Hyperlactatemia in patients with non-acetaminophen-related acute liver failure

Markers of Tissue Perfusion as Predictors of Adverse Outcomes in Patients with Left Ventricular Dysfunction Undergoing Coronary Artery Bypass Surgery

BACKGROUND

Cardiac surgery patients may be exposed to tissue hypoperfusion and anaerobic metabolism.

OBJECTIVE

To verify whether the biomarkers of tissue hypoperfusion have predictive value for prolonged intensive care unit (ICU) stay in patients with left ventricular dysfunction who underwent coronary artery bypass surgery.

METHODS

After approval by the institution's Ethics Committee and the signing of informed consent, 87 patients with left ventricular dysfunction (ejection fraction < 50%) undergoing coronary artery bypass surgery were enrolled. Hemodynamic and metabolic biomarkers were collected at five time points: after anesthesia, at the end of the surgery, at ICU admission, and at six and twelve hours after. An analysis of variance for repeated measures followed by a Bonferroni post hoc test was used for repeated, continuous variables (hemodynamic and metabolic variables) to determine differences between the two groups over the course of the study period. The level of statistical significance adopted was 5%.

RESULTS

Thirty-eight patients (43.7%) who presented adverse outcomes were older, higher Euro score (p<0.001), and elevated ΔpCO2 as analyzed 12 hours after ICU admission (p<0.01), while increased arterial lactate concentration at 6 hours postoperatively was found to be a negative predictive factor (p<0.01).

CONCLUSIONS

Euro SCORE, six-hour postoperative arterial lactate, 12-hour postoperative ΔPCO2, and eRQ are independent predictors of adverse outcomes in patients with left ventricular dysfunction after cardiac surgery.

Liver Transplantation for Acute Liver Failure- Indication, Prioritization, Timing, and Referral

Acute liver failure (ALF) is a major success story in gastroenterology, with improvements in critical care and liver transplant resulting in significant improvements in patient outcomes in the current era compared to the dismal survival rates in the pretransplant era. However, the ever-increasing list of transplant candidates and limited organ pool makes judicious patient selection and organ use mandatory to achieve good patient outcomes and prevent organ wastage. Several scoring systems exist to facilitate the identification of patients who need a liver transplant and would therefore need an early referral to a specialized liver unit. The timing of the liver transplant is also crucial as transplanting a patient too early would lead to those who would recover spontaneously receiving an organ (wastage), and a late decision might result in the patient becoming unfit for transplant (delisted) or have an advanced disease which would result in poor post-transplant outcomes. The current article reviews the indications and contraindications of liver transplant in ALF patients, the various prognostic scoring systems, etiology-specific outcomes, prioritization and timing of referral.

Prognostic Scores in Acute Liver Failure Due to Viral Hepatitis

Viral infections are among the major causes of acute liver failure (ALF) worldwide. While the role of agents such as hepatitis A, B, C, D and E viruses in precipitating ALF are well known, improvements in serological assays have led to the detection of viral agents such as Epstein Barr virus, cytomegalovirus etc. as atypical causes of ALF. Despite the plethora of literature available on viral hepatitis and ALF, there is very limited large-scale epidemiologic data on the prevalence, risk factors of progression and outcomes in ALF of viral causes. This is important as viral infections remain the leading cause of ALF in the East and in developing countries, while the impact of viral ALF in the West has largely been ameliorated by effective vaccination and sanitization programs. This review focuses specifically on the available prognostic scores that aid in the management of ALF of viral etiologies while also briefly reviewing the current literature on newer viral agents known to cause ALF, risk factors of progression, outcomes and how management algorithms can be developed by incorporation of prognostic scoring systems for referral and transplant listing.

Higher circulating natural killer cells and lower lactate levels at admission predict spontaneous survival in non-acetaminophen induced acute liver failure

Massive cellular necrosis in acute liver failure (ALF) is dominantly immune mediated and innate immune cells are major pathophysiological determinants in liver damage. In fifty ALF and fifteen healthy, immune cells phenotyping by flow-cytometry, DAMPs using ELISA were analysed and correlated with clinical and biochemical parameters. ALF patients (aged 27 ± 9 yr, 56% males, 78% viral aetiology) showed no difference in neutrophils and classical monocytes, but significantly increased intermediate monocytes (CD14⁺CD16⁺) (p < 0.01), decreased non-classical monocytes (CD14^-CD16⁺) and CD3^-veCD16⁺CD56⁺ NK cells compared to HC. ALF patients who survived, showed higher NK cells (9.28 vs. 5.1%, p < 0.001) among lymphocytes and lower serum lactate levels (6.1 vs. 28, Odds ratio 2.23, CI 1.27-3.94) than non- survivors had higher. Logistic regression model predicted the combination of lactate levels with NK cell percentage at admission for survival. In conclusion, Combination of NK cell frequency among lymphocytes and lactate levels at admission can reliably predict survival of ALF patients.

