"Continuous" therapy is not truly continuous. Down-time adversely affects azotaemic control. Physicians prescribing CRRT should be aware of the consequences of such down-time on the quality and quantity of renal replacement therapy delivered.

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Background/Aims: To determine the impact of replacement fluid infusion site on filter life and azotemic control during continuous veno-venous hemofiltration (CVVH). Methods:Pre-dilution CVVH was conducted from February 2001 to December 2001 and then practice was changed to post-dilution (from January 2002 to July 2002). Filter life was prospectively observed and the following data obtained for each filter: starting date and time, ending date and time, heparin use, heparin dose and protamine use. Daily creatinine, urea, INR, APTT and platelet count were also collected. Results: Forty-eight patients were studied (33 in pre-dilution and 15 in post-dilution) for a total of 309 filters (202 in pre-dilution and 107 in post-dilution). The median filter life was significantly shorter in the post-dilution period (18.0 vs. 13.0 h, p = 0.021). Multivariate linear regression analysis showed that pre-dilution was a significant independent predictor of increased filter life (p = 0.029), together with platelet count (p = 0.0035) and heparin dose (p = 0.046). There was no significant improvement in daily creatinine and/or urea reduction in the post-dilution period (% Δ creatinine: 7.9 vs. 10.2%/day, p = 0.99, urea: 5.4 vs. 9.7%/ day, p = 0.78). Conclusions: Post-dilution was associated with reduced filter life without any beneficial effect on daily changes in urea and creatinine levels. Pre-dilution appears a preferable technical approach to CVVH.

IntroductionDespite studies demonstrating benefit, patients with femoral vascular catheters placed for continuous renal replacement therapy are frequently restricted from mobilization. No researchers have reported filter pressures during mobilization, and it is unknown whether mobilization is safe or affects filter lifespan. Our objective in this study was to test the safety and feasibility of mobilization in this population.MethodsA total of 33 patients undergoing continuous renal replacement therapy via femoral, subclavian or internal jugular vascular access catheters at two general medical-surgical intensive care units in Australia were enrolled. Patients underwent one of three levels of mobilization intervention as appropriate: (1) passive bed exercises, (2) sitting on the bed edge or (3) standing and/or marching. Catheter dislodgement, haematoma and bleeding during and following interventions were evaluated. Filter pressure parameters and lifespan (hours), nursing workload and concern were also measured.ResultsNo episodes of filter occlusion or failure occurred during any of the interventions. No adverse events were detected. The intervention filters lasted longer than the nonintervention filters (regression coefficient = 13.8 (robust 95% confidence interval (CI) = 5.0 to 22.6), P = 0.003). In sensitivity analyses, we found that filter life was longer in patients who had more position changes (regression coefficient = 2.0 (robust 95% CI = 0.6 to 3.5), P = 0.007). The nursing workloads between the intervention shift and the following shift were similar.ConclusionsMobilization during renal replacement therapy via a vascular catheter in patients who are critically ill is safe and may increase filter life. These findings have significant implications for the current mobility restrictions imposed on patients with femoral vascular catheters for renal replacement therapy.Trial registrationAustralian and New Zealand Clinical Trials Registry ACTRN12611000733976 (registered 13 July 2011)Electronic supplementary materialThe online version of this article (doi:10.1186/cc14001) contains supplementary material, which is available to authorized users.

We conducted a prospective observational study to assess the efficacy of continuous venovenous hemofiltration (CVVH) with no anticoagulation. A standard anticoagulation protocol for CVVH, which prescribed no anticoagulation for patients at risk of bleeding, was applied to 48 critically ill patients treated with CVVH. Circuit life was prospectively observed, and the following data were obtained for each circuit: heparin use and dose, protamine use, daily prothrombin time-international normalized ratio, activated partial thromboplastin time, and platelet count. Out of 300 consecutive circuits, 143 (47.6%) received no anticoagulation, 31 (10.3%) received regional anticoagulation, and 126 received low dose heparin. No patients experienced bleeding complications secondary to CVVH. Platelet count was significantly lower in the no anticoagulation group (73 x 10(3)/microl) compared with the low dose heparin group (119 x 10(3)/microl) and the protamine group (104 x 10(3)/microl) (p < 0.01 for both comparisons). There was no significant difference in mean circuit life among the three groups (heparin, 20.9 hours; no anticoagulation, 19.3 hours; protamine, 21.2 hours; not significant). In conclusion, for a group of patients deemed to be at risk of bleeding, CVVH without anticoagulation achieved an acceptable circuit life, which was similar to that obtained in other patients with low dose heparin anticoagulation or regional anticoagulation with heparin/protamine.

Objective To evaluate the efficacy and safety of a regional heparinization and a regional citrate method of anticoagulation in CVVH. Design Randomized controlled cross-over study Subjects Ten critically ill patients with acute renal failure Setting ICU of tertiary hospital Intervention CVVH was performed with pre-filter fluid replacement at 2000ml/h and a blood flow rate of 150ml/min. Regional heparinization was by the administration of heparin pre-filter at 1500IU/h and protamine post-filter at 15mg/h. Regional citrate anticoagulation was by means of a citrate-based replacement fluid (14 mmol/L) administered pre-dilution. Results We studied nine males and one female. The mean age and APACHE II score were 70.5 and 17 respectively. Median circuit life was 13 hours (IQR 9.28) for the regional heparinization method compared to 17 hours (IQR 12,19.5) for the regional citrate method (p=0.77). There were no episodes of bleeding in either group. Conclusion Regional heparinization and regional citrate anticoagulation achieve similar circuit life in critically ill patients receiving CVVH.

Treatment of critically ill patients with continuous renal replacement therapy (CRRT) requires a set of new skills and knowledge base for the intensive care unit (ICU) nurse. After a decision to treat is made, nurses effectively manage the technique by following a series of steps in sequence. These sequential steps include patient and machine circuit preparation, connection of the extracorporeal circuit (EC) to the patient's vascular access, and nursing management of a treatment in progress. During treatment, nurses prepare fluids, adjust fluid settings to provide fluid balance, prepare electrolyte additives, monitor acid base and electrolyte levels, monitor patient and machine "vital signs," and, when necessary, diagnose circuit clotting and perform a disconnection of the EC from the patient. All of these aspects of CRRT nursing are essential for a successful CRRT nursing policy or protocol. This chapter provides a clinical review for this every day sequence when using CRRT in the ICU setting.

Objective To test the ability of a novel super high-flux (SHF) membrane with a larger pore size to clear myoglobin from serum. Setting The intensive care unit of a university teaching hospital. Subject A patient with serotonin syndrome complicated by severe rhabodomyolysis and oliguric acute renal failure Method Initially continuous veno-venous hemofiltration was performed at 2 l/hour ultrafiltration (UF) with a standard polysulphone 1.4 m 2 membrane (cutoff point, 20 kDa), followed by continuous venovenous hemofiltration with a SHF membrane (cutoff point, 100 kDa) at 2 l/hour UF, then at 3 l/hour UF and then at 4 l/hour UF, in an attempt to clear myoglobin.