BME 450 Final Project - External Ventricular Drain

For my senior design project in BME 450, we were tasked with finding a clinical problem and attempting to design and implement a solution. We chose to reach out to the Tiba lab, who were having undesirable amounts of blood in their cerebrospinal fluid when testing on pigs. Our goal was to brainstorm, design, and manufacture a method to minimize this, while also minimizing excess damage to the brain tissue.

Dimensions are in millimeters

First Iteration

I designed our alpha prototype to fit around the existing catheter used to take CSF from the pig's ventricles, which was approximately 3mm in diameter. This prototype was tested on a euthanized pig in the Tiba lab and was found to be just small enough to fit in the existing bore hole through the skull, although it was deemed too thick and significantly longer than needed. The alpha prototype was printed out of white resin on a SLA printer.

Second Iteration

For the second iteration, I added a bevel on one end, to minimize trauma to the brain matter. The overall thickness of the sheath was also reduced to an outer diameter of 3.5mm from 4.5. Finally, the length was reduced from 150mm to 50mm. This prototype was also printed out of white resin on a SLA printer.

The second iteration of our prototype was inserted into a male to female luer lock, and then tightened into place using a screw mechanism. As shown in the "Our Device" section, the catheter was inserted into the right side of the luer lock and tightened, and then the catheter was inserted from the left side. The screw mechanism on the left side could be used to prevent the catheter from moving once it was in position. By testing on store bought pig brains, we were able to test our second prototype by inserting the sheath, and then advancing the catheter out of the sheath once the ventricle was reached. As shown in the "Verification and Validation" section, inserting just the catheter without a sheath, which was the lab's previous method, resulted in much more brain matter in the catheter than our sheath method. This brain matter of course represents additional damage to the brain, while also clogging the catheter and preventing CSF removal and testing.

Final Poster

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