TEAM MEMBERS: Miguel Benson, Erik Bieging, Ross Gerber, Aman Ghotra, Abdikarim Mahamud Department of Biomedical Engineering TEAM ADVSIOR: Mitch Tyler, MS PE Department of Biomedical Engineering TEAM CLIENT: Tom Brazelton, MD, MPH Department of Pediatrics UW-Madison Hospital and Clinics

Abstract We propose a physical prototype of a gurney-compatible- child seat for transporting children in ambulances. Current seats do not recline; Emergency Medical Technicians (EMTs) must unstrap the child out of seat and remove the seat off the gurney to lay the child flat on the gurney for specific medical treatments. However, this procedure takes up valuable time (~3 minutes) and protracts the time it takes to reach the hospital. As a result, our prototype reclines, and eliminates the need to remove the seat off the gurney to lay the child flat on the gurney. Also, our prototype supports children (1-10 years old) of various anatomical features unlike current ambulatory child seats. Initial testing of four subjects (1-10 year old) have given promising results but more testing needs to be done to assess prototype’s mechanical and safety constraints. Also, we need to seek lighter yet robust material to fabricate future design of the child seat.

Background –An estimated 5000 ambulance crashes annually [1] –Safest to transport children sitting up(<30 kg) in child seat attached to gurney in an ambulance [2] –For specific medical conditions, EMTs must unstrap child out of seat and remove the seat off the gurney to lay the child flat on the gurney [3]

Background/Motivation Problems with Current Design: –Seat does not recline Time consuming (~3 mins) because must remove the seat off gurney to lay child flat –Seat is bulky Do not always carry seats in ambulances –Children more prone to injury

Problem Statement Develop a safe and compact child seat for transporting children (6-30 kg) in ambulances that allows Emergency Medical Technicians (EMTs) to recline the child in the seat from the sitting position to the lying position when strapped onto a stretcher.

Design Constraints The Child Seat: 1. Must be compatible with current stretchers; 2. Must secure a child (up to 10 year old) -Mass: 6-30 kg -Shoulder width: cm, -Hip to shoulder height: cm [4]; 3. Must not restrict EMT’s ability to care for the child; 4. Must be cost-efficient and user-friendly; 5. Must be collapsible; 6. Must recline from degrees; 7. Must be easily sterilized.

Overview of the Design We have incorporated four unique features that make the child seat more conducive to ambulance transportation: –Recline Lock –Sliding Strap –Back Rest –Leg Support Overview of Design Concept

Recline Lock Mechanism Function: –Reclines the seat Mechanism: –Similar to a hinge joint –2 plates joined at center rotate freely about the joint –1 plate permanently fixed to the seat while the other is attached to the back rest on a rail mechanism –Lock in position with pin Materials: –Wood and Screws Figure A: Design Concept Figure B: Prototype ModelFigure C: Prototype Model

Sliding Strap Anchor Function: –Used to adjust strapsMechanism: –Latch secures slide in place –Over-center design allows for free hands –Deformable rubber disk for latch supportMaterials: –Wood, Screws, Nails, Plastic Figure D: Design Concept Figure E: Prototype DesignFigure F: Prototype Design

Back Rest Track Function: –Anchors back of seat to stretcher –Allows seat and stretcher to be reclined simultaneouslyMechanism: –Beam tracks on the back rest slide into groves in anchored back –Anchored back is strapped firmly to stretcher –Allows back rest to move relative to the stretcher while recliningMaterials: –Wood, PVC piping, screws Figure G: Design Concept Figure H: Prototype Design

Leg Support Function: –Elevates patient’s legs if necessary Mechanism: –Slides out from beneath base of seat –Supported metal rails fit into base of seat Materials: –Wood, railing Figure J: Prototype DesignFigure I: Design Concept

Materials and Cost MaterialsCost Plywood, Wood, Foam, Straps Donated by our client Hinges, Hooks, Nails, Screws, Nuts and Bolts $10.00 Sliding Bars $ 5.00 Fabric, Glue $ 5.00 Total Cost $20.00

Subject Testing Tested our prototype on four subjects from the following age groups: –1 year old –4 year old –6 year old –10 year old Figure K: 1 year old subject in upright position Figure L: 1 year old subject in laying position

Testing (cont.) Figure M: 6 year old subject in upright position Figure N: 6 year old subject in laying position Subject Testing Results: –All 4 subjects fit well in seat –Easy to adjust seat with subjects in it –Difficult for one operator to adjust seat and straps simultaneously

Future Considerations PROBLEMS POSSIBLE SOLUTIONS 1. Heavy Design 1. Use light yet robust material (i.e. plastic seat with metal frame) 2. Strap mechanism difficult to slide 2. Add rails to keep mechanism in proper orientation 3. Have not done crash testing 3. Use Burlington Testing Facility next semester 4. Lock mechanism only has 2 options 4. Add more locking positions 5. Only a 3-point harness is used 5. Add straps to complete 5-point harness 6. Buckle between legs has one setting 6. Add more positions to fit more children

Acknowledgements: We would like to thank Dr. Tom Brazelton and his colleagues, and Biomedical Engineering Department for providing us an opportunity to work on this project. Also, we would like to thank our advisor, Mitch Tyler, for providing us feedback and pointing us in the right direction. References: [1] Safe Ride News. [2] Detroit News. [3] Brazelton, T. University of Wisconsin Hospital and Clinics. Interview. [4] Physical Characteristics of Children.

AMBUL ATORY

CHILD SAFET

Y SEAT