title: Tourniquet-applied upper limb orthopaedic surgery results in increased inflammation and changes to leukocyte, coagulation and endothelial markers.
abstract: OBJECTIVE
  During this pilot clinical study, patients scheduled for elective tourniquet-applied upper limb orthopaedic surgery were recruited to investigate the effects of surgery on various biological markers (n = 10 patients).
  
  
  METHODS
  Three venous blood samples were collected from the arm at the ante-cubital fossa, at baseline (pre-operatively), 5 and 15 minutes after reperfusion (post-operatively). Neutrophil and monocyte leukocyte sub-populations were isolated by density gradient centrifugation techniques. Leukocyte activation was investigated by measuring the cell surface expression of CD62L (L-selectin), CD11b (Mac-1) and the intracellular production of hydrogen peroxide (H2O2), via flow cytometry. C-reactive protein (CRP) was measured using a clinical chemistry analyser. Plasma concentrations of protein C and von Willebrand factor (vWF) were measured using enzyme-linked fluorescent assays (ELFA).
  
  
  RESULTS
  Following tourniquet-applied upper limb orthopaedic surgery, there was a decrease in neutrophil CD62L expression (p = 0.001), an increase in CD11b expression and in the intracellular production of H2O2 by neutrophils and monocytes (p<0.05). An increase in CRP concentration (p<0.001), a decrease in protein C concentration (p = 0.004), with a trend towards elevated vWF levels (p = 0.232) were also observed during this time.
  
  
  CONCLUSIONS
  Conventionally, patients undergoing orthopaedic surgery have been monitored in the peri-operative period by means of CRP, which is a non-specific marker of inflammation. This test cannot differentiate between inflammation due to current or pre-existing disease processes and the development of ischaemia-reperfusion injury surgery. The findings from this study suggest that markers such as CD11b, protein C and H2O2 may provide alternative ways of assessing leukocyte and coagulation activation peri-operatively. It is proposed that by allowing orthopaedic surgeons access to laboratory markers such as CD11b, protein C and H2O2, an accurate assessment of the extent of inflammation due to surgery per se could be made.
authors.affiliation: Department of Biological Sciences, University of Chester, Chester, United Kingdom. stephen.hughes@chester.ac.uk
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Hughes
authors.forename: Beverly D
authors.initials: BD
authors.lastname: Hendricks
authors.forename: David R
authors.initials: DR
authors.lastname: Edwards
authors.forename: Jim F
authors.initials: JF
authors.lastname: Middleton
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002097:C-Reactive Protein / Q000378:metabolism; D039481:CD11b Antigen / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D019041:L-Selectin / Q000378:metabolism; D007962:Leukocytes / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D011486:Protein C; D014111:Tourniquets; D034941:Upper Extremity / Q000601:surgery*; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D039481:CD11b Antigen; D011486:Protein C; D014841:von Willebrand Factor; D019041:L-Selectin; D002097:C-Reactive Protein; D006861:Hydrogen Peroxide