Design of a Malignant Hyperthermia Screening Device at University of Pittsburgh

1. University of Pittsburgh Senior Design – BioE1161 Design of a Malignant Hyperthermia Susceptibility Screening DeviceSara DollLisa KaczmarskiPhilip MagcalasDepartment of AnesthesiologyChildren’s Hospital of Pittsburgh

2. Overview-The Problem Malignant Hyperthermia (MH) is a chain reaction event wherein susceptible patients, when administered common gas anesthetics, undergo drastic physiological changes. • greatly increased body metabolism • muscle rigidity • fever up to or beyond 43°C There are currently no standard devices or procedures in common practice to screen the general population for this condition.

3. Overview-The Solution It is hypothesized that MH susceptible muscle, when compared to normal muscle, will be significantly different in compound muscle action potential (CMAP) and force of contraction. The solution lies in the design of a device that restricts arm movement, while measuring the isometric force produced by the thumb when the ulnar nerve is stimulated. This may then be used to develop a standardized protocol for MHS screening. Such a device would ultimately be beneficial to: • Anesthesiologists • Patients and their families • The general Population

4. Project Goals 1. Create a device that meets design requirements • comfortably accommodates 3 to 5-year-old patients • securely restrains the patient’s forearm and hand • fastens securely to bed in operating room • can be easily sanitized • can be transported with ease (lightweight) • has minimal assembly or adjustment requirements • can be used with both the right and left hands • maintains the arm at the same height as the OR bed 2. Test and assess the effectiveness of the final device in measuring forces within a specific range

5. Device Features 1- Arm board 3 – Force Transducer Mount 2- Arm/hand restraints 4 - Support

6. Materials Board Wood Metal Polymer Straps Fabrics Polymers Arm/Hand Restraints U-shaped cushions Adjustable straps Top restraint Force Transducer Mount Track Integrate into board Attach on edge Orientation Left hand only Ambidextrous Range of motion Fixed Planar Angular Support Moveable cart Vises on side of OR bed Integrate into existing equipment Elevator Recess for armboard Design Options

7. The Design Process • Prototypes (3 total) - Frequent meetings • continuous design feedback and refinement of design requirements from mentors • Anthropometric data • Material samples • arm board and straps • The process of manufacturing • Carrying out reality from concept - importance of details, details, details

8. Concept Prototype #1 Jan. Dec. The Evolution of Design

9. Concept #2 Prototype #2 Nylon Velcro straps Flexible polymer metal rigid, 1-1/2” polymer Jan. Feb. The Evolution of Design (cont’d)

10. The Evolution of Design (cont’d) Prototype #3 Mar.

11. 1- Arm board 2- Arm/hand restraints x 4 3 – Force Transducer Mount x 3 4 - Support The Final Design

12. The Final Design (cont’d) TOP BOTTOM

13. Benefits of our Design Arm board ambidextrous sized for wide range arm/hand sizes simple construction Force Transducer Mount translation in two planes interchangeable (support 2 diff. FT) ambidextrous Support integrates with existing equipment sturdy separable from arm board Arm restraints adjustable removable flexible single material, single piece sanitizable strong (resistance to tear)

14. Benefits of our Design Overall - Simplicity in design in assembly in manufacture - Satisfies ALL design requirements

15. Competitive Analysis Competitors • Halothane caffeine contracture testing (muscle biopsy segments) Our Strengths • Non-invasive • Not necessary to wait for laboratory results • Less expensive • Quick procedure, which may be performed pre-op Our Weaknesses • Potentially less accurate • Not testing on actual muscle fiber • Not standardized process Our device’s strengths outweigh the weaknesses …However - Contingent upon accuracy of device - Reliant upon efficiency of data acquisition program, which lies outside the scope of this project

16. Manufacturability Acrylic Workable Cost Durable SolidWorks Ease of Use Available Experience Human factors Contextual Inquiry Device Observation Design Plan Assessment Heuristic Evaluation Other Considerations for Design

17. Regulatory Concerns Class II (moderate risk) • ‘isokinetic testing and evaluation system’ (890.1925) • contact with skin but non-invasive No Predicate Device Currently  510(k) and PMA exempt • Investigational device - clinical evaluation required for further development • IDE regulation will be required However in the future, should the decision be made to pursue marketing this device, this will require a Class II PMA device application

18. Constraints to Further Development Regulatory • Again, no predicate device. Final FDA approval will be complicated Market • Limited now to Children’s Hospital until a more precise MH susceptible screening protocol can be established. Economic Resources • Limited breadth of project funds Human Resources • Time constraints of all involved

19. Our Goals What we Actually Achieved Device In Pre-Assembly • Straps (Adjustable size) • Assembled • Force transducer • Grass/Astromed FT03, FT10 obtained • Mounting Device Currently in machining • Arm Board and Support • Currently in machining • Overall - accomplished a simple, compact design that satisfies all design requirements Project Management • Build a device that: • Comfortably accommodates 3 to 5 year old patients • Ambidextrous • Fastens securely to OR bed • Can be easily sanitized and transported with little assembly • Allows for accurate measurement of contraction force and clear data interpretation Test and assess the effectiveness of the final device in measuring forces within a specific range • Force Transducer Calibration • Known force range • Located an amplifier • Preliminary signal processing • Waveform filtering • Establish force-voltage relationship

20. December - Preliminary SolidWorks drawing for armboard, support - Order force transducer (Grass – model FT03) January - Gather materials for prototype - Build initial prototype February - Prototype testing - Design revisions - Finalize SolidWorks drawing - Order final materials March - Build/Assemble device April - Device testing, as time allows - Draft final report and presentation December - Discussed device requirements with advisors - Researched materials Project management (cont’d) Projected Schedule Completed Schedule January - Gathered materials for and built Prototype 1 - Ordered force transducers (Grass FT03, FT10) - Prototype 1 assessment February - Design revisions - Gathered materials for and built Prototype 2 - Prototype 2 Assessment - Preliminary SolidWorks drawing March - Ordered final materials - Anthropometric research - Gathered materials for and built Prototype 3 - Finalized dimensions and SolidWorks Drawings - Submitted design to machining April - Device machining underway - Draft final report and presentation

21. Who was responsible what Project management (cont’d) • Lisa Kaczmarski • Material Research • Materials Acquisition • Contact with Suppliers • Prototype 1 • Final Product (straps and armboard) • Philip Magcalas • Device Concept Drawings • Anthropometric Research • Force Transducer Mount Solid Works • Prototype 2 • Final Product (FT supports) • Sara Doll • Armboard SolidWorks • Strap SolidWorks • Concept SolidWorks • Mentor Meetings • Prototype 3

22. Acknowledgements • Dr. Brandom’s Clinical Research Fund • Children’s Hospital of Pittsburgh • Dr. Barbara Brandom • Dr. Robert Sclabassi • Dr. Andreas Hoyer • Prof. Mark Gartner • Dr. Mingui Sun • Joe Beuten • Total Plastics, Inc. • George Kurzdorfer • University of Pittsburgh • Department of BioEngineering

23. Thank you!Questions?

24. Design Details – Arm Board H=30cm W=33cm

25. Design Details - Support H=9.8cm W=17.5cm

26. Design Details – Force Trans. Mount H=4.4cm W=10.2cm H=7.3cm W=28.1cm

27. Design Details - Straps large small