The CRRT medical abbreviation stands for continuous renal replacement therapy, a gentle form of dialysis that runs around the clock in an intensive care unit. Renal means kidney, and the therapy takes over the kidneys' job of clearing waste and extra fluid from the blood while they cannot do it themselves.
Instead of the three or four hour sessions used in regular HD, CRRT works slowly and steadily over many hours or days. That slower pace is easier on people whose blood pressure is low or unstable, which is common in critical illness. Families usually first hear the term at the bedside when an ICU team explains why a machine is being connected.
At a glance
Stands for
Continuous renal replacement therapyUsed in
Intensive care units, for critically ill adults and childrenCommon modes
CVVH, CVVHD and CVVHDFAccess
A large temporary dialysis catheter in a neck, chest or groin veinDo not confuse with
HD, intermittent hemodialysis done in shorter sessionsSpecialty
Nephrology and critical care
What the CRRT medical abbreviation means at the bedside
During CRRT, blood leaves the body through one side of a catheter, passes through a filter in a machine, and returns through the other side. The filter removes waste products such as urea and potassium, and pulls off extra fluid at a controlled rate set by the care team. Because it never stops, the shifts in fluid and salts are small from hour to hour.
The most frequent reason is acute kidney injury, written as AKI, in someone who is too unstable for a standard dialysis session. Septic shock, severe heart failure with fluid overload, and serious salt or acid problems in the blood are other common settings.
CVVH, CVVHD and CVVHDF explained
CRRT is an umbrella term. The mode tells you how the filter cleans the blood. CVV stands for continuous venovenous, meaning blood is taken from and returned to a vein.
| Mode | Full name | Main way it cleans |
|---|---|---|
| CVVH | Continuous venovenous hemofiltration | Pushes fluid through the filter, carrying waste with it |
| CVVHD | Continuous venovenous hemodialysis | Lets waste spread into a cleansing fluid on the other side of the filter |
| CVVHDF | Continuous venovenous hemodiafiltration | Uses both methods together |
Notes may also list the anticoagulant that keeps the filter from clotting, often citrate or heparin, and the hourly fluid removal goal.
How CRRT compares with regular hemodialysis
Both remove waste and fluid through a filter, but the schedule and setting differ a lot.
| Feature | CRRT | Intermittent HD |
|---|---|---|
| Timing | Around the clock | Sessions of about 3 to 4 hours |
| Setting | ICU only | Hospital unit, outpatient center or home |
| Blood pressure | Better tolerated when it is low | Faster fluid removal can drop pressure |
| Typical use | Short term, during critical illness | Short term or long term, as in ESRD |
A middle option called SLED, sustained low-efficiency dialysis, runs for longer than a standard session but not all day.
Reading a CRRT line in an ICU note
Nephrology note: "Oliguric AKI, K 6.1, on norepinephrine. Start CRRT, CVVHDF, citrate, net UF 100 mL/h." This reads as kidney injury with very little urine, a high potassium level, and blood pressure support with a medicine. The plan is continuous dialysis in the combined mode, using citrate to stop clotting and removing about 100 mL of extra fluid each hour.
Nurses track the machine's pressures, filter life, fluid balance and blood tests several times a day. When the person stabilizes, the team may switch to intermittent HD or stop dialysis if the kidneys recover.
Questions families often ask
It is natural to want to know how long the machine will be needed and whether the kidneys will heal. Some people regain kidney function, some need dialysis for longer, and the team watches urine output and lab results to judge which way things are going. Asking for a daily update on fluid goals and kidney numbers can help families follow progress.
This page describes a type of ICU kidney support in general. Each person's care plan comes from their critical care and kidney specialists, who are the right people to ask.
Browse the surgery and procedures hub for related terms.
Frequently asked questions
In the ICU, what is CRRT?
CRRT is continuous renal replacement therapy, a slow form of dialysis that runs all day and night. It is used for critically ill people whose kidneys have stopped working well and who may not tolerate a standard session.
Is CRRT the same as dialysis?
It is a type of dialysis. The difference is that CRRT runs continuously and removes fluid gently, while regular hemodialysis works in shorter, faster sessions.
What does CVVHDF stand for?
CVVHDF stands for continuous venovenous hemodiafiltration. It is a CRRT mode that combines filtering and dialysis to clear waste from the blood.
Can someone on CRRT go home with it?
No. CRRT is used only in intensive care. If kidney support is still needed after recovery, the team moves to intermittent hemodialysis or another long term option.