Effect of end-stage liver failure on the incidence and resolution of the adult respiratory distress syndrome

Perioperative Management of the Liver Transplant Recipient

Perioperative management of the liver transplant recipient is a team effort that requires close collaboration between intensivist, surgeon, anesthesiologist, hepatologist, nephrologist, other specialists, and hospital staff before and after surgery. Transplant viability must be reassessed regularly and particularly with each donor organ. Regular discussions with patient and family facilitate realistic determinations of goals based on patient aspirations and clinical realities. Early attention to hemodynamics with optimal resuscitation and judicious vasopressor support, respiratory care designed to minimize iatrogenic injury, and early renal support is key. Preoperative and postoperative nutritional support and physical rehabilitation should remain a focus.

Multiple System Organ Failure in the Adult Respiratory Distress Syndrome

Recently completed studies suggest that patients with the adult respiratory distress syndrome (ARDS) manifest early evidence of multiple-site endothelial injury. Ex trapulmonary disease is usually the cause of death in these patients. Furthermore, prognosis in individual cases of ARDS is strongly influenced by specific organ failures (e.g., hepatic and renal failure). The mechanisms by which ARDS and extrapulmonary organ system fail ure interact, however, are poorly delineated. We ad dress three aspects of the multisystemic nature of ARDS. First, we analyze evidence that suggests ARDS is a mul tisystem disorder fron the outset, involving panendothe lial injury mediated by cellular interactions and humoral substances that act similarly at many vascular target sites. Second, we discuss the role of three extrapulmo nary organs in the modulation of ARDS: the liver, the gastrointestinal mucosa, and the kidneys. Third, we ad dress the unifying hypothesis that uncontrolled ongoing inflammation, which is often but not always caused by infection, is the essential link between ARDS and its progression to multiple system organ failure.

Profile and outcome of patients with liver cirrhosis requiring mechanical ventilation

OBJECTIVE

Few studies have addressed the outcome of patients with cirrhosis requiring mechanical ventilation (MV). We aimed to investigate the short-term outcome of such patients.

METHODS

Retrospective review of data of 73 consecutive patients with cirrhosis requiring MV over a 2-year period (2006-2008). Data on patient's characteristics, reason for MV, the presence of other organ failure, and first day Acute Physiology Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA), Child-Pugh (CP), and Model for End-Stage Liver Disease (MELD) scores were collected, with 30-day mortality being the primary outcome measure.

RESULTS

Observed mortality in ICU and at 30 days was 75.3% and 87.7%, respectively. Area under curve was 0.77 (95% CI, 0.65-0.86) for APACHE II, 0.94 (95% CI, 0.85-0.98) for SOFA, 0.83 (95% CI, 0.7-0.96) for CP, and 0.93 (95% CI, 0.85-0.98) for MELD (P = .096) in predicting 30-day mortality. By univariate analysis, indication for intubation (P = .001), need for vasopressor support (P = .002), the presence of renal failure (P < .03), and duration of MV (P < .001) were significantly associated with mortality. On multivariate analysis, only duration of MV (adjusted odds ratio 0.63, 95% CI: 0.42-0.95, P = .03) was the independent predictor of mortality with a majority of patients, 51/64 (79.7%), dying in the first 48 hours of intubation.

CONCLUSIONS

Patients with cirrhosis requiring MV have a dismal prognosis. Such patients and their families should be informed about the overall outcome to assist their decisions about life support and intensive care, outside the transplant setting. Prognostic scores, especially SOFA and MELD, may aid in determining which patients may benefit from aggressive therapy.

New preservation strategies for preventing liver grafts against cold ischemia reperfusion injury

BACKGROUND

In spite of improvements in University of Wisconsin (UW) preservation solution, the injury from grafts during cold storage is an unresolved problem in liver transplantation. The aim of the present study was to evaluate the beneficial effect on ischemia-reperfusion injury associated with liver transplantation of the inversion of K(+) and Na(+) concentrations and the replacement of hydroxyethyl starch (HES) by polyethylene glycol (PEG) in UW preservation solution.

METHODS

Using an orthotopic liver transplantation model, the effects on rat liver preservation of a modified preservation solution (UW-PEG) were evaluated, based on the inversion of K(+) and Na(+) concentration and the replacement of HES by PEG 35 kDa (0.03 mmol/L) in UW preservation solution.

RESULTS

The use of UW-PEG preservation solution ameliorated the biochemical and histological parameters of hepatic damage. Thus, at 24 h after transplantation, transaminase levels were reduced significantly when livers were preserved during 8 h in UW-PEG preservation solution compared with the original UW solution. In addition, histological findings revealed fewer and smaller areas of hepatocyte necrosis. The benefits of UW-PEG solution cannot be explained by modifications in oxidative stress or neutrophil accumulation associated with liver transplantation. However, the results of hepatic and portal blood flow indicated that the benefits of this modified preservation solution, UW-PEG were associated with improvements in the microcirculatory disorders after reperfusion.

CONCLUSIONS

The UW-PEG solution, while retaining all the advantages of UW solution, improved hepatic ischemia-reperfusion injury associated with liver transplantation.

The effects of desferrioxamine and quercetin on hepatic ischemia-reperfusion induced renal disturbance

BACKGROUND

The aim of this study was to analyze the effects of 45min of hepatic ischemia and 1h of reperfusion on renal oxidative stress parameters, on renal tissue damage, and the role of Desferrioxamin (Dfx) and Q on these parameters.

