Expandability of Cephalic Veins after Brachial Plexus Block in Arteriovenous Fistula Formation for Hemodialysis

Abstract

Background: Arteriovenous fistula (AVF) for hemodialysis is essential for patients with end-stage renal disease. However, it is difficult to maintain AVF reliably. It is vitally important to select proper blood vessels for AVF formation. In a previous study, a minimum diameter of 3 mm for the autologous vein was proposed. However, patients who did not meet the minimum vascular diameter before anesthesia, but fulfilled other criteria, showed satisfactory venous dilatation after brachial plexus block (BPB). This study investigated the extent of vein expansion by BPB and the surgical outcomes of dilated veins after BPB. Methods: Sixty-one patients who underwent AVF formation using an autologous vein between August 2018 and December 2019 were included in the study. The clinical characteristics of the patient groups, hemodynamic parameters including the diameter of blood vessels before and after BPB, and complications were investigated. Based on the venous diameter measured by sonography before anesthesia, patients were divided into group A (26 patients) and group B (35 patients), with venous diameters <3 mm and ≥3 mm, respectively. Results: The venous diameter expanded after anesthesia by 41% overall, by 62% in group A, and by 25% in group B. This difference between groups A and B was statistically significant (p=0.001). No other variables showed statistically significant differences. Conclusion: Sufficient venous dilatation was observed after BPB. Therefore, if the vein is sufficiently dilated after BPB, even in patients with a pre-anesthesia venous diameter <3 mm, surgery may still be performed with an expected desirable outcome.