Successful radial artery puncture is a prerequisite for the establishment of radial artery access and smooth radial artery intervention. However, compared with the femoral artery, the radial artery is relatively small and prone to spasm, so the difficulty of puncturing the radial artery is higher than that of the femoral artery, especially for the presence of radial artery developmental anomalies, mental stress and other unfavorable factors, the puncture may become more difficult. It can be said that radial artery puncture is the first technical difficulty of radial artery route interventional therapy, and the inability to successfully carry out radial artery puncture is also the most common reason leading to the failure of radial artery route coronary intervention. The mastery of standardized and reasonable puncture technology is conducive to improving the success rate of radial artery puncture. In this paper, we will talk about the radial artery puncture techniques and discuss some of the problems often encountered in radial artery puncture. I. Techniques of radial artery puncture 1. Selection of the puncture point The selection of the appropriate puncture point can reduce the difficulty of the operator’s puncture and help to improve the success rate of puncture, so the selection of the puncture point is very important. Because the radial artery is more superficial as it is closer to the distal end, but it has more branches, so if the puncture point is too close to the distal end, the possibility of accidentally entering the branch vessels will increase; and if the puncture point is too close to the proximal end, due to the deeper radial artery, it will also increase the difficulty of the puncture, and once the puncture fails in the selected site, it is often necessary to move forward to the proximal end to re-select the puncture point. If the original puncture site is too close to the proximal end, this may also make it difficult to re-select the puncture point. Usually, the puncture point is 1 cm proximal to the radial styloid process because the radial artery is relatively straight and superficial, which makes the puncture easy to be successful, and the radial artery has relatively few branches at this site, which makes the chance of accidental insertion of the puncture into the branching vessels less likely. However, in some cases, the radial artery may not be the most suitable puncture point due to its tortuosity and variations, so the choice of puncture point should be individualized. The ideal puncture point should be chosen at the site where the radial artery travels straight and has obvious pulsation. 2, local anesthesia techniques In local infiltration anesthesia, too much subcutaneous injection of anesthetics before puncture will cause swelling of the puncture site, thus affecting the operator’s judgment of the radial artery pulsation, which will increase the difficulty of the puncture, so it is recommended to apply the “two-step method” to give local anesthesia drugs, i.e., a small amount of injection of anesthesia drug subcutaneously before puncture, and then supplemented with anesthesia drug before sheath insertion after the success of the puncture. That is, a small amount of subcutaneous injection of anesthetic drug before puncture, and after successful puncture, a certain dose of anesthetic drug is added before sheath tube placement. However, when injecting anesthetic drugs, the needle should not be too deep, so as not to accidentally injure the radial artery. In radial artery puncture, it is best to elevate the patient’s wrist and keep the wrist joint in a state of hyperextension, which is conducive to improving the success rate of radial artery puncture. During the puncture, the index finger, middle finger and ring finger of the left hand of the patient should be placed on the strongest radial artery pulsation in order to indicate the direction of radial artery travel of the patient from the puncture site from far to near. The index finger points to the site that is the puncture of the “target point”, the three fingers point to the line that is the direction of the needle, a situation to be avoided here is that some operators for a clearer feeling of the arterial pulsation of the finger pressure, which will cause the distal end of the radial artery blood flow is blocked, artificially increasing the difficulty of the puncture. The angle of needle insertion is generally 30-45°, but for thicker or harder blood vessels, the angle of needle insertion should be slightly larger; for thinner blood vessels, the angle of needle insertion should be slightly smaller; after insertion of the needle, if the end of the needle to see the blood flow, you can then send the needle forward for a little while, and then slowly withdrawn (for the use of the Terumo cannula needle for puncture, you should exit the core of the needle first and then retract the trocars, and it should be noted that the exit of the core of the needle should be ensured that the fixed trocars) until the end of the blood spray. It should be noted that the trocar should be secured when withdrawing the trocar) until blood is ejected from the end of the needle and then the guidewire is fed. If you do not see blood coming back from the end of the needle after inserting the needle, do not hastily withdraw the needle, use the index finger of the left hand to judge the position of the needle in relation to the radial artery at this time, then withdraw the needle to the subcutaneous area, adjust the direction of the needle tip and insert the needle again, every time you insert the needle, if you don’t see any blood coming back, you should judge the position of the tip of the needle and then re-puncture. 4.Send the guidewire If the blood spurt at the end of the puncture needle is good, the index finger and thumb of the left hand should fix the needle handle to ensure that the position of the puncture needle does not move while the right hand sends the guidewire, and the action should be gentle, and once resistance is encountered, the guidewire should stop sending the guidewire immediately, and the guidewire can be partially withdrawn, and then the guidewire should be sent again to facilitate the smooth sending of the guidewire by changing the angle of the puncture needle or by adjusting the guidewire’s direction of advancement by rotating the needle, and it should not be pushed by force to avoid accidental injuries. At this time, do not force the guidewire, so as not to accidentally injure the small branches and lead to the occurrence of forearm hematoma. Normally, the guidewire should be sent forward at least beyond the level of the ulnar humerus before being sent along the sheath. 