Tested liquid flow rate: Aspirator was run for 30 second intervals Liquid Recorded collected volume Flow rate was cal

1. Collection chamber, tubing, and suction tip Engineering World Health: Medical Aspirator Lucas Vitzthum, Jonathan Meyer, Nick Harrison, Fan Wu Advisor: John Webster Ph.D. Client: Bonnie Tompkins M.D. Final Design Abstract Costs Medical aspirators are suction devices used to remove mucous and other bodily fluids from a patient. Many developing world hospitals do not possess aspirators because they can neither afford nor repair the current devices on the market. The goal of this project is to create a less expensive, locally repairable, and less power dependant alternative to current medical aspirators. The design should provide the broadest possible range of uses for developing world hospitals. Table shows costs and 3rd world source for each part used in the design. Our device is comprised of a fan motor, a piston-driven vacuum chamber system, a fluid collection chamber, and tubing with an autoclavable tip. Overall Design with motor, piston and collection chamber Power source to radial motion: The power source is a 12 V car battery which powers a car heater fan motor. Radial to linear motion: A wire rod connects the outer rim of the fan motor to a bolt in a linear slot.  The top of the bolt is connected to the piston head (plastic bottle) with another wire rod.  The piston is constricted to purely linear movement with a range equal to the diameter of the motor. Background • Medical aspirators are common in the U.S. • Found in almost any hospital, ambulance, or dental clinic. • Suction devices used to remove mucous, blood, or other bodily fluids • Generally include disposable suction tips and a removable collection receptacle. • Generally powered by 120V AC outlets, batteries, or a combination of both • Designed for use in modern, state of the art medical environments. • Sizes can range from hand held devices to larger stationary surgical units • Third world hospital conditions are radically different • Inconsistent electricity • Lack of medical professionals. • Limited space Piston system and Vacuum Chamber: The linear wire rod is connected to a piston (plastic bottle and duct tape), and moves it back and forth in the vacuum chamber (PVC pipe), alternately drawing and expelling air from the chamber. Diagram of motor and piston system Problem Statement *Projected cost is a high estimate, as most of the materials can be salvaged free of cost. Tubing and Collection Chamber: Flexible tubing connects the vacuum chamber to the collection chamber (a hard plastic bottle). Tubing also connects the collection chamber to the autoclavable tip. Future Work • Statement: • Design a medical aspirator that can be built and repaired from locally available parts in the developing world for less than $100. • Motivation: • Current devices are inaccessible to developing world hospitals • Too expensive • Too specialized • Not locally repairable One-way valves: The valves are made from a flap of inner-tube rubber glued over a small hole in a food can lid. The flap is pushed open when air flows in one direction, but pushed closed when air flows in the opposite direction. • Improve vacuum and flow rate • Add bleed valve to control flow • Develop instructions to build locally • Contact third-world country hospitals and clinical engineers to implement device and begin use Prototype Testing References Source: www.medfinity.com Design Criteria Aspirator suction machine., 2007, from http://www.medicalsupply4u.com/prodList.asp?idCategory=1 12&showFilter=0&idProduct=51 Electro surgery continuing education model. (2007). March 12, 2007, from http://www.valleylabeducation.org/esself/Pages/esself23.html Hill, D. (2005). Duke engineering program improves hospital conditions In developing countries. Retrieved 4/12, 2007, from http://www.dukenews.duke.edu/2005/09/DEWH.html • Tested liquid flow rate: • Aspirator was run for 30 second intervals • Liquid • Recorded collected volume • Flow rate was calculated as liters/minute • Air • Connected to flow meter • Must be completely manufactured from locally available parts and expertise • Must Reliably provide suction throughout an entire surgery or operation (up to 8 hours). • Must not interfere in operating room procedures or with staff. • Must be safe for use in human surgeries • Vacuum pressure range of 0 – 550 mmHg • Flow rate range of 0 – 30 lpm. • Cost: less than $100 • Life in Service: 5 years • Weight: Less than 10 kg without battery. • Size: Less than 0.15 m3 (2/3 by 2/3 by 1/3 m) • Power: 12 V car battery Acknowledgments Thanks to AmitNimunkar, Frank Fronczak Ph.D., Bonnie Tompkins, M.D.. and John Webster Ph.D. Fig 1. Graph showing flow rate (L/min) aspirated with prototype. Error bars show standard error with n=3.