Application of caudal block guided by ultrasound in clinical anesthesia

Sacral anesthesia has the advantage of stable circulation because of its limited blockade scope and little influence on cardiovascular system. The traditional way of sacral block anesthesia is based on bony markers. Most adult anatomical markers are not clear, or because of obesity, anatomical variation, deformity and other conditions, it is often difficult to palpate the sacral horn, inaccurate location of sacral hiatus, leading to puncture difficulties, high failure rate of anesthesia. Therefore, sacral block is mostly used in pediatric short surgery, but seldom used in adults. With the rapid development of biotechnology and microelectronics, bedside ultrasound has been widely used in clinical anesthesia for its powerful advantages of portability, non-invasiveness, safety, visualization and repeatability. Ultrasound scanning can identify blood vessels, nerves, muscles, tendons, joints and other tissues. Ultrasound-guided sacral block can identify sacral canal structure, sacral canal space, measure space depth, accurately locate sacral hiatus, guide puncture path, direct puncture process, reduce repeated puncture, significantly reduce the failure rate of sacral block, vascular nerve injury, toxic reaction of local anesthetics, etc. At the same time, it can observe and monitor the process of drug injection and evaluate the anesthetic effect. The effectiveness and safety of sacral block were greatly improved. Under the guidance of ultrasound, sacral anesthesia is widely used in clinical anesthesia and postoperative analgesia, ranging from single sacral block to continuous sacral block, from short operation to long complex operation. With the popularization of equipment and the deepening of the concept of rapid rehabilitation, it can also be used in outpatient examination, pain treatment and rehabilitation medicine in the future. The application scenario will be more and more, and the applicable population will gradually expand to all patients. This article reviews the application of ultrasound-guided sacral block in clinical anesthesia.