Because hemodialysis is performed on a regular basis over a long period of time, it is important to have a vascular pathway that can be repetitively punctured and has a sufficiently high flow rate to allow blood to be drawn out.
Such a pathway is the primary vascular route for hemodialysis patients and is the lifeline that keeps them alive. In clinical practice, this is usually done by surgically creating an artificial "short circuit" between the arteries and veins, which is known in standard terms as an arteriovenous fistula.
Of course, the early use of external fistula, that is, a silicone tube directly connected to the arteries and veins, but because of the complexity of the operation, susceptible to infection, and damage to the blood vessels, now basically no longer used. There are many blood vessels on the surface of the human body, and generally when blood is collected for examination or even blood donation, the veins of the forearm are directly punctured, so why is it necessary to create an arteriovenous fistula to draw out the blood when doing hemodialysis? This is because hemodialysis, in order to ensure the effect, to prevent coagulation, the blood needs to be drawn out of the faster and stable, and at the same time, due to the frequent dialysis, but also easy to puncture and repair.
Superficial veins are not sufficiently filled to allow a large volume of venous blood to flow to the dialysis machine, making dialysis ineffective, and arteries are too deep, making puncture more difficult and slow to repair, which makes multiple punctures less likely. An arteriovenous fistula is a surgical procedure that creates a vascular pathway for long-term hemodialysis.
The artery is anastomosed to a superficial vein, and the arterial blood, which has a high flow rate, is introduced directly into the superficial vein to ensure adequate blood flow and reduce the difficulty of puncture. Of course, if the patient's veins are too small, too deep, or too hardened and narrowed for direct arteriovenous anastomosis, an artificial blood vessel for hemodialysis is inserted subcutaneously to connect the arteries to the veins, and after a few weeks the artificial blood vessel heals with the surrounding tissues so that it can be used as a puncture to draw blood during hemodialysis.
Vascular access for dialysis is usually made in the upper extremity where it is not used: the left arm for right-handed people and the right arm for left-handed people. The dialysis access is usually placed at the wrist near the hand.
If the vein is very thin (female, elderly, or diabetic) it may be placed proximal (high) to the arm. If vascular access cannot be placed in the upper limb, an arteriovenous catheter can be used and placed in the thigh.
Because it takes 2 to 6 weeks for an arteriovenous fistula for hemodialysis to mature for use, patients with renal failure who are likely to undergo hemodialysis should undergo arteriovenous fistula surgery as soon as possible to avoid the pain and risk of deep venous cannulation if the fistula has not matured by the time they are ready for dialysis. This is to avoid the pain and danger of deep vein cannulation when the fistula is not yet mature enough for dialysis. Once the hemodialysis is started, the arteriovenous fistula is almost like the life of the kidney patient, so it must be well taken care of and the condition of the blood vessel must be checked regularly.
As long as the vascular access for hemodialysis is smooth, kidney patients can live a happy life with regular and effective hemodialysis.
2. Why arteriovenous endovascular fistula
1. Arteriovenous endovascular fistula is a commonly used vascular access for maintenance hemodialysis patients
2. It has the advantages of safety, sufficient blood flow (200-300ml/min), and less chance of infection
3. Generally, endovascular fistula can be maintained for 4-5 years
4.
5. easy to puncture and other advantages
3. how to build the arteriovenous endovascular fistula
At present, there are two main clinical arteriovenous endovascular impotence plasty surgical methods.
(1) Suture method can be used according to the surgical site, arterial distance and caliber size ratio of the end-side anastomosis, end-side anastomosis and side-side anastomosis. The end-to-end anastomosis is usually an interrupted suture.
The lateral anastomosis is usually performed with continuous sutures or with interrupted sutures, but usually with continuous sutures on one side and interrupted sutures on the other. The fistula in the wrist, for example, should be closed with 6 or 7 0 sutures for vessels over 4 mm and 8 or 9 0 sutures for vessels under 4 mm, with needles at both ends to facilitate needle insertion into the lumen and to speed up the suture process.
The skin incision should be staggered as much as possible with the blood vessels of the fistula to be made, in order to prevent stenosis caused by the scar of the incision in the future. The anastomotic patency test: at the end of the anastomosis, pulsations and tremors are palpable at the venous end of the anastomosis, and a vascular murmur can be heard.
If there are only pulsations, but no tremors or vascular murmurs, proximal thrombosis is suspected. The anastomosis should be reopened and a #3 Fogarty catheter inserted proximal to the vein to remove the thrombus and reanastomose.
For procedures in which the burning artery is not ligated, the radial artery distal to the anastomosis should be palpated. It should also be noted that long free vessels are susceptible to undetectable vascular tortuosity during anastomosis, which can interfere with blood flow and should be prevented and eliminated.
