Thoracic Epidural Analgesia Augments Ileal Mucosal Capillary Perfusion and Improves Survival in Severe Acute Pancreatitis in Rats

Abstract

Acute pancreatitis has been linked to intestinal barrier dysfunction and systemic inflammatory response with high mortality. Thoracic epidural analgesia improves intestinal perfusion. The authors hypothesized that thoracic epidural analgesia influences microcirculation injury, inflammatory response, and outcome of acute pancreatitis in rats. Control groups underwent a sham procedure or untreated pancreatitis induced by intraductal taurocholate injection. In the treatment groups, epidural analgesia was commenced immediately or after a 7-h delay. Fifteen hours after injury, the ileal mucosal perfusion was assessed by intravital microscopy. Thereby, the intercapillary area between all perfused capillaries and between continuously perfused capillaries only was used to differentially quantify total and continuous capillary mucosal perfusion. Villus blood flow and serum levels of amylase, lactate, and interleukin 6 were determined, and pancreatic injury was scored histologically. Seven-day survival was recorded in an additional 30 rats undergoing untreated pancreatitis or pancreatitis with epidural analgesia. In untreated pancreatitis, decreased total capillary perfusion increased the total intercapillary area by 24%. Furthermore, loss of continuous perfusion increased continuous intercapillary area to 228%. After immediate and delayed epidural analgesia, continuous perfusion was restored (P < 0.05). Blood flow decreased 50% in untreated pancreatitis but was preserved by epidural analgesia (P < 0.05). Biochemical and histologic signs of pancreatitis were not affected by epidural analgesia. Lactate and interleukin-6 levels increased in untreated pancreatitis, which was prevented in the treatment groups (P < 0.05). Epidural analgesia increased 7-day survival from 33% to 73% (P < 0.05). Thoracic epidural analgesia attenuated systemic response and improved survival in severe acute pancreatitis. These effects might be explained by improved mucosal perfusion.