The influence of combined regional anesthetic blockade, compared with local anesthesia, on hemodynamic parameters and pain criteria in patients receiving an arteriovenous fistula for hemodialysis.

Abstract

Background: In the creation of arteriovenous fistulas (AVF) for hemodialysis, regional brachial plexus block (BPB) has a sympatholytic effect, increasing blood flow and diameters in the vessels.

Methods: A prospective, randomized, clinical-surgical pilot study was carried out, comprising 40 patients, randomly allocated into two groups (BPB or local anesthesia-LA). The diameter (veins and arteries), and the flow, peak systolic velocity (PSV), pulsatility index (PI), and pulsatility index ratio (PIR) of the arteries were evaluated before and after anesthesia. Flow was measured in the AVF at the end of the procedure and 30 days after. To analyze pain perception, the visual analog scale (VAS) was applied during anesthesia (T1), during surgery (T2), and at discharge (T3). All analyses were performed using R v. 4.3.1. A p-value <0.05 was considered statistically significant.

Results: Comparing BPB with LA, in the pre- and post-anesthesia periods, there was an increase in the diameters of the cephalic and basilic veins (p < 0.001) and the ulnar artery (p < 0.001). There was a significant increase in the PSV of the radial and brachial (p < 0.001) and ulnar (p = 0.0017) arteries. There was an increase in flow in the radial, ulnar, and brachial arteries (p < 0.001). There was a significant decrease in the PI for the radial (p = 0.0022), ulnar and brachial (p < 0.001) arteries. The BPB group had a significant change in the PIR of the arteries (p < 0.001). Regarding pain perception, the BPB group presented a decrease at T2 (p < 0.001).

Conclusions: For this study, in the group that received BPB, there was an increase in the diameters of the arteries and veins as well as the flow and PSV of the arteries, and decreasing the PI, the PIR, and in the perception of intraoperative pain.