Acoustic puncture assist device: A novel technique to identify the epidural space

BACKGROUND: Acoustic puncture assist device (APAD) is designed to detect and signal the loss of resistance during the epidural procedure. We aimed to evaluate this device in terms of successful identification of the epidural space and the incidence of accidental dural puncture. PATIENTS AND METHODS: Following Institutional Review Board approval and written informed consent obtained from all patients, 200 adult patients (107 males) American Society of Anesthesiologists I-III who underwent lower limb orthopedic surgery under lumbar epidural anesthesia using APAD were enrolled in the study. APAD system was connected to the epidural needle using normal saline prefilled extension tube. Numbers of successful epidural attempts and accidental dural tap were documented. RESULTS: The mean values of the depth of epidural space and the time to perform epidural puncture were 5.8 ± 1.0 cm and 3.3 ± 1.4 min, respectively. In 63% of patients, epidural puncture was successful from the first attempt and in 1% it was successful from the fourth attempt. Epidural anesthesia by APAD was successful in 198 cases (99 %). Dural tap occurred in 2 cases (1%). CONCLUSIONS: Using APAD, the success of identifying the epidural space was high and reliable.