there are no faulty sensors in the pair
that might give the user false readings and the second test that is performed is used to calibrate
the system and test if the whole system functions together and can detect the motion of the tube.
It is worth noting that all the samples and their tolerance for the severity of their failure were
chosen using the ISO 19269-6 standard. This was then tested and the results for the sensor
triggers were processed with different statistical tests.
iii) Tubing and Fluid Testing Plans – Konrad Wolfmeyer
These verification procedures are performed to demonstrate that the tubing/fluid system can be used to
properly model the pathway of an NG tube during a nasogastric intubation procedure.
With the possibility of fluid being added and taken out of the stomach, it is necessary that the tubing
system is properly sealed to protect the electronics that are located outside of the tubes. The stomach
will be the priority for this testing protocol since it will house liquid for aspiration purposes. Testing for
water resistance will be similar to that of the ASTM D951-99 standard test method for water resistance
[17]. Each part being tested for water resistance will be weighed prior to testing. Then they will be placed
on a surface and sprayed continuously for 10 seconds. Immediately after, any liquid on the surface will be
removed with paper towel. Lastly the part will be weighed and an examination of the part will be made
to find any leakages. This test will be done multiple times and a Tukey test, with a 95% confidence level,
will be used to determine if there is any significant difference between the weights before and after the
spray test. If significant difference determined or leaks are observed, the design will have to be adjusted
to fix the issue
Since the sensors will be placed along the esophagus model for real time feedback to the user, there is a
possibility for obstructing the placement of the NG tube. These possible obstructions would not be found
in an actual esophagus which is why they should be minimized as much as possible. A simple way to test
the occurrence of obstructions would be to insert the NG tube into the nasal cavity and run it into the
stomach. Once any obstruction due to the sensors is felt, it should be documented. The target occurrence
rate of an obstruction being felt should be less than 10% of the time the procedure is done. If the
occurrence rate is higher than the target rate, the reasons should be identified and adjusted. The testing
procedure should be continually repeated until the occurrence rate is less than the target.
Lastly, the model should be as anatomically realistic as possible to give the medical professionals the
best training possible. Any dimensions of the parts should be close to anatomical dimensions. If the

25
dimensions are significantly different from anatomical dimensions, the reason should be properly
justified and documented.
7.2 Design Verification Subcomponent Testing Results
i) Physical System Testing Results – Cameron Locker
The system will be run in three separate conditions to simulate the condition of a deviated septum. We
will measure the time and accuracy of the procedure. They first must be able to place the tube in the non-
obstructed nostril, them that have to be able to deliver food to the stomach. It is important to receive
feedback from the nursing school about the anatomical structure of the nose.
Feedback about the structure of the nose:
Feedback about the ease of access in the body:
After receiving feedback from the nurses, the nasal cavity was identified as an area for improvement. The
original design had too large an entrance. This made placement of the tube too easy and was anatomically
incorrect. Another feature that was change was the way the right and left cavity fed into each other. The
original design had some rough edges that would cause the tube to get stuck in and would make it too
hard for the placement of the tube to enter the neck.
ii) Electrical System Testing Results – Fenil Patel
Individual sensor testing
All the sensors need to give the least amount of false positives. There would be three different times the
same sensor would be tested in three different light conditions at room temperature and humidity. The
light conditions would help us make sure that the infrared sensors would work under low light conditions.
The data that would be obtained is just positive signal whenever any movement is detected by the sensor.
This should avoid false triggers and false positives. There would be an independent t-test done on the
data to ensure that there are acceptable number of false positives. The test would have the sensor detect
at least 70% of the times and this is appropriate since false detection of the sensor would not cause
grievous problems and some false positives are tolerable. To mention it again the number of samples and
their tolerances were chosen according to the ISO 16269 – 6 standard.

26
Figure 7.1: This chart represents the number of detections and no detections when there is a stimulus
present in the vicinity of the sensor.
The worst performance of the sensors is in dark conditions. For every three detections there is a no
detection. This means that there are chances of false negatives. The sensors were run for long period of
time roughly five minutes to see if there were any false positives and since none were detected in any of
the sensors, the test to check for false positive would not have revealed enriching data and therefore it
was not conducted.
iii) Tubing and Fluid System Testing Results – Konrad Wolfmeyer
The goal of testing how sealed the subsystem should be to get the amount of leaks to zero because leaking
fluids can cause short circuits and ruin the circuit boards and sensors. Also significant difference between
the weights of the stomach before and after spray testing will be used to determine if there is sufficient
water resistance. Leak observations and the water resistance spray test results, consistent with the ASTM
D951-99 standard, were inputted into Table 7.2 in Appendix B.
A Tukey pairwise comparison was done between the two columns and a significant difference was
observed; results can be seen in Appendix B. Leaks were also found in 3 of the 4 tests and were attempted
to be patched up. This means that the current stomach was not sufficiently waterproof. To fix this issue,
the stomach was lined with plastic to in an attempt to provide more complete water resistance. The
results can be seen in Table 7.3 below.
Table 7.3: Water resistance spray test for plastic lined stomach
Date of Test Weight (g) - before Weight (g) - after Leaks?
11/08/2016 367.37 368.01 One
11/09/2016 368.52 369.11 None
11/16/2016 367.12 368.33 None
11/18/2016 366.91 367.65 None
34
11
38
7
45
0
0
10
20
30
40
50
D ND D ND D ND
Dark Medium Light
Frequency
Number of Detections and No Detections under different light
conditons
Sensor detection

27
A Tukey pairwise comparison was done between the two columns with the plastic lined stomach and a
significant difference was not observed; statistical analysis can be seen in Appendix B. A leak was found
in the first test but not in the other tests once it was patched up.
As mentioned in Section 7.1, the placement of sensors in the system may cause obstructions when placing
a NG tube. The goal is to get the percentage of hitting an obstruction caused by the sensors to be 10% or
less. A NG tube will be placed into the stomach 10 times every time a test is done. There are also 4 sensors
in this subcomponent, so there is a total of 40 possible obstructions every time a test is completed. So an
obstruction should be felt 4 or less times out of the 40 possible to get a prevalence of 10% or less.
Table 7.5: Total nasogastric tube sensor obstruction testing results
Total obstructions from testing Total possible obstructions Percentage
17 200 8.5
Once a total of 50 different runs were complete, there was a total of 8.5 percent sensor obstructions when
placing the nasogastric tube, as seen in table 7.5. All of the results for those tests can be seen in Table 7.4
of Appendix B. This meets the goal of 10% or less.
There is no raw data for how anatomically correct the system feels when placing a NG tube. However,
feedback from the nurses on adjustments to the system was inputted into Table 7.5 found below. This
feedback was then used to iterate the subcomponent. The main criticisms were about how the esophagus
and trachea interface are not very accurate and the stomach was for laying down instead of sitting up.
Those old models can be found in Appendix A and the new iterations completed can be seen in Section 5.
Table 7.6: Feedback from nurses on how physiologically accurate the system is
Feedback on how physiologically realistic the
subsystem is:
Plans to fix the issue:
There isn’t esophageal contraction Not in the scope for senior design
The esophagus/trachea interface isn’t
anatomically correct
Make a second iteration of that part to make
it more realistic
Correct dimensions for the length of the
esophagus
No fixing is needed
Stomach should be adjusted so the patient is
sitting up instead of laying down
Design a new stomach that will simulate the
patient sitting up
After performing verification testing for the tubing and fluid subcomponent, a better system was
developed that met all of its needs. The obstructions due to the sensors were limited to under 10%
which means the sensors shouldn’t cause significant resistance when placing an NG tube. The stomach
was also testing to be water resistant which means that the stomach will be able to hold fluid for when
aspiration training is done. Lastly, iterations of the system were completed after getting feedback from
nurses to develop a more realistic product. When this product is developed beyond senior design, more
testing and iterations will be done to make it even better and meet even more needs of the nursing
school. The main need that will be investigated is into how the esophagus can be made to contract and
relax during swallowing during the procedure.