METHODS

Thirty Wistar albino rats were randomized to five groups. Group I was the control group. Group II received no treatment. Groups III and IV received intramuscular injections of desferrioxamine (100mg/kg) and quercetin (50mg/kg), respectively. Group V was administered Dfx and quercetin in combination. After treatment for 3 days, groups II, III, IV, and V were exposed to total hepatic ischemia for 45min. Plasma alanine aminotransferase levels, renal malondialdehyde and reduced glutathione (GSH) activities were measured after reperfusion for 1h. Histopathological and ultrastructural analysis of renal tissues was carried out.

RESULTS

Plasma creatinine and BUN levels were markedly increased in the IR group and pretreated groups. Kidney MDA increased in the IR group, Q and Dfx+Q significantly decreased kidney MDA Kidney GSH levels markedly decreased in the IR group, Dfx significantly increased kidney GSH. No evidence of overt injury was observed in any renal tissue under light and electron microscopy.

CONCLUSIONS

Our data demonstrated that 45min of hepatic ischemia and 1h of reperfusion may alter renal functions and may cause oxidative stress on renal tissue. Q and Dfx seem to have a beneficial effect via the GSH system and modulation of MDA levels.

Acute respiratory distress syndrome is a serious complication of microwave coagulation therapy for liver tumors

BACKGROUND

Acute respiratory distress syndrome (ARDS), also known as noncardiogenic pulmonary edema, is a severe complication in cirrhotic patients undergoing microwave coagulation therapy (MCT) for liver tumor. In this study, cirrhotic patients with ARDS after MCT were compared with others without ARDS.

METHODS

Four patients with ARDS after open MCT and 17 other patients without ARDS were compared in terms of preoperative status, intraoperative findings, and postoperative management.

RESULTS

The preoperative Child-Pugh score and intraoperative amount of irradiation showed no significant differences were observed. The postoperative cumulative water balance until the third day was 1,692 +/- 1,315 mL for the ARDS group and 165 +/- 1,524 mL for the non-ARDS group (P = .079), and by the fourth day the respective values were 1,992 +/- 1,585 mL and 66 +/- 1,685 mL, showing a significant difference (P = .049). The postoperative cumulative sodium administration until the third day was 510 +/- 132 mEq for the ARDS group and 362 +/- 122 mEq for the non-ARDS group with a significant difference (P = .044), and by the fourth day the respective values were 642 +/- 141 mEq and 477 +/- 160 mEq (P = .073). Of the 17 patients in the non-ARDS group, 6 were given aldosterone antagonist until the fourth postoperative day, but it was not administered to any of the patients in the ARDS group.

CONCLUSIONS

The water balance and sodium administration have to be closely monitored to prevent cirrhotic patients undergoing MCT from developing ARDS. Aldosterone antagonist appears to be useful for the prevention of ARDS.

Role of ischemic preconditioning and the portosystemic shunt in the prevention of liver and lung damage after rat liver transplantation

BACKGROUND

This study evaluates whether surgical strategies such as the portosystemic shunt and ischemic preconditioning can protect against hepatic and pulmonary injury associated with liver transplantation.

METHODS

The effect of the portosystemic shunt, ischemic preconditioning, and both surgical procedures together were evaluated in rat liver transplantation. Alanine aminotransferase, hyaluronic acid levels in plasma, adenosine triphosphate and nucleotide levels in liver and edema, malondialdehyde levels, and myeloperoxidase activity were measured 24 hr posttransplantation. Plasmatic tumor necrosis factor (TNF) levels were measured as a possible proinflammatory factor responsible for hepatic and pulmonary damage associated with liver transplantation.

RESULTS

Hepatocyte and cell endothelial damage were observed in liver grafts subjected to 8 hr of cold ischemia. This was associated with increased plasma TNF levels and lung inflammatory response. Portosystemic shunt application in the recipient protected endothelial cells but did not confer an effective protection from hepatocyte damage or reduce the increased plasma TNF levels and lung damage after liver transplantation. However, preconditioning of the donor liver conferred protection against both the endothelial cell and hepatocyte damage observed after liver transplantation. Preconditioning also attenuated the increased plasma TNF release and pulmonary damage. The combination of both surgical strategies resulted in levels of liver injury, TNF, and lung damage similar to those seen after liver transplantation.

CONCLUSIONS

These findings indicate that ischemic preconditioning could be a preferred treatment to reduce hepatic and pulmonary damage associated with liver transplantation. However, this strategy may not be effective in several clinical situations requiring a portosystemic shunt.

Preconditioning protects liver and lung damage in rat liver transplantation: role of xanthine/xanthine oxidase

This study was designed to evaluate whether ischemic preconditioning could confer protection against liver and lung damage associated with liver transplantation. The effect of preconditioning on the xanthine/xanthine oxidase (XOD) system in liver grafts subjected to 8 and 16 hours of cold ischemia was also evaluated. Increased xanthine levels and marked conversion of xanthine dehydrogenase (XDH) to XOD were observed after hepatic cold ischemia. Xanthine/XOD could play a role in the liver and lung damage associated with liver transplantation. This assumption is based on the observation that inhibition of XOD reduced postischemic reactive oxygen species (ROS) generation and hepatic injury as well as ensuing lung inflammatory damage, including neutrophil accumulation, oxidative stress, and edema formation. Ischemic preconditioning reduced xanthine accumulation and conversion of XDH to XOD in liver grafts during cold ischemia. This could diminish liver and lung damage following liver transplantation. In the liver, preconditioning prevented postischemic ROS generation and hepatic injury as well as the injurious effects in the lung following liver transplantation. Administration of xanthine and XOD to preconditioned rats led to hepatic ROS and transaminase levels similar to those found after reperfusion and abolished the protective effect of preconditioning on the lung inflammatory damage. In conclusion, ischemic preconditioning reduces both liver and lung damage following liver transplantation. This endogenous protective mechanism is capable of blocking xanthine/XOD generation in liver grafts during cold ischemia.

