Healthy kidneys have several functions in the body, the most important functions are removal of metabolic waste products like urea, creatinine and to produce urine. When kidney function goes below 10% to 15%, is needed. is a therapy that filters waste, removes extra fluid and balances electrolytes (sodium, potassium, bicarbonate, chloride, calcium, magnesium and phosphate).In , blood is removed from the body and filtered through a semi permeable membrane called a dialyzer, or artificial kidney, and then the filtered blood is returned to the body.
To perform there needs to be an access created to get the blood from the body to the dialyzer and back to the body. There are three access types for :
1. Arteriovenous (AV) fistula
2. AV graft and
3.Central venous catheter.
Blood is taken out via one limb of the access, filtered in the machine and returned back to body via other limb of the access. Various monitors keep track of blood flow, blood pressure, how much fluid is removed and other vital information.The purpose of dialysate is to pull toxins from the blood into the dialysate. The way this works is through a process called diffusion.
The extra fluid is removed through a process called filtration. The fluid is pushed off by higher pressure on the blood side than on the dialysate side.
Usually 10 to 12 hours of is required per week. Each dialysis session lasts 4 hours.Usually three dialysis session a week is recommended , however some patients prefer doing two dialysis a week. Alternative schedules include nocturnal and short daily dialysis. With nocturnal hemodialysis, the patient has dialysis for about eight hours overnight while sleeping. Also, because nocturnal dialysis is performed during nonproductive sleeping hours, many people report they feel that their lives are more "normal" because they don't have to take time out of their days for dialysis.
Hemodialysis is an effective treatment for those with end stage renal disease. However, hemodialysis alone will not provide a complete treatment for those with kidney failure. Diet and fluid restrictions need to be followed, and medicines may need to be taken to replace other functions of the kidneys, such as regulating blood pressure and stimulating production of red blood cells to prevent anemia.
Common complication during hemodialysis:
• Blood lossy
• Allergic reaction to dialyzer
• Muscle cramping
• Hematoma or swelling at needle insertion sites
• Clotting of vascular access
Other dialysis modalities available
Continuous renal replacement therapy (CRRT) : CRRT is any extracorporeal blood purification therapy designed to substitute for impaired renal function over an extended period, and intended to be applied for up to 24 hours a day. CRRT is the modality of choice for treating ICU patients with renal failure, especially in the case of hemodynamically unstable renal failure patients.
Sustained low efficiency dialysis (SLED): SLED is a modification to intermittent HD where the blood is pumped at a rate of 150-200 mL/min for 6 to 12 hours. This modality offers more hemodynamic stability, better correction of hypervolemia, and more adequate solute removal, compared with intermittent hemodialysis. The costs are lower than for CRRT. SLED is slowly replacing CRRT as the preferred dialysis modality for hemodynamically unstable patients with acute kidney injury.
Plasmapheresis: Plasmapheresis is a term used to refer to a procedure in which extracorporeal separation of blood components results in a filtered plasma products. The filtering of plasma from whole blood can be accomplished via semipermeable membranes. Membrane plasma separation uses differences in particle size to filter plasma from the cellular components of blood. Some of the Indication for plasmapheresis are: Rapidly progressive glomerulonephritis(RPGN), Lupus nephritis, Hemolytic uremic syndrome(HUS), TTP, Myasthenia gravis, CIDP etc.