Design and Prototype Fabrication of a UCSD Photonics Neonatal Video Laryngoscope 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 10/26/200 Photo: Kevin Walsh, OLR PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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. 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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 Maximum Resolvable Frequency Modulation Transfer Function 1 18 Spatial Frequency (in Line Pairs 16 0.8 Contrast 14 Measured MTF for 12 Vertical Lines Given Resolution 0.6 10 Measured MTF for 8 0.4 per mm) Horizontal Lines Measured Vertical 6 Resolution 4 Average Measured 0.2 MTF 2 Measured Horizontal 0 Resolution 0 Given MTF 0 20 40 60 80 0 50 100 150 200 Distance in mm Spatial Frequency (Line Pairs per mm) Image from Medigus website 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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. Calculated efficiency is just over 50%. The most elegant solution is a tapered acrylic light pipe acting as the blade. Image from Fraen website 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
Assembly and Optical Testing of Initial Model UCSD 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 4 cm LED/Waveguide Lit Target 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
Medical Testing and Feedback UCSD Photonics The medical team tested the device on a Premi-Blue Neonatal Simulator (Gaumard). 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
Final Model UCSD Photonics 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
Final Model Videos UCSD Photonics 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
UCSD Photonics Thank you kabaker@ucsd.edu 10/26/200 PHOTONIC SYSTEMS INTEGRATION LABORATORY – UCSD JACOBS SCHOOL OF ENGINEERING 9
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