28
7.3 Design Verification Plans for Final Prototype
After verifying and validating the subcomponents, they would be assembled into the first prototype. This
first prototype would then go through a verification procedure to verify that the final prototype meets
the design specifications. One of the most important design specifications is that the solution provides
real time feedback and a sense of success or failure to the user. The sensors would be placed on the tubing
subcomponent as shown in Figure 7.2. The first procedure would be to determine whether or not the
sensors work when integrated with the other subcomponents or not. This procedure would be divided
into two parts: The nasogastric tube taking the esophagus tract and the nasogastric tube taking the
trachea tract. It is important to test both tracts because the user would need to know if the nasogastric
tube enters the esophagus or trachea, then warning them when it is in the trachea. Both of these parts
would be tested 5 times and then expanded more if the sensors do not react to the tube. First the
nasogastric tube would be put through the models nostril and pushed until the first sensor in the nasal
cavity. If the sensor gives output for the tube being detected, a 1 will be placed in Table 7.5; a 0 will be
put in the table if it doesn’t work. This will be repeated for all of the sensors on the esophagus tract. Next
the trachea tract will be tested in the same manner except the nasogastric tube will be intentionally placed
into the trachea; this data would be placed into Table 7.6. As mentioned above, this would be repeated 5
times. It’s worth noting that those 5 different test runs will occur on different occasions to account for the
possibility of the sensors not working under different conditions or over time. The end goal is for all of the
sensors to give output and the system will be investigated if that is not the case.
Another aspect of real time feedback is how quick the computer would get the output of the sensors and
notify the user. If the computer is not reading the output quick enough, the feedback is not necessarily
real time. Another important procedure could be done to determine this accuracy. Similarly, to the above
procedure, this procedure would be run a minimum of 5 times for each sensor and done for both the
esophagus and trachea tracts. The nasogastric tube would be inserted into the model and a stopwatch
would begin. Lap will be pressed once the tube is in the sensors range and then pressed again once the
computer gives output that it’s been detected. The difference between the laps would be found and the
goal would be a difference of less than or equal to .5 seconds. It is believed that .5 seconds would be an
appropriate tolerance but it would be adjusted if found otherwise. Lap times for each sensor would be
placed in Tables 7.7 and 7.9 while difference data would be placed in Tables 7.8 and 7.10.
Figure 7.2: Drawing of the general model with the sensor placements in blue and their corresponding
number

29
7.4 Design Verification Final Prototype Testing Results
Table 7.5: Esophagus tract sensor verification
Esophagus Tract Sensor Verification Test
Sensor 1 Sensor 2 Sensor 4 Sensor 5 Sensor 6
Run 1 1 1 1 1 1
Run 2 1 1 1 0 0
Run 3 1 1 1 1 0
Run 4 1 1 1 1 1
Run 5 1 1 1 1 1
Table 7.6: Trachea tract sensor verification
Trachea Tract Sensor Verification Test
Sensor 1 Sensor 2 Sensor 3 (Trachea)
Run 1 1 1 1
Run 2 1 1 1
Run 3 1 1 1
Run 4 1 1 1
Run 5 1 1 1
Table 7.8: Esophagus tract time difference data (in seconds)
Esophagus Tract Time Test – Difference Data
Run 1 0.42 0.44 0.44 0.27 2.7
Run 2 0.14 0.46 0.45 0.39 0.5
Run 3 0.43 0.47 0.42 0.43 2.46
Run 4 0.35 1.24 0.4 0.44 2.55
Run 5 0.43 0.42 0.31 0.48 0.46
7.10: Trachea tract difference time data (in seconds)
Trachea Tract Time Test – Difference Data
Run 1 0.49 0.54 0.31
Run 2 0.24 0.46 0.04
Run 3 0.43 0.37 1.02
Run 4 0.25 0.44 0.39
Run 5 0.49 0.45 0.46

30
Figure 7.3: Esophagus tract; percentage of runs completed within the .05 seconds tolerance for sensor
feedback
Figure 7.4: Trachea tract; percentage of runs completed within the .05 seconds tolerance for sensor
feedback
Minor issues arose when performing the verification testing for the esophagus tract sensors. As seen
in Table 7.5, occasionally sensors 5 and 6 would not get triggered while other times they would. This
was determined to simply be due to cheap sensors and future iterations would include better ones.
The trachea tract sensors, results located in Table 7.6, were all triggered when testing which is what
was set out to do.
As mentioned in Section 7.3, to verify that the communication between the sensors and computer
was within .5 seconds, lap testing was completed. This was done for the esophagus and trachea tract,
results of which can be seen in Tables 7.7 and 7.9 in Appendix B. The difference between the lap data
for each sensor was then recorded in Tables 7.8 and 7.10. Both tracts were found to have 80% or more
of the sensors to send data to the computer within .5 seconds; 84% for the esophagus tract and 80%
for the trachea tract. Figures 7.3 and 7.4 show the percentage of runs completed within the .05
seconds tolerance for sensor feedback for the esophagus and trachea tract respectively. Figure 7.3
shows that there were many issues for sensor 6 when trying to record feedback. It could not be
definitively determined, but it is believed to be a faulty sensor. This would need to be replaced to give
a more accurate and quicker feedback response. It is worth noting that there were no significant

