CRRT flow

 Q: Which of the following may cause the clotting of the filter in Continous Renal Replacement Therapy (CRRT)? (select one)

A) High flow across the circuit

B) Low flow across the circuit

C) Both high and low flow across the circuit

Answer: C

Many patients may not be candidates for anticoagulation during CRRT and varied pressure due to varied flow across the CRRT circuit may render this intervention futile. 

The optimum blood flow across the CRRT circuit is considered to be around 200 mL/min. Low blood flow causes stasis of the blood and leads to filter clotting. On the other hand, high blood flow may trigger pressure alarms and stop the blood flow as a safety measure installed in the CRRT machine. Extracorporeal circuit tubing and hemofilter can process a limited volume of blood before its degradation. High blood flow accelerates this process. 

#nephrology

References:

1. Baldwin I, Bellomo R, Koch B. Blood flow reductions during continuous renal replacement therapy and circuit life. Intensive Care Med 2004; 30:2074.

2. Fealy N, Aitken L, du Toit E, et al. Faster Blood Flow Rate Does Not Improve Circuit Life in Continuous Renal Replacement Therapy: A Randomized Controlled Trial. Crit Care Med 2017; 45:e1018.