RRT in medical terms most commonly stands for renal replacement therapy, the umbrella term for treatments that do the work of failing kidneys. In hospital settings, RRT can also refer to a rapid response team, a group of clinicians called to a patient’s bedside when vital signs suddenly worsen. Both meanings come up frequently in medical records and conversations with healthcare providers, so understanding each one matters.
Renal Replacement Therapy: The Basics
Renal replacement therapy includes any treatment that takes over the filtering job your kidneys normally handle: removing waste, balancing electrolytes, and clearing excess fluid from your blood. The three main forms are hemodialysis, peritoneal dialysis, and kidney transplantation. A kidney transplant is the most preferred form of RRT because it most closely restores normal kidney function, but not everyone is eligible, and donor organs are in short supply. People who are waiting for a transplant or who aren’t candidates for one are maintained on one of the two types of dialysis.
When RRT Becomes Necessary
Doctors generally recommend starting dialysis when kidney filtration drops to roughly 5 to 9 milliliters per minute, a fraction of the normal rate of about 90 or above. Several international guidelines agree that dialysis should begin before filtration falls below 6 mL/min, even if a person feels relatively well, because waiting longer carries serious risks.
Symptoms often force the decision before that threshold. Persistent nausea and vomiting that don’t respond to medication, fluid buildup in the lungs, uncontrolled high blood pressure, confusion or memory problems from waste accumulation in the blood, and a severe overall decline in quality of life are all recognized triggers. In some cases, complications like inflammation around the heart or abnormal bleeding tip the balance toward immediate dialysis.
Hemodialysis
Hemodialysis routes your blood through an external machine that filters out waste and extra fluid, then returns the cleaned blood to your body. Sessions typically happen three times a week at a dialysis center and last several hours each. The machine does in a few hours what healthy kidneys do around the clock, so the process involves pulling a relatively large volume of fluid and solutes in a short window.
To connect you to the machine, you need a vascular access point. There are three options:
- Arteriovenous fistula (AVF): A surgical connection between an artery and a vein, usually in the forearm. It’s the most durable option with the lowest risk of clotting and infection, but it takes about six weeks to mature before it can be used, and roughly one in four never matures successfully.
- Arteriovenous graft: A synthetic tube connecting an artery and vein. It’s considered when a fistula isn’t feasible, though it carries higher rates of infection and clotting.
- Central venous catheter: A tube placed into a large vein in the neck or chest. It can be used immediately, making it the go-to for urgent dialysis. The trade-off is a higher infection risk and poorer long-term durability.
The most common complication of hemodialysis is low blood pressure during or after sessions, which can cause dizziness, nausea, or cramping. Infection at the access site is another ongoing concern, particularly with catheters. Over time, cardiovascular problems including irregular heart rhythms are a significant risk for people on long-term hemodialysis.
Peritoneal Dialysis
Peritoneal dialysis uses the lining of your abdominal cavity as a natural filter. A catheter is placed in your abdomen, and a sterile fluid is pumped in. Waste and excess water pass from blood vessels in the abdominal lining into that fluid, which is then drained out and replaced.
There are two approaches. Continuous ambulatory peritoneal dialysis (CAPD) involves manually exchanging the fluid four or five times throughout the day. Automated peritoneal dialysis uses a machine to cycle the fluid while you sleep. Most people start with CAPD. Both versions let you dialyze at home rather than traveling to a center, which many patients find more convenient and less disruptive to daily life.
The main risks are infection of the catheter exit site and peritonitis, an infection of the abdominal lining. Low blood pressure can also occur, though it tends to be less of a problem than with hemodialysis because fluid removal is slower and more gradual.
Continuous Renal Replacement Therapy (CRRT)
CRRT is a specialized, slower form of dialysis used in intensive care units for patients who are too unstable for standard hemodialysis. Where a typical hemodialysis session pulls fluid quickly over a few hours, CRRT runs around the clock, removing water and waste very gradually. This gentle pace makes it far easier on blood pressure, which is critical for patients already in shock or on medications to support their circulation.
Beyond hemodynamic stability, CRRT offers tighter control over the body’s acid-base balance and better management of fluid overload. It’s the first choice for patients with acute kidney injury alongside conditions like sepsis, acute liver failure, brain swelling, or elevated pressure inside the skull. In sepsis specifically, CRRT can lower levels of inflammatory molecules circulating in the blood, shorten the time a patient needs organ support, and reduce ICU stay.
Kidney Transplant
A successful kidney transplant eliminates the need for dialysis entirely. The survival advantage is substantial. Even among patients over 70, five-year survival after transplantation is about 80%, compared with 53% for matched patients who remain on dialysis. That benefit isn’t immediate: in the first several months after surgery, transplant recipients face a higher risk of infection-related death. After roughly nine months, survival progressively favors transplantation.
Kidneys from living donors and standard-criteria deceased donors provide the earliest survival benefit. Kidneys from older or less-than-ideal donors still offer a long-term advantage, but the elevated risk period lasts longer, around 17 months. After a transplant, you’ll take immune-suppressing medications for life to prevent your body from rejecting the new kidney, which is the main ongoing trade-off.
Rapid Response Team: The Other RRT
In a hospital setting, RRT often means rapid response team. This is a group of clinicians, typically a critical care nurse, a respiratory therapist, and a physician on backup, who are called to a patient’s bedside when something is going wrong but before a full cardiac arrest occurs. The idea is straightforward: intervene during the window when a patient is deteriorating rather than waiting until the heart stops.
Traditional “code blue” teams are summoned only after a patient’s heart has already stopped beating. Rapid response teams fill the gap before that point. Any nurse, and at many hospitals any staff member or even a family member, can activate the team when a patient on a general medical or surgical ward shows worrying changes in heart rate, blood pressure, breathing, or mental status. The goal is to assess the patient immediately, start treatment at the bedside, and prevent an ICU transfer, cardiac arrest, or death. If you see RRT mentioned on a hospital whiteboard or hear it announced overhead, this is what it refers to.