Efficacy of different doses of dexmedetomidine mixed with ropivacaine used for thoracic paraverte-bral nerve block combined with general anesthesia in patients undergoing radical resection of lung cancer / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the efficacy of different doses of dexmedetomidine mixed with ropivacaine used for thoracic paravertebral nerve block (TPVB) combined with general anesthesia in the pa-tients undergoing radical resection of lung cancer. Methods One hundred patients of both sexes, aged 18-64 yr, with body mass index of 18-25 kg∕m2, of American Society of Anesthesiologists physical statusⅡorⅢ, scheduled for elective radical resection of lung cancer, were divided into 5 groups (n＝20 each) using a random number table method: general anesthesia group ( group G), TPVB with ropivacaine com-bined with general anesthesia group (group R), TPVB with 0. 5 μg∕kg dexmedetomidine mixed with ropiva- caine combined with general anesthesia group (group RD0. 5), TPVB with 1. 0 μg∕kg dexmedetomidine mixed with ropivacaine combined with general anesthesia group (group RD1. 0), and TPVB with 2. 0 μg∕kg dexmedetomidine mixed with ropivacaine combined with general anesthesia group ( group RD2. 0). Two-point TPVB was performed, and anesthetic 10 ml was injected into each puncture site. Zero point five per-cent ropivacaine was administered in group R. Dexmedetomidine 0. 5, 1. 0 and 2. 0 μg∕kg mixed with ropi-vacaine at the final concentration of 0. 5% were injected in group RD0. 5, group RD1. 0 and group RD2. 0, respectively. Anesthesia was maintained by intravenously infusing propofol and remifentanil and cisatracuri-um was intermittently injected to maintain muscle relaxation. The occurrence of intraoperative hypotension and bradycardia was recorded. The emergence time, extubation time, duration of postanesthesia care unit (PACU) stay and requirement for rescue analgesia during emergence from anesthesia were also recorded. Small marginal lung samples next to the tumor were harvested immediately after removing the tumor tissues. The expression of caspase-3 and Bcl-2 was determined by Western blot, the content of IL-1β in lung tissues was determined by enzyme-linked immunosorbent assay, the cell apoptosis was evaluated by TUNEL, and apoptosis index ( AI) was calculated. The injury to lung tissues was observed with a light microscope and scored. Results Compared with G and R groups, AI, IL-1β content and lung injury score were signifi-cantly decreased, the expression of caspase-3 was down-regulated, and the expression of Bcl-2 was up-regulated in the other three groups, the incidence of hypotension and bradycardia was significantly in-creased in group RD1. 0, the incidence of bradycardia was significantly decreased in group RD0. 5, and the incidence of hypotension and bradycardia was significantly increased, and the emergence time, extu-bation time and duration of PACU stay were prolonged in group RD2. 0 ( P＜0. 05). Compared with group RD0. 5, IL-1β content was significantly decreased, and the incidence of hypotension and bradycardia was increased in group RD1. 0, and IL-1β content was significantly decreased, the incidence of hypoten-sion and bradycardia was increased, and the emergence time, extubation time and duration of PACU stay were prolonged in group RD2. 0 ( P＜0. 05). Compared with group RD1. 0, the incidence of hypotension and bradycardia was significantly increased, and the emergence time, extubation time and duration of PACU stay were prolonged in group RD2. 0 ( P＜0. 05). There was no significant difference in the AI, expression of caspase-3 and Bcl-2, lung injury score, or requirement for rescue analgesia among RD0. 5, RD1. 0 and RD2. 0 groups ( P＞0. 05). Conclusion Dexmedetomidine 0. 5 μg∕kg mixed with ropiva-caine for TPVB combined with general anesthesia provides better efficacy in the patients undergoing radical resection of lung cancer.