Learn about venous dialysis

Intravenous dialysis is one of the treatment methods for patients with renal failure. In it, a patient's blood is pumped into a filter consisting of two fluid reservoirs made up of parallel semi-permeable membranes or bundles of hollow capillary fibers.

1. Venous dialysis

Intravenous dialysis is one of the treatments for kidney failure. In it, the patient's blood will be pumped into a filter consisting of two fluid compartments made up of parallel semi-permeable membranes or bundles of hollow capillary tubes. In either section, blood in the first chamber is pumped along one side of the semi-permeable membrane, while the crystalline filtrate is pumped in a separate chamber in the opposite direction along the other side.
The difference in solute concentrations between the blood and the dialysate will produce desirable changes in the patient's serum solutes, such as an increase in bicarbonate, a decrease in urea and creatinine, and a rebalancing of sodium, potassium, chlorine, and sodium. magnesium. The pressure in the dialysis fluid compartment has negative pressure relative to the blood cavity pressure and the dialysis cavity has a higher osmotic pressure to prevent the ultrafiltration of the filtrate into the blood and help eliminate the excess fluid inside. patient's body. The blood that is filtered through a filter is then returned to the patient's body.
Patients are often given systemic anticoagulants during dialysis to prevent blood clotting in the dialysis machine. However, hemodialysis can also be performed with a local anticoagulant used in the dialyzer circulation (such as heparin or trisodium citrate) or a 50-100 mL saline flush for 15 to 30 minutes that will clear the blood vessels. blood clots in the dialysis machine circulation.

2. The goal of dialysis

The proximate goals of dialysis are:
Balance fluid and electrolytes Remove toxins The long-term goal in patients with renal failure is
Optimize the patient's function, blood pressure and comfort. Prevent complications of elevated uremia syndrome Prolong life
Lọc máu liên tục giúp kéo dài sự sống cho người bệnh
Lọc máu liên tục giúp kéo dài sự sống cho người bệnh

The optimal dose in a dialysis procedure is unknown, but most patients are comfortable with dialysis every 3 to 5 hours and 3 times a week. One way to assess the adequacy of each dialysis session is by measuring the BUN before and after each dialysis session. A reduction of ≥ 65% in blood urea nitrogen compared to pre-dialysis ([urea nitrogen before dialysis − urea nitrogen after dialysis] / urea nitrogen before dialysis × 100% ≥ 65%) indicates a complete dialysis case and efficient. In addition, physicians can use other formulas that are more computational, such as KT/V ≥ 1.2 (where K is the urea clearance of the dialysate in mL/min, V is the volume of stools. urea distribution [equivalent to total body water] in mL, and T is the filtration time in minutes). The dialysis dose can be increased by altering the blood flow, dialysis time, membrane surface area, and membrane porosity of the dialysis machine. Night-time dialysis (6-8 hours, 3 to 6 days/week) and short daily dialysis sessions of 1.5 to 2.5 hours, if available, will be selectively selected for patients with any of the following:
Excessive fluid gain between dialysis sessions Persistent hypotension during dialysis Poorly controlled blood pressure Uncontrollable hyperphosphatemia