Hepatic dysfunction increases length of stay and risk of death after injury

BACKGROUND

The relative importance of dysfunction or failure of different organ systems to recovery from critical illness is unclear. The purpose of this study was to evaluate the contribution of hepatic dysfunction to outcome after injury.

METHODS

We retrospectively evaluated patients admitted to our trauma center from 1994 to 1998 for the development of hepatic dysfunction, defined as serum bilirubin > or = 2.0 mg/dL. Additional variables on patient demographics, injuries, hospital course, and development of other organ system dysfunction were collected from the trauma registry and hospital records.

RESULTS

Using logistic regression analysis, hepatic dysfunction was significantly associated with increased intensive care unit length of stay (LOS) and death. The added development of hepatic dysfunction significantly increased LOS in patients with no other organ dysfunction, those with renal dysfunction, and those with respiratory dysfunction.

CONCLUSION

Hepatic dysfunction influences recovery after injury independent of the dysfunction of other organ systems. The development of hepatic dysfunction prolongs LOS and increases mortality.

The combination of ischemic preconditioning and liver Bcl-2 overexpression is a suitable strategy to prevent liver and lung damage after hepatic ischemia-reperfusion

The present study evaluates the effectiveness of ischemic preconditioning and Bcl-2 overexpression against the liver and lung damage that follow hepatic ischemia-reperfusion and investigates the underlying protective mechanisms. Preconditioning and Bcl-2, respectively, reduced the increased tumor necrosis factor (TNF) and macrophage inflammatory protein-2 (MIP)-2 levels observed after hepatic reperfusion. Bcl-2 overexpression or anti-MIP-2 pretreatment seems to be more effective than preconditioning or anti-TNF pretreatment against inflammatory response, microcirculatory disorders, and subsequent hepatic ischemia-reperfusion injury. Furthermore, each one of these strategies individually was unable to completely inhibit hepatic injury. The combination of preconditioning and Bcl-2 overexpression as well as the combined anti-TNF and anti-MIP-2 pretreatment totally prevented hepatic injury, whereas the benefits of preconditioning and Bcl-2 were abolished by TNF and MIP-2. In contrast to preconditioning, Bcl-2 did not modify lung damage induced by hepatic reperfusion. This could be explained by the differential effect of both treatments on TNF release. Anti-TNF therapy or preconditioning, by reducing TNF release, reduced pulmonary inflammatory response, whereas the benefits of preconditioning on lung damage were abolished by TNF. Thus, the induction of both Bcl-2 overexpression in liver and preconditioning, as well as pharmacological strategies that simulated their benefits, such as anti-TNF and anti-MIP-2 therapies, could be new strategies aimed to reduce lung damage and inhibit the hepatic injury associated with hepatic ischemia-reperfusion.

Risk factors for ARDS in the United States: analysis of the 1993 National Mortality Followback Study

OBJECTIVE

To identify specific comorbid factors that are present in US decedents with ARDS.

DESIGN

We searched the 1993 National Mortality Followback Study for all decedents who had a code for ARDS mentioned on their death certificate. We also searched for comorbid conditions both on the death certificates (sepsis, medical or surgical misadventures, cirrhosis) and in the study database (current or former smoking, use of alcohol at least 3 d/wk, race, gender, and age). We calculated proportional mortality ratios (PMRs) for these risk factors.

RESULTS

Of the 19,003 decedents for whom data were available, 252 decedents, representing an estimated 19,460 US decedents, had ARDS listed on their death certificate. PMRs among decedents with ARDS were significantly increased for medical or surgical misadventures (PMR, 11.8; 95% confidence interval [CI], 3.8 to 36.7), sepsis (PMR, 5.6; 95% CI, 2.0 to 16.0), nonwhite race (PMR, 2.6; 95% CI, 1.4 to 5.0), and cirrhosis (PMR, 2.2; 95% CI, 1.1 to 4.6). PMRs were increased but not statistically significant for current smokers (PMR, 1.2; 95% CI, 0.5 to 3.0) or former smokers (PMR, 1.8; 95% CI, 0.7 to 4.3) compared to never smokers, and drinking alcohol on > or = 3 d/wk in the year prior to death, when compared to drinking alcohol less than < 3 d/wk (PMR, 1.8; 95% CI, 0.6 to 4.9).

CONCLUSIONS

The results of this study confirm the positive associations between ARDS mortality and the presence of sepsis and cirrhosis, and suggest possible new relationships between ARDS mortality and nonwhite individuals and patients with medical or surgical misadventures.

