title: Ischemic preconditioning attenuates pulmonary dysfunction after unilateral thigh tourniquet-induced ischemia-reperfusion.
abstract: BACKGROUND
  Acute lung injury is a recognized complication of lower limb ischemia-reperfusion that has been demonstrated experimentally and in the clinical setting of aortic surgery. The application of a tourniquet can cause lower limb ischemia-reperfusion in orthopedic surgery. We studied the effect of unilateral thigh tourniquet-induced lower limb ischemia-reperfusion on pulmonary function, and the role of ischemic preconditioning in attenuating pulmonary dysfunction.
  
  
  METHODS
  Thirty ASA I or II patients scheduled for lower extremity surgery were randomized into 2 groups: a limb ischemia-reperfusion group with tourniquet application (ischemia-reperfusion group, n = 15) and an ischemia preconditioning group (preconditioning group, n = 15), in which patients received 3 cycles of 5 minutes of ischemia, alternating with 5 minutes of reperfusion before extended use of the tourniquet. Blood gas, plasma malondialdehyde, and serum interleukin-6 (IL-6), IL-8, and IL-10 levels were measured just before tourniquet inflation, 1 hour after inflation and 2 hours, 6 hours, and 24 hours after tourniquet deflation. Arterial-alveolar oxygen tension ratio, alveolar-arterial oxygen tension difference, and respiratory index also were calculated.
  
  
  RESULTS
  In comparison with the baseline values, arterial Po(2) and arterial-alveolar oxygen tension ratio were decreased, while alveolar-arterial oxygen tension difference and respiratory index were increased significantly 6 hours after tourniquet deflation in both groups (P < 0.01). However, these changes were less significant in the ischemic preconditioning group than those in the lower limb ischemia-reperfusion group (P < 0.01). Similarly, the increases in the malondialdehyde, IL-6, and IL-8 from 2 hours to 24 hours after release of the tourniquet in the lower limb ischemia-reperfusion group were attenuated by ischemic preconditioning.
  
  
  CONCLUSIONS
  Pulmonary gas exchange is impaired after lower limb ischemia-reperfusion associated with the clinical use of a tourniquet for lower limb surgery. Ischemic preconditioning preceding tourniquet-induced ischemia attenuates lipid peroxidation and systemic inflammatory response and mitigates pulmonary dysfunction.
authors.affiliation: Department of Anesthesiology, The First Affiliated Hospital of Wenzhou Medical College, Wenzhou, China.
authors.forename: Li-na
authors.initials: LN
authors.lastname: Lin
authors.forename: Liang-rong
authors.initials: LR
authors.lastname: Wang
authors.forename: Wan-tie
authors.initials: WT
authors.lastname: Wang
authors.forename: Lie-lie
authors.initials: LL
authors.lastname: Jin
authors.forename: Xi-yue
authors.initials: XY
authors.lastname: Zhao
authors.forename: Liu-pu
authors.initials: LP
authors.lastname: Zheng
authors.forename: Li-da
authors.initials: LD
authors.lastname: Jin
authors.forename: Liu-ming
authors.initials: LM
authors.lastname: Jiang
authors.forename: Xiang-qing
authors.initials: XQ
authors.lastname: Xiong
mesh_terms: D055371:Acute Lung Injury / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002245:Carbon Dioxide / Q000097:blood; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D016753:Interleukin-10 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D019194:Ischemic Preconditioning / Q000379:methods*; D015227:Lipid Peroxidation; D008168:Lung / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects*; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D012039:Regional Blood Flow; D015427:Reperfusion Injury / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D013848:Thigh / Q000098:blood supply*; D013997:Time Factors; D014111:Tourniquets / Q000009:adverse effects*; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; C508606:CXCL8 protein, human; C508609:IL10 protein, human; C508600:IL6 protein, human; D018836:Inflammation Mediators; D015850:Interleukin-6; D016209:Interleukin-8; D016753:Interleukin-10; D002245:Carbon Dioxide; D008315:Malondialdehyde; D010100:Oxygen