Dialysis is a therapy that aims to remove waste products produced by the body that the kidneys no longer expel. This occurs in advanced stages of chronic kidney disease with severe reduction in kidney function. Dialysis becomes necessary when kidney dysfunction exceeds 85-90%. Dialysis rebalances substances in the blood such as potassium, sodium, calcium, phosphorus, and bicarbonate. It is a therapeutic procedure introduced in the 1940s, but its main application began in the 1960s. To date, it remains the most suitable method for those who need to purify their blood.
When is Dialysis Needed?
The kidneys are responsible for filtering the blood and removing harmful waste and excess fluids. Once these wastes and excess fluids are transformed into urine, the body expels them, thus preventing the presence of toxins in the blood. When chronic kidney failure does not allow the blood to be cleansed of all toxins, a state of malaise occurs, and in severe cases, if not addressed, it can lead to death.
For this reason, dialysis is necessary because it removes unwanted substances and fluids by filtering in place of the kidneys. The therapy also helps regulate the patient’s blood pressure. The trusted nephrologist will periodically monitor kidney function through blood tests to determine blood chemistry substances such as: blood urea nitrogen, creatinine, sodium, potassium, calcium, phosphorus, uric acid, and/or evaluating GFR (glomerular filtration rate expressed in ml/min) according to guidelines (MDRD, Crockcroft-Gault).
Dialysis, the duration of the treatment
Dialysis can also be performed for a temporary period. The duration of the treatment is linked to the causes that make it necessary. It is not excluded that kidney failure may be only a temporary factor, so when the kidneys resume functioning and filtering, dialysis is no longer necessary. If, however, dialysis is permanent, it requires a kidney transplant, which remains the only solution to also restore hormone release in the body. Until a compatible donor is found for the dialysis patient, the treatment continues regularly. There are also cases where a kidney transplant is no longer possible, due to age or overall health condition: in this case, the patient must undergo dialysis for life.
The two types of dialysis
Dialysis is differentiated into hemodialysis, also known as extracorporeal dialysis, and peritoneal or intracorporeal dialysis. The definition is based on the filtering process that can occur inside or outside the human body through a machine, the artificial kidney. In hemodialysis, blood circulation occurs in an external circuit. We speak of diffusion when the dialysis fluid allows the transfer of waste and excess fluids from the blood to the dialysis fluid itself. In hemodialysis, the membrane, or dialysis filter, is artificial and is located inside the machine. In Italy, hemodialysis represents the main type of dialysis for those with chronic kidney failure.
The arteriovenous fistula
During extracorporeal dialysis, the patient is connected to a circuit or artificial kidney. The connection is made with a needle-cannula inserted into the arm. The entry port is created by an arteriovenous fistula that joins a vein and an artery. The fistula can only be used 6 weeks after its creation through surgical intervention.
How hemodialysis works
The machine draws blood through a pump, pushing it into the filter where it is purified through the membrane, and then reinserts it into the body. Fluid removal occurs through pressure generated by the pump and dialysis machine. The treatment lasts about 4 hours and must be performed 3 times a week.
The risks of hemodialysis
Risks may include:
bleeding risk after treatment due to heparin presence
infections or blood clots at the vascular access site
cardiac rhythm disturbances due to poor potassium removal
This is why monitoring at specialized centers is necessary.
The Use of Central Venous Catheter
It is used when kidneys suddenly stop functioning and dialysis needs to be started immediately. It is a temporary solution until a fistula can be created.
Lifestyle on dialysis
Dialysis patients can work, study, travel, play sports, and drive, if properly monitored by qualified personnel.
Side effects
Dialysis can cause:
hypotension
fatigue
paresthesia
itching
cramps
Beach activities should be approached with caution if using a catheter.
Foods to avoid
Dialysis patients should avoid:
alcoholic beverages and spirits
bouillon cubes, meat extracts
pickled or oil-preserved foods
cured meats
margarine, packaged sauces
salty snacks and junk food
Beverages for dialysis patients
Fresh beverages are better, but they should neither be ice-cold nor sweetened. It’s also helpful to dissolve sugar-free lemon ice cubes in the mouth.