Implementation of a novel high frequency ultrasound device for guiding epidural anesthesia-in vivo animal study

Epidural anesthesia has been used widely for anesthesia surgery in many clinical applications. However, the risk of epidural anesthesia may be occurred as the puncture needle was inserted too deeper to cause the dural puncture. In most cases, the anesthetists finish the anesthesia operation according to their clinical experiences. In our previous study, a novel idea of combining the ultrasound needle transducer and epidural catheter has been proposed for guiding the epidural anesthesia insertion. In present study, the implementation of this novel ultrasonic device was performed, and the animal experiments were also carried out for verifying the system performance. The portable device including a high frequency ultrasound pulser/receiver, 40-MHz high frequency needle transducer, high speed analog-to-digital converter, LCD monitor, and a FPGA chip was used to control the pulse signal by adjusting the pulse repetition frequency and pulse frequency. The distance between the tip of the epidural needle, ligamentum flavum, and dura mater can be measured in real-time by monitoring the reflected ultrasound signal in A-mode image display.