Hepatic Venous Oxygen Saturation Research Articles

Simultaneous measurement of hepatic tissue pH, venous oxygen saturation and hemoglobin by near infrared spectroscopy.

The purpose of this study was to investigate the feasibility of using near infrared (NIR) spectroscopy of the liver to simultaneously assess oxygen content in combination with tissue pH, an indicator of anaerobic metabolism. Six anesthetized swine were subjected to 45 min of hemorrhagic shock followed by resuscitation with blood and crystalloid. Calibration models between NIR spectra and reference measurements of tissue pH, hepatic venous oxygen saturation (S(V)O2), and blood hemoglobin concentration (Hb) were developed using partial least-squares regression. Model accuracy was assessed using cross validation. The average correlation (R2) between NIR and reference measurements was 0.87, 0.68, and 0.93, respectively for pH, Hb, and S(V)O2. Estimated accuracy, the root mean squared deviation between spectral, and reference measurements was 0.03 pH units, 0.3 g/dL, and 6%. NIR determination of hepatic oxygen content and tissue pH during shock and resuscitation demonstrated that there can be a variance between hepatic venous oxygenation and regional tissue acidosis. NIR spectroscopy provides a technique to explore the implications of post-shock depression of tissue pH and evaluate new methods of resuscitation.

Insulin (GIK) Improves Central Mixed and Hepatic Venous Oxygenation in Clinical Cardiac Surgery

Objective - Insulin is a vasodilating agent and it was hypothesized that insulin (GIK) could improve systemic and regional oxygenation in cardiac surgery with cardiopulmonary bypass (CPB). Two questions were addressed: 1) Does insulin improve central mixed and hepatic venous oxygenation during CPB? and 2) Does this treatment reduce systemic levels of the proinflammatory mediators C3a and IL-6? Design - Prospective, randomized, controlled study at a university hospital. Thirty patients were included and 16 of these received an infusion of insulin, glucose and potassium (GIK) using an euglycemic clamp technique. The insulin infusion was started during hypothermia, 15 min before rewarming. Blood gases and hemodynamic parameters were measured during hypothermia (before the insulin infusion was started), during rewarming at 35°C, and 30 min after CPB was discontinued. Inflammatory markers were measured: preoperatively, during hypothermia and 2 h after CPB. Results - GIK was associated with reduced systemic vascular resistance ( p = 0.02 vs the control group), higher bypass pump flow ( p = 0.001), higher central mixed oxygen saturation ( p = 0.036) and oxygen tension ( p = 0.001) and higher hepatic venous oxygen saturation ( p = 0.04) and oxygen tension ( p = 0.006). C3a and IL-6 increased during surgery in both groups but there were no differences between the groups. Conclusion - 1) GIK infusion improved central mixed and hepatic venous oxygenation in patients undergoing heart surgery. 2) During the conditions of this study, this had no effect on the proinflammatory mediators C3a and IL-6.

Splanchnic metabolism of fuel substrates in acute liver failure

Background/Aims: This study aimed to characterize the exchange of fuel substrates in the splanchnic circulation in acute liver failure. Methods: Liver vein catheterization was used in 22 patients with acute liver failure after development of hepatic encephalopathy grade III-IV. Healthy controls, patients with cirrhosis and patients with acute on chronic liver disease were also studied. Results: In acute liver failure there was splanchnic removal of glucose (0.21±0.44 mmol/min), release of lactate (0.34±0.37 mmol/min), pyruvate (0.08±0.06 mmol/min) and ketone bodies (0.04±0.02 mmol/min), while extraction of amino acids and free fatty acids was insignificant. In the acute liver failure group, a normal hepatic venous oxygen saturation (0.69±0.12) and normal pyruvate/lactate ratio suggested absence of hypoxia even though the acetoacetate/β-hydroxybutyrate ratio was decreased. Only in the acute liver failure group did the measured splanchnic oxygen content difference exceed what could be accounted for even by hypothesizing complete oxidation of all extracted blood-borne fuel substrates; oxidation of endogenous substrates may be quantitatively important in this condition. Conclusion: Acute liver failure was associated with a state of accelerated glycolysis in the splanchnic region, leading to release of lactate in the absence of splanchnic hypoxia.

