Leg Compression Device to Assist in Ultrasound Testing for Deep Vein Thrombosis

1. Leg Compression Device to Assist in Ultrasound Testing for Deep Vein Thrombosis Design Team: Mark Rawls and Jordan Winston Advisors: Dr. Raul Guzman and Dr. Paul King

2. What is Deep Vein Thrombosis? • Deep vein thrombosis (DVT) refers to the formation of a thrombus (blood clot) within a deep vein, commonly in the thigh or calf. • Symptoms include fever, rapid heart rate, pain and swelling in the area • If not diagnosed and treated, a pulmonary embolism can result which can be life threatening

3. Problem Formulation • Technicians attempting to perform the venous duplex test for Deep Vein Thrombosis must position an ultrasound transducer, manipulate an ultrasound console and squeeze the patient’s leg. Therefore, the technician has more tasks to perform than available hands.

4. Current Testing Process

5. Potential Solution Directions • Innovations Workbench was used to develop potential solutions: • Affixation of Transducer to Leg • Relocation of Ultrasound controls • Device to Compress Leg

6. Effective Solution Direction • Fixing a transducer to the leg is not feasible due to the amount of shifting and compensating that is required during the test • Relocating the ultrasound controls to the transducer is not feasible due to the immense cost involved in re-designing the common ultrasound machine • Designing a device to compress the leg is the most feasible option in both cost and practicality Courtesy: http://www.hku.hk/surgery/vdc/vdc_diagnostics.htm#Duplex

7. Leg Compression Device Demands/Desires • Demands: • Adjustable Size • Attachment at Variable Locations • Foot Control • Safety Concerns • Rapid Squeeze/Release • Durability • Desires: • Easy attachment • Easy Detachment • Variable Pressure • Inexpensive Assembly

8. Potential Design Solutions/Evolution

9. Design Comparison

10. Final Design Selection: “2” Maximum applied force can be set on the foot pedal through calibration bolt Pulse force is applied at approximately a 3:1 advantage Pump attached with hinges to accommodate motion of arms.

11. Device Specifics • A hydraulic system for the compression device was selected for its simplicity and rapid response • The maximum necessary span of our device was found to be 22 cm • The maximum force of the pinch needed for the device is about 20 pounds of force (89 Newtons) • The device is equipped with a safety pressure valve and a calibration bolt to control the maximum force applied during compression

12. Market Potential Market Potential 600,000 patients per year are hospitalized for DVT in North America Approximately 6000 registered hospitals in the U.S. Initial market for the device will be about 3,000 units Each unit could be sold for around $333, corresponding to $1,000,000 in initial income Subtracting $500,000 for patent protection, regulatory approval, manufacturing costs, and marketing leaves an initial profit of $500,000 In the future, with approximately 10% replacement annually, and costs decreasing to 25% of income, the device could generate an additional $75,000 per annum in profit

13. Ideas for Further Innovation • Slotted arms on body of compression device • Make arm moveable about pivot point (like an expandable wrench) • Telescoping force pump at top of device for extended range of motion/compression

14. Design Timeline