Kidney replacement therapy (KRT) is a medical intervention that takes over kidney functions when these organs can no longer perform effectively. This therapy becomes necessary when kidney function significantly declines, leading to a buildup of waste products and imbalances in the body. KRT’s primary purpose is to filter the blood, remove excess fluids and toxins, and help maintain the body’s chemical balance, which failing kidneys cannot achieve on their own. This intervention does not cure kidney disease but acts as a life-sustaining treatment, allowing individuals to manage their condition and improve their overall well-being.
When Kidney Replacement Becomes Necessary
The kidneys are organs responsible for filtering waste products and excess fluids from the blood, regulating blood pressure, and maintaining balanced levels of essential minerals like sodium, potassium, and calcium. When kidneys lose most of their filtering ability, waste products such as urea and creatinine accumulate in the bloodstream, leading to end-stage renal disease (ESRD). KRT is considered when kidney function drops to a level where the estimated glomerular filtration rate (eGFR) falls below 15 mL/min/1.73 m². KRT may also be used temporarily in cases of acute kidney injury where kidney function suddenly ceases. The decision to begin KRT is made by healthcare providers based on an individual’s symptoms, test results, and overall health status.
Dialysis: Two Primary Approaches
Dialysis is a form of kidney replacement therapy that artificially removes waste products and excess fluid from the blood when the kidneys fail. There are two main types: hemodialysis and peritoneal dialysis, both achieving the same fundamental goal through different mechanisms.
Hemodialysis
Hemodialysis involves circulating the patient’s blood outside the body through an artificial kidney machine, known as a dialyzer. The machine draws blood, typically from a vascular access site in the arm, and pumps it through the dialyzer. Inside the dialyzer, blood flows through tiny tubes or fibers, separated by a semi-permeable membrane from a special cleaning fluid called dialysate. Waste products and excess water diffuse from the blood across this membrane into the dialysate, and the cleaned blood is then returned to the patient’s body.
Treatments are commonly performed three times a week, with each session lasting about three to four hours. These treatments can take place in a specialized dialysis center or at home. Home hemodialysis may allow for more frequent, shorter sessions, offering more flexibility and mimicking natural kidney function more closely.
Peritoneal Dialysis
Peritoneal dialysis utilizes the natural filtering membrane lining the abdomen, called the peritoneum, to clean the blood inside the body. A soft, thin tube, or catheter, is surgically placed into the abdomen, through which a sterile dialysate solution is introduced into the peritoneal cavity. This solution remains in the abdomen for a prescribed period, known as the “dwell time,” during which waste products and excess fluids from the blood vessels in the peritoneum pass into the dialysate. After the dwell time, the used dialysate is drained from the abdomen and discarded.
This process of filling, dwelling, and draining is called an exchange. Peritoneal dialysis has two main forms: Continuous Ambulatory Peritoneal Dialysis (CAPD), performed manually multiple times a day, and Automated Peritoneal Dialysis (APD), which uses a machine, often overnight, to manage exchanges. Both methods offer flexibility, allowing patients to perform treatments at home.
Kidney Transplantation: A Different Path
Kidney transplantation offers an alternative to long-term dialysis by surgically placing a healthy kidney from a donor into the recipient’s body. This procedure aims to restore kidney function, allowing the new organ to perform the filtering and regulatory tasks that the failing kidneys no longer can. The transplanted kidney is typically placed in the lower abdomen and connected to the recipient’s major blood vessels and bladder. The recipient’s native kidneys are usually left in place unless they cause complications.
Donor kidneys can come from either deceased donors or living donors. Living donation often involves a relative or a compatible unrelated individual, and these kidneys can sometimes begin functioning immediately after surgery. Matching between donor and recipient is a complex process, involving compatibility checks for blood type, tissue type (human leukocyte antigens or HLA), and crossmatching to minimize rejection. Advancements in medicine allow for successful transplants even with some incompatibilities.
Navigating Life with Kidney Replacement Therapy
Adjusting to life with kidney replacement therapy involves adopting new routines and managing ongoing health requirements. Regardless of the specific therapy chosen, adherence to treatment schedules is important for maintaining health. For dialysis patients, this means consistently attending sessions or performing home treatments as prescribed.
Managing diet and medication are also important components of daily life with KRT. Individuals undergoing dialysis often have dietary restrictions to control fluid, sodium, potassium, and phosphorus intake. For transplant recipients, taking immunosuppressive medications precisely as prescribed is necessary to prevent the body from rejecting the new kidney. These medications must be taken for the lifetime of the transplanted organ. Regular communication with the healthcare team, including dietitians and pharmacists, helps individuals navigate these adjustments and maintain their well-being.