Liver transplantation in acute liver failure: Dilemmas and challenges

Acute liver failure (ALF) refers to a state of severe hepatic injury that leads to altered coagulation and sensorium in the absence of pre-existing liver disease. ALF has different causes, but the clinical characteristics are strikingly similar. In clinical practice, however, inconsistency in the definition of ALF worldwide and confusion regarding the existence of pre-existing liver disease raise diagnostic dilemmas. ALF mortality rates used to be over 80% in the past; however, survival rates on medical treatment have significantly improved in recent years due to a greater understanding of pathophysiology and advances in critical care management. The survival rates in acetaminophen-associated ALF have become close to the post-transplant survival rates. Given that liver transplantation (LT) is an expensive treatment that involves a major surgical operation in critically ill patients and lifelong immunosuppression, it is very important to select accurate patients who may benefit from it. Still, emergency LT remains a lifesaving procedure for many ALF patients. However, there is a lack of consistency in current prognostic models that hampers the selection of transplant candidates in a timely and precise manner. The other problems associated with LT in ALF are the shortage of graft, development of contraindications on the waiting list, vaguely defined delisting criteria, time constraints for pre-transplant evaluation, ethical concerns, and comparatively poor post-transplant outcomes in ALF. Therefore, there is a desperate need to establish accurate prognostic models and explore the roles of evolving adjunctive and alternative therapies, such as liver support systems, plasma exchange, stem cells, auxiliary LT, and so on, to enhance transplant-free survival and to fill the void created by the graft shortage

Preoperative Serum Bilirubin and Lactate Levels Predict Postoperative Morbidity and Mortality in Liver Surgery: A Single-Center Evaluation

Background and Aims:

In spite of huge developments in liver surgery during the last decades, morbidity and mortality continue to pose problems in this field. The aim of this study was to identify preoperative predictors for postoperative mortality and morbidity in liver surgery.

Material and Methods:

In a single-center study, an extensive analysis of a prospective database, including clinical criteria and laboratory tests of patients undergoing liver surgery between July 2007 and July 2012 was performed. Cutoff values of selected laboratory tests were calculated.

Results:

In all, 337 patients were included in the study. Univariate analysis showed a statistically significant association of preoperative bilirubin, lactate, hemoglobin levels, platelet count, and prothrombin time with postoperative morbidity and mortality. Multivariate analysis revealed preoperatively elevated serum bilirubin and lactate levels as independent predictors for increased postoperative morbidity and mortality after liver surgery.

Conclusions:

The identified laboratory values showed a statistically significant association with postoperative morbidity and mortality in liver surgery and might be helpful in preoperative patient selection.

Systematic review: acute liver failure - one disease, more than 40 definitions

BACKGROUND

Acute liver failure (ALF) is a clinical syndrome with very high mortality estimates ranging between 60% and 80%.

AIM

To investigate the explicitness and extent of variability in the used ALF definitions in the ALF prognostic literature.

METHODS

All studies that pertain to the prognosis of patients with ALF were electronically searched in MEDLINE (1950-2012) and EMBASE (1950-2012). Identified titles and abstracts were independently screened by three reviewers to determine eligibility for additional review. We included English articles that reported original data from clinical trials or observational studies on ALF patients.

RESULTS

A total of 103 studies were included. Of these studies 87 used 41 different ALF definitions and the remaining 16 studies did not report any explicit ALF definition. Four components underlying ALF definitions accounted for the differences: presence and/or grading of hepatic encephalopathy (HE); the interval between onset of disease and occurrence of HE; presence of coagulopathy and pre-existing liver disease.

CONCLUSIONS

The diversity in acute liver failure definitions hinders comparability and quantitative analysis among studies. There is room for improvement in the reporting of acute liver failure definitions in prognostic studies. The result of this review may be useful as a starting point to create a uniform acute liver failure definition.

