Performance Comparison of Centered and Tilted Blunt and Lighthouse Tip Cannulae for Drainage in Extracorporeal Life Support.

Abstract

Introduction: Extracorporeal membrane oxygenation is a lifesaving treatment for patients with refractory acute respiratory, circulatory, or combined cardiopulmonary failure. The patient is cannulated with one or two cannulae for drainage and reinfusion of blood. Blood is drained from the patient, pumped through a membrane lung for oxygenation and returned to the patient. Treatment efficiency depends on correct cannula positioning and interactions between drainage and reinfusion cannula.

Methods: An experimental setup was built to study the isolated drainage performance of 24 Fr rigid models of a blunt and lighthouse tip cannula, both when centered and when tilted towards the vessel wall. Planar particle image velocimetry was used to investigate the flow field with water as the fluid medium.

Results: For similar flow configuration, higher shear stresses were recorded in the blunt tip rather than lighthouse tip cannula. Moreover, in the lighthouse tip cannula, side-holes furthest from the tip (proximal side-holes) had the highest drainage. Results did not change substantially when the cannula was tilted towards the vessel wall.

Conclusions: The effective drainage point of the lighthouse tip cannula was located near the proximal side-holes. Lower shear stresses were recorded in the lighthouse tip cannula when compared with the blunt tip cannula, for all considered flow rate ratios and cannula positions.