Liver-lung interactions following Escherichia coli bacteremic sepsis and secondary hepatic ischemia/reperfusion injury

We hypothesized that ischemia/reperfusion (I/R) injury of the liver during normotensive gram-negative bacteremic sepsis alters the kinetics of circulating endotoxin, tumor necrosis factor-alpha (TNF-alpha), and coinduced mediators, thereby exacerbating sepsis-induced lung inflammation. Liver and lung dysfunction were studied after hematogenous infection of Sprague-Dawley rats with 10(9) Escherichia coli serotype O55:B5 (EC) and 90 min of secondary hepatic ischemia in EC + I/R and saline-infused (normal saline NS) x I/R rats, followed by brief (1 h) or longer reperfusion (24 h). TNF- alpha:leukotriene interactions in this model were examined using the 5-lipoxygenase-activating protein inhibitor MK-886. Compared with sham-operated EC + Sham animals, peak serum endotoxin, TNF-alpha, alanine aminotransferase, interleukin-6 (IL-6), and hepatic neutrophil (PMN) influx were higher in EC + I/R rats through 24 h (p < 0.05) despite comparable arterial pressure. Lung PMN influx and wet/dry weight ratios were likewise enhanced in EC + I/R versus EC + Sham or NS + I/R rats. MK-886 attenuated TNF-alpha concentrations and ischemic liver injury but not mortality. Thus, focal hepatic I/R augments circulating endotoxin, TNF-alpha, and postbacteremic lung inflammation early after normotensive E. coli bacteremic sepsis.

The Impact of Liver Dysfunction on Outcome in Patients with Multiple Injuries

Multiple organ dysfunction syndrome (MODS) is the leading cause of late deaths after traumatic injury. The relative importance of dysfunction of individual organ systems in determining outcome from MODS has not been clearly defined. Some studies have suggested that hepatic dysfunction associated with MODS increases mortality, whereas others have suggested that it contributes little to outcome in trauma patients. To clarify the role of the hepatic dysfunction after traumatic injury we retrospectively reviewed all trauma patients with an Injury Severity Score ≥14 admitted from January 1, 1994 through June 30, 1997 for the presence of hepatic dysfunction defined as a serum bilirubin ≥2.0 mg/dL. Of the 1962 patients who met the entry criteria 154 developed hepatic dysfunction during their hospital stay. Patients with hepatic dysfunction were older (46 ± 2 versus 41 ± 1 years), were more severely injured (Injury Severity Score 31.5 ± 0.9 versus 23.3 + 0.2), and had a lower prehospital blood pressure (102 ± 3 versus 117 ± 1 mm Hg) compared with patients who did not develop hepatic dysfunction. Patients with hepatic dysfunction were more likely to present with shock as reflected in a lower initial emergency room blood pressure (109 ± 3 versus 128 ± 1 mm Hg) and base deficit (-6.9 ± 0.6 versus -3.5 ± 0.1 mEq/L). Patients who developed hyperbilirubinemia had longer lengths of stay in the intensive care unit (15.8 ± 1.2 versus 3.4 ± 0.2 days) and the hospital (27.4 ± 1.7 versus 11.1 ± 0.2 days) and a higher in-hospital mortality (16.2% versus 2.5%). These data demonstrate that the development of hepatic dysfunction reflects the severity of injury and is associated with a significantly worse outcome after traumatic injury.

Strategies to modulate the deleterious effects of endothelin in hepatic ischemia-reperfusion

BACKGROUND

This study evaluates whether bosentan (endothelin [ET] receptor antagonist) or preconditioning (mechanism that inhibits the postischemic ET release) could reduce the microvascular disorders and the injurious effects of tumor necrosis factor (TNF) associated with hepatic ischemia-reperfusion (I/R).

METHODS

Hepatic I/R was induced in rats and the effects of bosentan or preconditioning on the deleterious effects of ET in hepatic I/R were evaluated. Transaminase and TNF levels in plasma; edema, vascular permeability, lactate, ET, and TNF levels in liver; and edema and myeloperoxidase activity levels in lung were measured after hepatic reperfusion.

RESULTS

The administration of bosentan or the induction of preconditioning previous to I/R attenuated the increase in vascular permeability, edema and lactate levels observed in liver after I/R. However, the addition of ET before preconditioning abolished its benefits. Preconditioning prevented both the increase in hepatic TNF and its release from the liver into the systemic circulation. This resulted in an attenuation of liver and lung damage. Addition of ET or TNF to the preconditioned group abolished the benefits of preconditioning, whereas the previous inhibition of TNF release with GdCl3 in the preconditioned group pretreated with ET did not modify the effects of preconditioning. The inhibition of ET with bosentan prevented the increase of both hepatic and plasma TNF, thus attenuating the liver and lung injury, whereas TNF addition abolished the benefits of bosentan.

CONCLUSIONS

These findings suggest that both bosentan and preconditioning, by inhibition of ET could attenuate the microvascular disorders and the deleterious effect of TNF on the liver and lung elicited by hepatic I/R.

Thoracic manifestations associated with advanced liver disease

Advanced liver disease and portal hypertension may produce various intrathoracic complications that involve the pleural space, lung parenchyma, and pulmonary circulation. Dyspnea and arterial hypoxemia are the common clinical symptoms and signs in patients with such complications. In these patients, intrathoracic complications most often develop during the course of hepatic disease, but a few patients may be seen first with respiratory symptoms or radiographic abnormalities. Therefore, radiologists should be made aware of these disorders that occur in patients with chronic liver disease. In this article, the authors describe and illustrate the clinical and imaging spectrum of thoracic abnormalities associated with advanced liver disease and portal hypertension.

Diabetic patients have a decreased incidence of acute respiratory distress syndrome

OBJECTIVE

Our ability to predict which critically ill patients will develop acute respiratory distress syndrome (ARDS) is imprecise. Based on the effects of diabetes mellitus on the inflammatory cascade, we hypothesized that a history of diabetes might alter the incidence of ARDS.

DESIGN

A prospective multicenter study.

SETTING

Intensive care units at four university medical centers.

