Supplementary Material for: Patterns and Mechanisms of Artificial Kidney Failure during Continuous Renal Replacement Therapy

Background: We aimed to describe the previously unstudied relationship between circuit pressures and circuit clotting, here labeled as ‘artificial kidney failure' (AKF), in patients receiving continuous renal replacement therapy (CRRT). Methods: We performed an observational study of CRRT-treated critically ill patients to continuously record the multiple CRRT circuit pressures. Results: Three patterns of access outflow dysfunction (AOD) were also noted: severe, moderate and mild. Compared with circuits without AOD, circuits experiencing at least one AOD episode had shorter lifespans (14.2 ± 12.7 vs. 21.3 ± 16.5 h, p = 0.057). This effect was more obvious with moderate or severe AOD (8.7 ± 4.6 vs. 20.6 ± 15.7 h, p = 0.007). If any AOD events occurred within the first 4 h, the sensitivity and specificity in predicting early-immediate AKF were 53.4 and 94.4%, respectively. Conclusions: Early and intermediate AKF during CRRT is most likely dependent on AOD, which is a frequent event with variable severity.