Blood Flow in Hemodialysis: How Much Is Appropriate?

Hemodialysis is an important medical treatment, mainly used to treat kidney diseases and help patients eliminate waste and excess water from the body. Blood flow is a crucial parameter in this process. So, what is the appropriate blood flow rate in hemodialysis? This article will provide a popular science interpretation of this.

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1. Basic principles of hemodialysis

Hemodialysis uses extracorporeal circulation and a dialyzer (artificial kidney) to simulate the filtration function of the kidneys. During this process, when the patient's blood passes through the dialyzer, it exchanges substances with the dialysate, thereby removing metabolic waste, excess water, and toxins from the body.

Factors such as blood flow, dialysate flow, and dialysis time all affect dialysis effectiveness.

2. Definition and significance of blood flow

Blood flow refers to the amount of blood passing through a blood vessel cross-section per unit time, usually expressed in milliliters per minute (ml/min). In hemodialysis, the size of the blood flow is directly related to the contact area and contact time between the dialyzer and the blood, thus affecting the dialysis efficiency. Sufficient blood flow can ensure that the dialyzer can fully function and improve the dialysis effect.

Factors affecting the adequacy of hemodialysis mainly include dialysis blood flow, type of vascular access, dialysis time, dialysate flow and temperature, etc. Adequate blood flow is the prerequisite for ensuring the quality of maintenance hemodialysis and is the most important influencing factor.

3. Principles for adjusting blood flow

Adjustment of blood flow should be based on the patient's specific conditions.

Generally speaking, blood flow should be maintained between 200 and 300ml/min. For special circumstances such as elderly patients, patients with cardiovascular disease, or children, blood flow may need to be adjusted appropriately. The purpose of adjusting blood flow is to ensure the effect of dialysis while minimizing the impact on the patient.

In hemodialysis, the blood flow of "blood pump controlled" arteriovenous fistulas is usually between 150 and 350ml/min. High blood flow within a certain limit can improve dialysis efficiency, but the high blood flow of arteriovenous fistulas during dialysis is closely related to cardiac function. Relationships get a lot of attention. The Japanese Society of Nephrology, the most authoritative medical institution in Japan, also made it clear that even if the blood flow reaches 400~500ml/min, heart-related mortality will not increase.

4. Factors affecting blood flow and flow selection

1. For kidney patients with autologous arteriovenous fistulas, the blood flow that can be achieved during dialysis is closely related to the development status of the internal fistula. A qualified internal fistula should achieve a blood flow of more than 250ml/min during dialysis. Kidney friends should pay special attention not to force excessive blood flow because the hemodialysis machine controls the blood flow by the blood pump. Once the set blood flow exceeds the limit that the internal fistula can provide, the blood vessel wall of the internal fistula will collapse, easily causing The puncture needle to damage the blood vessel wall.

2. For kidney friends with intravenous indwelling catheters, due to the difference in the insertion position of the catheter and the difference in usage time, the blood flow that the catheter can achieve in actual use is also different. Generally, the blood flow of the catheter for hemodialysis is 200~350ml/ min.

3. For kidney patients with artificial blood vessel fistula, because its lumen is large, it is usually connected to larger arteries and veins (such as the brachial artery and the median cubital vein), and the puncture point is on the artificial blood vessel, so the lumen is not easy to collapse, so the blood The flow rate can be set to 500ml/min (theoretical value, the actual value should be determined based on the specific situation of the kidney patient).

4. Other problems include: For kidney patients with cardiac insufficiency, high blood flow may increase the burden on the heart and lead to aggravation of heart failure. Blood flow should be appropriately controlled depending on the situation. For dialysis patients who have just started hemodialysis during the induction period, to prevent dialysis imbalance syndrome, it is not advisable to adjust the blood flow to too high. For kidney patients who temporarily use direct arterial puncture for difficult vascular access, due to the thin distal diameter of the limb arteries, the puncture is difficult, and the kidney patients are in obvious pain. The puncture site is not braked well, and it is difficult to achieve a large blood flow, and the blood flow is average. At 150~250ml/min.

5. Effects of insufficient or excessive blood flow

Insufficient blood flow: It may lead to insufficient dialysis and affect the treatment effect. At the same time, it may also increase risks during dialysis, such as coagulation, hypotension, etc.

Excessive blood flow: It may increase the burden on the heart and cause problems such as arrhythmia and angina pectoris. In addition, excessive blood flow may also lead to insufficient material exchange between dialysate and blood, affecting the dialysis effect.

