(1414) Effect of Catheter Diameter and Blood Flow Rate on Continuous Venovenous Hemodialysis

Introduction: Maintenance of continuous veno-venous hemodialysis (CVVHD) depends on access, blood flow and filter patency. Blood clot formation in the access catheter can reduce dialysis run time, impeding efficiency. Catheter-related circuit failure (CF) interrupts therapy leading to potential adverse outcomes for patients. Theoretically, large bore catheters with wider lumens sustain higher blood flow rates (BFR) that may limit potential filter lifespan but should improve clearance, reduce CF frequency and improve outcomes on CVVHD. The goal of this study is to compare CVVHD outcomes in patients after transitioning from 11.5fr to larger 13.5fr dual lumen dialysis catheters, while increasing BFR from 200 to 250 cc/min.

Methods: This retrospective cohort study was conducted at Westchester Medical Center (WMC). Data using 11.5fr catheters at 200 BFR were collected between Nov 2020-July 2023 (n=496). Comparison data from Jan-July 2024 (n=54) were collected after transition to 13.5fr catheters at 250 BFR. This study included all adult patients with the criteria above who underwent CVVHD via temporary dialysis catheters. Exclusion criteria were patients previously on CVVHD or with prior catheters in place and undergoing withdrawal of care, organ procurement or transplant intraoperative CVVHD. WMC does not use standardized systemic anticoagulation or regional citrate with CVVHD. Data was obtained from the electronic medical record.

Results: Both 11.5fr/200BFR and 13.5fr/250BFR groups were similar and evaluated for time of first filter lifespan until CF, 72 hour mortality after initiation of CVVHD and hospital mortality.
There was no significance in time to initial CF: 11.5fr/200BFR (22.60h, SD=22.86) and 13/5fr/250BFR (26.84h, SD=22.68); t(548)= -1.295, p=0.1958.
There was also no significant difference in the rate of 72h mortality 1.51 (95%CI 0.77-3.38, p=0.2241) or hospital mortality 1.12 (95%CI 0.78-1.66, p=0.5325).

Conclusions: Critically ill patients requiring CVVHD have multiple risk factors that may contribute to early CF and high mortality. Our data showed no significant changes to initial filter lifespan or patient mortality with increasing catheter size or BFR. Despite these finding, our changes effectively increased clearance during CVVHD which may impact other aspects of patient morbidity.