ELECTRONIC SUPPLEMENTARY MATERIAL
Quality assessment of the studies included in the literature review
Table S1: Quality assessment table of included articles from the literature review. A modified version of the Newcastle Ottawa Quality Assessment Scale (as
detailed in methods section) was used to score each article on specific criteria for ‘selection’ and ‘exposure’ criteria, with each being awarded a maximum of
three stars.
Title of study
First Author
Date of
Publication
Technique/s
for NET
localization
Selection
(3)
Exposure
(3)
1
A controlled comparison of traditional feeding tube verification methods to a
bedside, electromagnetic technique [20]
Kearns P
2001
EM, Aus,
Asp, pH
***
***
A multicenter, prospective study of the placement of transpyloric feeding
tubes with assistance of a magnetic device [61]
Boivin M
2000
Mag
***
***
A new technique for placement of nasoenteral feeding tubes using external
magnetic guidance [62]
Gabriel S
1997
Mag
***
***
A new technique for post-pyloric feeding tube placement by palpation in
lean critically ill patients [42]
Sekino M
2012
Aus
**
***
A novel method for insertion of post-pyloric feeding tubes at the bedside
without endoscopic or fluoroscopic assistance: A prospective study [67]
Slagt C
2004
Aus/ECG
***
***
A novel technique for post-pyloric feeding tube placement in critically ill
patients: A pilot study [68]
Young R.J
2005
EM
**
***
A randomized study of a pH sensor feeding tube vs a standard feeding tube
in patients requiring enteral nutrition [26]
Botoman VA
1994
pH
***
***
1
A simple aspiration test to determine the accuracy of oesophageal
placement of fine-bore feeding tubes [69]
Ward M
2009
Asp
**
***
A simple indicator of correct nasogastric suction tube placement in children
and adults [63]
Rulli, F.
2007
Illum
*
-
A team-based protocol and electromagnetic technology eliminate feeding
tube placement complications [5]
Koopmann M
2011
EM
**
***
An evaluation of the Cortrak Enteral access system in our intensive care
[56]
Dolan M
2012
EM
*
**
Bedside placement of pH-guided transpyloric small bowel feeding tubes in
critically ill infants and small children [27]
Dimand, R.
1997
pH
*
***
Bedside postpyloric feeding tube placement: A pilot series to validate this
novel technique [28]
Gatt M
2009
pH
**
***
Bedside sonographic control for positional enteral feeding tubes: A
controlled study in intensive care unit patients [64]
Gubler, C.
2006
UltraS
*
**
Bedside sonographic-guided versus blind nasoenteric feeding tube
placement in critically ill patients [40]
Hernandez_Socorro,
C.
1996
Blind
***
***
Capnometry and Air Insufflation for Assessing Initial Placement of Gastric
Tubes [45]
Elpern, E. H.
2007
Cap, Aus
***
***
Colorimetric capnography to ensure correct nasogastric tube position [46]
Meyer, P.
