The artificial maintenance of kidney function refers to medical procedures that take over the roles of failing kidneys. These interventions are necessary when the kidneys can no longer adequately filter waste products and excess fluid from the blood. They are important for sustaining life and managing the health complications that arise from kidney failure.
Understanding Kidney Failure
Healthy kidneys perform several functions beyond filtering waste. They balance electrolytes like sodium and potassium, regulate fluid levels, and produce hormones such as erythropoietin, which stimulates red blood cell production, and renin, which influences blood pressure. Kidneys also help activate vitamin D, involved in calcium regulation.
When kidneys fail, their ability to perform these functions declines, often to less than 15% of normal levels. This leads to a buildup of waste products, such as urea and creatinine, and excess fluid in the body. This accumulation can cause symptoms like swelling in the limbs, fatigue, nausea, and confusion, and can lead to complications including anemia, high blood pressure, and heart disease.
Hemodialysis
Hemodialysis is a method for artificially maintaining kidney function, involving an external machine called a dialyzer. This process filters blood outside the body to remove waste products and excess fluid. Before treatment, a vascular access point is created, such as an arteriovenous (AV) fistula, an AV graft, or a catheter, allowing for efficient blood flow to and from the machine.
During a hemodialysis session, blood is drawn from the patient’s access point and circulates through the dialyzer. Inside the dialyzer, blood passes through a semi-permeable membrane. On the other side, a special solution called dialysate flows, designed to draw out waste products and extra fluids from the blood through diffusion and ultrafiltration. Diffusion allows waste substances to move from higher concentration in the blood to lower concentration in the dialysate, while ultrafiltration removes fluid based on pressure gradients.
After the blood is purified and its fluid and electrolyte balance restored, it is returned to the patient’s body. Hemodialysis treatments typically last about four hours and are performed three times a week, though the schedule can vary based on individual patient needs. This procedure can be conducted in a specialized clinic or, in some cases, at home with proper training and equipment.
Peritoneal Dialysis
Peritoneal dialysis offers an alternative to artificial kidney function, utilizing the peritoneum, the natural lining of the abdomen, as an internal filter. This method involves introducing a sterile dialysate solution into the peritoneal cavity through a surgically placed catheter. The peritoneum contains numerous blood vessels, allowing it to act as a semi-permeable membrane for filtering waste.
As the dialysate dwells in the peritoneal cavity, waste products and excess fluid from the blood vessels in the peritoneum pass into the solution. This exchange occurs over several hours, during which the dialysate absorbs toxins such as urea, creatinine, and excess electrolytes. After the prescribed dwell time, the waste-laden dialysate is drained from the abdomen and discarded, and fresh dialysate is introduced.
Two primary types of peritoneal dialysis exist. Continuous Ambulatory Peritoneal Dialysis (CAPD) is a manual method where the patient performs exchanges throughout the day, typically 3-5 times daily, with each exchange taking about 30 minutes. Automated Peritoneal Dialysis (APD) uses a machine called a cycler to perform multiple exchanges overnight while the patient sleeps. Both methods allow for greater flexibility compared to in-center hemodialysis, as they can often be performed at home or even while traveling.
Life with Artificial Kidney Function
Living with artificial kidney function requires adjustments to a patient’s daily routine and lifestyle. Adherence to treatment schedules is important for managing the condition and maintaining health. These therapies become a regular part of life, often dictating daily planning and activities.
Dietary considerations are an important part of managing artificial kidney function. Patients need to restrict fluid intake to prevent fluid overload between treatments and limit certain minerals like potassium and phosphorus, which can build to harmful levels. Working with a dietitian helps patients create meal plans that balance nutritional needs with these restrictions.
Medication management is also a regular part of life with artificial kidney function. Patients take medications to manage blood pressure, anemia, bone health, and other complications. Despite these changes, artificial kidney function allows individuals to manage their condition, extend their lives, and maintain a quality of life, enabling participation in many aspects of daily living.