Table 2 Anticoagulation modalities for continuous renal replacement Method Filter prime Initial dose Saline solution 2 L saline Heparin 2 L saline 2500–10000 U LMW heparin 2 L saline 40 mg 10–40 mg/6 h Regional heparin Regional citrate Prostacyclin Hirudin 2500 U/2 L saline 2 L saline 2 L saline + heparin 2 L saline Danaparoid 2 L saline 2500 U bolus Argatroban 2 L saline Nafomostat mesilate 2 L saline 150–250 mL pre-filter 5–10 U/kg 5–10 U/kg 4% trisodium citrate 150–180 mL/h 4–8 ng/kg/min 625 µg/kg/h – – Maintenance dose 100–250 mL/h pre-filter 3–12 /kg/h 3–12 U/kg/h; + protamine post-filter Monitoring Visual check ACT 200–250; PTT 1.5–2.0 × normal Factor Xa levels; maintained between 0.1–0.41 U/mL PTT: post-filter ACT 200–250 100–180 mL/h ACT: 200–250 maintain 3–7% of BFR, ionized calcium Ca replaced by 0.96–1.2 mmol/L central line 4–8 ng/kg/min Usually no monitoring if heparin not required 6–25 µg/kg/h PTT, Ecarin (Monitor clotting time carefully in renal failure) 400 IU/h PTT antifactor Xa 2 µg/kg/min (reduce in hepatic dysfunction) 0.1 mg/kg/h PTT ACT Renal replacement therapy Advantages Disadvantages No anticoagulant used Poor filter patency Standard method; easy to use; inexpensive Decreased risk of bleeding Reduced bleeding risk No bleeding; no thrombocytopenia; improved filter efficacy, longevity Alternative to heparin and citrate. Usually in liver failure Alternative to heparin. Usually used if HITT Bleeding risk; thrombocytopenia Special monitoring; not available everywhere; expensive Complex; risk of thrombocytopenia; protamine effects; hypotension Complex; needs Ca monitoring; alkalosis May need low-dose heparin addition; hypotension Bleeding risk; no reversal agent Alternative to heparin. Usually used if HITT Alternative to heparin. Usually used if HITT Bleeding; no reversal agent Bleeding risk; no reversal agent Alternative to heparin Bleeding Source: Mehta RL. 1992. New developments in continuous arterio-venous hemofiltration/dialysis. In Andreucci VE, Fine L (eds). International Yearbook of Nephrology, 1992. Heidelberg: Springer. Copyright © Springer Verlag. Reproduced with permission from Springer Verlag. NOTE: Dashes mean no loading dose. Abbreviations: ACT, activated clotting time; BFR, blood flow rate; HITT, heparin induced thrombocytopenia; LMW, low molecular weight; PTT, partial thromboblastin time. Another advantage of CRRT is the improved efficiency of solute removal. Although the clearance rate of small solutes is slower per unit time with CRRT (17 mL/min vs more than 160 mL/min with conventional hemodialysis), CRRT is continuously administered; therefore, urea clearance is more efficient after 48 h than with alternate day intermittent hemodialysis. Clark et al (1997) developed a computer model based on 20 critically ill patients to compare solute clearance in intermittent and continuous renal replacement therapies, and found that for a 50 kg male, an average of 4.4 dialysis sessions/week would be required to achieve equivalent uremic control. In patients with a weight greater than 90 kg, equivalent uremic control could not be achieved with intermittent therapies even if daily dialysis was prescribed. Therapeutics and Clinical Risk Management 2005:1(2) Fluid management is often a difficult issue in ICU, where nutritional requirements (TPN) and the use of IV medications necessitate the administration of large amounts of fluid to critically ill patients. The inability to severely fluid restrict fluid intake in ICU patients results in excessive volume overload, which may compromise tissue perfusion and has been associated with adverse outcomes (Mehta et al 2002). Attempts to restrict fluid in this setting may additionally compromise adequate nutrition (Campbell 1999). The capacity to adjust fluid balance on an hourly basis, even in hemodynamically unstable patients, is largely responsible for the growing popularity of CRRT. CRRT may also have an immunomodulatory effect. The rationale for the use of CRRT for the treatment of sepsis arises from the observed association between sepsis severity 147