Table 2.

Advantages and disadvantages of the different CRRT modalities, as well as its alternatives iHD and PD

Technique	Physical principle	Minimum duration (hours)	Advantages	Disadvantages
PD	Diffusion	24	• Technically, the simplest modality • Require less infrastructure and lower costs • No need for anticoagulation • Possible in hemodynamically unstable patients	• Slow small molecule and uremic toxin clearance • Less predictable fluid removal • Risk of infections (e.g., peritonitis) • Not possible if recent abdominal surgery • May have impact on respiratory stability
IHD	Diffusion	4–6	• Rapid removal of toxins, electrolytes and fluid overload • Minimal/no need for anticoagulation • Relatively lower cost than the techniques below • Less restrictions on patients mobility	• Not recommended in critically ill hemodynamically unstable patients • Increased risk of hypotension and electrolytes disequilibrium • Require vascular access • Technically expertise required • Clearance rebound
PIRRT/SLED	Diffusion	6–12	• More rapid solutes removal than CRRT, but slower than IHD • More hemodynamically stable than IHD • Technically simpler than the techniques below • Relatively lower cost (e.g., less bags needed) • More restrictions on patients mobility than IHD but less than the techniques below	• Not recommended in critically ill hemodynamically unstable patients • Require vascular access and anticoagulant • Risks of hypotension and disequilibrium • Lower efficiency than other modalities
CVVH	Convection & ultrafiltration	24	• Convection allows highly efficient middle molecule and cytokine removal • Continuous removal of uremic toxins and fluid • Possible use in hemodynamic unstable patients	• Technically complex (e.g., complex circuit and high cost) • Require vascular access and anticoagulant (systemic or regional) • Need patient immobility • Prolonged exposure to membranes • Less efficient for small molecule removal than IHD
CVVHD	Diffusion & ultrafiltration	24	• Continuous removal of uremic toxins and fluid • Possible use in hemodynamic unstable patients • Better removal of small molecules than CVVH	• Technically complex (e.g., complex circuit and high cost) • Require vascular access and anticoagulant (systemic or regional) • Need patient immobility • Prolonged exposure to membranes • Less efficient for small molecule removal than IHD
CVVHDF	Diffusion, convection & ultrafiltration	24	• Convection allows highly efficient middle molecule and cytokine removal • Continuous removal of uremic toxins and fluid • Possible use in hemodynamic unstable patients • Better removal of small molecules than CVVH	• Technically most complex CRRT modality (e.g., complex circuit with frequent bag changes and high cost) • Require vascular access and anticoagulant (systemic or regional) • Need patient immobility • Prolonged exposure to membranes • Less efficient for small molecule removal than IHD

PD peritoneal dialysis, IHD intermittent hemodialysis, PIRRT prolonged intermittent renal replacement therapy, SLED slow low efficiency dialysis, CVVH continuous venovenous hemofiltration, CVVHD continuous venovenous hemodialysis, CVVHDF continuous venovenous hemodiafiltration