Changes in hepatic venous oxygen saturation in hepatic warm ischemia/reperfusion injury in pigs.

To clarify the changes that occur in hepatic venous oxygen saturation (ShVO2) during hepatic ischemia/reperfusion (I/R) injury, we examined the relationship between ShVO2, hepatic tissue blood flow (HTBF), and portal vein pressure (PVP) in a warm I/R model using pig livers. Female pigs weighing 18-23 kg were subjected to warm I/R under extracorporeal circulation between the superior mesentric vein and the left jugular vein to avoid portal congestion. The warm ischemic times were 120 min (n = 4), 180 min (n = 14), and 240 min (n = 4). ShVO2, HTBF, and PVP were measured after reperfusion. The survival rates of the pigs 3 days after reperfusion were 100% in the 120-min group, 57% in the 180-min group, and 25% in the 240-min group. In the 180-min group, the ShVO2 was lower in the pigs that died than in those that survived. There was a significant correlation between ShVO2 and both PVP and HTBF after reperfusion. Histological examination revealed findings of severe I/R injury in pigs with a low ShVO2, and mild I/R injury in pigs with a stable ShVO2. These observations suggest that the changes in ShVO2 could reflect the degree of hepatic I/R injury, especially that related to microcirculatory disturbances occurring at the sinusoid levels.

Changes in hepatic venous oxygen saturation related to the extent of regeneration after partial hepatectomy in rats

Background: Changes in hepatic oxygen metabolism in relation to the extent of liver regeneration are expected after partial hepatectomy. There are few reports, however, about hepatic oxygen metabolism during liver regeneration. In this study, we evaluated changes in hepatic oxygen metabolism related to the regeneration rate, and the relationship between hepatic venous oxygen saturation (Shvo 2) and liver regeneration after partial hepatectomy. Methods: The work was done using 50% hepatectomized rats with continuous infusion of octreotide for inhibition of liver regeneration or with saline as control. The hepatic hemodynamics, oxygen metabolism, and Shvo 2 levels as well as the regenerating liver status were evaluated for 3 days after hepatectomy. Results: Administration of octreotide resulted in a significant reduction of the regenerating liver weight on days 1 and 3 after hepatectomy compared with the control group. Significantly decreased DNA synthesis and proliferating cell nuclear antigen labeling index were also found on day 1. Meanwhile, hepatic oxygen consumption (HVO 2) and oxygen extraction ratio were significantly decreased in the octreotide-treated group on day 1. In contrast, the Shvo 2 levels in the octreotide-treated group were significantly higher than those in the control group, and were inversely correlated with the HVO 2. Conclusion: The remnant liver demands an increased amount of oxygen in relation to the extent of regeneration, and changes in the Shvo 2 are inversely correlated with the HVo 2. Therefore, monitoring the Shvo 2 could be useful for estimating liver regeneration after partial hepatectomy.

Markers of splanchnic perfusion and intestinal translocation of endotoxins during cardiopulmonary bypass: Effects of dopamine and milrinone

Objectives: To investigate markers of splanchnic perfusion and the extent of endotoxemia during cardiopulmonary bypass (CPB) and to compare the effects of dopamine and milrinone on both splanchnic perfusion and endotoxemia. Design: Prospective, randomized, blinded study. Setting: University teaching hospital. Participants: Twenty-four patients scheduled for elective coronary artery bypass graft surgery (CABG). Interventions: Patients were allocated to receive placebo (eight patients), dopamine (eight patients), or milrinone (eight patients) during CPB, and at seven times intraoperatively assays were performed of arterial and hepatic venous endotoxin levels, as well as measurements and/or calculations of intramucosal gastric pH (pHi), arterial and hepatic venous lactate-pyruvate ratio (lac/pyr), and hepatic venous oxygen saturation (S HVO 2). Measurements and Main Results: Both splanchnic and systemic endotoxin levels increased significantly, and this was unaffected by either dopamine or milrinone. Gastric pHi did not change, and there were only modest increases in lac/pyr, which remained within the normal range of less than 10 in both splanchnic and systemic blood. In the placebo group, S HVO 2 decreased at the onset of CPB and also significantly decreased during rewarming and at the end of CPB and surgery. In the dopamine-treated patients, S HVO 2 was greater compared with placebo and milrinone during both hypothermic and rewarming phases. Conclusion: Endotoxemia occurs during routine CPB. Neither pHi nor lac/pyr values showed adverse change, but hepatic venous oximetry may be a more sensitive indicator of splanchnic dysoxia in that S HVO 2 was reduced during rewarming. Whether dopamine or milrinone confer protection against splanchnic ischemia remains uncertain.