31
iteration adjustments that needed to be completed after verification testing, just minor adjustments
to sensors.
7.5 Design Validation Plans and Testing Results for Final Prototype
This testing would be done once the whole system has been assembled into a full prototype. Three
tests would be performed with 4 different people; these would include two health professionals and
two people with no experience on NG tubing methods. They would be asked to place the NG tube
into the stomach of the model. The data obtained would represent the final position of the tube and
their feedback would be used to determine how the model could be updated to provide a more
realistic simulation. The tolerance for the detection of the tube would be displaying on the computer
within .5 seconds of triggering the sensor. This would be attributed to the placement of the sensors
and the total length of the esophagus. The test would be done by asking the user a set of questions
to make sure the system works correctly and that any difficulties their encounter are addressed.
The most important tests done would result in qualitative data such as reduced lubrication of the
esophageal tub or incorrect feedback from the sensors. These would then be used to make
adjustments to the system and provide the user with a better experience; there is not much
quantitative data that could be used to improve the device besides sensor calibration.
The main method for validation is the ongoing meeting with the nurses from the School of nursing
here at Purdue. By testing out solution individually with skilled medical professionals, we are able to
gather valuable data. It is important to gather qualitative data from the nurses about the look, feel,
and general ease of use of the design.
Table 7.11: Validation testing Feedback
Is model
realistic?
Is model
better than
existing
models?
Could this
train a nurse
to place a NG
tube?
Comments and Possible Additional
Features:
Nurse 1 Yes Yes I think so Much better than what is already used.
Missing features typically found in the
esophagus:
• Contraction/relaxing of the
esophagus walls
• Swallowing reflex
Nurse 2 Not totally Yes For the most
part
Being able to aspirate is a very cool feature
that could be used for different vitals.
Difficult to 100% model the gastrointestinal
system but overall good job
Nurse 3 Somewhat Yes Definitely
could train
better that
what is used
right now
The resistance, which causes the coiling, is
very good for teaching how to move the
tube when you would experience an
obstruction in the body
Nurse 4 Somewhat Yes Yes Typically, there is head flexion and you tell
the patient to swallow. This closes the
trachea and helps the tube go down

32
The feedback from those at the nursing school was overall very positive. The general consensus was
that the Nasogastric Intubation Dummy is a good tool for training users on the procedure. Most went so
far as to say that the solution was better than what is currently used at the school. This meets what was
needed to be validated. Some improvements were suggested to make the solution more realistic. During
the procedure, it is expected to tilt the head back and tell the patient to swallow, this is an interesting
idea that could really improve the quality of the design if implemented properly. Another suggestion is
to add contracting elements to the fluid system. The walls track leading to the stomach contract and add
resistance to the placement.
7.6 Discussion Relating Final Prototype Results to Literature, Design Specifications, and
Customer Needs
The original engineering difficulty that was set out to be answered was to provide the nurses with a
cheaper and better nasogastric training dummy. Some of the specifications that were needed to be
modeled were an ability to aspirate and administer drugs, an active feedback system, complications in the
system and a life like method to perform the procedure.
All of the goals above were achieved to a certain extent in the dummy. The most important one was the
ability to provide a sense of success and failure. This was performed by adding PIR sensors in the dummy
that can provide a real time feedback. This would include the ability to provide visual and sound feedback
on the GUI. Another important ability was the ability to aspirate and administer drugs into the dummy.
This was also made possible by adding a stomach that did not contain any leaks.
The most important one was a cheaper dummy that could offset the cost by a factor of 10. The current
solutions in the market cost at least 1000 dollar and out solution was modelled under 100 dollars. This is
one of the most significant achievements of the project. The burden of buying a nasogastric training
dummy was greatly reduced to facilitate wide spread use of technology to those who cannot afford the
current market solution.
SECTION 8: PROJECT PLANNING

