Ultrasound-guided Approach Combined With Pressure Measurement Technique to Thoracic Paravertebral Block

Posterolateral thoracotomies are among the most painful procedures of surgery and may cause severe postoperative chest pain and impaired respiratory performance. Paravertebral block (PVB) is an established method of administering postoperative analgesia for thoracic procedures. PVB blocks the somatic and sympathetic nervous systems and is placed by injecting a local anesthetic (LA) into the paravertebral space where the nerve and its branches are located after exiting the intervertebral foramen. But previous study showed 5-10% of failure rate in PVB using ultrasound machine. Pressure measurement during needle advancement could improve reliability of correct needle placement. When the needle tip reaches paravertebral space, there is a sudden lowering of pressures due to respiratory cycle. Therefore, sensitivity and specificity could be improved and correct needle placement become objective and reproducible when PVB using ultrasound is combined with pressure measurement during needle advancement.