Hemodialysis is a method of extracorporeal (outside the body) purification of blood from excess accumulated toxins. It is relevant for patients with end-stage chronic kidney disease (grade 5) and renal failure, whose body is not able to remove life-threatening toxins (creatinine, urea, potassium, and others) on its own.
Types of hemodialysis for patients with CKD
Hemodialysis is a subtype of dialysis and requires a machine for renal replacement therapy sessions. Depending on the methodology and capabilities of the device, the following types of RRT are possible:
It is based on diffusion and ultrafiltration methods. The patient’s blood passes through a filter (dialyzer), which consists of many semi-permeable membranes. Blood flows from one side, and from the other a special dialysis solution with the required concentration of substances. Due to the difference in concentrations, toxins are transferred from the blood to the dialysate, as a result of which the body is cleansed of toxins.
It uses mainly convection processes, which are based on the removal of the liquid part of the blood along with the products of nitrogen metabolism. Since the water component must be replenished, a replacement fluid (substitute) is supplied before or after the filter (pre and post-dilution).
Combines the two previous methods using both convection and diffusion at the same time. This allows for the transfer of more toxins of different sizes and improves the effectiveness of the procedure. Among the requirements of the HDF: a machine that supports the supply of substitute in real-time, a water treatment that is capable of producing an ultrapure dialysate solution. As a result, there is an increase in the effectiveness of the procedure in relation to the removal of more toxic molecules of different sizes.
Isolated ultrafiltration (ISO)
A separate mode that allows only fluid to be removed from the bloodstream by ultrafiltration. This is necessary for patients who are resistant to diuretic therapy, as well as with cerebral or pulmonary edema, heart volume overload.
Which mode is best?
There is no definite answer to this question. For each patient, depending on the level of uremia, fluid overload, clinical situation, and other factors, the specialist should select an individual method of programmed dialysis.
Hemodialysis or plasmapheresis?
These procedures are applied for different purposes and conditions. Plasmapheresis allows you to separate plasma from blood using a special filter (which is somewhat similar to the HD filter). The blood is returned back to the patient, and the plasma part is cut off into a special bag and a replacement solution is injected in its place, which can be albumin, freshly frozen plasma, and physiological saline. This removes unwanted substances contained in the liquid part of the blood. These include various antibodies (in particular IgE), endotoxins, enzymes, etc.
The plasmapheresis procedure is used for conditions such as cirrhosis of the liver, bronchial asthma, various allergic dermatitis, sepsis, thrombocytopenic purpura, and many others. Dialysis is mainly used only in patients with end-stage chronic renal failure or acute renal failure.
Hemodialysis or peritoneal dialysis
Peritoneal dialysis (PD) – uses the human peritoneum to filter toxins and can be performed both manually and using an apparatus (cycler). The essence of the therapy consists in infusing a special liquid through a catheter into the abdominal cavity, finding it there for a certain time, and draining with further repetition of this sequence. The peritoneum is well supplied with blood and acts as a semipermeable membrane in this method. Due to the difference in concentration between the blood and the dialysis fluid poured in, the HD process takes place.
Initially, many patients are advised to start with peritoneodialysis. Its advantages are as follows:
- Does not require vascular access.
- Can be done at home.
- Provides good mobility.
However, along with the advantages, there are also disadvantages/requirements:
- Sterile conditions. Installed catheters require proper care, as they provide access directly to the peritoneum. With improper care, dirty hands, instruments, bacterial flora may enter and, as a result, inflammation (peritonitis) and infection of the catheter tunnel.
- The “shelf life” of the peritoneum is about 5 years, after which it ceases to properly filter toxins. Further, in the absence of a donor or the possibility of transplantation, hemodialysis is started.
- Possible complications, including hernias, weight gain.
In Ukraine, not all regions and centers have an opportunity for PD, therefore, patients often start RRT with HD / HDF sessions.
Renal replacement therapy procedures are prescribed for the following conditions:
- Acute renal failure (ARF) – a sudden increase in the level of nitrogen metabolism products – urea and creatinine.
- Chronic kidney disease (CKD) in the terminal stage – a gradual suppression of kidney function as a result of any disease, such as diabetes mellitus or glomerulonephritis of various origins.
