Quantitative and qualitative investigation of shunt failure in an in vitro hemorrhagic hydrocephalus model

A direct relationship was observed between blood concentration and the pressurization rate, such that shunts and EVDs that were exposed to higher concentrations of blood consistently reached 30 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub><mml:mrow><mml:mi>c</mml:mi> <mml:mi>m</mml:mi> <mml:mi>H</mml:mi></mml:mrow> <mml:mn>2</mml:mn></mml:msub> <mml:mi>O</mml:mi></mml:mrow> </mml:math> threshold while the samples in the low-concentration groups did not. In contrast, a reverse relationship was observed between bulk flow rate and pressurization rate, such that the samples exposed to 0.5% at 0.7 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mfrac><mml:mrow><mml:mi>m</mml:mi> <mml:mi>L</mml:mi></mml:mrow> <mml:mi>min</mml:mi></mml:mfrac> </mml:mrow> </mml:math> had a significantly smaller pressurization rate than samples exposed to 0.5% at 0.3 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mfrac><mml:mrow><mml:mi>m</mml:mi> <mml:mi>L</mml:mi></mml:mrow> <mml:mi>min</mml:mi></mml:mfrac> </mml:mrow> </mml:math> (<i>P = 0.029</i>). These findings highlight the role of clot formation in PHH shunt obstruction and suggest avenues for improved catheter design or clinical management.