右美托咪定在胸外科手术麻醉中的应用进展

开胸、单肺通气及侧卧位,会导致一系列的病理生理改变,容易发生肺内分流、低氧血症;同时,由于吸入麻醉剂抑制了肺脏的缺氧性肺血管收缩机制,进一步增加了低氧血症的发生率;手术创伤导致肺的缺血再灌注损伤、术后疼痛继发肺不张等,都是胸外科麻醉面临的问题。目前,胸段硬膜外复合全凭静脉麻醉是胸外科较为理想的麻醉方式,并联合椎管内应用吗啡进行术后疼痛,但存在术中知晓和术后镇痛不全等不足。盐酸右美托咪定是一种新型α2 受体激动剂,对α2 ∶ α1 的选择性结合比为1 620 ∶ 1,能高选择性激动中枢及外周的α2 肾上腺素能受体,对肺脏具有保护作用,调节HPV,减少低氧血症的发生;稳定循环,避免血流动力学波动,有效地抑制应激;作为镇痛的一种新辅助用药完善术后镇痛;顺行性遗忘作用与丙泊酚协同麻醉,预防术中知晓;改善术后的认知功能。论文对右美托咪定在胸外科麻醉中的作用机制及优势进行综述。

Research progress in application of Dexmedetomidine in anaesthesia of thoracic surgery

One-lung ventilation, lateral position and thoracotomy will bring a series of pathophysiologicchanges that lead to pulmonary shunt and perioperative hypoxemia in the patients; meanwhile, the inhalation ofanesthetics inhibits protective mechanism of hypoxic pulmonary vasoconstriction (HPV) in the lungs which furtherincreases the incidence rates of hypoxemia and atelectasis. The patients will face significant problems of thoracotomyinducedlung ischemia-reperfusion injury and postoperative pain together with atelectasis. At present, thoracicepidural anesthesia combind with total intravenous anesthesia is an ideal anesthesia for thoracic surgery, Morphine isthe main analgesic injected into the epidural space for postoperative analgesia, however, there are some deficienciessuch as intraoperative awareness and postoperative insufficient analgesia. Dexmedetomidine is a new type of alpha-2receptor agonist, its binding rate with alpha-2 receptor is 1,620 times higher than that with the alpha-1 receptor, itcan selectively activate the central and peripheral alpha-2 adrenergic receptors. Dexmedetomidine has protectiveeffect on the lungs, can effectively improve the self-protection mechanism (HPV) of the lungs to reduce hypoxemia,maitain the stability of circulation, inhibit the stress respones; and as a new adjuvant analgesic, improve postoperativeanalgesia. Dexmedetomidine has the effect of anterograde amnesia, and is effective in preventing intraoperativeawareness combined with Propofol and improving postoperative cognitive function. To summarize the mechanismand advantages of Dexmedetomidine will be elaborate to investigate the perioperative anesthesia managements ofthoracic surgery.