- Persistent increase in potassium levels (hyperkalemia).
- Severe fluid retention in the body (overhydration), which resistant to drug correction.
At this time, there are various data on absolute contraindications to the HDF session, but in most cases, only relative factors are distinguished, among which:
- Mental disorders.
- Oncological processes of any organ system with metastasis.
- Multiple organ failure.
- Septic processes.
- Hemorrhagic syndrome.
- Absence of dialysis access.
- Severe hemodynamic disturbances.
Preparation for initiation
People who are first faced with the need for dialysis sessions are worried about many points. Next, we will describe the basic features of receiving an RRT procedure.
Choice of vascular access
Before the start of the procedures, each patient should be prepared “vascular access”, which will provide access to blood for its further purification. This can be the formation of an arteriovenous fistula (AVF), placement of a prosthesis, or a temporary/permanent central venous catheter (CVC).
The most preferred is AVF. It is the connection of two vessels (artery and vein), usually in the arm, that provides sufficient blood flow for the session. The operation is carried out under local anesthesia and is quite fast in duration. After the formation of the fistula, she needs to “mature”. It takes about a month, however, in case of urgent need, medical personnel can try to use it in 2-3 weeks.
Next AV prosthesis. It is a tube, an artificial vessel that connects an artery and a vein. It is used when it is impossible to form an AV fistula (“weak”, “small” veins).
Closing the top three is the placement of the catheter. Some patients can begin their journey in hemodialysis with a catheter, which is inserted into the jugular or subclavian vein. Most often, temporary CVCs are installed, for a period of about a month, in parallel, solving the issue of fistula formation. During this time, the AVF should “mature”, and the catheter should be removed since when inserted for more than a month, the risks of infection and other complications increase. But there are also special versions, called permanent CVCs, which can serve for about 2 years with proper care.
Duration of the procedure. How often to do
For minimally effective HD sessions, you will need to be in the center 3 times a week for 4 hours. It is such a visit that is recommended for the effective removal of excess toxins, the regular removal of fluid that accumulates in the interdialytic intervals. In addition, this mode improves blood pressure control, reduces the frequency of negative reactions.
Before the procedure, the patient must be weighed on a scale in order to determine how much he has added to the liquid that will need to be removed by the machine, the so-called “dry weight”. It is advisable to wear the same clothes or to know how much it weighs in order to reduce the error in DW measurements. The total number of grams or kilograms of interdialytic increase must be reported to your nurse, who will enter the data on the device.
After installing all the data, the patient takes his place (lying or sitting, depending on his own preferences). It is advisable to take the most comfortable position since lying for such an amount of time is often unusual and uncomfortable at first.
In the case of access to an AVF or a prosthesis, the patient prepares the arm (sometimes the leg), the nurse treats it with antiseptics, and proceeds to insert the needles. As a rule, two needles are used, through one the blood is taken from the patient, and the other is returned. After the injection, a corresponding line from the dialysis machine is connected to each of the needles and the start of the procedure begins. During the session, the patient informs the medical staff of any discomfort. In the end, there is a return of blood, extraction of needles, and a set of manipulations to stop bleeding.
With the catheter, the situation is approximately the same, the site of its exit is examined and processed, the “locks” are removed (to prevent the formation of blood clots and infection, heparin/saline/antibiotics are injected at the end of the procedure, depending on the local protocols of the department and the clinical situation) and flushing. Dialysis catheters are used special, two-way. One line used for the collection of the initial blood, the other is the return of purified blood. After connecting the lines to the CVC, the session begins. On disconnection, the catheter is filled with new “locks” and bandaged.
Hemodialysis in Kropyvnytskyi
Our department provides the following types of renal replacement therapy (RRT):
Dialysis sessions using all the methods described above for patients from the Kropyvnytskyi, Kirovograd regions, and all of Ukraine can be obtained on our CNE “City Hospital No. 2 named after St. Anne” KCC. Our institution is contracted with the NHSU for an outpatient hemodialysis package and provides a full range of services according to the specification, including control of anemia, calcium-phosphorus metabolism, nutritional status.
All procedures for patients with a signed declaration with a family doctor and a referral from a nephrologist with a diagnosis of N18.5 Chronic kidney disease, stage 5 are performed free of charge.