PATIENTS

One hundred thirteen consecutive patients with septic shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All patients were prospectively followed during their intensive care course for the development of ARDS. A history of diabetes was identified in 28% (32/113) of the patients. In this study, nondiabetics were more likely to develop septic shock from a pulmonary source (48%, 39/81) compared with diabetics (25%, 8/32) (p = .02). Forty-one percent (46/113) of the patients with septic shock developed ARDS. Forty-seven percent of the nondiabetic patients developed ARDS compared with only 25% of those with diabetes (p = .03, relative risk = 0.53, 95% confidence interval = 0.28-0.98). In a multivariate logistic regression analysis, when we adjusted for several variables including source of infection, the effect of diabetes on the incidence of ARDS remained significant (p = .03, odds ratio = 0.33, 95% confidence interval = 0.12-0.90).

CONCLUSIONS

In patients with septic shock, a history of diabetes is associated with a lower risk of developing ARDS compared with nondiabetics.

The effects of circulating interleukin-8 and adhesion molecules on pulmonary dysfunction in pediatric orthotopic liver transplantation

We investigated the effects of circulating inflammatory cytokines and adhesion molecules induced by ortho-topic liver transplantation (OLT) on pulmonary function. Although the plasma interleukin-8 (IL-8) levels increased gradually, peaking at the end of the operation, these increases were considered minimal. The baseline endothelial adhesion molecule (E-selectin) level was several times higher than the normal value, but after reperfusion of the new transplanted liver, the plasma E-selectin concentrations decreased to within the normal range and remained almost normal during the postoperative period. Similar changes were observed in the plasma levels of other types of adhesion molecules. Although PaO(2)/FIO(2) showed a significant inversed correlation with the peak IL-8 concentration, after the exclusion of two patients, one of whom died and one of whom rejected the transplanted liver, no correlation was able to be found between the PaO(2)/FIO(2) ratio and the maximum IL-8 concentration. Furthermore, there was no correlation between the adhesion moleclues and PaO(2)/FIO(2). These results suggest that IL-8 exerts only a slight effect on respiratory function following successful pediatric liver transplantation, and that circulating adhesion molecules do not affect perioperative lung function.

Protective effect of liver ischemic preconditioning on liver and lung injury induced by hepatic ischemia-reperfusion in the rat

This study evaluates whether preconditioning could modulate the injurious effects of tumor necrosis factor (TNF) on liver and lung following hepatic ischemia-reperfusion (I/R) by inhibiting hepatic postischemic TNF release. The inhibition of hepatic TNF release from Kupffer cells with gadolinium chloride (GdCl(3)) previous to ischemia maintained TNF at control levels, attenuating the increases in transaminases, vascular permeability, and edema associated with hepatic I/R injury. TNF addition reverted this beneficial effect, indicating the implication of the TNF released mainly from Kupffer cells in hepatic I/R injury. Preconditioning prevented hepatic TNF increases, thus attenuating the liver injury, while TNF addition abolished the benefits of preconditioning. Inhibition of nitric oxide (NO) synthesis abolished the effect of preconditioning, whereas GdCl(3) addition avoided the injurious effect of NO inhibition. In addition, NO administration before I/R offered similar results to those found in preconditioning, while TNF addition abolished the benefits of NO. Thus, the effect of preconditioning on TNF release after hepatic I/R is mediated by NO. Inhibition of hepatic TNF release from Kupffer cells with GdCl(3) prevented both the increase in plasma TNF and the injurious effect in lung seen after hepatic I/R, and these effects were reverted with TNF addition. Preconditioning resulting in reduced hepatic TNF levels prevented the systemic TNF release, thus reducing the lung damage following hepatic I/R. However, TNF addition abolished the protective effect of preconditioning on lung injury. These findings indicate that preconditioning attenuates hepatic postischemic TNF release from Kupffer cells, thus probably reducing the liver and lung injury following hepatic I/R, and that this effect of preconditioning is mediated by NO.

Early predictive factors of survival in the acute respiratory distress syndrome. A multivariate analysis

To identify the potential impact of novel therapeutic approaches, we studied the early predictive factors of survival at the onset of acute respiratory distress syndrome (ARDS) in a 24-bed medical ICU of an academic tertiary care hospital. Over a 48-mo period, a total of 3,511 adult patients were admitted and 259 mechanically ventilated patients met ARDS criteria, as defined by American-European consensus conference, i.e., bilateral pulmonary infiltrates and PaO2/FIO2 lower than 200 without left atrial hypertension. These patients were randomly included in a developmental sample (177 patients) and a validation sample (82 patients). Demographic variables, hemodynamic and respiratory parameters, underlying diseases, as well as several severity scores (SAPS, SAPS-II, OSF) and Lung Injury Score (LIS) were collected. These variables were compared between survivors and nonsurvivors and entered into a stepwise logistic regression model to evaluate their independent prognostic roles. The overall mortality rate was 65%. SAPS-II, the severity of the underlying medical conditions, the oxygenation index (mean airway pressure x FIO2 x 100/PaO2), the length of mechanical ventilation prior to ARDS, the mechanism of lung injury, cirrhosis, and occurrence of right ventricular dysfunction were independently associated with an elevated risk of death. Model calibration was very good in the developmental and validation samples (p = 0.84 and p = 0.72, respectively), as was model discrimination (area under the ROC curves of 0.95 and 0.92, respectively). Thus, the prognosis of ARDS seems to be related to the triggering risk factor, the severity of the respiratory illness, and the occurrence of a right ventricle dysfunction, after adjustment for a general severity score.