2009
Aus/CO2,
CO2, Aus
***
***
Comparison of four bedside indicators used to predict duodenal feeding
tube placement with radiography [21]
Welch SK
1994
Aus, pH,
Asp, other
***
***
Confirmation of nasogastric tube placement by colorimetric indicator
detection of carbon dioxide: A preliminary report [47]
Thomas B
1998
CO2
**
***
2
Confirmation of nasogastric tube position by pH testing [29]
Taylor SJ
2005
pH
***
**
Confirmation of transpyloric feeding tube placement by ultrasonography [65]
Greenberg M
1993
UltraS
**
**
Confirming Nasogastric Tube Position in the Emergency Department pH
Testing Is Reliable [31]
Stock A
2008
pH
**
-
Determination of a practical pH cutoff level for reliable confirmation of
nasogastric tube placement [30]
Gilbertson HR
2011
pH
**
***
Determining Feeding Tube Location by Gastric and Intestinal pH Values
[32]
Phang JS
2004
pH
***
***
Does the use of an enteral feeding tube with a pH-sensitive tip facilitate
enteral nutrition? [33]
Ireton-Jones C
1993
pH
**
**
Effectiveness of pH Measurements in Predicting Feeding Tube Placement
[34]
Metheny N
1989
pH
**
***
Effectiveness of the auscultatory and pH methods in predicting feeding tube
placement [16]
Turgay AS
2010
pH, Aus
***
***
Effectiveness of the auscultatory method in predicting feeding tube location
[38]
Metheny, N
1990
Aus
*
***
Electrocardiogram-guided placement of enteral feeding tubes [52]
Keidan I
2000
ECG
*
**
Electromagnetic guided feeding tube insertion: Enhancing patient safety
[70]
Karmally, Z
2011
EM
*
**
Electromagnetic sensor guided nasojejunal tube placement in critically ill
patients [71]
Elliot, S
2010
EM
*
**
Feasibility and safety of the placement of nasoduodenal feeding tubes by
nurses with the assistance of an electromagnetic guidance system (Cortrak)
Mathus-vliegen, E
2009
EM
*
***
3
[72]
Gastric tube placement in young children [36]
Ellett M
2005
CO2, pH,
Birub
**
**
Guiding nasoenteral feeding tubes into the distal duodenum with magnets:
Results from 161 intubations [73]
Gabriel, S
1998
Mag
***
**
Hold that x-ray: aspirate pH and auscultation prove enteral tube placement
[39]
Neumann M
1995
Aus, pH
***
***
Implementation of an electromagnetic imaging system to facilitate
nasogastric and post-pyloric feeding tube placement in patients with and
without critical illness [57]
Windle EM
2010
EM
**
***
Increasing the safety of blind gastric tube placement in pediatric patients:
the design and testing of a procedure using a carbon dioxide detection
device [41]
Gilbert RT
2012
CO2
**
**
Indicators of postpyloric feeding tube placement in children [22]
Gharpure V
2000
Asp, pH,
Bilrub, Enz
***
***
Indicators of Tube site During Feedings [23]
Metheny N
2005
Asp
***
**
Intestinal placement of pH-sensing nasointestinal feeding tubes [35]
Berry S
1994
pH
*
**
Jejunal tube placement in critically ill patients: A prospective, randomized
trial comparing the endoscopic technique with the electromagnetically
visualized method [43]
Holzinger, U
2011
EM
*
**
Magnetic detection to position human nasogastric tubes [74]
Tobin, R
2000
Mag
**
**
Magnetically guided nasoenteral feeding tubes: a new technique [75]
Gabriel, S
2001
Mag
***
**
4
Methods to test feeding tube placement in children [24]
Westhus N
2004
pH, Enz,
Asp, Asp +
pH
***
**
Nasoenteral feeding tube placement by nurses using an electromagnetic
guidance system (with video) [58]
Mathus-Vliegen E
2010
EM
**
*
Nasointestinal tube placement with a pH sensor feeding tube [76]
Heiselman D
1993
pH
*
**
Noninvasive Verification of Nasogastric Tube Placement Using a MagnetTracking System: A Pilot Study in Healthy Subjects [77]
Bercik P
2005
Mag
***
-
Nonradiographic assessment of enteral feeding tube position [78]
Harrison M
1997
Aus
***
**
pH and concentration of bilirubin in feeding tube aspirates as predictors of
tube placement [79]
Metheny N
1999
Bilrub + pH
***
*
pH and concentrations of pepsin and trypsin in feeding tube aspirates as
predictors of tube placement [80]
Metheny N
1997
Enz + pH
***
**
Placement of nasoenteral feeding tubes using external magnetic guidance
[59]
Gabriel S
2004
Mag
**
**
Placement of nasoenteral feeding tubes using magnetic guidance: retesting
a new technique [60]
Ozdemir B
2000
Mag
**
**
Placement of nasointestinal ph-sensing feeding tube: A prospective
evaluation [81]
Jimenez E
1998
pH
***
**
Prospective randomised comparison study of two methods of jejunal
