The effects of ropivacaine combined with dexmedetomidine for target thoracic paravertebral nerve blocks by multiple injections for preemptive analgesia on postoperative analgesia of patients of pulmonary cancer undergoing thoracotomy / 中国医师进修杂志

ABSTRACT

Objective To evaluate the efficacy of dexmedetomidine mixed with ropivacaine for thoracic paravertebral nerve blocks by multiple injections for preemptive analgesia on postoperative analgesia of patients undergoing thoracotomy. Methods Ninety patients, all genders, ASA Ⅰ or Ⅱ, aged 35-64, BMI 18-24 kg/m2, undergoing radical operation for esophageal carcinoma were randomly divided into three groups (each group 30 patients) group C received general anesthesia, group R received ropivacaine for thoracic paravertebral nerve block and group RD received dexmedetomidine mixed with ropivacaine for thoracic paravertebral nerve block.Three groups all used intravenous infusion of propofol, refentanyl and inhalation sevoflurane for anesthesia maintenance, and PCIA pump started before the end of surgery in 3 groups.Meanwhile, group R and group RD received ultrasound-guided T4-T8thoracic paravertebral nerve blocks by multiple injections on operation side preoperatively.In group R, the mixture of 0.5% ropivacaine 19 ml and 1ml of normal saline was injected, and in group RD, the mixture of dexmedetomidine 1 μg/kg and 19 ml of 0.5% ropivacaine was injected.The analgesia process lasted 48 h after surgery of these 3 groups, and the VAS score was maintained<4 points.When the VAS score was 4 or more points, intravenous injection of morphine 5- 10 mg was delivered. Postoperative PCIA liquid and morphine consumption, somnolence, nausea, vomiting, respiratory depression, itching and urinary retention was recorded. Additionally, the occurrences of adverse events about thoracic paravertebral nerve blocks were recorded.Results The dosages of propofol, refentanyl in group R and group RD were lower than those in group G(7.2 ± 0.6),(6.1 ± 0.5)mg/(kg·h)vs.(8.1 ± 0.5)mg/(kg·h), and there were significant differences(P<0.05).The dosage of propofol in group RD was lower than that in group R (6.1 ± 0.5) mg/(kg·h) vs. (7.2 ± 0.6) mg/(kg·h), and there was significant difference (P <0.05). Compared with group G, the consumption of PCIA liqud and the usage rate of morphine was reduced in group R and group RD (P < 0.05); the consumption of PCIA liqud and the usage rate of morphine was lower in group RD than that in group R(P<0.05).The rate of nausea and vomiting and itch in group R and group RD was lower than that in group G,and there were significant differences(P<0.05). No significant difference in somnolence showed between three groups (P > 0.05). Conclusions Ropivacaine combined with dexmedetomidine for target thoracic paravertebral nerve blocks by multiple injections for preemptive analgesia can significantly improve the efficacy of postoperative analgesia after thoracotomy, meanwhile,it can also save the dosage of anesthetic drugs during the operation.