What are dialysis and what types exist?

Dialysis is a vital medical treatment for individuals whose kidneys can no longer perform their normal functions. This therapy, essential for maintaining health in cases of advanced chronic kidney disease, has become a pillar of modern medical care.

Dialysis is a medical procedure designed to remove waste, excess water, and toxins from the body when the kidneys can no longer do so effectively. The kidneys, vital organs of the urinary system, filter the blood to remove waste products and excess fluid from the body in the form of urine. When the kidneys fail, dialysis acts as an artificial substitute for this function.

How Dialysis works

There are two main types of dialysis: hemodialysis and peritoneal dialysis. In hemodialysis, blood is removed from the body, filtered through a special machine called a dialyzer, cleaned, and returned to the bloodstream. On the other hand, in peritoneal dialysis, the peritoneal membrane inside the abdomen is used as a natural filter. A special fluid is introduced into the abdominal cavity through a catheter, which absorbs waste and is then drained from the body.

History of Dialysis

The history of dialysis dates back to ancient times, with references to primitive methods of blood purification. However, it was during the 20th century that more advanced techniques were developed. The first successful hemodialysis procedure was performed in the 1940s, ushering in the modern era of dialysis therapy.

Indications for Dialysis

Dialysis is prescribed when kidney function declines to a point where it cannot maintain proper body homeostasis. This can occur due to a variety of diseases, including chronic kidney disease, acute kidney failure, drug intoxication or poisoning. Patients requiring dialysis often present with symptoms such as fatigue, swelling, shortness of breath, and fluid retention.

Types of Dialysis

Dialysis comprises a set of therapeutic techniques designed to remove waste and fluid from the body in patients with kidney dysfunction. While hemodialysis and peritoneal dialysis are the most common modalities, there are other less common options that also deserve attention.

Hemodialysis is a procedure in which a patient's blood is removed from their body through a vascular access, such as an arteriovenous fistula or central catheter, and pumped into a dialyzer. Inside this device, blood passes through semipermeable membranes that separate waste and excess fluid from the bloodstream. This process is carried out in a dialysis center under the supervision of specialized medical personnel.

On the other hand, peritoneal dialysis involves the infusion of a dialysate fluid into the patient's abdominal cavity through a peritoneal catheter. This fluid contains a special solution that absorbs waste and excess fluid through the peritoneal membrane, which acts as a natural filter. After a set period of time, dialysate fluid with absorbed waste is drained from the patient's abdomen.

In addition to these main modalities, there are other less common options:

Hemodiafiltration: This method combines hemodialysis with conventional blood filtration. The blood is passed through a dialyzer, but negative pressure is also applied to allow additional removal of toxins through filtration.

Hemofiltration: Similar to hemodiafiltration, hemofiltration involves the removal of toxins and fluids through a filtration process. However, in this case, the ultrafiltered liquid is eliminated from the body without being recirculated.

Diffusion dialysis: In this approach, waste is removed from the blood using a concentration gradient across a semipermeable membrane. This method is often used in combination with hemofiltration or hemodiafiltration to improve the effectiveness of toxin removal.

Choosing the right type of dialysis for a specific patient depends on several factors, such as the patient's medical condition, resource availability, and individual preferences. Each modality has its own advantages and disadvantages, and it is important that the medical team and the patient work together to make the most appropriate decision for their particular situation.

Side Effects and Complications

Although dialysis is essential for many patients with advanced kidney disease, it also carries risks and side effects. These may include hypotension, nausea, vomiting, muscle cramps, vascular access site infections, unwanted weight loss, and electrolyte imbalances. It is important that patients are informed about these risks and that steps are taken to minimize them.

Recent Advances in Dialysis Therapy

Continued research in the field of nephrology has led to significant advances in dialysis therapy. New techniques and technologies have been developed to improve the effectiveness and safety of dialysis procedures, as well as to increase the comfort and quality of life of patients. These advances include high-efficiency dialyzers, remote monitoring systems, and improved vascular access methods.

Ethical and Social Considerations

Equitable access to dialysis therapy is a major concern in many countries, especially those with underdeveloped or inequitable health systems. Additionally, ethical issues arise related to the allocation of limited resources, end-of-life decision making, and quality of life for long-term dialysis patients. It is crucial to address these considerations from an interdisciplinary perspective that takes into account medical, ethical, social and economic aspects.

Through techniques such as hemodialysis and peritoneal dialysis, these procedures help cleanse the blood and remove waste from the body, improving quality of life and prolonging patient survival. However, it is important to recognize the challenges and limitations associated with dialysis therapy, as well as work toward solutions that promote equitable access and comprehensive care for all patients affected by chronic kidney disease.