5, insertion of the sheath tube Before insertion of the sheath tube, in order to reduce the pain of the patient, it is often necessary to supplement a certain amount of anesthesia at the puncture site, and make a skin incision to reduce the resistance of the sheath tube delivery. Currently used arterial sheaths are often coated with hydrophilic material, which helps to reduce the friction of the sheath when it is infiltrated with water and prevents the occurrence of radial artery spasm. When feeding the sheath, the index and middle fingers of the left hand fix the position of the guidewire at the puncture point, the thumb presses down on the extracorporeal portion of the guidewire, and the right hand holds the tip of the sheath, keeping it in the same direction of the vessel’s alignment, and advancing it slowly. If resistance is encountered, the guidewire should be withdrawn to determine whether the sheath has penetrated the vessel. After placing the sheath, the dilatation tube and guidewire should be withdrawn together. If arterial blood can be withdrawn smoothly through the lateral tube, it can be determined that the sheath is located in the true lumen of the blood vessel and the radial artery puncture is successful. Second, the radial artery puncture process of common problems and treatment 1, the same part of the repeated puncture unsuccessful common reasons for this situation are: (1) failed to puncture the radial artery: if the radial artery still exists at this time, do not be in a hurry to repeat the operation of the puncture, should first analyze the probable causes of the failure of the puncture, and then change the different circumstances of the puncture technique and then enter the needle, such as for the more hard and easy to roll radial artery, the patient’s arterial pulse is very strong, but the patient’s arterial pulse is very strong. For example, for the hard and easy to roll radial artery, the patient’s arterial pulsation is very strong, but it is difficult to puncture, in this case, the choice of bare needle puncture is more advantageous, puncture appropriate to increase the angle and speed of the needle is often helpful to hit the radial artery; on the other hand, for the radial artery is more thin, the pulsation of the patient is weak, the choice of trocars to puncture into the true lumen of the higher success rate, in this case, should be a small angle of the puncture, and at the same time, slowly into the needle is often conducive to the success of the puncture. (2) The radial artery at the puncture site is tortuous: usually in this case, it is difficult to ensure that the direction of the needle during puncture is consistent with the radial artery, so it is difficult to succeed in the puncture, and it is necessary to replace the puncture point to the radial artery at the straight part of the route and then carry out the puncture. (3) Radial artery spasm: this is often manifested as the radial artery pulsation is weakened or even disappeared, at this time the choice of blind puncture may further aggravate the degree of radial artery spasm, waiting for the radial artery pulsation to restore the puncture may be a more sensible choice, there are scholars believe that subcutaneous nitroglycerin can help to shorten the radial artery spasm after the recovery time. (4) The formation of local hematoma: in this case, it is difficult to achieve success in the original site of puncture, and should be avoided after the hematoma site to re-select the puncture point. 2, the puncture needle into the radial artery, but the tail of the puncture needle blood flow is not smooth The usual causes of this situation are: (1) puncture needle tip beveled surface is not completely into the vascular lumen: in this case, the tip of the needle may be located in the radial artery of the anterior wall or the posterior wall, the operator can often be adjusted to make the tip of the needle into the vascular lumen by adjusting the depth of the puncture needle and the angle of the needle completely. (2) Radial artery spasm: in most cases, the puncture supporting guidewire can often be delivered smoothly anteriorly, and generally does not pose much of an obstacle to the establishment of the radial artery access. (3) Puncture needle into the radial artery branch: after adjusting the position of the puncture needle is still unable to successfully forward delivery of the guidewire often suggests that this possibility, the puncture point is too close to the wrist is common, and often need to proximally move forward to the puncture site and then again into the needle. 3, the puncture needle back to the blood is good, but send into the guidewire resistance Common causes include: (1) guidewire into the radial artery branch: often manifested in part of the guidewire into the guidewire continue to send the guidewire resistance, at this time along the guidewire into the part of the arterial sheath, through the sheath of the lateral tube back to the blood to prove that the sheath is located in the true lumen of the vessel, and then along the sheath of the guidewire into the long ultra-smooth guidewire, due to the guidewire curved at the anterior end and the softer guidewire is often able to plastic Due to the curved and soft anterior end of the guidewire, the guidewire can often be shaped into collaterals and then successfully delivered anteriorly to the distal end of the main vessel, and then placed into the arterial sheath along the ultra-smooth guidewire. (2) Severe tortuous radial artery: the sheath can be delivered along the sheath to ensure that the sheath is located in the true lumen of the vessel, and then replaced with a long, ultra-smooth guidewire, which often facilitates the passage of tortuous vessel segments. (3) guidewire top in the radial artery wall: most of the former guidewire soon felt resistance, can be withdrawn guidewire, by rotating the direction of the puncture needle to adjust the guidewire forward direction or change the depth of the needle into the puncture needle and then again into the guidewire can often be successful. (4) Serious curvature of the radial artery: adjust the direction of the guidewire under fluoroscopy and then try to pass through the curved section of the vessel, if necessary, it may be necessary to change the puncture site. (5) Radial artery malformation: such as residual radial artery, radial artery development, such as small causes will also cause increased resistance when the guidewire is sent forward. 4, placed into the sheath resistance is greater The main reasons for this situation are: (1) the sheath into the radial artery branch: at this time can be partially retracted first sheath, through the return of blood to confirm that the sheath has retreated to the lumen of the main blood vessels, along the sheath into the long hydrophilic coated guidewire to the level of the brachial artery, and then along the delivery of the contrast catheter, in the contrast catheter along the delivery of sheaths; (2) spasm of the radial artery: it can be confirmed by the contrast, encountered in such cases Can consider additional local anesthetic drugs along the direction of the sheath, such as: lidocaine, etc., to help relieve arterial spasm; if necessary, need to replace the radial artery sheath with a small outer diameter (such as 4F arterial sheath), this time should be sent along the original sheath to the proximal end of the long ultra-smooth guidewire, and then withdrawn from the original sheath along the guidewire and along the delivery of the 4F arterial sheath. (3) The sheath tube breaks through the vessel wall: it is often manifested that after feeding the sheath tube, the side tube of the sheath tube can not smoothly withdraw blood, the sheath tube can be withdrawn at the same time while maintaining a continuous withdrawal state, once the blood can be smoothly withdrawn, which indicates that the sheath tube has already entered the lumen of the radial artery, and then the sheath tube should be sent along the guidewire after sending the long guidewire smoothly to the distal end.