Circuit Hemodynamics and Circuit Failure During Continuous Renal Replacement Therapy

Abstract

Objectives: To study hemodynamic changes within continuous renal replacement therapy circuits and evaluate their relationship with continuous renal replacement therapy longevity. Design: Analysis of downloaded variables recorded by continuous renal replacement therapy machines during multiple episodes of clinical care. Setting: Tertiary ICU in Melbourne, Australia. Patients: Cohort of 149 ICU patients: 428 episodes of continuous renal replacement therapy. Interventions: None. Measurements and Main Results: Indices of continuous renal replacement therapy function representing 554,991 minutes were assessed including blood flow, access pressure, effluent pressure, prefilter pressure, and return pressure. We defined three patterns of artificial kidney failure: early (≤ 12 hr), intermediate (> 12–24 hr), and late (> 24 hr) in 35%, 31%, and 34% of circuits, respectively. Mean access pressure in late artificial kidney failure was 7.5 mm Hg (7.1–7.9 mm Hg) less negative than early failing circuits and pressures demonstrated lower variability in such late failing circuits. Access dysfunction, defined as access pressure less than or equal to –200 mm Hg occurred in the first 4 hours in 118 circuits (27%) which had a shorter (median [interquartile range]) life at 12.9 hr [5.5–21.3 hr]) hours than access dysfunction-free circuits (18.8 hr [10.1–33.4 hr]; p < 0.0001). Multivariate analysis found the first occurrence of access dysfunction (as a time-varying covariate) was independently associated with increased hazard of subsequent failure (hazard ratio, 1.75; 1.36–2.26). Classification and regression tree analysis of summary pressure indices in the first 2 hours confirmed minimum access pressure to be a significant predictor, as well as indices of transmembrane pressure and return pressure. A pressure-based predictor correctly identified early and late failing circuits (86.2% and 93.6% specificity, respectively). Conclusions: Access dysfunction is a predictor of continuous renal replacement therapy circuit failure. Future monitoring of continuous renal replacement therapy hemodynamics may facilitate remedial actions to improve circuit function.

Effect of Dynamic Circuit Pressures Monitoring on the Lifespan of Extracorporeal Circuit and the Efficiency of Solute Removal During Continuous Renal Replacement Therapy

“…The study still had some limitations, such as the inclusion of a narrow population (most were post-operative patients) and the lack of RCA data. A recent retrospective study ( 11 ) suggested that the occurrence of an AOD event within 4 h after the initiation of CRRT significantly reduced the lifespan of the extracorporeal circuit by 12.9 h compared with the absence of an AOD event. COX analysis of two studies ( 10 , 11 ) suggested that AOD events were independent risk factors for circuit survival, which indicates that AOP status warrants concern.…”

“…With developments in science and technology, mainstream CRRT machines can continuously record changes in pressure, such as access outflow pressure (AOP), pre-filter pressure (PFP), effluent pressure (EP), and return inflow pressure (RIP), every minute during therapy and store the data on internal storage. A few trials have investigated the pressure changes during CRRT ( 10 , 11 ), and stored pressures data can be downloaded into an Excel spreadsheet to obtain the detailed pressure data and the precise circuit lifespan ( 12 ).…”

Effect of Dynamic Circuit Pressures Monitoring on the Lifespan of Extracorporeal Circuit and the Efficiency of Solute Removal During Continuous Renal Replacement Therapy

“…The study still had some limitations, such as the inclusion of a narrow population (most were postoperative patients) and the lack of RCA data. A recent retrospective study [11] suggested that the occurrence of an AOD event within 4 h after the initiation of CRRT signi cantly reduced the lifespan of extracorporeal circuit by 12.9 h compared to the absence of an AOD event. COX analysis of two studies [10,11] suggested that AOD events were independent risk factors for circuit survival, which indicates that AOP status warrants concern.…”

“…Our study has important clinical signi cance because continuous pressures data are still not completely utilized. In our study, we collected various modalities of anticoagulation and multiple RCA data (48.6%) compare to other trails [10,11]. Moreover, we creatively combined the dynamic pressure monitoring with the solute removal e ciency during CRRT and offered a new idea for circuit replacement.…”

“…With developments in science and technology, mainstream CRRT machines can continuously record changes in pressure, such as access out ow pressure (AOP), pre-lter pressure (PFP), e uent pressure (EP), and return in ow pressure (RIP), every minute during therapy and store the data on internal storage. A few trials have investigated the pressure changes during CRRT [10,11], stored pressures data can be downloaded into an Excel spreadsheet to obtain detailed pressure data and the precise circuit lifespan [12]. CRRT removes waste and maintains the electrolyte and acid-base balance via various techniques, such as dispersion, convection, ultra ltration and adsorption.…”