Cholestatic liver injury increases circulating TNF-alpha and IL-6 and mortality after Escherichia coli endotoxemia

We employed a bile duct ligation (BDL) model of cholestatic liver injury to test the hypothesis that this form of preexisting hepatic dysfunction alters the kinetics of circulating TNF-alpha and IL-6 after Escherichia coli endotoxemia, thereby augmenting mortality and lung injury by a TNF-alpha:leukotriene (LT) axis of inflammation. Male rats were catheterized 13 d after BDL or sham surgery and studied while awake 18 to 24 h later. Cholestasis after BDL was confirmed by baseline serum bilirubin (BDL = 7.34 +/- 0.72 mg/dl, mean +/- SEM, n = 17 versus Sham = 0.25 +/- 0.07, n = 20; p < 0.005) and histopathology. Sham and BDL animals received E. coli lipopolysaccharide serotype O55:B5 (LPS, 5 mg/kg i.v.) or 0.9% NaCl (NS) ending at t = 0 and were monitored over 24 h for vital signs and hemodynamics. In parallel studies, lipoxygenase inhibition was performed using diethylcarbamazine or the 5-lipoxygenase activating-protein inhibitor MK-886. Blood was collected at baseline and at t = 1.5, 3.5, and 24 h for formed elements and for serum endotoxin, TNF-alpha, IL-6, bilirubin, and alanine aminotransferase (ALT). Organs were evaluated at 24 h for histopathology, including neutrophil (PMN) densities and wet/dry weight (W/D) ratios. Cholestasis reduced survival after otherwise nonlethal endotoxemia, with seven of 11 BDL + LPS rats dying within 24 h versus no deaths in BDL + NS (n = 6), Sham + LPS (n = 14), or Sham + NS (n = 6) animals (p < 0.01). Despite equivalent serum endotoxin between groups, circulating TNF-alpha was 8-fold higher in BDL + LPS than in Sham + LPS rats at 1.5 and 3.5 h (p < 0.001), whereas serum TNF-alpha did not differ between BDL + NS and Sham + NS rats. IL-6 likewise was increased differentially by 1.5 h in BDL + LPS animals (11.98 +/- 2.42 ng/ml) versus Sham + LPS rats (3.05 +/- 0.58 ng/ml, p < 0.05). Hypothermia, bradycardic hypotension, and leukopenia were most severe and prolonged in BDL + LPS rats, which also had significantly higher ALT values, W/D ratios, and organ PMN counts. LT inhibition failed to reduce BDL-related differences in serum cytokines or survival after endotoxemia. Thus, cholestasis augments inflammatory responses to gram-negative endotoxemia, sensitizing the host to enhanced fluid flux in multiple organs and to mortality by a LT-independent mechanism.

Acute lung injury in the medical ICU: comorbid conditions, age, etiology, and hospital outcome

The independent effects of chronic disease, age, severity of illness, lung injury score (LIS) and etiology, and preceding nonpulmonary organ-system dysfunction (OSD) on the outcome of acute lung injury (ALI) have not been examined in an exclusively medical-intensive-care-unit (MICU) population. Therefore, 107 consecutive MICU patients with ALI (76% with acute respiratory distress syndrome [ARDS]) were prospectively investigated. The impact of comorbidities, age > 65 yr, acute physiology score (APS), LIS, etiology of ALI, and OSD on hospital survival were studied. The overall mortality was 62 of 107 patients (58%), including 47 (58%) with ARDS. With univariate analysis, age > 65 yr, organ transplantation, human immunodeficiency virus (HIV) infection, active malignancy, chronic steroid use, and a septic or aspiration-related etiology of ALI were associated with a > or = 1.2-fold greater relative risk (RR) of hospital mortality. With multiple logistic regression, independent predictors of hospital death were age > 65 yr, organ transplantation, HIV infection, cirrhosis, active malignancy, and sepsis. APS, LIS, aspiration-related etiology of ALI, preceding OSD, and other comorbidities were not independently predictive of hospital death. Multivariate analysis of the ARDS cohort showed similar results, although cirrhosis and malignancy did not reach statistical significance. We conclude that comorbid conditions, older age, and sepsis etiology are independent predictors of hospital death in exclusively MICU patients with ALI (76% of whom satisfied criteria for ARDS). These factors should be considered in analyzing studies of new therapies and interpreting trends in mortality for ALI and ARDS.

Markers for predicting the development of acute respiratory distress syndrome

The acute respiratory distress syndrome (ARDS) is a relatively common, inflammatory lung disorder that is associated with major morbidity and high mortality. The pathogenesis of ARDS is complex, and unfortunately, the development of ARDS in an individual patient is difficult to anticipate. In this chapter, we outline the rationale for why accurately predicting the development of ARDS would be valuable. We also review the accumulated data on approaches for predicting ARDS and discuss the potential difficulties in establishing predictive markers.

Organ-specific therapy in critical illness: interfacing molecular mechanisms with physiological interventions

Sepsis and SIRS is the outward manifestation of a generalized uncontrolled inflammatory response, which, if sustained, induces widespread endothelial damage and MODS. Immunomodulating therapies, at present, have proven ineffective in reducing morbidity and mortality, presumably because of the heterogeneous nature of sepsis and septic shock and the reciprocating and redundant nature of this inflammatory cascade. Organ-specific therapies can support life but impair both organ-specific function and remote organ function. Novel therapies aimed at minimizing further organ dysfunction may improve outcome in a cost-effective fashion by preventing both further primary organ dysfunction or remote organ dysfunction secondary to the subsequent activation of the inflammatory response.