33
8.1 Project Schedule
Table 8.1: Finalized project schedule and Gantt chart
Task Name
Start Finish % Complete Status Duration
Meet with Purdue Nursing School 08/30/16 08/30/16 100% In Progress 1d
Preliminary presentation 09/02/16 09/02/16 100% Complete 1d
Sketch design of prototype 08/22/16 09/02/16 100% Complete 10d
Check feasibility of design 08/30/16 09/12/16 100% Complete 10d
Sub-Component 1: Physical Model 09/01/16 09/30/16 100% Complete 22d
Acquire mannequin and tubing 09/01/16 09/14/16 100% Complete 10d
Prepare dummy 09/14/16 09/19/16 100% Complete 4d
Pace tubing and sensors 09/20/16 09/30/16 100% Complete 9d
Sub-Component 2: Electrical System 09/01/16 10/14/16 100% Complete 32d
Finalize material list 09/01/16 09/09/16 100% Complete 7d
Finalize electrical system circuit diagram 09/09/16 09/14/16 100% Complete 4d
Finish sensor and Raspberry Pi component linking 09/14/16 09/21/16 100% Complete 6d
Finish coding of sensors 09/21/16 09/30/16 100% Complete 8d
Wireless connectivity of Raspberry Pi 09/30/16 10/07/16 100% Complete 6d
Testing of sub-component 09/30/16 10/14/16 100% Complete 11d
Sub-Component 3: Tubing and Fluid System 09/01/16 11/16/16 100% Complete 55d
Finalize/research material list 09/01/16 09/09/16 100% Complete 7d
Design/create fluid system 09/09/16 09/30/16 100% Complete 16d
Test and iterate tubing and fluid system 09/30/16 11/16/16 100% Complete 34d
Susan Fisher will be gone 10/01/16 10/01/16 100% Complete 1d
Demonstration of prototype with Purdue Nursing School (1) 10/18/16 10/18/16 100% Complete 1d
Iterations and testing of prototype (1) 10/18/16 11/01/16 100% Complete 11d
Demonstration of prototype with Purdue Nursing School (2) 11/01/16 11/01/16 100% Complete 1d
Iterations and testing of prototype (2) 11/01/16 11/25/16 100% Complete 19d
Development of project pitch video 11/16/16 12/01/16 100% Complete 12d
Final demonstration 12/09/16 12/09/16 100% Complete 1d
Pitch video and DHF due 12/12/16 12/12/16 80% In Progress 1d
Senior design final presentation 12/15/16 12/15/16 0% Not Started 1d

34
Currently, the majority of tasks that needed to be completed are completed. The finalized schedule
differs from the other schedules, found in Appendix C, in many ways. In previous schedules there was a
graphical user interface section. It was determined that this would not be plausible with the high
demands from the other subcomponents and only three group members. This final schedule also
includes deadlines for the DHF, final demonstration and final presentation. Besides those, there were
not any other edits. All of the required testing and iterations were completed, even though some had to
be delayed due to unforeseen circumstances. The only remaining things on the schedule that must be
completed within the next two weeks are the DHF and the senior design final presentation. Future
iterations of the product may be necessary in the future but until it is determined whether the team
plans to consider senior design, nothing else will need to be completed or added to the schedule.

35
Budget for Proof of Concept Prototype Development
Estimated Costs For
Senior Design
Fair Market Value Of
Supplied Or Donated
Resources
Charges
(Actual Costs)
Physical system:
Materials costs
Mannequin
head
20 30 25
Box body 20 15 10.66
3D Nasal Cavity 0 20 0
Sub total 40 65 35.66
Electrical
System:
Switch mode Ubec 5 5 3.77
Infrared
motion design
5 10 10
Raspberry Pi 0 49.00 0.00
Aukru Sensor 13 13 8.99
Sub total 23 72 22.76
Fluid system:
Plastic tubing 5 5 0
3D trachea esophagus 0 10 0
Sub total ($) 5 5 0
Total ($) 68 142 58.42
Difference between
estimate and charged
costs
9.58
i) Physical Model Budget Justification – Cameron Locker
The mannequin is the main chassis for all other subcomponents. The concept to repurpose a CPR
dummy is expensive. Many CPR training dummies cost more than what is put on the chart. The goal is
find a place to donate an old dummy not in use. We will be using the machine shop to cut into the
dummy and make adjustments.
ii) Electrical System Budget Justification – Fenil Patel
The most important part of the projects depends on the quality of products used in this subcomponent.
All the sensors that are going to be used are a must and their prices aren’t very high in order for them to
be too expensive to afford in the project. All of the sensor can be bought under 20 dollars with a few
expendables just in case some malfunction. The cheapest and the best quality of sensors were
researched into and added to the budget.