③ Treatment of vasospasm: After opening the vascular clamp, blood flow is insufficient, often due to vasospasm. It can be appropriate analgesia, sedation, warm saline wet compresses, 1% procaine or lidocaine local infiltration observation.
Suture subcutaneous, skin, tension should not be too large. The dressing should be applied without pressure to avoid vascular compression.
Intramuscular injection of scopolamine (654-2) 10mg twice daily for 3d can be used after surgery. Systemic anticoagulation has more disadvantages than advantages, and is seldom used nowadays because of the bleeding tendency of uremia.
However, in patients with hypercoagulable states, recurrent thrombosis, and exclusion of mechanical causes, anticoagulants and antiplatelet aggregating agents can be used. Antibiotics and delayed suture removal can be used as appropriate.
(2) titanium wheel nails method ① titanium wheel nails specifications: the general use of the diameter of 2.0mm, 2.
5mm, 3.0mm three kinds.
② Surgical method: according to the suture method in the selected surgical site routine disinfection, laying sterile towel, anesthesia, incision of the skin, separation and free the arterial vessels to be anastomosed to confirm that the distal section of the arterial blockage of the blood supply is still the case, respectively, disconnect the arterial and venous ligation of the distal end of the proximal end of the vascular clamps to block the flow of blood, the selection of the appropriate caliber of the Chin wheel nails and fixed in the specification corresponding to the anastomotic clamp, respectively, the free end of the arterial from the dorsal to the distal part. The free ends of arterial and venous veins are pierced out from the dorsal side through the holes, and the periphery of the vessels is carefully lifted up with hooks or pointed toothless tweezers and turned out to be symmetrically hung on 4 wheel nails, and the tips of the nails are pressed by perforated push-pins to pierce the wheel nails from the periphery of the vessels to the intima-media side and fix them firmly, and the end of the veins is injected with an appropriate amount of heparinized physiological saline, and the nails with the severed end of the vessels are then matched with the anastomotic clips, and then the nails are buckled with the clamps, and then the nails are interlaced with each other. The arterial and venous ends of the vein are mechanically flared and anastomosed. Next, the venous and arterial clamps were released sequentially, and after observing and confirming good blood flow, the skin was sutured and sterile dressings were applied.
No special postoperative treatment is needed, the success rate of the operation is high, the blood flow in the fistula can be kept relatively stable, and it is not easy to complicate high output heart failure in the long term, and the vein will not be in a serious state of aneurysm, and the appearance of the patient can be satisfied. In addition, this method is simple, easy to master, at all levels of units can be carried out.
However, the Chinchilla nail method can only do end-to-end anastomosis, so its application is somewhat limited.
4. patients with arteriovenous fistula should do what self-care
patients with arteriovenous fistula should do self-care: (1) understand the importance of endovascular fistula to the life of the subjective importance of active cooperation with medical personnel.
(2) keep the skin of the arm on the fistula side clean, and wash the arm on the fistula side thoroughly with soap and water before each dialysis. (3) Avoid contact with water at the puncture site on the day dialysis ends, and cover it with a sterile dressing for more than 4 hours to prevent infection.
If a hematoma occurs at the table puncture site, it can be compressed to stop the bleeding, and cold compresses with ice packs, and hot compresses can be applied after 24 hours, and rubbed with Xitretinoin breast tone (sulfonate mucopolysaccharide) to reduce swelling at the endocardial fistula site, if there is a hard nodule, rubbed with Xitretinoin *** for 15 minutes 2 times a day. (4) the fistula side of the arm can not be stressed, the sleeve should be loose, can not wear too tight jewelry.
Do not put the fistula arm behind the pillow at night, and try to avoid lying on the side of the fistula arm. Avoid holding heavy objects in the fistula arm.
(5) The fistula arm should not be used for blood pressure measurement, infusion of fluids, intravenous injection, blood sampling, and so on. (6) learn to judge for themselves whether the arteriovenous endovascular fistula is open, that is, with the non-operative side of the hand touching the surgical side of the anastomosis, such as touching the tremor is clear, or with a stethoscope, hear the vascular murmur is clear.
If the tremor and murmur disappear, and there is tenderness or pain at the fistula, the patient should go to the hospital. It is also important to tell the patient that arteriovenous fistula checkups must be performed 3 to 4 times a day for early detection of problems.
(7) appropriate activities on the fistula side of the arm, can hold a rubber fitness ball for exercise. (8) Avoid trauma to the arm on the fistula side, it is best to wear a wrist brace regularly to avoid hemorrhage.
The wrist brace should be tightened moderately, not too tight pressure arteriovenous fistula, in order to prevent the fistula occlusion. Patients with aneurysms should be protected with elastic bandages to avoid further expansion and accidental rupture.