Mediators, cytokines, and growth factors in liver-lung interactions

Multiple mediators have been implicated in the interactions between the liver and the lungs in various disease states. The best characterized mediator of liver-lung interaction is alpha 1-antitrypsin. Several cytokines and mediators may be involved in the pathogenesis of the hepatopulmonary syndrome and in the cytokine cascades that are activated in systemic inflammatory states such as acute respiratory distress syndrome. Hepatocyte growth factor or scatter factor is a recently described peptide with a broad range of biologic effects that may mediate lung-liver interactions.

Pulmonary intravascular phagocytosis in liver disease

Pulmonary intravascular phagocytosis, the uptake of circulating particles by lung cells, has been detected in rats with chronic biliary cirrhosis and in humans with malignancy and liver diseases. Clinical and experimental evidence supporting the association of pulmonary intravascular phagocytosis with liver cirrhosis is reviewed, and its relationship to pulmonary intravascular macrophage is discussed. A hypothesis is asserted that the induction of pulmonary intravascular macrophage in liver cirrhosis leads to increased susceptibility to adult respiratory distress syndrome in these patients.

Oxygen kinetics during liver transplantation: the relationship between delivery and consumption

In anesthetized humans, oxygen consumption is independent of oxygen delivery above a critical threshold. Below this critical level, lactic acid is a marker of anaerobic metabolism and tissue oxygen debt, and heralds a supply dependency of oxygen consumption. The goal of this study was to determine whether a threshold value for oxygen delivery below which oxygen consumption becomes supply dependent can be identified in patients with normal, impaired, or absent liver function. Measurements were made in 34 surviving patients (group 1) and in 16 nonsurvivors with sepsis and postoperative liver graft failure (group 2). Hemodynamic measurements and blood samples were taken 10 minutes after introduction of anesthesia, 10 minutes after cross-clamping, and 10 minutes after reperfusion of the new liver. At these time points, we measured blood lactate, cardiac output, and arterial and mixed venous oxygen contents in order to calculate oxygen consumption and oxygen delivery. In both groups, cardiac output, oxygen delivery, and oxygen consumption decreased during the anhepatic phase and increased after unclamping of the inferior vena cava. Lactate increased in both groups during surgery, but was significantly higher in nonsurvivors (6.6 +/- 0.4 mmol/L) than in survivors (4.6 +/- 0.1 mmol/L) (P < .05). With similar changes for oxygen delivery and oxygen consumption during increased lactate levels we could not identify a clear supply dependency of oxygen consumption in survivors and nonsurvivors during liver transplantation. We conclude that the interpretation of blood lactate levels during circulatory shock can be biased due to a reduced lactate clearance in patients with impaired liver function, unrelated to the status of the relationship between oxygen delivery and consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of intensive care unit patients using a model based on the presence or absence of organ dysfunctions and/or infection: the ODIN model

OBJECTIVE

To evaluate the sensitivity, specificity and overall accuracy of a model based on the presence or absence of organ dysfunctions and/or infection (ODIN) to predict the outcome for intensive care unit patients.

DESIGN

Prospective study.

SETTING

General intensive care unit in a university teaching hospital.

PATIENTS

1070 consecutive, unselected patients.

INTERVENTIONS

There were no interventions.

MEASUREMENTS AND MAIN RESULTS

We recorded within the first 24 h of admission the presence or absence of dysfunction in 6 organ systems: respiratory, cardiovascular, renal, hematologic, hepatic and neurologic, and/or infection (ODIN) in all patients admitted to our ICU, thus establishing a profile of organ dysfunctions in each patient. Using univariate analysis, a strong correlation was found between the number of ODIN and the death rate (2.6, 9.7, 16.7, 32.3, 64.9, 75.9, 94.4 and 100% for 0, 1, 2, 3, 4, 5, 6 and 7 ODIN, respectively; (p < 0.001). In addition, the highest mortality rates were associated with hepatic (60.8%), hematologic (58.1%) and renal (54.8%) dysfunctions, and the lowest with respiratory dysfunction (36.5%) and infection (38.3%). For taking into account both the number and the type of organ dysfunction, a logistic regression model was then used to calculate individual probabilities of death that depended upon the statistical weight assigned to each ODIN (in the following order of descending severity: cardiovascular, renal, respiratory, neurologic, hematologic, hepatic dysfunctions and infection). The ability of this severity-of-disease classification system to stratify a wide variety of patients prognostically (sensitivity 51.4%, specificity 93.4%, overall accuracy 82.1%) was not different from that of currently used scoring systems.

CONCLUSIONS

These findings suggest that determination of the number and the type of organ dysfunctions and infection offers a clear and reliable method for characterizing ICU patients. Before a widespread use, this model requires to be validated in other institutions.

FK 506 pre-treatment is associated with reduced levels of tumor necrosis factor and interleukin 6 following hepatic ischemia/reperfusion

Using a rat model, the effect of pre-treatment with FK 506 on hepatic ischemia/reperfusion injury was investigated. All control animals died within 72 h of the ischemia/reperfusion injury. Pre-treatment of the animals with FK 506 (0.3 mg/kg in 0.5 ml saline) administered intravenously improved survival. The most striking protection against fatal ischemia/reperfusion injury was achieved in rats that were given FK 506 6 and 24 h prior to the induction of the hepatic ischemic insult (70% and 80% 10-day survival rates, respectively). The hepatoprotective effect of FK 506 was assessed further in a second experiment in which the serum levels of tumor necrosis factor (TNF) and interleukin 6 (IL-6) were measured. These results suggest that a 60-min period of hepatic ischemia and subsequent reperfusion triggers the release of both TNF and IL-6, and that FK 506 pre-treatment (6 h before the ischemic episode) significantly inhibits the production and/or release of these two cytokines compared to untreated controls. These data provide additional information concerning the immunosuppressive and hepatoprotective activities of FK 506. Based upon these data, it is probable that FK 506 attenuates hepatic ischemia/reperfusion injury, at least in part, by reducing TNF and IL-6 levels.

