Abstract PR515

Abstract

Background & Objectives: Paravertebral block has become a popular technique and is considered as effective as epidural block for pain control. Local anesthetic (LA) spread pattern within the thoracic paravertebral space (PVS) could be highly variable. Injection of LA into the posterior compartment or the anterior compartment of the PVS results in a cloud-like spread or a longitudinal multisegmental spread image, respectively1). However, There are no reports to examine the relationship between the pattern of the local anesthetics spread and analgesic effects after the same operation. We investigated the spread pattern of contrast dye through the catheter into the PVS in patients undergoing breast cancer operation and whether the spread pattern could be related with analgesic effects for acute post operative pain. Materials & Methods: Between June 2014 and January 2016, we designed a prospective study of 60 patients submitted to unilateral breast cancer surgery without reconstruction. After the operation, the catheter was placed into the PVS using the ultrasound-guided out-of-plane needle insertion approach at the forth thoracic vertebral level under general anesthesia. When we could confirm an anterior movement of the pleura by injection of 25mL of 0.33% ropivacaine, the catheter was judged to be in the PVS. A 5ml of radiographic contrast dye was injected through the catheter and the spread pattern was assessed by X-ray images. Patients recieved continuous 0.2% ropivacaine infusion at the rate of 3ml/h. A numeric rating scale (NRS) was used to assess pain intensity at rest and on moving at 1, 6 and 12 h after operation. Analgesic consumption was also noted. Results: The catheters were judged to be in the PVS in 43 among 60 patients. Fifteen patients showed multisegmental longitudinal spread pattern and 7 patients showed cloud-like spread pattern. Their median NRS (Interquartile range) at 1 h after operation were 3 (0.5-5.5) in multisegmental longitudinal pattern group and 4 (1.5-8) in cloud-like pattern group. Patients who required rescue analgesics within 1 h after operation were 66.7% or 42.9% in multisegmental longitudinal pattern group or in cloud-like pattern group, respectively. Conclusion: Multisegmental longitudinal pattern and cloud-like pattern of paravertebral block had the same analgesic effect after breast cancer operation. Therefore, pattern of contrast dye through the thoracic paravertebral catheter dose not predict analgesic efficacy.