Patient Information for Continuous Renal Replacement Therapy (CRRT)
What is Continuous Renal Replacement Therapy (CRRT)?
Blood filtration is a method of drawing blood out of the body through a blood purification machine. The blood passes through a filter to remove waste products, toxins, and excess fluids from the body before being returned to the patient. Various dialysis machines are used in clinical practice, but they share the same working principle.
Continuous renal replacement therapy, also known as continuous blood purification or continuous renal replacement therapy (commonly abbreviated as CRRT), is a specialized form of dialysis performed on critically ill patients in intensive care units. These patients suffer from kidney failure and have unstable hemodynamic or cardiovascular conditions, making intermittent dialysis unsuitable for them. Additionally, CRRT is applied to certain patients without kidney disease who require the removal of a toxin from their bodies.
Intermittent dialysis, also known as regular hemodialysis (commonly abbreviated as IHD), is a procedure performed periodically for patients at medical facilities, allowing them to be discharged on the same day if their condition is stable. Intermittent dialysis is typically performed for patients with end-stage renal disease, usually 2 to 3 times a week, with each session lasting 3 to 4 hours. Intermittent hemodialysis (IHD) is also performed in hospitals for patients with acute kidney injury who have stable hemodynamics.
Continuous renal replacement therapy (CRRT) causes less hypotension compared to intermittent hemodialysis (IHD) and is performed continuously for at least more than 12 hours, typically lasting 20 to 24 hours a day, and can continue for multiple consecutive days to continuously remove waste products and fluids from the patient's body. During CRRT, anticoagulant medications are usually required to prevent the filter from clotting.
Who needs Continuous Renal Replacement Therapy?
Approximately 5% of hospitalized patients experience acute kidney injury or acute renal failure. Among critically ill patients treated in intensive care units, the rate of acute kidney injury is about 40% to 60%. Multiple factors contribute to acute kidney injury in ICU patients, such as shock (patients experiencing hypotension due to various causes), infections, medications, or toxins.
Roughly 25% of ICU patients with acute kidney injury have an indication for dialysis. The preferred choice of dialysis for these critically ill patients is continuous renal replacement therapy (CRRT), especially when the patient has hemodynamic instability and requires vasopressors (blood pressure-raising medications).
Certain patients with normal kidney function also require continuous renal replacement therapy (CRRT) to filter and excrete toxins from the body in conditions such as severe acute pancreatitis with multiple organ failure, poisoning, critical COVID-19, or drug-induced metabolic acidosis.
How is Continuous Renal Replacement Therapy performed?
After evaluating that a patient has an indication for continuous renal replacement therapy (CRRT), doctors will explain the indication as well as the disadvantages and complications associated with the CRRT process to the patient and their family.
The patient or the patient's representative will receive counseling and sign a consent form.
The physician will insert an intravenous catheter (commonly called a dialysis catheter) into a large vein in the groin or neck area to withdraw blood from the body. This catheter is connected to the dialysis machine via a system of tubing.
The patient's blood flows through this tubing system to the dialysis machine, where it passes through a filter to remove toxic components or excess fluids from the body. Afterward, the blood is returned to the patient's body through the dialysis machine system.
The duration of continuous renal replacement therapy (CRRT) typically lasts 20 to 24 hours a day and continues for multiple days until the patient's kidneys recover.
Normally, an average CRRT filter is used for 24 to 36 hours before a new filter is needed. However, in certain medical conditions, the blood filter clots more rapidly, lasting only 8 to 18 hours, and requires more frequent filter replacements.
How long does a patient need Continuous Renal Replacement Therapy?
Continuous renal replacement therapy (CRRT) is carried out until the patient begins to show signs of kidney recovery or until the patient's blood pressure stabilizes so they can transition to intermittent hemodialysis (IHD).
What are the signs that the kidneys are recovering?
The first sign of kidney function recovery is when the patient begins to produce urine. Most patients who undergo continuous renal replacement therapy (CRRT) do so because of anuria or oliguria. However, even when the patient begins to urinate, the filtration capacity of the kidneys takes a much longer time to recover. It may take several weeks or months before the kidneys can filter solutes and eliminate waste.
It may take several months or longer for the kidneys to recover function following acute kidney failure. If the patient had normal kidney function prior to hospital admission, is young, and has no underlying medical conditions, their kidney function has more than a 90% chance of recovery.
What are the complications associated with Continuous Renal Replacement Therapy?
There are complications associated with continuous renal replacement therapy (CRRT). Some commonly encountered complications include:
Hypotension. Hypotension occurs less frequently during continuous renal replacement therapy (CRRT) compared to intermittent hemodialysis (IHD).
Hypothermia.
Coagulation disorders and abnormal bleeding due to the required use of anticoagulant medications.
Increased risk of infection related to catheter placement (dialysis catheter).
Complications related to catheter insertion (dialysis catheter) such as accidental arterial puncture, bleeding, venous thrombosis, etc.
Discomfort for the patient due to restricted movement of the leg where the catheter (dialysis catheter) is placed over a prolonged period.
Increased risk of pressure ulcers due to reduced mobility in the legs as well as limited position changes during dialysis.
"The information above is for reference purposes only and is not intended as medical advice. Please contact your doctor for detailed medical consultation."