February 4, 2004BME 272/2731 Investigation of Bubble Formation in Tuohy-Borst Adaptors Department of Biomedical Engineering Melanie Bernard, Isaac Clements, & Jason Hirshburg Advisor: Ted Larson III, M.D.

February 4, 2004BME 272/2732 Problem Statement Bubbles are seen within the Tuohy-Borst Adaptor –Can get stuck in small arteries in brain, inhibiting the supply of blood and oxygen –Causes stroke and death –Once present, bubbles are difficult to remove because they stick to inner surface of system –Occurs in adaptors of different geometries

February 4, 2004BME 272/2733 Problem Definition Constraints –Solution must apply to all adaptor types –Any system changes must not significantly change adaptor cost or the catheterization procedure. –Must eliminate problem without having other detrimental effects. Limitations –Time –Money –Equipment cardio/cathlab.htm

February 4, 2004BME 272/2734 Background Dr. Larson has 15 years of experience in interventional neuroradiology Catheters uses: –Angiography –Embolization of arteriovenous fistulas –Aneurysms –Preoperative embolization of neck and intracranial tumors

February 4, 2004BME 272/2735 Primary Objective Our task is to discover the cause of bubble formation and correct it Observations: Bubbles… –Up to 10-20% of tube diameter –Stick to inner surface of adaptor –Appear at the edge of the Y-junction –Occur before microcatheter is inserted –Typically occur when catheter flow is reversed and blood hits the edge of the Y-junction and interfaces with the saline (or contrasting agent)

February 4, 2004BME 272/2736 Market Potential Target group –Operating rooms worldwide Will meet customer needs –Catheterization procedures will be safer Is technologically feasible –Physical principles can be changed to eliminate bubble formation Is economically viable –Adaptor costs should not rise after our design changes

February 4, 2004BME 272/2737 Previous Work Observed device in a medical procedure on 11/18/03 Literature Search Innovation WorkBench Conducted flow experiments with colored water and actual adaptor and tubing. Observed device in a second medical procedure on 2/2/04 and obtained new supplies

February 4, 2004BME 272/2738 Previous Experiments : Results Observed lots and lots of bubbles already present throughout the system!

February 4, 2004BME 272/2739 Current Work Analyze results from previous experiments Revise the experimental setup and procedure

February 4, 2004BME 272/27310 Future Work Conduct revised experiments –Simulate actual pressures ~100 over 60 mmHg for blood pressure 250 mmHg for the saline Investigate effects of leaks –Simulate actual temperatures Body temperature for the blood Room temperature for the saline –Simulate blood properties If animal blood is not feasible use a substitute of similar properties Investigate properties of glycerin Software models of fluid flow, using Computational Fluid Dynamics (CFD) software. ~mehta/cfd.htm

February 4, 2004BME 272/27311 Questions…? Visit our website at 5_06/5_06_06.html

February 4, 2004BME 272/27312 Acknowledgements Dr. Ted Larson and staff Dr. Paul King Dr. Joan Walker Dr. Robert Roselli Dr. Todd Giorgio Dr. Cynthia Paschal Dr. Rick Haselton Dr. Bob Galloway We would like to thank the following professionals and experts for their input:

February 4, 2004BME 272/27313 Bibliography copy/5_06/5_06_06.html b1_CLiRpath-peripheral-IFU-revE-10.pdf