Thoracic Paravertebral Block Using Ropivacaine With/Without Dexmedetomidine in Video-assisted Pneumonectomy

The investigators aim to recruit 60 patients undergoing video-assisted pneumonectomy. All patients ASA physical status I-II grade, aged within 20-70 years, are randomly allocated into two groups: 75mg/20ml ropivacaine only group (Group R, n=30) and 75mg/20ml ropivacaine + 1μg/kg dexmedetomidine (Group RD, n=30). At the end of surgery, the investigators perform four points thoracic paravertebral block guided by ultrasound combined with nerve stimulator at T3-4, T4-5, T5-6, T6-7 of surgical side where 5ml solution is injected to each point. The characteristics of patients are analyzed to confirm whether they are comparable in both groups. Pain was assessed according to a numerical rating scale (NRS) (0 = no pain; 10 = worst pain imaginable). Patients were asked to evaluate the maximal degree of pain. Pain scores were recorded in post anesthesia care unit(PACU), and1, 2,4, 8, 12, 24, 36 and 48 hours after surgery. The study endpoints are evaluated by an anesthesiologist who does not know the group allocation. The postoperative rescue analgesic administration, adverse outcomes and patient satisfaction are also recorded.

All data were processed in SPSS 18.0 (SPSS Inc., Chicago, IL USA). Normality was tested by the Kolmogorov-Smirnov analysis. Comparisons of continuous outcomes among groups were examined using Kruskal-Wallis test. Chi-square analysis or Fisher's exact test was used to assess categorical outcomes between groups. A P-value<0.05 was considered statistically significant.