The Influence of Hepatic Venous Oxygen Saturation on the Liver's Synthetic Response to Metabolic Stress

Hepatic oxygen consumption (HVO2) and hepatic venous oxygen saturation (ShvO2) were assessed in the isolated perfused rat liver under conditions that mimic critical illness in an effort to assess their utility in predicting the functional status of the liver. Flow rates were adjusted over the physiologic range of oxygen transport as indicated by the hepatic venous O2 saturation range of 10%-75%. HVO2 was found to be transport (HDO2) dependent only when perfusate conditions contained an increased counterregulatory hormone (glucagon, epinephrine, dexamethasone) stimulus or a high lactate concentration. In the absence of a metabolic load, (substrate and hormone-free perfusate), HVO2 was transport independent even at an ShvO2 as low as 10%. Although transport dependency of HVO2 is frequently used to infer tissue ischemia, hepatic oxygen consumption was poorly correlated with synthetic function under all conditions. In contrast, hepatic albumin production was directly related to ShvO2 at all levels of HDO2 and under all perfusion conditions indicating that this metabolic process is particularly sensitive to reductions in oxygen availability, which is more reliably predicted by venous saturation measurements. However, glucose and urea synthesis were almost independent of ShvO2. These findings indicate that various hepatic processes are affected differentially by stress conditions and flow alterations that may exist during critical illness, and protein synthesis is particularly sensitive to oxygen deprivation. Additionally, hepatic venous oxygen saturation measurement, but not HVO2, serves as a useful surrogate marker for hepatic albumin production suggesting that regional venous oximetry may play an important role in the detection of hepatic functional impairment.

The Influence of Hepatic Venous Oxygen Saturation on the Liver's Synthetic Response to Metabolic Stress

The Influence of Hepatic Venous Oxygen Saturation on the Liver's Synthetic Response to Metabolic Stress

肝静脈カテーテルによる肝静脈血酸素飽和度モニタリング

肝静脈カテーテルによる肝静脈血酸素飽和度モニタリング

Early evaluation of graft viability using hepatic venous oxygen saturation in pig liver transplantation.

Early evaluation of graft viability using hepatic venous oxygen saturation in pig liver transplantation.

REDUCTION OF REPERFUSION INJURY WITH PROSTACYCLIN 12 AFTER LIVER TRANSPLANTATION

209 Organ shortage of suitable liver grafts is responsible for the use of marginal donors for liver transplantation (OLT). If these liver grafts develop an initial poor function after liver transplantation a supportive therapy is necessary to improve the liver function. Experimental data have shown that prostacyclin I2 (PGI2) has cytoprotective effects for hepatocytes. The purpose of this study was to evaluate the effects of PGI2 on postoperative liver graft function after OLT. In this prospective randomized trial we studied the effects of PGI2 on postoperative liver graft function, hemodynamics and tumour necrosis factor release in patients after OLT. With institutional approval and informed consent, 30 adult patients (10 female), receiving liver grafting were enrolled in this study. Patients were randomised to either receive PGI2 (n=15) or placebo. PGI2 was administered at a rate of 4 ng/kg/min body weight after reperfusion for 6 days. To evaluate regional splanchnic oxygenation a fiberoptic pulmonary artery catheter was inserted into the right hepatic vein and the difference(ΔSO2) of mixed venous saturation (SvO2) and hepatic venous oxygen saturation (SvhO2) was calculated. Measurements were performed directly after transplantation and 6-, 12-, 24- and 48- hours postoperatively. Levels of TNF were determined once daily for the time period of PGI2 treatment. Statistical analysis was performed using Wilcoxon Rank- Sum- test and Pearson correlation, significance was accepted at p<0.05. A significant correlation for ΔSO2 and the level of transaminasis was observed 24 and 48 hours after transplantation (p<0.05). PGI2 treatment induced a significant decrease in ΔSO2 after 12 and 24 hours after reperfusion (p<0.05). Hemodynamics were not changed in either group. Peak levels of ASAT were in tendency lower in the PGI2 treatment group (418±99 vs. 638±156 U/I). TNF levels were not altered in patients receiving placebo treatment. Several experimental data suggest a cytoprotective effect of PGI2 for hepatocytes. We conclude that introduction of PGI2 and OLT improves hepatic-splanchnic oxygenation. This effect might be attributed for reduction of reperfusion injury after OLT.

