Continuous Renal Replacement Therapy: Understanding the Procedure

Introduction

Acute kidney injury (AKI) is characterized by a failure in renal function. Numerous factors, such as dehydration, blood loss, infections, and some drugs, might contribute to it. AKI is a dangerous illness with a mortality rate of 30 percent to 70 percent. It can develop potentially fatal side effects, including uremia, electrolyte imbalance, and fluid overload.

Continuous renal replacement therapy (CRRT) is a type of dialysis that, specifically, is used in the treatment of acute kidney injury (AKI). In contrast to standard hemodialysis, which usually lasts for a few hours, continuous renal regional therapy (CRRT) can be utilized for days or even weeks at a time. For patients with severe AKI, this makes CRRT a more beneficial course of treatment and is used in nearly five to ten percent of patients with acute kidney injury (AKI).

What Is Continuous Renal Replacement Therapy?

Continuous renal replacement treatment (CRRT) is the most common kidney replacement option that is now accessible. This procedure is a combination of peritoneal dialysis and hemodialysis on an intermittent basis. Dialysis is gradual and continuous in this therapy, lasting up to 24 hours, allowing for solute and fluid equilibrium. It is performed through a pump-driven venovenous extracorporeal cardiopulmonary circuit, which helps in blood purification. CRRT is a mild, gradual type of dialysis that continuously eliminates abnormal fluid and waste from the circulation, just like a healthy person's kidneys would.

How Does Continuous Renal Replacement Therapy Differ From Dialysis?

CRRT is a slower form of dialysis that puts less pressure on the heart. CRRT is performed 24 hours a day, instead of four hours, to gradually and constantly remove waste products and fluid from the patient. Waste filtration in hemodialysis is usually finished quickly in a matter of hours. However, because CRRT differs technically from conventional hemodialysis, it proceeds more slowly, may be done steadily, and produces more stable blood pressure while it is being done. To prevent clotting in the dialysis circuit, specific anticoagulation is needed.

What Are the Different Types of Continuous Renal Replacement Therapy?

Continuous renal replacement therapy (CRRT) is generally employed for treating critically ill patients with acute kidney injury or other types of kidney failure. Numerous varieties of CRRT can be employed, such as:

• Constant Venovenous Hemofiltration (CVVH): This method of filtration involves passing a huge or sizable ultrafiltrate volume over a conventional or highly permeable membrane.

• Continuous Venovenous Hemodialysis (CVVHD): This method involves filtering blood and using diffusion techniques to remove waste materials. After that, new fluid is infused to replace the old one.

• Continuous Venovenous Hemodiafiltration (CVVHDF): Diffusive clearance is the method used to eliminate toxins and solutes from the patient's bloodstream. It uses an effective hemodia filter to remove fluid and particles by combining convection and diffusion techniques.

• Slow Continuous Ultrafiltration (SCUF): This method uses ultrafiltration to remove the body's stored excess fluid without adding additional fluid.

• Continuous Arteriovenous Hemofiltration (CAVH): This procedure involves taking blood out of an artery and filtering it before putting it back into a vein. It is a combination of convection and diffusion that is used to evacuate the fluid. Replacement fluid might be administered but is not used frequently.

• Continuous Arteriovenous Hemodialysis (CAVHD): This method involves drawing blood from an artery, and waste materials are filtered and eliminated through diffusion. In this process, replacement fluid is administered occasionally.

• Continuous Arteriovenous Hemodiafiltration (CAVHDF): This process involves drawing and filtering blood from an artery. Diffusion and convection work together to remove the fluid component and waste products. Replacement fluid might be administered, but only sometimes.

How Is the Procedure for Continuous Renal Replacement Therapy Done?

Before the Procedure -

The process begins with inserting a dialysis catheter (CVC), a sterile process. An intensive care unit (ICU) physician or radiologist with training in catheter placement performs this procedure.

During the Procedure -

The following are some of the most important steps in a standard CRRT procedure:

• CRRT apparatus consists of a pump, filter, and tubing linked to the patient.

• The catheter is often placed into a large vein in the groin or neck, where blood is extracted from the patient.

• The filter removes waste materials and extra fluid from the blood after it has been run through it.

• To maintain the right ratio of fluids and electrolytes, replacement fluids such as saline or a specialist electrolyte solution are added to the filtered blood.

• Another catheter, often placed into a vein in the opposing arm, delivers the treated blood to the patient.

• To guarantee a safe and efficient process, the CRRT equipment keeps track of the patient's vital signs, including temperature, blood pressure, and other parameters.

• Several hours, sometimes even days, are involved throughout the process, depending on the patient's state and the type of CRRT used.

• Healthcare professionals closely watch the patient throughout the process for any indications of difficulties or side effects, including infection, bleeding, or abnormal electrolyte levels.

After the Procedure -

The team may attempt to discontinue the CRRT when the patient recovers. Initially, they examine the health of patients' kidneys. Proceed with hemodialysis or restart the ERRC if kidney support is still required. This procedure is three to five days a week.

What Are the Complications of Continuous Renal Replacement Therapy?

The following factors are associated with the primary CRRT complications:

• Problems relating to catheters.

• Blood loss.

• Loss of connection.

• Infection.

• Difficulty in gaining access.

• Mechanical consequences are associated with cardiopulmonary bypass.

• Variations in the salt balance.

• Complications associated with hemodialysis.

• Low blood pressure.

• Unintentional removal of tubes, such as those connected to a breathing tube, dialysis catheter, or ventilator.

• Hemorrhage.

• Venous thrombosis.

Secondary complications include:

• Infection is linked to catheters.

• Peritonitis.

• High blood sugar.

• Lack of protein.

Conclusion

Continuous renal replacement therapy (CRRT) is used to treat acute kidney injury patients who are critically ill and require dialysis. It is considered a useful tool in critical care situations, providing gradual and ongoing assistance to maintain fluid and electrolyte balance. CRRT is a lifeline for patients with impaired renal function, contributing to their overall rehabilitation and well-being even though it is resource-intensive and requires specialized knowledge.