3. Intravenous dialysis routes

3.1 Central venous catheters Central venous catheters are an inlet used for dialysis if the patient does not have an AVM or an AVM is immature or the patient cannot have an arteriovenous catheterization circuit is. The main disadvantages of central venous catheters are their relatively narrow diameter and inadequate blood flow for optimal clearance, in addition to the high risk of catheter site infection and hematopoiesis. block.
Central venous catheterization for dialysis patients is best done using the right internal jugular vein. Most are internal jugular venous catheters, which, with good anti-infective skin care and if the catheter is used only for dialysis, can be used for 2 to 6 weeks. Catheters tunnel under the skin and have a longer duration of use (from 29% to 91% remaining functional at 1 year) and may be useful for patients who cannot have an arteriovenous catheterization.
3.2 Arteriovenous Catheterization Arteriovenous Catheterization (FAV) is better than central venous catheterization. Because arteriovenous bypass surgery has a longer lifespan and is less prone to infections. However, arteriovenous catheterization also tends to have complications such as infection, thrombosis, aneurysm, or pseudoaneurysm. A newly operated arteriovenous catheter can take 2 to 3 months to mature and be able to use dialysis. However, it may take more time to repair the AVM, so it is best for CKD patients to have an AVM at least 6 months before dialysis is needed. Surgical anastomosis of the brachial artery, radial artery, or femoral artery to the adjacent vein using the lateral artery vein technique. When an adjacent vein is not suitable for surgery, an artificial vessel can be used. For patients with weak veins, surgery using autologous subcutaneous veins is also an option.
Phẫu thuật tạo thông động tĩnh mạch
Phẫu thuật tạo thông động tĩnh mạch trong lọc máu tĩnh mạch

4. Complications of venous dialysis

4.1 Complications of Intravascular Access vascularization will significantly limit the quality of dialysis, increasing the long-term burden and mortality. These complications are enough that patients and physicians should be vigilant for suggestive signs including pain, edema, skin redness, disruption of skin structure on the AVM, absence of murmur and pulse at the catheter. arteriovenous, periarteriovenous hematome, and prolonged bleeding at the needle puncture site for dialysis. Infections are treated with antibiotics, surgery, or a combination of both.
Arteriovenous catheterization is monitored for signs and symptoms of failure by assessing sequential dilution blood flow on doppler ultrasound, urea dilution techniques, or temperature. hydrostatic pressure measurement in the venous cavity. One of the above tests is usually recommended to patients at least once a month. Treatment of complications such as thrombosis, stenosis, pseudoaneurysm, or aneurysm may include methods such as angioplasty, stenting, or surgery.
4.2 Complications of dialysis The most common complication of dialysis is hypotension. Hypotension has many causes including rapid water withdrawal, thermal vasodilation, acetate contamination of the dialysis fluid, transmembrane osmotic shift, allergic reactions, sepsis, and comorbidities. eg autonomic neuropathy, myocardial infarction and arrhythmia, cardiomyopathy with low ejection fraction).
Other common complications include:
Restless leg syndrome Cramps Itching Nausea and vomiting Headache Chest and back pain In most cases of dialysis, these complications occur with no known cause, but some cases may be due to first-time dialysis syndrome (when the patient's blood first comes into contact with the cellulose membrane or cuprophane membrane in the dialyzer) or disequilibrium syndrome. A syndrome is thought to be caused by the rapid elimination of urea and other osmolytes from the serum leading to translocation of osmotic fluid into the brain parenchyma. More severe cases of disequilibrium syndrome manifest as disorientation, blurred vision, restlessness, confusion, convulsions, and even death.
Dialysis-associated amyloidosis affects patients who have been on dialysis for many years and presents as carpal tunnel syndrome, arthritis, ankylosing spondylitis, and osteomyelitis. Dialysis-associated amyloidosis is thought to be less common with today's widely used high-flux dialyzers because beta-2 microglobulin is more efficiently filtered using these filters.
In summary, patients with impaired kidney function need continuous dialysis. There are many methods of dialysis, in which intravenous dialysis is the most commonly used and effective method. The patient's blood is then pumped into a filter consisting of two fluid-filled compartments made up of parallel semi-permeable membranes or bundles of hollow capillary tubes. However, each patient will have different methods of ultrafiltration in accordance with their disease status.
Vinmec International General Hospital is a high-quality medical facility in Vietnam with a team of highly qualified medical professionals, well-trained, domestic and foreign, and experienced.
A system of modern and advanced medical equipment, possessing many of the best machines in the world, helping to detect many difficult and dangerous diseases in a short time, supporting the diagnosis and treatment of doctors the most effective. The hospital space is designed in a modern way, but still gives patients the comfort, friendliness and peace of mind as if they were at home.

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Reference source; msdmanuals.com

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