Dialysis is a filtration process. In 1961, Thomas Graham discovered that a parchment membrane immersed in water allowed salts to pass through while retaining proteins.
What is hemodialysis?
Hemodialysis is a procedure that purifies the blood by passing it through a filter known as an "artificial kidney" or dialyzer.
The dialyzer works on the following principle: blood flows through a semi-permeable membrane made of cellulose or a similar material, while on the other side, a dialysate solution circulates. This solution contains certain amount of minerals and salts found in the body naturaly, but this solution does not contain the waste products that have accumulated in the body due to kidney failure. The membrane has very small openings of various sizes. These openings allow excess waste products and fluids from the blood to pass into the dialysate at varying rates, with smaller molecules moving faster than larger ones. This process effectively purifies the blood and restores proper blood composition ratios.
This device regulates blood flow, pressure and exchange rate.
Since a small amount of blood is present in the dialyzer at any particular moment, the blood must circulate through it for an extended period, typically around 4 hours, to adequately cleanse the body. Most patients require hemodialysis three times a week. The duration and intensity of dialysis can be customized for individual patients.
Blood is transported to and from the dialyzer through special plastic tubes known as dialysis lines. These lines are connected to the patient in one of two ways:
1) Fistula: A surgically created connection between an artery and a vein, usually in the forearm, it widens the vein and thickens its wall to accommodate needle insertion and withdrawal during each dialysis sessions. After the procedure, only a small scar remains.
2) Central Venous Catheter: A soft plastic tube inserted into a vein below the collarbone. Its ends are brought to the skin's surface and closed with a cap when the catheter is not in use.
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What is peritoneal dialysis (PD)?
Peritoneal dialysis (PD) utilizes the peritoneum as natural filter to cleanse the blood of waste products.
A soft tube, or catheter, is surgically inserted into the abdominal wall to facilitate this process.
The catheter remains permanently in place.
How to prepare for a doctor's visit?
To ensure the most productive doctor's visit, please take the time to prepare in advance.