Serum cytokine levels in human septic shock. Relation to multiple-system organ failure and mortality

PURPOSE

Cytokines have been associated with the development of sepsis and diffuse tissue injury following septic or endotoxic challenges in humans. Furthermore, relative organ-system dysfunction, not specific organ dysfunction, appears to predict outcome from critical illness. We hypothesized that persistence of inflammatory cytokines within the circulation, reflecting a generalized systemic inflammatory response, is associated with multiple-system organ failure (MSOF) and death from critical illness. In addition, since hepatic function is central to host-defense homeostasis, we further reasoned that critically ill patients with hepatic cirrhosis would have an increased incidence of MSOF and death following sepsis associated with a persistence of cytokines in the blood.

PATIENTS AND METHODS

We measured serum levels of tumor necrosis factor (TNF), interleukin (IL) 1, IL-2, IL-6, and interferon gamma (IFG) serially for the first 48 h following the onset of hypotension (systolic blood pressure < 90 mm Hg) thought likely to be due to sepsis in all patients presenting to one ICU. These data were correlated with initial severity of shock and retrospective determination of septic or nonseptic origin, preexistent hepatic cirrhosis, subsequent development of MSOF, and outcome.

RESULTS

Fifty-three specific episodes of shock in 52 patients were recorded (35 septic and 18 nonseptic episodes). Mortality was higher in septic patients (41 vs 17 percent, p < 0.01), as was the development of MSOF (29 vs 6 percent, p < 0.001), incidence of cirrhosis (21 vs 0 percent, p < 0.01), and TNF levels over the study interval (p < 0.01). Nonseptic patients also had an initial elevation in TNF over 48-h levels (p < 0.05) that were higher than serum levels reported for normal subjects (chi 2, p < 0.05). There was no relation between peak TNF level and outcome. Sixty-seven percent of the cirrhotic patients had development of MSOF and died, while only 30 percent of the noncirrhotic patients had development of MSOF or died (p < 0.05). The TNF and IL-6 levels in patients who had MSOF or who died were both elevated and did not decrease over time independent of presence or absence of sepsis (p < 0.01). Similarly, IL-6 levels after 12 h were higher in cirrhotic patients than in noncirrhotic septic patients (p < 0.05). No elevation in IL-1, IL-2, or IFG was seen in any patient subpopulation.

CONCLUSIONS

TNF and IL-6 serum levels are higher in septic than in nonseptic shock, but the persistence of TNF and IL-6 in the serum rather than peak levels of cytokines predicts a poor outcome in patients with shock.

Tumor necrosis factor and endotoxin in the pathogenesis of liver and pulmonary injuries after orthotopic liver transplantation in the rat

This study examines whether tumor necrosis factor and endotoxin are involved in the pathogenesis of primary nonfunction of graft and pulmonary complication after orthotopic liver transplantation. Livers from Lewis rats were stored for either 1 or 4 hr in ice-cold Euro-Collins solution (1-hr storage and 4-hr storage group, respectively). Subsequently, donor livers were implanted orthotopically. In some experiments, anti-tumor necrosis factor antibody was administered intravenously before and immediately after the surgery into animals that received livers stored for 4 hr. Blood samples for the measurement of tumor necrosis factor and endotoxin were collected by way of an indwelling catheter placed in the suprahepatic vena cava. Serum tumor necrosis factor was elevated at all time points studied postoperatively in rats of the 4-hr storage group; however, tumor necrosis factor was not detected in the serum in the 1-hr storage group. Endotoxin was also elevated significantly in the serum of the former group compared with levels in the serum of the latter group. The peak value of endotoxin occurred 1 hr earlier than that of tumor necrosis factor, suggesting that the rise in endotoxin stimulated release of tumor necrosis factor. The histological study of livers stored for 4 hr showed substantial hepatocellular degeneration 24 hr after surgery, whereas hepatocellular damage was minimal in the 1-hr storage group. Serum ALT levels 24 hr after the operation in the 1-hr and 4-hr storage groups were 169 +/- 46 IU/L and 374 +/- 41 IU/L (mean +/- S.E.M., p less than 0.05), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Liver dysfunction in critical illness

Abnormal liver function commonly accompanies critical illness. Ischaemic hepatitis occurs with shock and is characterised by elevated plasma aminotransferase concentrations. 'ICU jaundice' occurs later in critical illness, especially after trauma and sepsis. The major biochemical abnormality is conjugated hyperbilirubinaemia. The clinical setting suggests that hepatic ischaemia and hepatotoxic actions of inflammatory mediators are the major aetiological factors. Massive blood transfusion, effects of nutritional support and drug toxicity may contribute. Both the presence and degree of jaundice are associated with increased mortality in several nonhepatic diseases. It is proposed that Kupffer cell phagocytic depression associated with liver dysfunction permits systemic spread of endotoxin and inflammatory mediators and thus predisposes to multiple organ failure. Immunosuppression, metabolic abnormalities, impaired drug oxidation and myocardial depression may contribute to the poor prognosis. There is no specific treatment, but prompt resuscitation, definitive treatment of sepsis and meticulous supportive care will likely reduce the incidence and severity.