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MAGNETIC AND ARTICULATING (MNA) BOUGIEASSISTED BREATHING TUBE PLACEMENT DURING INTUBATION
Dalhousie University Senior Design Project
Group #7
GROUP MEMBERS: CHRIS CLONEYLAURA HADLEYBRIAN JOSEPHIAN WESTHAVER
SUPERVISOR: DR. TED HUBBARD
CLIENTS: DR. ANDREW MILNE1,2, DR. DENNIS DRAPEAU1
1 DEPARTMENT OF ANESTHESIA – DALHOUSIE UNIVERSITY2 SCHOOL OF BIOMEDICAL ENGINEERING – DALHOUSIE UNIVERSITY
2
Overview
Recap Introducer External magnet Testing Requirements and Recommendations
3
Problem
4
Problem
5
Problem
6
Problem
7
Last Semester
Bougie, a.k.a. Introducer
External Magnet
8
Final Device
9
Introducer – Overview
Pictures of how the device is made and describing what is coming next
Tip selection Design Issues Tip encasement
4545
4545
10
Introducer – Type of Tip
11
Introducer – Type of Tip
12
Introducer – Type of Tip
13
Introducer – Type of Tip
14
Introducer – Type of Tip
Spherical Magnets Latex Encasing
15
Introducer – Design Issues
Pictures of how the device is made and describing what is coming next
Flop (Flimsy Tip) Buckling (Force Direction) Tip encasement
45
4545
4545
16
Introducer – Flop Issue
?
Due to Force of Breathing Tube
17
Introducer – Flop Issue
?
Due to Force of Breathing Tube
18
Introducer – Flop Issue
Seven 5 mm magnets = 35 mm of magnets 55 mm maximum length
Leaves 10 – 20 mm plastic
19
Introducer – Buckling Issue
Buckling issue occurs when the angle between the trachea and mouth is sharp, and the magnetic tip buckles at the tracheal opening
?
20
Introducer – Buckling Issue
?
21
Introducer – Buckling Issue
22
Introducer – Tip Encasement
External Magnet
brought in
23
0 1 2 3 4 5 6 7 80
5
10
15
20
25
30
35
Tip 1
Tip 3
Tip 4
Tip 5
Tip 6
Tip 7
Tip 8A
Tip 8B
Ball Number
V -
Heig
ht
(mm
)
Introducer – Tip Encasement
?
24
0 1 2 3 4 5 6 7 80
5
10
15
20
25
30
35
Tip 1
Tip 5
Tip 8A
Ball Number
V -
Heig
ht
(mm
)
Introducer – Tip Encasement
– Control
?
– Too Stiff
25
0 1 2 3 4 5 6 7 80
5
10
15
20
25
30
35
Tip 1
Tip 5
Tip 8A
Ball Number
V -
Heig
ht
(mm
)
Introducer – Tip Encasement
– Control
– Too Stiff
Layered Latex Dipping
26
Introducer – Final Design
4545
4545
27
External Magnet – Overview
Mounting BracketPin
Handle
Magnet Stack
Cap
28
External Magnet – Stack Size
The size of the magnet stack was chosen through qualitative testing.
The final magnet stack was as large as possible but still comfortable for a range of hand sizes.
External Magnet - Handle
A block of plastic was sized using modeling clay on the intubation mannequin
2”
2”
2 ”
External Magnet - Handle
1 ”
Magnets are sized using standard test procedures discussed last term, and a suitable hole is cut
External Magnet - Handle
Steel mounting bracket is designed to hold magnets, and placed in the new cavity at right
External Magnet - Handle
Curvature of design intended to give more accurate targeting of trachea, and placement under chin contours
External Magnet - Handle
Rounded corners for patient and operator safety
External Magnet - Handle
Holes placed for additional mounting apparatus
35
Testing – Overview
Distance Thick Neck Model Time Trials Failure Modes Neck Positioning
36
Testing – Distance
External Magnet
brought down
37
Testing – Distance
20 30 40 50 60 70 80 903.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
11.0
Bougie Angle (α - deg)
Magnet
Dis
tance (
d -
com
)
Estimated maximum distance required
**Error bars are based on results from 9 introducers with a t-distribution (95% CI)
38
Testing – Thick Neck Model
Thin pieces of rubber representing an obese patient, or a patient with a goiter or tumour.
Thickness(mm)
Result
4 No Effect
7 No Effect
12 No Effect
15 No Effect
20Reduced Articulation
24Reduced Articulation
29Inadequate Articulation
39
Testing – Time Trials
Fourteen completed trials: 12 successful on 1st
attempt 2 successful on 2nd
attempt
40
Testing – Time Trials
Fourteen completed trials: 12 successful on 1st
attempt 2 successful on 2nd
attempt
41
Testing – Time Trials
Fourteen completed trials: 12 successful on 1st
attempt 2 successful on 2nd attempt
Introducer Only: 8.7 ± 1.4 s (95%
CI) Breathing Tube
Placement: 21.5 ± 2.0 s (95% CI)
**Confidence interval was calculated assuming t-distribution
42
Testing – Neck Contortion
43
Destructive Testing – Failure ModesFailure Mode # Trials Force Required Diagram - NotesTip in tension 8 4.0 ± 1.2 lb (95% CI)
One low value of 1.75 lb
One ball in tension
3 3.5 ± 1.5 lb (95% CI)
Latex stretched extremely far before rupture
Tip in shear 3 14.9 ± 4.0 lb (95% CI)
Epoxy crushed but tip did not dislocate
**Confidence interval was calculated assuming t-distribution
44
Requirements
Requirement Result
Medical grade materials Plastics and metal Latex
Disposable or easily sterilized Introducer: disposable External Magnet: sterilizable
Portable, volume less than 3500 cm3 Introducer: External Magnet:
Light, weigh less than 3 kg Introducer: External Magnet:
1-2 attempts to introduce breathing tube
Fourteen Trials 12 of 14 successful on first
attempt
Less than 25 seconds 8.7 ± 1.4s (introducer only) 21.5 ± 2.0s (total)
45
Recommendations and Unknowns
Material change: Nitrile Packaging
Cases Contraindications
Further testing Cadaver testing Human clinical trial(s)
Device inspection, classification and approval
46
Anaesthesiologist Using Our Device
47
Anaesthesiologist Using Our Device
Clients satisfied with level of completion and quality of work
Quotations from meetings: “”
48
Questions ?
Thank you to: Department of
Anaesthesia Dr. Dennis Drapeau Dr. Andrew Milne
Department of Mechanical Engineering Dr. Ted Hubbard Peter Jones
Shell
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