ABSTRACT
Objective To investigate the effect of dexmedetomidine on the damage to the nonventilated lung in the patients undergoing one-lung ventilation (OLV).Methods Forty patients of both sexes, aged 18-64 yr, with body mass index of 18-25 kg/m2, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ, scheduled for elective radical surgery for lung cancer under general anesthesia, were randomly divided into either control group (group C) or dexmedetomidine group (group D) with 20 in each group.After induction of anesthesia, the patients were tracheally intubated and mechanically ventilated.After correct positioning was confirmed by fiberoptic bronchoscopy, dexmedetomidine was infused for 20 min as a dose of 0.5 μg/kg, followed by an infusion of 0.5 μg · kg-1 · h-1 until the moment of tumor resection.The equal volume of normal saline was given in group C.Immediately after the beginning of OLV, at 60 min of OLV, and immediately after the end of OLV, the specimens of normal lung tissues around the tumor were obtained for microscopic examination of pathologic changes which were scored, and for determination of the expression of hypoxia-inducible factor-1 alpha (HIF-1α) and heme oxygenase-1 (HO-1) by Western blot.Results Compared with group C, the pathological score was significantly decreased on the non-ventilated side immediately after the end of OLV, and the expression of HIF-1α and HO-1 in the lung tissues on the non-ventilated side was up-regulated in group D (P＜0.05).Conclusion Dexmedetomidine can mitigate the damage to the non-ventilated lung in the patients undergoing OLV, and the mechanism is associated with up-regulated expression of HIF-1α and HO-1.