placement of enteral feeding tubes in critically ILL patients: Endoscopic
versus electromagnetic visualised method [44]
Holzinger U
2009
EM
*
-
Rapid Placement of Transpyloric Feeding Tubes: A Comparison of pHassisted and Standard Insertion Techniques in Children [82]
Moore L
1996
pH
**
***
5
Report on the development of a procedure to prevent placement of feeding
tubes into the lungs using end-tidal CO2 measurements [48]
Burns M
2001
CO2
**
**
Serum paracetamol concentration: an alternative to X-rays to determine
feeding tube location in the critically ill [83]
Berger M
2003
Other
**
*
Small bowel feeding tube placement using an electromagnetic tube
placement device: Accuracy of tip location [84]
Rivera R
2011
EM
**
***
Successful placement of postpyloric enteral tubes using electromagnetic
guidance in critically ill children [85]
October, T. W
2009
EM
*
***
The effectiveness of ultrasonography in verifying the placement of a
nasogastric tube in patients with low consciousness at an emergency center
[66]
Kim, H. M
2012
pH, Aus,
UltrS
***
**
The use of carbon dioxide monitoring to determine orogastric tube
placement in premature infants: a pilot study [49]
Ellett M
2007
CO2
*
**
The use of the Cortrak Enteral Access SystemTM for post-pyloric (PP)
feeding tube placement in a Burns Intensive Care Unit [86]
Hemington-Gorse,
S. J
2011
EM
-
*
Transpyloric feeding tube placement in critically ill patients using
electromyogram and erythromycin infusion [53]
Levy H
2004
ECG
***
***
Ultrasound to confirm gastric tube placement in prehospital management
[87]
Chenaitia H
2012
UltraS
***
***
Use of a colorimetric carbon dioxide sensor for nasoenteric feeding tube
placement in critical care patients compared with clinical methods and
radiography [50]
Munera-Seeley V
2008
CO2
*
**
Use of a noninvasive electromagnetic device to place transpyloric feeding
tubes in critically ill children [54]
Kline, A. M
2011
EM
***
***
Use of a pressure gauge to differentiate gastric from pulmonary placement
Swiech K
1994
other
**
***
6
of nasoenteral feeding tubes [88]
Use of an electromagnetic placement device for enteral feeding tubes
reduces nursing time and financial burden [89]
Kenar J
2010
EM
*
*
Use of capnometry to verify feeding tube placement [51]
Araujo-Preza, C. E
2002
CO2
*
***
Verification of an electromagnetic placement device compared with
abdominal radiograph to predict accuracy of feeding tube placement [55]
Powers J
2011
EM
**
**
Visual Characteristics of Aspirates from Feeding Tubes as a Method for
Predicting Tube Location [25]
Metheny N
1994
Asp
***
*
1.
Abbreviations for the techniques are shown here:
7
Abbreviation
Full name of technique
EM
Electromagnetic methods
Aus
Auscultation/insufflation
Asp
Aspirate: Visual inspection
pH
Aspirate: pH testing
Bilrub
Aspirate: Bilirubin testing
Enz
Aspirate: Enzyme testing (pepsin, trypsin)
Mag
External magnet guidance
Illum
Illumination using fibre optic
UltraS
Ultrasound/sonography
Blind
Blind insertion
CO2
Capnography / Capnometry (colourmetric indicator of end-tidal
CO2)
ECG
Electrocardiographic tracing and Electromyography
Bilirub + pH
Combined: Bilirubin and pH
Enz + pH
Combined: Enzyme and pH
Aus/ECG
Combined: Auscultation and ECG
Aus/CO2
Combined: Auscultation and Capnography / Capnometry
8
other
vacuum effect (a change from 40mL of aspirated air to <=
10mL after 60 mL of air instillation), paracetamol
concentration, Pressure gauge
Determining global appropriateness of methods to confirm NET tip location
Methods
The global appropriateness and applicability of available methods to confirm NET tip location were also evaluated. To do this the performance characteristics
of each method were appraised against the needs and requirements of a representative ‘global user base’.
Identifying the ‘global user base’: In order to determine the requirements for a successful global solution, a panel of stakeholders were selected to represent
those involved in each stage of the process to confirm the NET tip location; from development to employment. In addition, this panel was comprised of users
with various social, economic and geographic perspective. This panel consisted of experienced surgeons with familiarity working in developed and
developing nations, two manufacturers / designers with an extensive background in medical device design and marketing, two dieticians and one nurse.
