Thoracic Paravertebral Block Using Ropivacaine and Dexmedetomidine

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

The hypothesis of the study is whether dexmedetomidine plus local anesthetic ropivacaine could extend the pain relieve time compared with only ropivacaine when thoracic paravertebral block is performed at the end of 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.

Thoracic paravertebral block, Dexmedetomidine, Video-assisted Pneumonectomy, Ropivacaine, Pain, Postoperative

Thoracic paravertebral block is performed using 75mg/20ml ropivacaine + 1μg/kg dexmedetomidine at the end of video-assisted pneumonectomy.

Thoracic paravertebral block is performed using 75mg/20ml ropivacaine at the end of video-assisted pneumonectomy.

The procedure is guided by ultrasound combined with nerve stimulator at T3-4, T4-5, T5-6, T6-7 of surgical side.

Pain Numerical Rating Scales （NRS) at rest（0: no pain--means the minimum value; 10: worst possible pain--means the maximum value)

using a 5-point Likert scale (5-point: completely satisfied, 4-point: quite satisfied, 3-point: slightly dissatisfied, 2-point: dissatisfied, 1-point: very dissatisfied)

a rescue analgesic morphine 5mg will be administered for any pain score ≥4 （0: no pain--means the minimum value; 10: worst possible pain--means the maximum value)

Inclusion Criteria: ASA physical status I-II grade Undergoing elective video-assisted pneumonectomy under general anesthesia. Participants aged from 30-70 years old. Exclusion Criteria: Refusal for paravertebral block Inability to obtain informed consent Coagulation disorders, neuropathy, or body mass index greater than 40 kg/m2 Pregnancy Infections at the site of injection for the paravertebral block Allergy to local anesthetics or alpha-2 adrenergic agonists Heart block or bradycardia (heart rate < 60 beat per minute) Clinically significant cardiovascular, pulmonary, renal, or hepatic diseases