Exploring the appropriate concentration of ropivacaine for paravertebral block with pulsed infusion after pneumonectomy

Abstract

Objective To compare the effectiveness of different concentrations of ropivacaine in thoracic paravertebral block with pulsed infusion after pneumonectomy. Methods Ninety patients, ASA I or Ⅱ, underwent pneumonectomy were randomly allocated into three groups (n=30): 0.2% ropivacaine group (group A), 0.35% ropivacaine group (group B), and 0.5% ropivacaine group (group C). MAP and HR were monitored at 2, 4, 8, 12, 24, 48 h after the surgery. Postoperative pain was assessed by rest visual analogue scale (rVAS) and movement visual analogue scale (mVAS) and the cases of VAS≤3 at each time points. The sensory blockade plane was examined by temperature method and the number of effective press times was evaluated within 48 h after the operation. The adverse events such as hypotension, nausea, vomiting and respiratory depression were observed during 48 h after the surgery. Results Compared with group A, rVAS and mVAS decreased in group B and group C, and the cases of mVAS≤3 increased at 4, 8, 12, 24, 48 h after surgery (P 0.05). The number of effective press times indicated that group A>group B>group C (P<0.05). Conclusion Better analgesic effect with 0.35% and 0.5% ropivacaine can be obtained in thoracic paravertebral block, but considering the medical safety, 0.35% ropivacaine is more suitable for paravertebral block with pulsed infusion after pneumonectomy. Key words: Pulsed therapy, drug; Amides; Nerve block; Thoracic paravertebral; Pneumonectomy; Dose-response relationship, drug