What is CRRT?
Continuous Renal Replacement Therapy is designed to provide artificial kidney support to patients who could not tolerate traditional hemodialysis. CRRT is intended to run for 24 hours a day, but the average therapy time is actually closer to 16 hours a day due to interruption. It deals with all sized waste molecules in the blood.
What are the functions of CRRT?
- Reduce clotting in the hemofilter to maximize the CRRT circuit life.
- Replace the excretory function of the kidney.
- Deals with acute renal failure, chronic renal failure, fluid overload, drug overdose, life-threatening electrolyte imbalance, major burns with compromised renal function.
- Remove fluid in special circumstances—post surgery pulmonary edema, ARDS etc.
- Provide excellent control of azotemia, electrolytes and acid base balance.
- Remove proinflammtory medicators of inflammation, such as IL-1, IL-6, IL-8, TNF-a.
What are the side effects of CRRT?
You may have the following risks:
- Ischemia of the limb
- Hematoma formation
- Arterial wall injury
- Spasm of the artery cannulated
Besides, this mode of therapy asks regular monitoring of hemodynamic status and fluid balance; ongoing alarms and an expensive mode of therapy, regular infusion of dialysate.
What are the features of CRRT?
- No pump is required in this therapy. The mean arterial pressure drives the blood into the filter or dialyzer.
- It gives rapid and constant blood flow rate.
- It has the advantage of improved dialyzer performance and decreased line and dialyzer clotting.
What types of CRRT are there?
- Slow Continuous Ultrafiltration (SCUF) removes fluid without the need for replacement fluids known as substitution solutions. It helps prevent or deal with fluid overload in cases when waste products don't need to be removed, or the PH levels don't need to be corrected.
- Continuous Venovenous Hemofiltration (CVVH) is a form of convective dialysis which removes large volumes of fluids and waste products from the patient. This mode is also very effective for clearing mid sized molecules, such as inflammatory cytokines.
- Continuous Venovenous Hemodialysis (CVHD) primarily uses diffusion along with a cleansing fluid known as a dialysate solution to boost the removal of waste products. This provides reasonably effective solute clearance, although mostly small molecules are removed.
- Continuous Venous Venous Hemodiafiltration (CVVHD). With this therapy, both small and middle molecules are cleared, and both dialysate and replacement fluids are required.
What are the CRRT facts?
- In Australia, 90% of patients in an ICU (Intensive Care Unit) with acute renal failure receive CRRT, in Europe about 50% and numbers in America continue to rise.
Dos and don'ts of CRRT
- The patient should remain in the bed till the catheter in situ.
- Avoiding interruptions in CRRT by preventing clotting provides continuous therapy.
Anticoagulation may be or may be not necessary, which depends on doctor's preference, patient's condition and other factors.