5. What is an arteriovenous fistula
Patients on long-term hemodialysis need to establish a permanent blood line, which is the lifeline of patients on maintenance hemodialysis, and the establishment and maintenance of the blood line has a direct impact on the quality of life of hemodialysis patients. It includes adjacent arteriovenous endovascular fistula and vascular graft endovascular fistula. The main complications are thrombosis, pseudoaneurysm. Clinical arteriovenous endovascular fistula is a blood channel between adjacent arteries and veins established by surgical anastomosis together. So we should pay attention to the following points when doing self-care; First, 48-72 hours after surgery to elevate the limbs on the side of the operation, to reduce swelling; Second, one week after the operation can be in the doctor's guidance to carry out the exercise of the endocardial fistula; Third, when the endocardial fistula puncture unsuccessful subcutaneous hematoma should be localized compression to stop the bleeding, with 50% magnesium sulfate liquid wet compresses and to be appropriate *** to help reduce the swelling, and at the same time, the observation of the endocardial fistula tremor; Self-stylus At any time to listen to the fistula murmur, touch the tremor; four, blood pressure, blood collection, infusion should be avoided on the side of the fistula, skin allergies should be reported to the nurse; five, the use of endocardial fistulae should be avoided in the same puncture repeated puncture, in order to reduce the incidence of pseudoaneurysm and prolong the service life of endocardial fistulae; six, the day of dialysis puncture point can not be done hot packs can be the second day of the hot packs, in order to help the vascular repair, to reduce scarring; seven, the first time endocardial fistula patients in the use of the patient in the first time, the patient's blood pressure should be applied to the fistula to prevent the occurrence of the fistula. The first time the endocardial fistula use patients at the end of dialysis compression hemostasis, the time is appropriate 1-1.5 hours, not too long, the pressure should not be too tight, in order not to bleed appropriate, in order to prevent endocardial fistula blockage; eight, open the tourniquet, such as bleeding, you can stretch out the forefinger and middle finger compression puncture point for 15-20 minutes, and at the same time, change the new band-aid, to prevent the puncture point of infection; nine, the preparation of a wrist guard, for the protection of the endocardial fistula when the dialysis, to prevent bleeding caused by trauma, to prevent the endocardial fistula. To prevent hemorrhage caused by trauma and to restrain pseudoaneurysm; (due to high blood flow, successful use of the fistula and long regular puncture, leading to the occurrence of pseudoaneurysm, the appearance of blood vessels bulging, thinning of the wall); 10, pay attention to the maintenance of the skin, and daily use of skin oil to increase the skin's smoothness and comfort.
Another classification for permanent blood access is vascular graft endovascular fistula, whose characteristics and self-care are similar to those of autologous fistula. However, because the artificial tube implanted through surgery is more severe damage to the subcutaneous tissue, longer in the limb recovery, severe swelling and easy to infection, patients should elevate the upper limb on the operated side after surgery, which is conducive to reduce swelling. Listen to the vascular murmur every day, test the temperature of the limb on the operated side by hand, prevent infection and thrombosis, and after puncture, it is not suitable to use tourniquet to stop bleeding by compression, and choose point-like compression method. To ensure the patency of the blood vessels, 1-2 hours to open the compression point if there is still bleeding, do not be alarmed at the desirability of using point-like compression, can also achieve the effect of hemostasis.
6. arteriovenous fistula self-care measures
arteriovenous fistula self-care measures are: (1) pay attention to the fistula pulsation situation: morning, three meals and bedtime should touch the fistula, or use a stethoscope to check whether the fistula is smooth (the fistula can be felt when the normal sound of rustling, water or vibration); if the fistula found to be silent, it should be immediately to the hospital! If you find no sound, you should go to the hospital immediately for treatment.
(2) Keep the skin clean, wash hands with warm water before dialysis, cut nails, do not pick and scratch the needle eye on the side of the fistula. (3) After the use of endocardial fistula, if you find that the eye of the needle local redness, pain, itching, oozing, can be used to povidone-iodine solution coated, every 3?4h - times.
Usually, you can use Xitetu (polysulfonic acid mucopolysaccharide cream), which can be anti-inflammatory, promote the absorption of edema and hematoma, inhibit thrombosis and growth, promote local blood circulation, *** the function of regeneration of damaged tissues, and can quickly relieve pain. (4) After dialysis, if you find that the blood vessels of the endocardial fistula are in severe pain, accompanied by weakened endocardial fistula tremor, suggesting that there may be endocardial fistula thrombosis.
It is necessary to go to the hospital in time. (5)The limb on the side of the fistula should not be used for blood pressure measurement or blood sampling; it should not be lifted; it should not be pressed underneath the body; it should not be worn with tight clothes or a watch; and it should be kept warm on the side of the fistula.
(6) Ensure blood volume and prevent dehydration.