36
iii) Tubing and Fluid System Budget Justification – Konrad Wolfmeyer
This component contains all of the tubing and fluid movement within the dummy. This includes a
removable stomach, which is important for the cleaning of and reusability of the project. Most of the
materials for this subcomponent would actually be designed using Autodesk Inventor so they would not
need to be purchased. Plastic tubing may need to be purchased, however, there are many extra tubing
options in the senior design lab. This subcomponent would not be a major factor in the budget.

37
REFERENCES
[1] "Misplaced NG tubes a major patient safety risk", Ahcmedia.com, 2016. [Online]. Available:
http://www.ahcmedia.com/articles/135136-misplaced-ng-tubes-a-major-patient-safety-risk. [Accessed:
28- Aug- 2016]. [3] 2016. [Online]. Available:
https://www.aamc.org/download/321532/data/factstableb2-2.pdf. [Accessed: 13- Sep- 2016].
[2] "The Esophagus (Human Anatomy): Picture, Function, Conditions, and More", WebMD, 2016.
[Online]. Available: http://www.webmd.com/digestive-disorders/picture-of-the-esophagus. [Accessed:
13- Sep- 2016].
[3] "Nasogastric Intubation and Feeding", Healthline, 2016. [Online]. Available:
http://www.healthline.com/health/nasogastric-intubation-and-feeding#Purpose2. [Accessed: 13- Sep-
2016].
[4] "SimMan®", Laerdal.com, 2016. [Online]. Available: http://www.laerdal.com/us/doc/86/SimMan.
[Accessed: 13- Sep- 2016].
[5] "Nasogastric Tube Feeding Simulator", 3-Dmed, 2015. [Online]. Available: https://www.3-
dmed.com/product/nasogastric-tube-feeding-simulator. [Accessed: 13- Sep- 2016].
[6] "NG Tube and Trach Care Trainer", Laerdal.com, 2016. [Online]. Available:
http://www.laerdal.com/us/doc/96/NG-Tube-and-Trach-Care-Trainer. [Accessed: 13- Sep- 2016].
[7] "Life/form® NG Tube & Trach Skills Simulator - LF01174U - Advanced Trauma Life Support (ATLS) - 3B
Scientific", A3bs.com, 2016. [Online]. Available: https://www.a3bs.com/lifeform-ng-tube-trach-skills-
simulator-w99834-lf01174u,p_1455_14397.html. [Accessed: 13- Sep- 2016]. [6X]"Nasogastric Tube
Feeding Simulator", 3-Dmed, 2015. [Online]. Available: https://www.3-dmed.com/product/nasogastric-
tube-feeding-simulator. [Accessed: 13- Sep- 2016].
[8] K. Choi, X. He, V. Chiang and Z. Deng, "A virtual reality based simulator for learning nasogastric tube
placement", Computers in Biology and Medicine, vol. 57, pp. 103-115, 2015.
[9] 2016. [Online]. Available: https://www.aamc.org/download/321532/data/factstableb2-2.pdf.
[Accessed: 13- Sep- 2016].
[10] "American Association of Colleges of Nursing | New AACN Data Show an Enrollment Surge in
Baccalaureate and Graduate Programs Amid Calls for More Highly Educated Nurses",Aacn.nche.edu,
2016. [Online]. Available: http://www.aacn.nche.edu/news/articles/2012/enrollment-data. [Accessed:
13- Sep- 2016].
[11] 2009. [Online]. Available: http://www.laerdal.com/binaries/ADBXVAWQ.pdf. [Accessed: 01- Sep-
2016].
[12] Z. Awad, "Correlations between esophageal diseases and monomeric length: a study of 617
patients”, Journal of Gastrointestinal Surgery, vol. 3, no. 5, pp. 483-488, 1999.

