What is RRT?
RRT stands for "Renal Replacement Therapy," though current nomenclature guidelines now recommend using "KRT" (Kidney Replacement Therapy) instead, as the term "kidney" is more familiar to most English speakers than "renal." 1
Definition and Scope
Kidney Replacement Therapy (KRT) encompasses all treatments that replace lost kidney function, including both dialysis and kidney transplantation. 1 The term requires further specification when used, as it is an umbrella term rather than a specific treatment modality. 1
Key Components of KRT:
Dialysis modalities include hemodialysis (HD), hemofiltration (HF), hemodiafiltration (HDF), and peritoneal dialysis (PD, either ambulatory or automated). 1
Kidney transplantation from either living donors (LDKT) or deceased donors (DDKT). 1
Frequency specifications include continuous or intermittent (short or prolonged) treatments. 1
Terminology Update and Rationale
The 2020 KDIGO Consensus Conference explicitly lists "Renal Replacement Therapy (RRT)" as a term to avoid, recommending "Kidney Replacement Therapy (KRT)" instead. 1 This nomenclature change reflects efforts to standardize medical terminology in ways that are more accessible to patients and families. 1
Patient Communication:
When speaking with patients and families, avoid technical terms like "RRT" or "KRT" entirely—instead use plain language such as "life support," "kidney machine," or describe the specific treatment type (hemodialysis, peritoneal dialysis, or transplant). 1
Communication should be provided in simple lay language at regular intervals, recognizing that patients may be traumatized by their illness. 1
Clinical Indications for Initiating KRT
Emergent Indications:
KRT must be initiated immediately when life-threatening changes in fluid, electrolyte, and acid-base balance exist. 1, 2 Specific emergent indications include:
- Refractory pulmonary edema unresponsive to diuretics 2, 3
- Severe hyperkalemia unresponsive to medical therapy 4, 2
- Refractory metabolic acidosis 4, 2
- Uremic symptoms or signs (serositis, uremic bleeding, cognitive impairment, pruritus) 4, 2
Non-Emergent Indications in CKD:
KDIGO recommends initiating dialysis when symptoms or signs attributable to kidney failure are present, typically occurring when GFR is between 5-10 ml/min per 1.73 m². 4 However, the GFR threshold is not absolute—clinical symptoms should drive the decision rather than GFR alone. 4
Additional indications include:
- Inability to control volume status or blood pressure despite optimal medical therapy 4
- Progressive deterioration in nutritional status refractory to dietary intervention 4
- Cognitive impairment attributable to uremia 4
Discontinuation of KRT
KRT should be discontinued when intrinsic kidney function has recovered sufficiently to meet patient needs, or when KRT is no longer consistent with the patient's goals of care. 1, 5
Urine output prior to discontinuation is the most robust predictor of successful KRT discontinuation, with sensitivity of 66.2% and specificity of 73.6%. 1, 5
For patients receiving acute KRT, sustained independence from treatment for a minimum of 14 days defines successful recovery from dialysis dependence. 1
Important Clinical Caveats
Conservative management without KRT remains a valid option for patients who choose not to pursue dialysis or transplantation, and this decision should be supported by comprehensive symptom management and advance care planning. 4, 5
In sepsis and acute kidney injury, either continuous or intermittent KRT can be used, with continuous therapies preferred for hemodynamically unstable patients to facilitate fluid balance management. 1
Patients with end-stage kidney disease receiving chronic KRT should be excluded from enrollment in clinical trials using natriuretic peptides as inclusion criteria, as these patients have chronically elevated peptide concentrations. 1