1. The puncture point should not be too high

2. The curvature should be large when making the tunnel. Plasticize the tunnel needle into a larger curvature, make a tunnel with a larger curvature under the skin, and fully free the subcutaneous tissue at the puncture point, so that the catheter can maintain a natural shape throughout the tunnel. radian.

It often occurs at the apex of the catheter tunnel and is related to the catheter placement technique.

Catheter wall adhesion means that an outlet of the catheter sticks to the blood vessel wall, forming a valve-like effect that cannot draw blood, but can return blood.

The main reasons include too shallow catheter position and small right atrial cavity.

When the catheter is too shallow and the tip is located in the superior vena cava, the inner diameter of the superior vena cava is smaller than the atrium, making it relatively easy for the catheter to adhere to the wall. Some patients have a small right atrial cavity, or the heart is relatively upright, and the curvature of the right heart edge on the X-ray is small. In this case, even if the catheter end is in the atrium, it will stick to the wall.

Two things should be done when inserting the catheter: 1. Ensure that the end of the catheter is placed in the predetermined position, that is, in the middle and upper part of the right atrium. When positioning based on the position of the rib body surface, take the intersection of the fourth rib or the fourth and fifth intercostal spaces with the sternum. If possible, the positioning of the intubation under DSA will be more accurate. 2. Since the right arm of the right atrium is more likely to cause adhesion, it is recommended to place the arterial lumen of the catheter on the left side of the atrium.

The position of the catheter tip is very important and is an important condition for ensuring good function of the catheter.

If the tip of the catheter is too shallow, it will not only easily lead to wall adhesion, but more importantly, it will easily lead to the formation of a fibrous sheath, which will eventually spread to cover the entire catheter.

Place the catheter tip into the right atrium and it is important to avoid contact between the catheter tip and the wall of the superior vena cava.

Inserting a catheter under the DSA is a better choice, as it can locate the tip of the catheter in real time. It should be noted that when the human body changes from a supine position to an upright position, the mediastinum and the heart will move downward by about 2 cm. This change should be considered and prepared in advance when inserting the catheter. Leave appropriate catheter length.

After the catheter is inserted, an anteroposterior radiograph of the chest should be taken to determine the position of the catheter tip. If the position is too shallow or too deep, adjust it immediately. Even if a period of time has passed since the catheter was inserted and the polyester sleeve has grown together with the subcutaneous tissue, you can remove the polyester sleeve and adjust the depth of the catheter.

The reasons are: 1. Insufficient flushing of the catheter after dialysis and blood remaining in it

2. There is not enough sealing fluid and insufficient anticoagulant filling in the catheter.

3. Catheters with side holes are prone to leakage of anticoagulant in the catheter. After the anticoagulant leaks, blood fills the catheter and easily forms thrombus.

4. The femoral vein TCC catheter is prone to thrombosis. The reason is that the opening of the femoral vein catheter is upward, and the density of the blood is greater than the anticoagulant. Due to the effect of gravity, the blood squeezes out the anticoagulant and deposits it into the catheter, making thrombosis easy to form.

Treatment: 1. First try to flush and aspirate with saline pressure, it is possible to aspirate the thrombus. If this fails, intracatheter thrombolysis can be used, in which urokinase or alteplase is instilled or pumped into the catheter. This can be repeated and most thrombi can be dissolved.

2. If thrombolysis fails, replacement of the TCC catheter can only be considered.

The fibrous sheath is a collagen layer produced by smooth muscle cells. It can form as early as 24 hours after the catheter is placed. It initially forms at the contact point between the catheter and the blood vessel wall, and eventually develops to cover the entire catheter. The fibrous sheath at the top of the catheter will block the catheter lumen.

The most important thing to prevent the formation of fibrous sheath is to place the catheter tip into the right atrium so that the entire catheter is suspended in the superior vena cava and avoid the catheter from contacting the blood vessel wall.

Once the fibrous sheath is formed, drug treatment is usually ineffective. Currently, the most common method is to replace the TCC catheter and add a balloon to destroy the fibrous sheath. When replacing the catheter, the fibrous sheath is confirmed by angiography, and then an 8 or 10 mm diameter balloon is used to remove the fibrous sheath from the confluence point of the innominate vein. The right atrium is dilated to destroy the fibrous sheath, and the catheter is then reinserted.