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Background: Intestinal ischemia-reperfusion injury (IIR) induces hepatic and pulmonary dysfunction and thus has been used as a model of multiple organ failure syndrome. This study examines the hypothesis that hepatic blood flow is markedly reduced in this injury model., Methods: Sprague-Dawley rats underwent 120 minutes of intestinal ischemia and 60 minutes of reperfusion (IIR). Hepatic blood flow was measured with radiolabeled microspheres and Doppler flow probes. Hepatic dysfunction was quantitated by measuring bile flow and serum alanine aminotransferase and hepatic tissue adenosine triphosphate levels. Sham-operated animals served as controls., Results: Intestinal ischemia reduced portal flow by 66% when compared with sham-operated animals (p = 0.0001) but had no effect on hepatic arterial flow. In contrast, reperfusion reduced hepatic artery flow by 80% when compared with controls (p = 0.002) with most of this change occurring within 5 minutes of reperfusion. IIR induced a 63% reduction in bile flow (p < 0.05), a fivefold rise in serum alanine aminotransferase level (p < 0.0002), and a 33% reduction in hepatic adenosine triphosphate level (p < 0.05)., Conclusions: These data suggest that IIR induces profound hepatic hypoperfusion, which is temporally related to acute hepatic dysfunction. This observation suggests that hepatic ischemia may contribute to IIR-induced liver injury.

Background: Thermal injury induces circulating levels of interleukin-6 (IL-6). The liver and lung have been proposed as major sources of IL-6 after injury; however, multiple cell types within these organs are capable of IL-6 production. In these experiments we further characterize cellular sources of IL-6 after thermal injury by examining tissue macrophage response in the liver and lung and IL-6 production of cultured pulmonary microvascular endothelial cells (PMECs)., Methods: Serum, liver and lung tissue, and tissue macrophage IL-6 response was determined in Wistar rats subjected to a 35 to 40% total body surface area scald injury. Cultured PMEC IL-6 production was determined after treatment with serum from the burned animals. IL-6 bioactivity was assayed by 7TD1 proliferation, and IL-6 messenger RNA levels were determined by reverse transcriptase-polymerase chain reaction. Alveolar macrophages were obtained by bronchoalveolar lavage. Kupffer cells and PMECs were obtained by enzyme digestion of liver and lungs., Results: Burn increases circulating IL-6 activity through postburn day 3 (388 +/- 50 units/0.1 ml versus 80 +/- 12 units/0.1 ml in controls). Burn increases lung and liver IL-6 messenger RNA without concurrent increase in the alveolar macrophages or Kupffer cells and persists in the lung after bronchoalveolar lavage. PMECs cultured in the presence of postburn day 3 serum (10% vol) release more IL-6 activity (1118 +/- 333 units/culture versus sham rat serum with 288 +/- 146 units/culture) than control cultures and have more readily detectable levels of IL-6 messenger RNA., Conclusions: Non-tissue macrophage sources including microvascular endothelium may be a contributing source of IL-6 in the lung after thermal injury.

Reperfusion of ischemic intestine results in acute liver dysfunction characterized by hepatocellular enzyme release into plasma, reduction in bile flow rate, and neutrophil sequestration within the liver. The pathophysiology underlying this acute hepatic injury is unknown. This study was undertaken to determine whether oxidants are associated with the hepatic injury and to determine the relative value of several indirect methods of assessing oxidant exposure in vivo. Rats were subjected to a standardized intestinal ischemia-reperfusion injury. Hepatic tissue was assayed for lipid peroxidation products and oxidized and reduced glutathione. There was no change in hepatic tissue total glutathione following intestinal ischemia-reperfusion injury. Oxidized glutathione (GSSG) increased significantly following 30 and 60 min of reperfusion. There was no increase in any of the products of lipid peroxidation associated with this injury. An increase in GSSG within hepatic tissue during intestinal reperfusion suggests exposure of hepatocytes to an oxidant stress. The lack of a significant increase in products of lipid peroxidation suggests that the oxidant stress is of insufficient magnitude to result in irreversible injury to hepatocyte cell membranes. These data also suggest that the measurement of tissue GSSG may be a more sensitive indicator of oxidant stress than measurement of products of lipid peroxidation.

During a recent prospective nonrandomized comparison of noninvasive imaging techniques in 100 children with suspected major blunt abdominal injury, an interesting subset of patients was defined. Of 95 hemodynamically stable patients, 44 were found to have immediate elevation of hepatic enzymes (SGOT, SGPT greater than 30 IU). Nineteen of these children (43%) were subsequently shown to have significant liver injuries. No child with a liver injury had normal enzymes on admission. The level of enzyme elevation (SGOT chi 890 +/- 142 IU, SGPT chi 536 +/- 105 IU) in those with liver injuries is significantly greater than those without injury (SGOT chi 273 +/- 44 IU, SGPT chi 115 +/- 19 IU) (P less than or equal to 0.0001 SGOT. P less than or equal to 0.0001 SGPT). Our study has allowed definition of a group of children who are at significant risk for liver injury based on immediately available serum determinations of GOT and GPT. We have begun to use this information in our institution to select children for further noninvasive imaging. We recommend that these studies be obtained emergently in all children with suspected upper abdominal trauma.

One hundred eighty-eight consecutive children with serious blunt abdominal or multisystem trauma were evaluated between August 1981 and July 1985. Of the 188 patients, 53 (28%) were found to have hepatic parenchymal injuries and are the basis of this report. Four of the 53 (8%) underwent emergency laparotomy for exsanguinating hemorrhage; two patients died, both of hepatic vein lacerations, and two are alive and well after right hepatic lobectomy. Forty-nine (92%) of the children with liver injuries did not require operation for hemorrhage. Four of these 49 patients developed serious complications; hemobilia occurred in one patient and bile peritonitis occurred in three. The one case of hemobilia was resolved without surgery. One child underwent a delayed operative biliary tract reconstruction that was successful. The other two children required a combination of debridement and drainage procedures. Fifty-one of the 53 children (96%) are currently alive without morbidity related to their liver injuries. Both children who died had multiple trauma including central nervous system injuries and had exsanguinating hemorrhage that required emergency laparotomy at initial evaluation. There were no children with "late" hemorrhage and none who developed septic complications. Nonoperative management of most childhood blunt abdominal trauma is possible. Widespread use of abdominal computerized tomography scanning has made this approach practical. This large series of consecutive liver injuries from a large pediatric trauma center illustrates the advantages and the risks of a selective but primarily nonoperative approach to liver trauma in children.