Hepatic venous hemoglobin oxygen saturation predicts regenerative status of remnant liver after partial hepatectomy in rats.

This study was designed to evaluate the use of hepatic venous hemoglobin oxygen saturation (ShVO2) as an indicator of hepatic oxygen supply-demand relation and also regenerative status of the liver after partial hepatectomy in rats. We assessed the ShVO2 levels for 7 days, as well as hepatic hemodynamics, oxygen consumption, DNA synthesis and energy charge of the remnant liver for 3 days after 50% hepatectomy or sham operation. Total hepatic oxygen consumption (HVO2) per liver weight, hepatic oxygen extraction ratio (HO2ER), and DNA synthesis were significantly elevated at days 1 and 3 after hepatectomy, compared with the preoperative levels. Meanwhile, significantly decreased ShVO2 levels were observed at days 1 and 3, and the ShVO2 levels were significantly correlated with the HVO2. Furthermore, the decreased ShVO2 levels were synchronized with the increased DNA synthesis in the remnant liver. Energy charge levels were also significantly decreased at day 1 after hepatectomy. These results suggest that the regenerating liver demands an increased amount of oxygen for mitochondrial oxidative phosphorylation to restore hepatic energy charge. In conclusion, the ShVO2 after hepatectomy may reflect oxygen metabolic status in the remnant liver and could be useful for estimating liver regeneration.

REDUCTION OF REPERFUSION INJURY WITH PROSTACYCLIN 12 AFTER LIVER TRANSPLANTATION

209 Organ shortage of suitable liver grafts is responsible for the use of marginal donors for liver transplantation (OLT). If these liver grafts develop an initial poor function after liver transplantaton a supportive therapy is necessary to improve the liver function. Experimental data have shown that prostacyclin I2 (PGI2) has cytoprotective effects for hepatocytes. The purpose of this study was to evaluate the effects of PGI2 on postoperative liver graft function after OLT. In this prospective randomized trial we studied the effects of PGI2 on postoperative liver graft function, hemodynamics and tumour necrosis factor release in patients after OLT. With institutional approval and informed consent, 30 adult patients (10 female), receiving liver grafting were enrolled in this study. Patients were randomised to either receive PGI2 (n=15) or placebo. PGI2 was administered at a rate of 4 ng/kg/min body weight after reperfusion for 6 days. To evaluate regional splanchnic oxygenation a fiberoptic pulmonary artery catheter was inserted into the right hepatic vein and the difference(ΔSO2) of mixed venous saturation (SvO2) and hepatic venous oxygen saturation (SvhO2) was calculated. Measurements were performed directly after transplantation and 6-, 12-, 24- and 48- hours postoperatively. Levels of TNF were determined once daily for the time period of PGI2 treatment. Statistical analysis was performed using Wilcoxon Rank- Sum- test and Pearson correlation, significance was accepted at p<0.05. A significant correlation for ΔSO2 and the level of transaminasis was observed 24 and 48 hours after transplantation (p<0.05). PGI2 treatment induced a significant decrease in ΔSO2 after 12 and 24 hours after reperfusion (p<0.05). Hemodynamics were not changed in either group. Peak levels of ASAT were in tendency lower in the PGI2 treatment group (418±99 vs. 638±156 U/l). TNF levels were not altered in patients receiving placebo treatment. Several experimental data suggest a cytoprotective effect of PGI2 for hepatocytes. We conclude that introduction of PGI2 after OLT improves hepatic-splanchnic oxygenation. This effect might be attributed for reduction of reperfusion injury after OLT.