38
[13] Shamiyeh, A., Szabo, K., Granderath, F., Syré, G., Wayand, W., & Zehetner, J. (2009). The esophageal
hiatus: what is the normal size? Surgical Endoscopy, 24(5), 988-991. http://dx.doi.org/10.1007/s00464-
009-0711-0
[14] "Esophagus Anatomy: Gross Anatomy, Microscopic Anatomy, Pathophysiologic Variants",
Emedicine.medscape.com, 2016. [Online]. Available: http://emedicine.medscape.com/article/1948973-
overview. [Accessed: 13- Sep- 2016].
[15] Radcliffe, Donald V. Stomach. Compton’s Encyclopedia Online v3.0. The Learning Company, 1998.
[16] Y. Liu, M. Johnson, E. Matida, S. Kherani and J. Marsan, "Creation of a standardized geometry of the
human nasal cavity", Journal of Applied Physiology, vol. 106, no. 3, pp. 784-795, 2009.
[17] Standard Test Method for Water Resistance of Shipping Containers by Spray Method, ASTM D951 –
99, 2010

39
Appendices
A. Appendix A – Section 5
a. Drawings of Prototype Solution
Figure 5.1: Figure on the left; full body sketch of the dummy showing the relative place of the parts
within the body.
Figure 5.2: Figure on the right; sketch showing a close up of the ‘stomach’ and its parts as well as
showcasing the dummies ability to open the abdomen and remove parts if necessary.
Figure 5.4: First iteration of the whole product. This represents the patient laying down instead of
sitting up.
b. Subcomponent Design
i. Physical System
ii. Electrical System

40
Yes or No tracking Code
Peak finder function

42
iii. Tubing and Fluid System - Konrad
1. Trachea and Esophagus Interface
Figure 5.12: First iteration of the interface
2. Stomach

43
Figure 5.x: First iteration of the stomach; when the patient is laying down
B. Appendix B – Section 7
a. Design Verification Subcomponent Testing Results
i. Physical System
ii. Electrical System
Table 7.x: Test results for sensor detection
Day 1
Sensor Dark Dark Dark Medium Medium Medium Light Light Light
1 ND D D D D D D D D
2 D ND D D D D D D D
3 D D D ND D D D D D
4 D D D D ND D D D D
5 D D ND D ND D D D D
Day 2
1 D D ND D D D D D D
2 D D D D D D D D D
5 D D ND D D D D D D
Day 3
1 D D D D ND D D D D
2 ND D ND D D D D D D
3 D D ND D ND D D D D
4 D ND D D ND D D D D
5 D D D D D D D D D

44
Dark Medium Light
Sensor D ND D ND D ND
1 7 2 8 1 9 0
2 6 3 8 1 9 0
3 7 2 7 2 9 0
4 7 2 7 2 9 0
5 7 2 8 1 9 0
Total 34 11 38 7 45 0
iii. Tubing and Fluid System – Konrad
Table 7.2: Water resistance spray test for original stomach
Date of Test Weight (g) - before Weight (g) - after Leaks?
10/21/2016 367.41 382.73 One
10/24/2016 369.68 384.12 One
10/26/2016 365.12 372.23 None
10/28/2016 367.42 374.89 One
Statistical analysis for Table 7.2:
One-way ANOVA: C1, C2
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 2 C1, C2
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 1 245.8 245.75 13.14 0.011
Error 6 112.2 18.70
Total 7 358.0
Model Summary
S R-sq R-sq(adj) R-sq(pred)
4.32472 68.65% 63.43% 44.27%

45
Means
Factor N Mean StDev 95% CI
C1 4 367.408 1.862 (362.116, 372.699)
C2 4 378.49 5.83 ( 373.20, 383.78)
Pooled StDev = 4.32472
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
C2 4 378.49 A
C1 4 367.408 B
Means that do not share a letter are significantly different.
Statistical analysis for Table 7.3:
One-way ANOVA: C1, C2
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 2 C1, C2
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
Factor 1 1.264 1.2640 2.80 0.145
Error 6 2.709 0.4515
Total 7 3.973
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.671975 31.81% 20.45% 0.00%
Means

