Application of nerve block positioning

In the hundred years of anesthesia history, anesthesia for many surgical advances of new technologies made possible by new advances will significantly reduce the anesthesia complications and improve the quality of perioperative management. After several nerve block in which the rise and decline, to 60 years due to the emergence of postoperative analgesia, nerve block was once again aroused attention [1], and has developed into a branch of anesthesiology. In recent years, many scholars of nerve block anesthesia carried out some research and study and put forward some new ideas and new technology to block the variety of ways, adding clinical selectivity, increased anesthetic effect. 1, nerve block basis of the progress: (1) clinical development of surgical anesthesia made new demands on  surgery has been continuously put forward new requirements for narcotic. With the increase in surgical patients, surgical anesthesia be required preoperative preparation is simple, rapid and effective anesthesia and postoperative recovery room length of stay shortened, so as to facilitate the realization of fast-track surgery; also requires bone and joint surgery patients to an early stage functional exercise. Many studies have also confirmed that, individually or with nerve block anesthesia combined, can improve postoperative recovery rate and shorten the postoperative stay in the recovery room time, anesthesia dosage reduction in intraoperative or postoperative opioids drug use also decreased. The general anesthesia patients often suffered from all kinds of common complications such as persistent pain, nausea, vomiting, drowsiness, etc., need to extend the hospital length of stay [2,3]. Pavlin [4] compared the right upper extremity surgical patients with brachial plexus block anesthesia for postoperative recovery, patients receiving brachial plexus block anesthesia time can be advanced from the hospital 70 min. Vloka [5,6] and other lower extremity venous stripping surgery for lower extremity nerve block compared with the results of spinal anesthesia, the purposes of femoral nerve block the patient's discharge time can be ahead of 70 min. For the patients, nerve block is also through the reduction of intraoperative and postoperative pain and accelerate a patient's recovery. (B) new technologies and the development of a new means, Ropivacaine is a new local anesthetic, bupivacaine similar chemical structure, it generates a feeling of narcotic and bupivacaine is similar, but in the human central nervous system the system and cardiovascular toxicity of the role is better than the RS-bupivacaine. In the clinical trials process, some patients unexpectedly high-dose intravenous injection of ropivacaine, but no one took place harmful systemic toxicity. In addition, it was suggested by the epidural administration of ropivacaine, it will produce more obvious sensory-motor separation, it can produce good analgesic effect and its role in motor block compared with bupivacaine weak. Is very suitable for nerve block. 2, nerve stimulator positioning of traditional nerve block depends on the patient's sense of the emergence of different acupuncture, that is, different sense of orientation, it is difficult to accurately determine the location of nerves, blocking satisfactory results, and often there is also easy to nerve injury and bleeding complications [7]. Can accurately determine the body surface of the Traveling brachial plexus, and make local anesthetic into the brachial plexus is to obtain a satisfactory brachial plexus block is the key to reducing its complications. Nerve stimulator-assisted positioning without the need for brachial plexus block in patients complained paresthesia, by virtue of stimulator to produce a single stimulus waves to stimulate the peripheral nerve to induce the movement of the nerve branches dominated by muscle fibers contract, to assist accurate positioning [8]. Since the beginning of the last century, have been applied under the guidance of the purposes of nerve stimulator nerve block were reported. Modern nerve stimulation device for the operation of doctors to provide feedback information, adding to the objective and precise means of assistive technologies. Nerve block anesthesia nerve stimulator pairs of physical interference with a small, anesthesia Indeed, the simple and economic characteristics. But the success rate depends on the operator's experience, especially in the deep nerve block success rate of the lower limit of its widely used. Nerve stimulator technology to improve positioning accuracy and nerve block success rate, and promoted the promotion of nerve block. This technology since the introduction of China has been the increasingly widespread application, avoiding unnecessary use of general anesthesia and complications, increase in anesthesia safety. 3 tube technology to overcome drug consecutive single-injection nerve block to maintain the shortcomings of a short time, reduced respiratory depression, nausea, vomiting, itching, urinary retention occurred. 4, and B-, by means of the combination of magnetic resonance imaging technology has been gradually integrated with the nerve block to improve the accuracy of the nerve block, reduce complications and observations following the spread of local anesthetic injected into the law. Thick surface Doppler ultrasound can locate the nerve to distinguish between arteries and veins, and nerve stimulator with the nerve block can increase the success rate, and is used to guide the deep vein puncture or arterial puncture. Second, the new nerve block positioning methods: (a) nerve stimulator: peripheral nerve stimulator advent of nerve block anesthesia is a breakthrough. Has changed the traditional sense of legal nonsense probe different type operation, precise positioning to be the nerve block, significantly improved the success rate of anesthesia, the greatest degree of reduction of the nerve injury. Meyer, etc. 80 years on the nerve stimulator and nerve block needle has been improved, and is widely used in peripheral nerve block and nerve plexus, thus contributing to the nerve stimulator-guided nerve block technologies. All kinds of needles to stimulate both the outer sheath with an insulating film, only in the conductive tip. Current focus, you can reflect more accurately the location of muscle contraction occurs; because it is close to the nerve rather than the touch nerves, so pairs of nerve damage greatly reduced, more accurate positioning, dosage reduction, obesity, or touch marks unclear profile control patients, The success rate has improved significantly. Nerve stimulator generates electrical stimulation of the use of pulsed current sent to the needle, when the puncture needle close to mixed nerve, mixed nerve can cause depolarization, and one motor nerve depolarization occurs more easily dominated by Oscillatoria muscle pumping, so that Oscillatoria can be pumped through the reaction of muscle to locate, without going through the needle contact with nerve produce paresthesia to judge. Including the electrical stimulation device, the puncture needle, electrodes and connecting wires. Nerve stimulator for nerve location and at the same as conventional nerve block to be placed posture, positioning, sterilization shop towel, followed by needle stimulator. Began to 2mA current to determine whether close to nerve, 2mA current motor can go from 1cm polarization, and then adjust needle direction, depth and stimulator current, until the smallest current (0.5-1mA) to produce the greatest muscle fibrillation pumping reaction, Note puncture needle close to nerves, this time to stop needles, no blood and fluid back to suck after the local anesthetic injection 2ml, if the muscle pump response to weakening or disappearance of fibrillation, namely, to be further confirmed. If accompanied by severe pain during injection may be prompted to nerve injection, this time should be to change direction. For example, B. Braun's Stimuplex HNS11 nerve stimulation device, its features are as follows: current amplitude range of 0-1MA (or 5MA), regulate and high accuracy. Pulse periods of 0.1,0.3 or 1.0 3 block adjustable. Pulse frequency can be set to 1 ~ 2Hz. For a given current, its current needed to trigger muscle contraction intensity and distance from the tip to the nerve-related, that is, the distance between the tip and nerve nearer the need to cause muscle contraction or feeling, the lower the current response. In daily clinical practice, usually the first to use 1mA of current to elicit a response. Where the threshold current of 0.2 ~ 0.3mA (pulse width 0.1ms) can rise to effects of muscle contraction, indicating that the needle had been close to the nerve stimulation. Amplitude and then low, may lead to nerve damage. Peripheral nerve block anesthesia may choose to stimulate the frequency of motor nerve fibers