Hepatic venous hemoglobin oxygen saturation in the assessment of liver regeneration after partial hepatectomy in rats

Hepatic venous hemoglobin oxygen saturation in the assessment of liver regeneration after partial hepatectomy in rats

Response of patients with cirrhosis who have undergone partial hepatectomy to treatment aimed at achieving supranormal oxygen delivery and consumption

Background: This study was undertaken to evaluate the response to therapy aimed at achieving supranormal cardiac and oxygen transport variables (cardiac index > than 4.5 L/min/m 2, oxygen delivery > 600 ml/min/m 2, and oxygen consumption > 170 ml/min/m 2) in patients with cirrhosis who have undergone partial hepatectomy and to assess the relationship between those parameters and outcome. Methods: Thirty-four consecutive patients underwent elective hepatectomy for hepatocellular carcinoma. The postoperative outcomes and hemodynamic and oxygen transport values in 16 patients (group S) who maintained supranormal values were compared with those in 18 patients (group N) treated to maintain normal hemodynamic values. Patients in group S received volume expansion and then, if necessary, dobutamine (3 to 15 μg/kg/min) to increase cardiac index, oxygen delivery, and oxygen comsumption simultaneously during the first 12 hours. Results: The hemodynamic targets were reached by 56% of patients in group S during the first 12 hours and 31% during the next 12 hours. Postoperative blood lactate levels at 12 and 24 hours were lower in group S than in group N, and total bilirubin concentrations, hepatic venous oxygen saturation, and arterial ketone body ratio, useful markers of postoperative liver function, also showed more favorable changes in group S than in group N. Postoperative morbidity and mortality rates were not significantly different in the two groups, but the incidence of hyperbilirubinemia and liver failure was much lower in group S than in group N. Conclusions: These results suggest that fluid therapy aimed at achieving a supranormal pattern by 12 hours after hepatectomy improved the systemic oxygen demand-supply dynamics and hepatic hemodynamics, decreasing the incidence of postoperative hyperbilirubinemia and liver failure in patients with liver cirrhosis. (Surgery 1998;123:278-86.)

Response of patients with cirrhosis who have undergone partial hepatectomy to treatment aimed at achieving supranormal oxygen delivery and consumption

Background: This study was undertaken to evaluate the response to therapy aimed at achieving supranormal cardiac and oxygen transport variables (cardiac index > than 4.5 L/min/m2, oxygen delivery > 600 ml/min/m2, and oxygen consumption > 170 ml/min/m2) in patients with cirrhosis who have undergone partial hepatectomy and to assess the relationship between those parameters and outcome. Methods: Thirty-four consecutive patients underwent elective hepatectomy for hepatocellular carcinoma. The postoperative outcomes and hemodynamic and oxygen transport values in 16 patients (group S) who maintained supranormal values were compared with those in 18 patients (group N) treated to maintain normal hemodynamic values. Patients in group S received volume expansion and then, if necessary, dobutamine (3 to 15 μg/kg/min) to increase cardiac index, oxygen delivery, and oxygen comsumption simultaneously during the first 12 hours. Results: The hemodynamic targets were reached by 56% of patients in group S during the first 12 hours and 31% during the next 12 hours. Postoperative blood lactate levels at 12 and 24 hours were lower in group S than in group N, and total bilirubin concentrations, hepatic venous oxygen saturation, and arterial ketone body ratio, useful markers of postoperative liver function, also showed more favorable changes in group S than in group N. Postoperative morbidity and mortality rates were not significantly different in the two groups, but the incidence of hyperbilirubinemia and liver failure was much lower in group S than in group N. Conclusions: These results suggest that fluid therapy aimed at achieving a supranormal pattern by 12 hours after hepatectomy improved the systemic oxygen demand-supply dynamics and hepatic hemodynamics, decreasing the incidence of postoperative hyperbilirubinemia and liver failure in patients with liver cirrhosis. (Surgery 1998;123:278-86.)