46
Factor N Mean StDev 95% CI
C1 4 367.480 0.718 (366.658, 368.302)
C2 4 368.275 0.622 (367.453, 369.097)
Pooled StDev = 0.671975
Tukey Pairwise Comparisons
Grouping Information Using the Tukey Method and 95% Confidence
Factor N Mean Grouping
C2 4 368.275 A
C1 4 367.480 A
Means that do not share a letter are significantly different.
Table 7.4: Nasogastric tube sensor obstruction test results
Test Date Run 1 Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Run 8 Run 9 Run 10 Total %
10/25/2016 1 1 0 0 0 0 1 0 0 0 3 7.5
10/27/2016 0 1 0 0 0 1 2 0 0 1 5 12.5
10/28/2016 0 0 0 1 0 0 0 1 0 0 2 5
11/02/2016 0 1 1 1 1 0 0 0 1 0 5 12.5
11/04/2016 1 0 0 0 0 0 1 0 0 0 2 5
b. Design Verification Final Prototype Testing Results
Table 7.7: Esophagus tract lap time data (in seconds)
Esophagus Tract Time Test – Lap Data
Lap
1
Lap
2
Lap
1
Lap
2
Lap
1
Lap
2
Lap
1
Lap 2 Lap 1 Lap 2
Run 1 1.22 1.64 3.64 4.08 8.83 9.27 10.4 10.67 11.5 14.2
Run 2 1.31 1.45 3.75 4.21 6.92 7.37 8.63 9.02 9.87 10.37
Run 3 1.46 1.89 4.1 4.57 7.2 7.62 9.18 9.61 10.28 12.74
Run 4 1.27 1.62 3.52 4.76 8 8.4 9.42 9.86 11.65 14.2
Run 5 1.32 1.75 3.5 3.92 7.53 7.84 8.36 8.84 9.82 10.28
Table 7.9: Trachea tract lap time data (in seconds)
Trachea Tract Time Test – Lap Data
Lap 1 Lap 2 Lap 1 Lap 2 Lap 1 Lap 2
Run 1 1.12 1.61 3.54 4.08 5.12 5.43
Run 2 1.21 1.45 3.75 4.21 5.38 5.42
Run 3 1.26 1.69 4.2 4.57 5.89 6.91

47
Run 4 1.37 1.62 3.32 3.76 4.33 4.72
Run 5 1.22 1.71 3.37 3.82 4.87 5.33
C. Appendix C – Section 8
a. Project Schedule
i. Schedule 1:
Figure 8.2: Original project Schedule
8/27/2016
Currently, the project is at the beginning of the schedule. Meeting with the nursing school is scheduled
for tomorrow morning to discuss the project and see what the current solutions look like. The
preliminary presentation has also been started as well as the DHF. Research into sensors and the
feasibility of the solution are things that need immediate attention. Also the sketch needs to be
completed so we have a better idea of what needs to be done and then discuss the feasibility of that
design with the mentors.
9/12/2016
The project is in the beginning parts of the prototyping stage. The subcomponents are currently on
schedule, an itemized list was completed and most items that need to be purchased have been
purchased. However, a manikin still needs to be purchased or found so the physical part of the project
can be completed; the corec and nursing school do not have any extras.
8/27/2016

48
Tasks to be completed in the next two weeks include meeting with the nurses, verifying the feasibility of
the project, the preliminary presentation and the sketch of the solution design. These are all necessary
to begin the steps to creating the prototype and then testing that prototype.
9/12/2016
We plan to start developing the individual subcomponents the next two weeks as well as test them in
order to make sure that they work properly. These are necessary before we combine them to create the
first prototype. Also, since Susan Fisher will be gone starting in October, plan to think of any final
questions for her.
ii. Schedule 2:
Figure 8.3: Second project schedule
10/17/2016
Currently, just some of the subcomponent parts are behind of schedule. The tubing/fluid is completely
put together and testing of the subcomponent is all that remains. However, the testing and iterations
are behind schedule mostly because the development of the 3D printed parts took longer than usual.
The physical subcomponent of the model has been completed and is awaiting the rest of the
subcomponents to be completed so they can be implemented into it. Subcomponent 4, the electrical
system, is completed and is currently being tested to determine the accuracy of the sensors. Once

49
testing is complete the sensors will be placed into the subcomponent 2 for full system testing. Lastly, the
GUI has not been completed because it was determined that it would be better for all group members
to work on it once the full system is ready. The first testing of the system with the nurses will not include
the GUI and will instead focus on if the feedback and system is working. It will then be iterated and the
second cycle of testing with the nurses will include the GUI. All of the subcomponents include
dependencies which include materials being gathered, subcomponent being built, testing and then
iterations. The iterations for the final prototype also depend on after meeting and testing with the
nurses. It is worth noting that the schedule was adjusted to include testing and iterations for the
individual subcomponents so that only testing of the full system would be focused on when the
prototype is complete.
Tasks to be completed within next two weeks include compiling the individual subcomponents into a
working prototype. Once the prototype is complete a meeting with the nursing school will be set up for
testing and feedback. Those results will then be used for future iterations
Project Budget
Original budget 9/9/2016

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