title: Assessment of hepatic ischaemia reperfusion injury by measuring intracellular tissue oxygenation using near infrared spectroscopy.
abstract: OBJECTIVE
  Hepatic ischaemia/reperfusion (I/R) injury is a major cause of liver damage during liver surgery and transplantation. The relationship between the severity of I/R injury and the degree of intracellular hypoxia has not been investigated.
  
  
  METHODS
  New Zealand white rabbits were used in 4 groups (n=6 each). At laparotomy, left lobe hepatic ischaemia was produced for 30, 45, or 60 min followed by 60 min reperfusion and compared with controls. Liver function, bile flow, and flow in the hepatic microcirculation (HM) were measured. Near infrared spectroscopy (NIRS) was used to monitor hepatic oxyhaemoglobin (HbO2), deoxyhaemoglobin (Hb), and cytochrome oxidase (Cyt Ox).
  
  
  RESULTS
  I/R injury produced deranged liver function tests, reduced bile flow, and reduced flow in the microcirculation in comparison with controls. During ischaemia, HbO2 and Cyt Ox were significantly reduced in comparison with controls. After reperfusion, a biphasic change in tissue oxygenation was observed, with an initial increase in HbO2 and Cyt Ox followed by a progressive reduction. The reduction in tissue oxygenation with ischaemia and reperfusion paralleled the ischaemia time. After I/R, the changes in Cyt Ox (intracellular oxygenation) significantly correlated with the parameters of hepatocellular injury to a higher degree than HbO2 (extracellular oxygenation).
  
  
  CONCLUSIONS
  This study shows the potential of monitoring the degree of I/R injury by measuring hepatic tissue intracellular oxygenation.
authors.affiliation: University Department of Surgery, Royal Free and University College Medical School, University College London, The Royal Free Hospital, Hampstead, UK.
authors.forename: A E
authors.initials: AE
authors.lastname: El-Desoky
authors.forename: D T
authors.initials: DT
authors.lastname: Delpy
authors.forename: B R
authors.initials: BR
authors.lastname: Davidson
authors.forename: A M
authors.initials: AM
authors.lastname: Seifalian
mesh_terms: D000818:Animals; D001646:Bile / Q000378:metabolism; D004195:Disease Models, Animal; D003576:Electron Transport Complex IV / Q000378:metabolism; D006439:Hemodynamics; D006454:Hemoglobins / Q000378:metabolism; D008099:Liver / Q000098:blood supply / Q000378:metabolism / Q000473:pathology*; D008102:Liver Circulation / Q000502:physiology; D008111:Liver Function Tests; D008833:Microcirculation / Q000502:physiology; D010101:Oxygen Consumption; D010108:Oxyhemoglobins / Q000378:metabolism; D011817:Rabbits; D015427:Reperfusion Injury / Q000175:diagnosis* / Q000378:metabolism; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin; D003576:Electron Transport Complex IV