An analysis of the mechanism of postoperative hyperbilirubinemia following resection of thoracic esophageal cancer in terms of hepatic venous oxygen saturation and excessive systemic reactions

Hepatic venous oxygen saturation (ShvO2), parameters of systemic circulation and cytokine (Interleukin 6) (IL-6)) level were measured in 21 patients with thoracic esophageal cancer in order to analyze the mechanism of occurrence of postoperative hyperbilirubinemia (PHB). ShvO2 fell during operation, especially during intrathoracic procedures, and a significant correlation was noted between the total time during which ShvO2 was below 60% and the postoperative peak serum bilirubin level (peak-Bil) (r = 0.595, p = 0.0037). Patients with PHB (group H) had worse systemic circulation and a lower oxygen supply postoperatively than patients without PHB (group N). Body weight and water balance recovered earlier in group N. Postoperatively, numbers of peripheral lymphocytes and platelets changed lower in group H, while CRP and IL-6 changed higher in group H. Furthermore, a significant correlation was noted between the IL-6 level just after operation and peak-Bil (r = 0.669, p = 0.0006). These results suggests PHB results from intraoperative liver hypoxia and poor postoperative systemic circulation. Individual severeness of reactions to the operative stress, excessive or adequate, plays a role in the occurrence of PHB as well.

Effects of Positive End-Expiratory Pressure on Hepatic Venous Oxygenation in Dogs

Background : Positive end-expiratory pressure(PEEP) ventilation causes reduction in cardiac output and increase of intra-thoracic pressure, hence reduction of hepatic blood flow. The purpose of this study is to evaluate the changes of hepatic venous oxygen saturation, tension and content during increase and removal of PEEP and to evaluate hemodynamic variable which has the greatest effect on hepatic oxygenation. Method : Eight dogs were anethetised with 1.0 vol% isoflurane and 100% oxygen. After 30 minutes of stabilization of vital signs, PEEP were increased from 0 cmH2O to 5 cmH2O and 10 cmH2O and lowered to 0 cmH2O again, and hemodynamic data (heart rate, arterial blood pressure, central venous pressure(CVP), pulmonary arterial pressure, pulmonary arterial occlusion pressure and cardiac output(CO)) and hepatic venous oxygenation data (hepatic venous oxygen saturation(ShvO2), tension(PhvO2) and content(ChvO2)) were measured at each step. Results : CO, ShvO2, PhvO2 and ChvO2 decreased significantly at 10 cmH2O PEEP compared to the baseline and 5 cmH2O PEEP and CO, ShvO2 and ChvO2 increased signicantly with removal of PEEP. CVP increased significantly at 10 cmH2O PEEP and decreased significantly with PEEP removal. PEEP showed close correlationship with CO and CVP considering all steps of PEEP and PEEP removal. ShvO2 and PhvO2 showed most close correlationship with CO considering all steps of PEEP and PEEP removal. Conclusion : ShvO2 with PEEP therapy is dependent upon CO. Therefore cardiac output maintenance is essential during PEEP therapy. For exact evaluation of hepatic oxygenation, it is valuable to monitor ShvO2. (Korean J Anesthesiol 1998; 35: 861∼869)

肝すい同時切除および肝切除における術中肝静脈血酸素飽和度測定の有用性に関する検討

肝膵同時切除 (HPD) 9例および肝切除13例を対象とし, 術中肝静脈血酸素飽和度 (Shvo 2) 測定を行い, 術後肝機能との関連につき検討した.Shvo 2値は肝の脱転操作, Pringle法および肝十二指腸間膜内リンパ節郭清の際に低下した.術中Shvo 260%以下低下時間は, 肝切除群では38.5±37.9分, HPD群では60.0±52.7分であった.Shvo 2 60%以下低下時間と術後T.Bil最高値の関係では, 肝切除とHPDをあわせた全例およびHPD群で有意の正の相関を認めた (おのおのp<0.01, p<0.05).術中Shvo2 60%以下低下時間と肝切除終了時の動脈血中ケトン体比の関係では, 全例, 肝切除群, HPD群いずれも有意の相関はなかった.Shvo2は術中の肝虚血侵襲をリアルタイムに反映し, 術後肝不全を予測するパラメーターの1つとして有用である可能性が示唆された.

阻血障害肝の早期機能評価法の検討 とくに肝静脈酸素飽和度（Ｓｈｖｏ２）の検討

阻血障害肝の早期機能評価法の検討 とくに肝静脈酸素飽和度（Ｓｈｖｏ２）の検討