Investigation of a novel method for improving hemodynamics of Fontan
circuit using an experimental model
Abstract
Background: The study objective was to test underlying physical
laws behind a proposed novel device for failing Fontan and investigate
whether the device could be implemented theoretically to improve
hemodynamics in failing Fontan circulation. Methods: A 4-arm
setup was designed and fabricated to simulate an actual Fontan circuit
in the form of a junction of the superior and inferior vena cavae (SVC,
IVC) with the right and left pulmonary arteries (RPA, LPA). A provision
for placement of an oscillating ball along the RPA-LPA path to push
fluid away from SVC and IVC was created. The rate of ball oscillations
and initial pressure of fluid on SVC and IVC limbs were varied. The
pressure-drop times in the vena cavae limbs were measured at varying
ball oscillations and resistances in the RPA-LPA pathway. The test was
considered positive if increasing oscillations of the ball allowed for
quicker pressure drop in the SVC and IVC limbs indicating quicker
discharge of fluid through the RPA and LPA. 48 different experiments
were conducted to simulate different physical conditions and the results
were plotted and analyzed to draw a conclusion. Results: The
time required for pressure drop in the experiment without ball was the
least across all set of readings. This meant that placing an oscillating
ball along the RPA -LPA path created obstruction to flow rather than
enhance it. Increasing rate of ball oscillations increased degree of
obstruction to flow. Conclusion: The proposed interventional
method is unsuitable for improving hemodynamics in failing Fontan
circulation.