What is dialysis?
Dialysis is a process to replace the function of the kidneys, in order to delete multiple waste substances in excess that are harmful to our body.
Additionally, this process can remove excess water and some electrolyte that accumulates in the body by kidney failure.
How many types of dialysis are there?
Basically there are two types of dialysis: peritoneal dialysis, in which a special catheter is placed in the abdominal cavity (catheter Tenckhoff), in this process a special fluid (dialysate) is administered and left in the peritoneal cavity several hours, then this fluid is removed by the same catheter, this procedure is repeated several times a day and can be performed in the patient's home, however this type of dialysis is less efficient than hemodialysis.
The other type of dialysis is hemodialysis which requires an access to the bloodstream of the patient for connecting to a machine that works as a filter or artificial kidney, in this process, blood that contains waste substances is extracted from the patient to be filtered by the hemodialysis machine at the same time the cleansed blood is put back into the body through the vascular access.
When do I need to start hemodialysis?
Dialysis is used as replacement therapy in renal function in patients with advanced renal failure, this is when the kidneys are working at 10-15% of their normal capacity.
It can also be used in patients with acute renal failure when the kidneys stop working temporarily because of diseases such as hypovolemic shock, sepsis (serious blood infection), urinary tract stones etc., in these cases is not permanent hemodialysis, but it is used to replace the function of elimination for the kidneys while they recover.
What is the duration of a hemodialysis session?
Each session lasts an average of three hours and can last up to 4 or 5 hours.
How often should I receive hemodialysis?
It is recommended to have three sessions a week, however it may require more sessions, this will be decided by the nephrologist (kidney disease specialist).
What are complications and side effects of hemodialysis?
During hemodialysis fluid is removed from the blood. If it is removed very quickly you can experience dizziness, low blood pressure, cramps, and chest pain. These risks can be reduced by performing more sessions in a row to reduce the amount of extraction of water in each session, as well as decrease the amount of fluids you drink between each hemodialysis session.
Likewise, hemodialysis requires access to the bloodstream of the patient, so there is risk of infections such as septicemia (blood infection) endocarditis (infection of the heart valves), among others.
During hemodialysis heparin is used, it is a medicine to prevent blood clotting in the circuit of the artificial kidney, when this medicine is used, there is a (low) risk of bleeding. If you have an allergy to this medication, it is important to notify your nephrologist and a nurse before starting hemodialysis, in order to prevent serious allergic reactions.
What is Vascular Access?
An angioaccess or vascular access is an entry route into the bloodstream to perform the exchange of the blood containing waste substances (urea, creatinine) for clean blood once it has been filtered through the external artificial kidney. There are several types, such as Mahurkar catheter which is a special tube that is usually placed below the clavicle, another type is the Permacath catheter which is similar to the previous but its’ trajectory is a few centimeters below the skin so that it is able to enter a vein of larger caliber (usually the subclavian vein), this makes it lasts longer than the Mahurkar catheter and reduces the risk of catheter infection.
Finally, there are the arteriovenous fistulas that involve joining a vein and an artery generally in the crook of the arm, this connection is stronger than a normal vein and allows repeated puncture of this site to introduce a new catheter for each hemodialysis, at the end of each session, the catheter is removed. This type of vascular access requires an operation that is conducted by a specialist in blood vessels (Angiologist), once this is done, you should wait at least six weeks to use the fistula.