The role of serum lactate in the acute care setting

Acute care services are increasingly faced with the double burden of high patient acuity and limited resources. Early identification of patients who are sick or who have the potential to deteriorate rapidly is crucial so that these resources may be allocated to those in greatest need. Traditional measures of illness and end points of resuscitation, such as vital signs, often fail to identify occult hypoperfusion with certain disease processes associated with high morbidity and mortality. Thus, biochemical markers that may predict illness earlier are becoming more relevant. We present a review of the evidence behind use of the serum lactate level in this setting.

Prognostic value of admission serum lactate concentrations in intensive care unit patients

BACKGROUND

Although blood lactate concentrations have an established prognostic value in circulatory shock or after cardiac arrest, their relationship with morbidity and length of stay in general intensive care unit (ICU) populations has not been well defined.

METHODS

This study included all 433 patients (246 surgical and 187 medical) consecutively admitted to the Department of medico-surgical intensive care. Hyperlactataemia was defined as a serum lactate concentration > or = 2 mEq/l.

RESULTS

On admission, 195 patients (45%) had hyperlactataemia. Hyperlactataemic patients had higher Acute Physiology and Chronic Health Evaluation (APACHE) II (13.3 +/- 6.9 vs 10.0 +/- 5.2) and Sequential Organ Failure Assessment (SOFA) (5.3 +/- 3.3 vs 3.3 +/- 2.3) scores than patients with normal lactate concentrations (both p < 0.01). There was no overall difference in length of ICU stay (LOS) between the two groups but survivors in the hyperlactataemic group had a longer LOS than survivors in the normal lactate group, whereas hyperlactataemic non-survivors had a shorter LOS than normal lactate non-survivors. Mortality was 9% in patients with normal lactate concentrations and 23% in hyperlactataemic patients. The mortality rate increased with increasing lactate concentrations, from 17% in patients with lactate concentrations from 2-4 mEq/l to 64% in those with concentrations more than 8 mEq/l. Non-survivors had higher lactate concentrations than survivors on admission, and after 24 and 48 hours. Risk factors for developing hyperlactataemia that were present on admission were SOFA score > 5, mean arterial blood pressure less than 70 mmHg, blood sugar greater than 110 mg/dl, and current use of vasopressors.

CONCLUSIONS

Our study documents a direct relationship between the serum lactate level on ICU admission and not only the risk of death in ICU but also the length of ICU stay. Hyperlactataemic survivors have a longer LOS and non-survivors a shorter LOS than normal lactate survivors and non-survivors, respectively.

Prognostic implications of lactate, bilirubin, and etiology in German patients with acute liver failure

BACKGROUND & AIMS

Among the potentially helpful indicators of poor prognosis in acute liver failure (ALF) are etiology, encephalopathy grade, blood lactate, and King's College Criteria (KCC). The accuracy of these parameters in predicting transplantation or death shows significant variation in different countries.

METHODS

We retrospectively analyzed 102 patients with ALF treated at our institution between 1996 and 2005. Baseline parameters, simplified acute physiology score III (SAPS-III), KCC, Model for End-Stage Liver Disease (MELD) score, and a novel score of bilirubin, lactate, and etiology (BiLE score) were compared between transplant-free survivors and patients who required liver transplantation or died, by using multivariate linear regression analysis and receiver operating characteristics (ROC).

RESULTS

The most common causes of ALF were indeterminate liver failure (21%), acute hepatitis B (18%), acetaminophen ingestion (16%), and Budd-Chiari syndrome (9%). Transplantation-free survival was 38%, 44% of patients underwent liver transplantation, and 18% died without transplantation. Eight-week survival was 77%. The BiLE score was the best predictor of death or need of transplantation, with 79% sensitivity and 84% specificity. ROC analysis revealed a better performance of BiLE score when compared with bilirubin, lactate, MELD score, and SAPS-III (area under the curve: 0.87 +/- 0.04, 0.73 +/- 0.51, 0.73 +/- 0.52, 0.71 +/- 0.05, and 0.68 +/- 0.59, respectively).

CONCLUSIONS

The simple, combined BiLE score emerged as the best predictor of poor outcome in our patient cohort and should be prospectively evaluated in other populations.