Ultrasound-guided H-FICB for Arthroscopic Knee Surgery： What is the Optimal Dose of Dexmedetomidine?

H-FICB was guided by ultrasound before general anesthesia. The patient was supine. First, the probe is placed transversely above the groin. Then slide the probe up and down to reveal a clear image of the internal oblique and sartorius muscles. There is a bowtie-like iliac fascia space at the junction of these two muscles. After the scanning, the needle was inserted behind the probe with the tip pointed to the ventral side under the guidance of real-time ultrasound; the tip passed through the skin into the iliac fascia space and advanced to the inguinal ligament. After no blood was extracted, 1 \~ 2 ml of normal saline was firstly injected to determine whether the tip position was correct.