Thoracic but not lumbar epidural anaesthesia increases liver blood flow after major abdominal surgery

Abstract

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. 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. 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. 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.