To quantify the changes in oxygen saturation of hemoglobin in the liver in hypoxia and liver transplantation, we applied a novel method using near-infrared spectroscopy. Instead of the conventional two-wave-length method, we obtained near-infrared data from a wide spectral range of 700 nm to 1,000 nm with continuous-wave spectroscopy. To correct the flattened spectral shape caused by photon scattering in living tissue, we then applied an equation taking into account the relationship between absorber concentration and actual absorption in scattering materials as assessed with time-resolved spectroscopy. Hepatic hemoglobin oxygen saturation was calculated with multicomponent analysis. In room air, hepatic hemoglobin oxygen saturation of rabbit was calculated as 57.4% +/- 2.5% (mean +/- S.E.M., n = 7). Arterial, portal and hepatic venous hemoglobin oxygen saturation were simultaneously measured as 97.5% +/- 0.7%, 77.1% +/- 3.4% and 55.5% +/- 4.6%, respectively. The changes in hepatic hemoglobin oxygen saturation seen in graded hypoxia were also close to those in hepatic venous hemoglobin oxygen saturation, suggesting that the average oxygenation state of sinusoidal blood approximates that in the central vein. We tested the clinical applicability of this method in a case of liver transplantation. It was determined that the hepatic hemoglobin oxygen saturation of the graft liver was heterogeneously distributed and that the initially low level of hepatic hemoglobin oxygen saturation was increased by the ligation of portal-systemic shunts.

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Background Delayed gastric emptying without mechanical obstruction after Roux-en-Y reconstruction has been defined as Roux stasis syndrome. It occurs in 10-30% of patients after such reconstruction. So far, the cause of this stasis has not been completely identified. This study aimed to reduce Roux stasis using surgical techniques. Methods From November 2007 to October 2010, we performed 101 distal gastrectomies with Roux-en-Y reconstruction. All the gastrojejunostomies were performed with end-to-end anastomoses. Roux stasis was analyzed with respect to tumor location, extent of the dissection, tumor progression, operation time, antecolic/retrocolic reconstruction, and the shape of the gastrojejunostomy. The shape of the gastrojejunostomy was evaluated by contrast gastroradiography 4 days after the operation. Results Roux stasis syndrome was observed in 17 of the 101 patients. There was no relationship between the extent of the dissection, tumor progression, or operation time and the occurrence of Roux stasis. There was no difference in the incidence of Roux stasis between antecolic and retrocolic reconstructions. However, the group that displayed a straight anastomotic shape on contrast radiography demonstrated an apparently lower incidence of Roux stasis (p = 0.0003). In addition, Roux-en-Y reconstruction following gastric cancer was more frequently followed by Roux stasis in the antrum than in the midstomach (p = 0.0036). Cases of Roux stasis occurred 11.8 days after surgery on average and resolved within 2 weeks on average. Conclusions Our findings demonstrate the substantial benefits of a straight anastomosis of the gastrojejunostomy for the prevention of Roux stasis syndrome.

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