CRRT (Continuous Renal Replacement Therapy)  Dr. Sree Bhushan Raju MD,DM(AIIMS),DNB,MBA,FICP, FISN, FIACM Professor & Head Dept of Nephrology,  Nizam's Institute of Medical Sciences,  Hyderabd

Definition of CRRT “Any extracorporeal blood purification therapy intended to substitute for impaired renal function over an extended period of time and applied for or aimed at being applied for 24hours/day” Bellomo R, Ronco C, Mehta R; Nomenclature for CRRT; AJKD 1996

Use of CRRT worldwide First-choice RRT in ICUs throughout Australia, Japan and Europe Best Kidney study Treatment of AKI in 1,738 patients in 54 ICUs on five continents CRRT- most common choice of initial RRT treatment, with 80% of patients CRRT- used first in 100% of ICUs in Australia IHD used as initial therapy in 30–40% of patients, restricted to North and South America

Comparision of different RRT modalities

Rt.jugular > Femoral > Lt.jugular > subclavian

Modes of CRRT

Solute and water transport in CVVH vs CVVHD

Indications of CRRT Haemodynamic instability Disrupted fluid balance due to cardiac failure or multiorgan failure Increased catabolic states (e.g., rhabdomyolysis) Sepsis Severe fluid overload Cerebral oedema

ADV. vs DISADV. Advantages of CRRT More haemodynamic stability No worsening of cerebral oedema Easier fluid removal Optimal flexibility User-friendly machines may be operated by ICU nurses Disadvantages of CRRT Patient immobilization Continuous anticoagulation Treatment should be interrupted for patient transport Higher ‘in-hospital’ costs Slow removal of toxins

Pre-dilution vs Postdilution Advantages of pre-dilution Advantages of postdilution Improved filter survival due to reduced haemoconcentration and membrane fouling Reduced filter costs Increased thermal losses Increased solute clearances (for similar replacement rate) Reduced requirement for replacement fluids (for similar clearance) Reduced fluid costs

Advantages of CRRT over IHD Allows adequate volume of nutrition without compromising fluid balance Decreased vasopressor requirements during fluid removal Increased hemodynamic stability Optimizes fluid balance in lung injury Continuous control of fluid balance

RCT on CRRT vs IHD

RCT on Dose of CRRT

Prescribed vs Delivered dose ATN study RENAL study Prescribed dose low (mL/kg/hr) 20 25 Delivered dose low (mL/kg/hr) 17.5 22 Prescribed dose high (mL/kg/hr) 35 40 Delivered dose high (mL/kg/hr) 27.1 33.4

Dose of CRRT The currently recommended dose for CRRT in critically ill patients with AKI is an actually delivered effluent flow of 20–25 mL/kg/hour In order to account for the discrepancy between prescribed and delivered dose, it is recommended to prescribe an effluent flow of 25– 30 mL/kg/hour

Timing of RRT - Controversial!

Unresolved issues Timing of CRRT Modality of CRRT Effect of CRRT on renal recovery and other patient centred outcomes

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