Determining user requirements: The users’ requirements for a successful global solution were obtained by a formal interview process. Each member of the
user panel was asked to discuss their experience with various methods, the advantages and disadvantages of the methods they had used and the most
important requirements for a successful method. From the interviews performed, a list was compiled of all stated requirements for a method to detect NET tip
location.
Weighting the importance of user requirements: Once a full list of requirements had been created, the stakeholders ranked them by importance, from their
perspective. This required them to assign a score of importance from 0 (not important at all) to 10 (the most important) to each of the requirements. The
9
stakeholders were then allowed to include additional comments at the end of the survey relating to any adaptations or improvements they would like to see in
a new method to confirm NET tip location.
Evaluating the global appropriateness of methods: In order to score the global appropriateness of each method a House of Quality (HOQ) matrix was
employed [12, 13]. This is an evaluation matrix that allows the requirements of the user to be mapped against the physical performance characteristics of the
method, so that its appropriateness as a technique can be directly determined. A schematic of a HOQ matrix (Figure S1) indicates the key input and output
sections of this analysis. User input sections are populated using data derived from user interviews and the importance ranking exercise as described above.
The reviewer input sections can be completed by using literature or the results from a trial, or in the case of a new concept, the design specifications, and
results from concept stage testing. The interaction matrix sections are completed by moving through each of the performance characteristics and looking for
any interaction / correlation (positive or negative) with any of the other performance characteristics, and / or the user requirements, e.g. the performance
characteristic of price per disposable tube is negatively correlated to the user requirement of low cost per tube and positively correlated to the performance
characteristic of durability of the tube. The completed top of house and inside house matrices can be used to determine which performance criteria are the
most interrelated and have the strongest connection to the user requirements. This is done for each performance characteristic with a weighted sum of how
many points of interaction they have with other performance characteristic (top of house) and user requirements (inside house). The weighting is based on
the strength of correlation as shown in Table S2. Thus the key output from this HOQ matrix is the weighted importance of the performance characteristics for
a NET tip location method. The importance weightings are the combination of the weightings of the user requirements and the interaction matrices. These
weights allow the review of current methods from the perspective of the ‘global user base’ and can inform a targeted approach to designing a new or
improved method.
10
Figure S1: Schematic of House of Quality matrix
Key:
‘Top of house’
Interaction
matrix
(Performance
characteristics)
User input
Reviewer input
Analysis output
‘Inside house’ Interaction
matrix
(User requirements –
performance characteristics)
Competitive
analysis
Importance
weightings
User
requirements
Performance characteristics
Target performance values
Importance weightings
11
Table S2: Weightings and symbol for the matrix correlation indicators for House of Quality analysis.
Inside
house
Top of
house
Matrix
Description
Positive correlation
Strong positive correlation
Negative correlation
Strong negative correlation
Strong relationship
Moderate relationship
Weak relationship
Weighting
1
2
1
2
3
2
1
Symbol
+
++
-Θ
Ο
▲
Table S3: Stakeholder requirements and ranking of importance
Stakeholders
Stakeholder requirement
High successful placement rate
Low risk to patients
Universal language suitability/suitable
for illiterate users
Clinician (Developing
nation experience)
General surgeon
Dietician
Manufacturer/
Designer
Ranked Average
8.0
10.0
9.0
9.0
9.0
6.0
10.0
10.0
9.0
8.8
9.0
8.0
9.0
8.0
8.5
12
Low learning curve/training required
Viable cost of materials
Low Price
Viable cost for manufacturing
Minimal maintenance required
Durable tube
Comfort not reduced
Relevant design expertise available
Ease of use (ergonomic)
Friendly design for visually impaired
operator
9.0
9.0
7.0
9.0
8.5
8.0
8.0
9.0
8.0
8.3
9.0
8.0
8.0
8.0
8.3
8.0
8.0
7.0
8.0
7.8
9.0
7.0
8.0
7.0
7.8
9.0
7.0
10.0
5.0
7.8
7.0
8.0
9.0
6.0
7.5
8.0
6.0
8.0
7.0
7.3
6.0
8.0
7.0
8.0
7.3
8.0
7.0
7.0
7.0
7.3
13
Friendly design for audiologically
impaired operator
Non-perishable product
Sterile/can be sterilised
Reliable supply of materials
Minimal extra disposables required
(beyond tubes)
Low/no power requirement
FDA/appropriate certificate/approval
obtained
Low environmental impact
Time for development
High product packing density
8.0
7.0
7.0
7.0
7.3
9.0
7.0
8.0
4.0
7.0
6.0
7.0
10.0
5.0
7.0
8.0
5.0
8.0
6.0
6.8
8.0
5.0
6.0
8.0
6.8
9.0
6.0
4.0
7.0
6.5
5.0
7.0
6.0
6.0
6.0
4.0
6.0
4.0
7.0
5.3
5.0
2.0
6.0
4.0
4.3
5.0
2.0
6.0
4.0
4.3
14
Low patent presence of similar
technology
0.0
1.0
15
8.0
6.0
3.8
Table S4 The results of the ‘top of house’ interaction matrix analysis, ranking the most interrelated performance criteria.
