title: Thoracic but not lumbar epidural anaesthesia increases liver blood flow after major abdominal surgery.
abstract: OBJECTIVE
  Epidural blockade in major abdominal surgery bears the potential to increase gastrointestinal perfusion and thus to improve patient outcome. The aim of this study was to assess the differential influence of thoracic and lumbar epidural anaesthesia and analgesia (EAA) on blood lactate levels and central venous oxygen saturation (ScvO2) as parameters of global oxygen supply/demand ratio, as well as on the plasma disappearance rate of indocyanine green (PDR(ICG)), a noninvasive method to evaluate liver perfusion.
  
  
  METHODS
  We enrolled 17 patients receiving thoracic and 17 patients receiving lumbar EAA in addition to general anaesthesia for major abdominal surgery. Lactate, ScvO2 and PDR(ICG) were measured postoperatively on the ICU. Subsequently, epidural application of local anaesthetics was started with a bolus of bupivacaine 0.25% (thoracic 10 ml, lumbar 12 ml) followed by continuous infusion of bupivacaine (thoracic 8 ml h(-1) 0.175%, lumbar 10 ml h(-1) 0.125%) and fentanyl (2 microg ml(-1)). Central venous pressure was maintained by titrated volume replacement. Lactate, ScvO2 and PDR(ICG) were measured again after 2 h.
  
  
  RESULTS
  In both the groups, the mean arterial pressure and heart rate as well as lactate levels and ScvO2 did not change significantly. Although there was a slight but not significant decrease of PDR(ICG) in patients with lumbar EAA (from 25.9 +/- 7.68 to 23.2 +/- 5.90; NS), thoracic EAA resulted in a significant increase of PDR(ICG) (from 21.3 +/- 5.13 to 24.0 +/- 6.66; P < 0.05) for the group mean, but with substantial variability in individual patients in the lumbar EAA group.
  
  
  CONCLUSIONS
  Liver perfusion was increased with thoracic but not lumbar EAA after major abdominal surgery in most patients. PDR(ICG) allows assessment of individual changes of liver blood flow due to therapeutic intervention, for example, EAA.
authors.affiliation: Department of Anaesthesiology and Intensive Care Therapy, Friedrich-Schiller-University, Jena, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kortgen
authors.forename: Malte
authors.initials: M
authors.lastname: Silomon
authors.forename: Christine
authors.initials: C
authors.lastname: Pape-Becker
authors.forename: Heiko
authors.initials: H
authors.lastname: Buchinger
authors.forename: Ulrich
authors.initials: U
authors.lastname: Grundmann
authors.forename: Michael
authors.initials: M
authors.lastname: Bauer
mesh_terms: D000005:Abdomen / Q000098:blood supply* / Q000601:surgery*; D000368:Aged; D000767:Anesthesia, Epidural; D005260:Female; D006801:Humans; D008102:Liver Circulation / Q000187:drug effects*; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D013909:Thorax