The K/DOQI guidelines stipulate that for adult hemodialysis patients who undergo dialysis three times a week and have almost no residual renal function, their dialysis blood flow should be greater than 250ml/min, Kt/V should be greater than 1.2, and URR should be greater than 65%. When Kt/V<1.2 or URR<65%, it means that dialysis is insufficient. At this time, you should first consider whether it is caused by low dialysis blood flow. China's hemodialysis adequacy clinical practice guidelines recommend that conventional dialysis blood flow is generally 200-300ml/min, and blood flow >300ml/min can improve solute clearance. Increasing the blood flow from 200ml/min to 300ml/min can increase the solute clearance rate by more than 15%, reduce the total amount of anticoagulant drugs, and reduce bleeding complications. The conventional dialysate flow rate is 500ml/min. Increasing the dialysate flow rate (600-1000ml/min) can increase the solute concentration gradient inside and outside the dialyzer membrane, promote toxin transport in the blood circulation, and improve the adequacy of dialysis.

6. Summary and suggestions

Blood flow in hemodialysis is a key parameter and its size should be adjusted according to the patient's specific condition. Patients and medical staff should pay close attention to blood flow and detect and deal with possible problems promptly. At the same time, patients should maintain good living habits and mentality, and actively cooperate with doctors' treatment suggestions to improve dialysis effects and quality of life.

Through the popular science interpretation of this article, I believe readers will have a deeper understanding of blood flow in hemodialysis. During the actual treatment process, patients and medical staff should reasonably adjust blood flow according to the patient's specific situation to ensure the smooth progress of the dialysis process. At the same time, we also look forward to the continuous advancement of medical technology in the future to bring better treatment experiences and effects to patients with kidney disease.

How Does Cistanche Treat Kidney Disease?

Cistanche is a traditional Chinese herbal medicine used for centuries to treat various health conditions, including kidney disease. It is derived from the dried stems of Cistanche deserticola, a plant native to the deserts of China and Mongolia. The main active components of cistanche are phenylethanoid glycosides, echinacoside, and acteoside, which have been found to have beneficial effects on kidney health.

Kidney disease, also known as renal disease, is a condition in which the kidneys are not functioning properly. This can result in a buildup of waste products and toxins in the body, leading to various symptoms and complications. Cistanche may help treat kidney disease ase through several mechanisms.

Firstly, cistanche has been found to have diuretic properties, meaning it can increase urine production and help eliminate waste products from the body. This can help relieve the burden on the kidneys and prevent the buildup of toxins. By promoting diuresis, cistanche may also help Reduce high blood pressure, a common complication of kidney disease.

Moreover, cistanche has been shown to have antioxidant effects. Oxidative stress, caused by an imbalance between the production of free radicals and the body's antioxidant defenses, plays a key role in the progression of kidney disease. ies help neutralize free radicals and reduce Oxidative stress, thereby protecting the kidneys from damage. The phenylethanoid glycosides found in cistanche have been particularly effective in scavenging free radicals and inhibiting lipid peroxidation.

Additionally, cistanche has been found to have anti-inflammatory effects. Inflammation is another key factor in the development and progression of kidney disease. Cistanche's anti-inflammatory properties help reduce the production of pro-inflammatory cytokines and inhibit the activation of inflammation mandatory pathways, thus alleviating inflammation in the kidneys.

Furthermore, cistanche has been shown to have immunomodulatory effects. In kidney disease, the immune system can be dysregulated, leading to excessive inflammation and tissue damage. Cistanche helps regulate the immune response by modulating the production and activity of immune cells, such as T cells and macrophages. This immune regulation helps reduce inflammation and prevent further damage to the kidneys.

Moreover, cistanche has been found to improve renal function by promoting the regeneration of renal tubes with cells. Renal tubular epithelial cells play a crucial role in the filtration and reabsorption of waste products and electrolytes. In kidney disease, these cells can be damaged, leading to damaged renal function. Cistanche's ability to promote the regeneration of these cells helps restore proper renal function and improve overall kidney health.

In addition to these direct effects on the kidneys, cistanche has been found to have beneficial effects on other organs and systems in the body. This holistic approach to health is particularly important in kidney disease, as the condition often affects multiple organs and systems. che has been shown to have protective effects on the liver, heart, and blood vessels, which are commonly affected by kidney disease. By promoting the health of these organs, cistanche helps improve overall kidney function and prevent further complications.

In conclusion, cistanche is a traditional Chinese herbal medicine used for centuries to treat kidney disease. Its active components have diuretic, antioxidant, anti-inflammatory, immunomodulatory, and regenerative effects, which help improve renal function and protect the kidneys from further damage. , cistanche has beneficial effects on other organs and systems, making it a holistic approach to treating kidney disease.