Circuit haemodynamics during non-citrate and regional citrate continuous renal replacement, and impact of blood flow on filter life

Abstract

Background: During continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA), blood flow (Qb) might affect vascular access dysfunction (AD) and, thereby, circuit life. Methods: Circuit life and circuit haemodynamics were studied in three intensive care units (ICUs) by analysing hemofilter device data (Prismaflex®, Baxter, Chicago, IL). The three sites shared similar RCA protocols but differed in Qb (120–130 vs 150–200 mL/h). Non-RCA circuits were compared with RCA circuits in which the impact of Qb was also assessed. Results: About 3,981,906 min of circuit pressures were analysed in 2568 circuits in 567 patients. High-Qb RCA was associated with more extreme pressures, and greater AD (IRR 3.7 (1.93–7.08) as well as reduced filter life 21.1 (10.2–42.6) vs 27.0 (14.8–41.6) h). AD in high-Qb RCA circuits was associated with a 49% reduction in filter life, versus 24% reduction in low-Qb RCA, associated with a rise in the rate of increase in transfilter pressure. Conclusions: High-Qb RCA-CRRT was associated with greater access dysfunction, earlier filter loss and increased haemodynamic impacts of access dysfunction, suggesting low-Qb RCA-CRRT may improve circuit mechanics, function and longevity.