Design and Prototype Fabrication of a Neonatal Video Laryngoscope

Design and Prototype Fabrication of a
Neonatal Video Laryngoscope
UCSD Photonics
Katherine Baker and Joseph Ford
University of California, San Diego
Jacobs School of Engineering
Wade Rich and Neil Finer
University of California, San Diego
Medical Center
October 15, 2009
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Photo: Kevin Walsh, OLR
Introduction / Motivation
UCSD Photonics
Dr. Neil Finer, Chief of the UCSD Medical Center’s Division of Neonatology, and
Wade Rich, Research Coordinator for the Division of Neonatology, approached
the Photonic Systems Integration Lab with a collaboration proposal.
• 25,000 extremely low birth weight infants born annually,
• Most require intubation, a difficult / traumatic process for neonates
• Current instruments designed for adults, not infants, esp. not neonates.
• Project goal: Working model of a neonatal video laryngoscope.
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Infant Intubation
UCSD Photonics
85 - 90% of extremely low birth weight infants need intubation.
Intubation requires 3 (average) to 10 tries
Multiple attempts lead to serious risks.
Images from Manual of Emergency Airway Management, ed. Murphy and People’s Daily Online
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Laryngoscopes
UCSD Photonics
Traditional Laryngoscopes
Video Laryngoscopes
GlideScope: Video Camera
Karl Storz: Coherent Fiber Bundle
Our goal was to create a working model neonatal video laryngoscope to
evaluate the feasibility of a commercial device.
Images are from Karl Storz website, GlideScope website
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Blade and Device Constraints
UCSD Photonics
Constraints
•Blade Width
•2.5mm by 6.5 mm tip
•Variable Blade Angle
•Image Quality
•Combination of Imager and Lighting
•Mechanical Properties
•Strength
•Heat
•Texture
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Imager Selection
UCSD Photonics
Effective Focal Length .712 mm
Field of View
100°
F-number
f/5.99
We identified a promising camera in the Medigus
IntroSpicio CCD Video Camera, with a camera head
measuring only 1.8 by 1.8 by 12 mm.
1.2
18
16
14
12
10
8
6
4
2
0
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Modulation Transfer Function
1
Given Resolution
Measured Vertical
Resolution
Measured Horizontal
Resolution
0
20
40
60
Distance in mm
80
Contrast
Spatial Frequency (in Line Pairs
per mm)
Maximum Resolvable Frequency
0.8
0.6
Measured MTF for
Vertical Lines
0.4
Measured MTF for
Horizontal Lines
0.2
Average Measured
MTF
0
Given MTF
0
50
100
150
200
Spatial Frequency (Line Pairs per mm)
Image from Medigus website
PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Design Solutions
UCSD Photonics
With a necessary optical power of at least 30 to 40 mW,
an LED at the tip would dissipate far too much heat.
We make use of a Fraen coupling lens.
The most elegant solution is a tapered
acrylic light pipe acting as the blade.
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Calculated efficiency is just over 50%.
Image from Fraen website
PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Waveguide Fabrication
UCSD Photonics
Acrylic blanks are cut at
the right aspect ratio.
The edges are sanded,
then flame-polished with a
hydrogen-oxygen torch.
Blanks are heated to
pliability, then stretched
to form a taper
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Assembly and Optical Testing of Initial ModelUCSD Photonics
Measured efficiency is 28%, but the LED
is bright enough that this is sufficient.
Ideal Backlit Target
Using an Inova X0 LED
flashlight as the handle
and light source, we
created a working model.
1 cm
LED/Waveguide Lit Target
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
4 cm
Medical Testing and Feedback
UCSD Photonics
The medical team tested the device
on a Premi-Blue Neonatal Simulator
(Gaumard).
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Final Model
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UCSD Photonics
PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Final Model Videos
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UCSD Photonics
PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
Conclusions and Future Directions
UCSD Photonics
• Neonate anatomy guided our design.
• We met all the constraints of the project.
• Less expensive wafer cameras could be used to reduce cost.
• We would need a sterilizable device to perform a clinical trial
• Further modifications could be made
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING
UCSD Photonics
Thank you
kabaker@ucsd.edu
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PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING