The two kidneys in the human body help flush out all the toxins and waste products from the blood. However, when kidney failure occurs, one needs to take medical help to cleanse the body of all the toxins produced within. The doctor will suggest one to undergo dialysis, an artificial replacement therapy, for the lost renal function. The process of dialysis helps carry out ultrafiltration of the body fluids through a semi-permeable membrane and diffusion of solutes. The blood from the body is allowed to flow through a semi-permeable membrane and a special dialysis fluid (dialysate) flows on the opposite side. The semi-permeable membrane does not allow red blood cells, large proteins, etc., to pass through it. There are basically two types of kidney dialysis: hemodialysis and peritoneal dialysis. Each of these dialysis procedures use different methods to carry out the same process of dialysis, that is, removal of waste and excess water from the blood.
What is Peritoneal Dialysis and Hemodialysis?
As we go into the arguments of peritoneal dialysis and hemodialysis, it is important that we understand each of these methods separately. Let us have a look at each of these two kidney dialysis processes below.
In peritoneal dialysis, a tube is inserted into the peritoneal cavity. A sterile solution containing glucose is passed through this tube. The peritoneal membrane acts as a semi-permeable membrane and the dialysate is allowed to remain there for some time. This helps it absorb the waste products from the body that is drained out through the tube, called the drain process. This cycle is carried out about 4 to 5 times a day and in some cases an automated system is used for overnight dialysis. When a dialysate is filled and then emptied from the abdomen, it is called one exchange. The time required for the wastes, toxins, extra fluid, etc., to move from the patient's blood through the peritoneum into the dialysate is called dwell time. Osmosis is the process that helps in ultrafiltration of the blood through peritoneal dialysis. The high glucose solution creates an osmotic pressure that helps the fluid from the blood move into the dialysate.
Hemodialysis is the process where the blood is pumped into the blood compartment of the dialyzer. The dialyzer is a special machine that helps filter the blood. The blood flows through the dialysis machine that contains thousands of synthetic hollow fibers. The dialysis solution is allowed to flow outside the fibers and thus, the water and waste from the blood can move around them. Once the blood is filtered, it is allowed to flow back into the body. Hemodialysis takes about 3 to 5 hours to remove the excess fluid, water and dissolved solutes from the blood with the help of a pressure gradient.
Difference Between Peritoneal Dialysis and Hemodialysis
Now, that we understand what happens in each of these processes, let us go into the details of difference between peritoneal dialysis and hemodialysis. We shall begin with peritoneal dialysis (PD) vs. hemodialysis (HD) diet. Your diet forms an important part of the treatment plan you choose. Those who are on PD are asked to follow a high protein diet than those on HD. This is because more proteins are lost through the peritoneum during PD. Those on HD are asked to limit their potassium intake as this macronutrient tends to build up within the body between treatments. Normally, people opting for PD are not asked to restrict their potassium intake. Phosphorous, calcium and sodium intake have to be watched during dialysis as either of the procedures do not remove these minerals well. In case of HD, people are asked to maintain their fluid balance as it may lead to swelling in the face, hands, legs, ankles and feet. Apart from the diet, there are many other differences between these two methods of dialysis. These differences are covered in the table below:
|Peritoneal Dialysis vs Hemodialysis|
|In this case, a catheter is directly placed in the abdominal cavity, i.e., peritoneum.||In HD, a shunt is placed in the vein and artery.|
|The tissues of the peritoneum act as the filter between the special dialysis fluid and blood in the body.||There are many synthetic hollow fibers in case of HD machine that help filter the dialysis solution and blood.|
|PD is carried out almost every day for about 4 to 5 times a day.||HD is carried out for 5 to 6 times a week, for about 6 to 8 hours/day.|
|PD can be carried out at home by the patient itself.||HD generally requires the patient to visit a hospital or clinic for the process of dialysis.|
|Osmosis helps in the process of peritoneal dialysis.||An artificial dialysis machine that acts like a kidney helps carry out the blood filtration.|
|PD has more dietary freedom for the patient.||Patients undergoing HD have to follow a strict dietary regulation.|
This was some information related to the comparison between peritoneal dialysis and hemodialysis. As you can see, one requires dialysis when the kidneys fail to carry out their function of filtration. Patients suffering from end stage kidney disease are often asked to undergo hemodialysis. Based on individual circumstances and the doctor's advice, one can choose a suitable method of dialysis.