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

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Problem

4

Problem

5

Problem

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Problem

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Last Semester

Bougie, a.k.a. Introducer

External Magnet

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Final Device

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Introducer – Overview

Pictures of how the device is made and describing what is coming next

Tip selection Design Issues Tip encasement

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4545

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Introducer – Type of Tip

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Introducer – Type of Tip

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Introducer – Type of Tip

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Introducer – Type of Tip

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Introducer – Type of Tip

Spherical Magnets Latex Encasing

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Introducer – Design Issues

Pictures of how the device is made and describing what is coming next

Flop (Flimsy Tip) Buckling (Force Direction) Tip encasement

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4545

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Introducer – Flop Issue

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Due to Force of Breathing Tube

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Introducer – Flop Issue

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Due to Force of Breathing Tube

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Introducer – Flop Issue

Seven 5 mm magnets = 35 mm of magnets 55 mm maximum length

Leaves 10 – 20 mm plastic

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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

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Introducer – Buckling Issue

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Introducer – Buckling Issue

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Introducer – Tip Encasement

External Magnet

brought in

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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

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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

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– 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

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Introducer – Final Design

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4545

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External Magnet – Overview

Mounting BracketPin

Handle

Magnet Stack

Cap

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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

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Testing – Overview

Distance Thick Neck Model Time Trials Failure Modes Neck Positioning

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Testing – Distance

External Magnet

brought down

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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)

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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

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Testing – Time Trials

Fourteen completed trials: 12 successful on 1st

attempt 2 successful on 2nd

attempt

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Testing – Time Trials

Fourteen completed trials: 12 successful on 1st

attempt 2 successful on 2nd

attempt

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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

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Testing – Neck Contortion

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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

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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)

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Recommendations and Unknowns

Material change: Nitrile Packaging

Cases Contraindications

Further testing Cadaver testing Human clinical trial(s)

Device inspection, classification and approval

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Anaesthesiologist Using Our Device

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Anaesthesiologist Using Our Device

Clients satisfied with level of completion and quality of work

Quotations from meetings: “”

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Questions ?

Thank you to: Department of

Anaesthesia Dr. Dennis Drapeau Dr. Andrew Milne

Department of Mechanical Engineering Dr. Ted Hubbard Peter Jones

Shell