The Hemodynamic Effects of Hemodialysis Needle Rotation and Orientation in an Idealized Computational Model

Abstract

Maintaining the patency of vascular access is essential for performing efficient hemodialysis. Appropriate cannulation technique is critical in maintaining the integrity of vascular access. This study focused on analyzing the hemodynamic effect of needle rotation, which is performed to alleviate the pressure if the needle becomes attached to the blood vessel wall. The hemodynamic benefits (normal wall shear stress [WSS] and smooth flow with no oscillatory motion) of this technique are investigated in an idealized model of the cephalic vein in order to determine a needle position that will reduce conditions known to contribute to vascular access failure. A computational fluid dynamics study was conducted, with antegrade and retrograde orientations simulated on the arterial needle, whereas the venous needle is placed in the antegrade orientation. In every case, needle rotation offered no hemodynamic benefit in minimizing the conditions known to cause endothelial damage, a precursor to vascular access failure. Venous needle rotation reduced the maximum WSS by 30%. However, the WSS was above the range, which may damage the endothelial layer. The arterial needle in the antegrade orientation produced a large region of oscillatory shear, whereas a retrograde orientation produced a region of smooth flow in the vicinity of the needle with only a small region of oscillatory shear. The flow through the venous needle back eye was negligible, whereas the arterial needle back eye was more efficient in the retrograde orientation. Therefore, the venous needle should not be rotated, whereas the arterial needle may be rotated to alleviate pressure with consideration given to the orientation of the needle.

Factors affecting arteriovenous fistula dysfunction: A narrative review

“…Vessel injury promotes inflammation as described above as well as platelet adhesion, which propagates inflammation and promotes thrombosis. 112,113 Area cannulation and retrograde direction of the arterial needle with bevel down were associated with higher risk of AVF failure in a study by Parisotto et al 114 Furthermore, the presence of needles in the AVF might contribute to abnormal WSS, as reported by Fulker et al, [115][116][117] with antegrade orientation of the arterial needle producing a larger area of oscillatory shear stress. Higher turbulent flow downstream of the venous needle and consequent endothelial dysfunction and loss of NO expression have been described.…”

Vascular access cannulation and haemostasis: a national observational study of French practices

“…A study involving 48 patients found greater pain severity and a larger hole left by the needle when the bevel was facing upwards [ 21 ], which appears to be confirmed by a study in 70 patients finding a lower risk of bleeding during cannulation when the bevel is facing downwards [ 22 ]. Modelling the flows and pressures did not reveal any relationship between the position of the bevel and dialysis dose [ 23 ].…”

Computational Fluid Dynamic Analysis of the Hemodialysis Plastic Cannula

“…A fully structured hexahedral grid was created in ICEM 14.5 (ANSYS, Inc., Canonsburg, PA, USA), consisting of ∼8 million cells. A previous grid independence analysis found a maximum variation of peak WSS of 3.1% using this grid size . Computational simulations were conducted in Fluent 14.5 (Fluent, Inc., Lebanon, NH, USA) under the assumption of non‐compliant walls due to the arterialization of the cephalic vein after AVF creation.…”