Performance criteria
Level of interrelation
Success rate (Specificity, sensitivity)
9
Market size (number of tubes, $$ for devices)
8
Lifetime of disposable
8
Size
7
Cost per tube for disposables
7
Cost for non-disposable components
7
Approved/certificated
7
Power supply (V)
6
Patient discomfort/pain rating during procedure
6
Size of visual indicators
6
Lifetime of non-disposable portion (time before
required maintenance/disposal)
6
Duration of procedure
5
Weight
5
Toxicity of materials
5
Training required
4
Predicted rate of use of disposables (per patient)
4
16
No words - uniformly recognisable symbols only
4
No Audible only alarms/signals
3
Lead time on products
2
17
Table S5: The results of the ‘inside of house’ interaction matrix analysis, ranking the most interrelated performance criteria with user requiremen.
Performance criteria
Level of interrelation
Cost per tube/disposables
34
Lifetime of non-disposable portion (time before
required maintenance/disposal)
29
Success rate (Specificity, sensitivity)
27
Cost for non-disposable components
26
Market size (number of tubes, $$ for devices)
25
Lifetime of disposable
25
Power supply (V)
25
Toxicity of materials
25
Predicted rate of use of disposables (per patient)
23
Training required
20
Approved/certificated
16
Duration of procedure
12
No words - uniformly recognisable symbols only
12
Size
11
Size of visual indicators
10
18
No Audible only alarms/signals
10
Patient discomfort/pain rating during procedure
9
Weight
9
Lead time on products
8
Table S6: The ‘House of Quality’ performance criteria ranked by average importance to stakeholders
Stakeholders
Performance criteria
Cost per
tube/disposables
Success rate
Cost for non-disposable
components
Lifetime of nondisposable portion
Lifetime of disposable
Predicted rate of use of
disposables (per
patient)
Power supply (V)
Toxicity of materials
Training required
Clinician
General
surgeon
Dietician
Manufacturer
/ Designer
Ranked
Average
10.1
8.3
9.3
9.8
9.5
8.9
9.6
9.3
9.6
9.1
8.6
8.1
8.0
8.2
8.2
8.9
7.8
7.7
7.8
7.9
8.2
8.0
7.3
8.1
7.8
7.0
7.1
5.9
5.8
6.6
6.5
6.5
6.5
7.0
6.4
6.4
6.0
6.3
6.9
6.1
6.3
6.7
6.7
6.2
6.2
19
Market size (number of
tubes, $$ for devices)
Approved/certificated
No words - uniformly
recognisable symbols
only
Patient discomfort/pain
rating during procedure
Duration of procedure
Size
Size of visual indicators
Weight
Lead time on products
No Audible only
alarms/signals
5.1
4.2
5.3
5.0
6.1
4.7
6.1
4.4
5.6
4.6
3.8
3.7
3.3
3.8
3.7
2.6
2.8
2.6
2.5
2.3
2.4
3.5
3.2
2.5
2.5
2.0
1.5
3.3
3.0
2.7
2.2
2.2
2.5
3.0
2.9
2.8
2.5
2.5
2.0
3.1
3.0
2.7
2.4
2.3
2.1
2.2
2.0
1.8
2.1
2.0
20