What every Intensivist should know about the role of ammonia in liver failure

Publisher Copyright: © 2023 The AuthorsPurpose: Acute liver failure (ALF) or acute-on-chronic liver failure (ACLF) patients have high short-term mortality and morbidity. In the context of liver failure, increased serum ammonia is associated with worse neurological outcomes, including high-grade hepatic encephalopathy (HE), cerebral edema, and intracranial hypertension. Besides its neurotoxicity, hyperammonemia may contribute to immune dysfunction and the risk of infection, a frequent trigger for multi-organ failure in these patients. Material and methods: We performed a literature-based narrative review. Publications available in PubMed® up to June 2023 were considered. Results: In the ICU management of liver failure patients, serum ammonia may play an important role. Accordingly, in this review, we focus on recent insights about ammonia metabolism, serum ammonia measurement strategies, hyperammonemia prognostic value, and ammonia-targeted therapeutic strategies. Conclusions: Serum ammonia may have prognostic value in liver failure. Effective ammonia targeted therapeutic strategies are available, such as laxatives, rifaximin, L-ornithine-L-aspartate, and continuous renal replacement therapy.proofepub_ahead_of_prin

Bench-to-bedside review: Current evidence for extracorporeal albumin dialysis systems in liver failure

Acute liver failure (ALF) and acute on chronic liver failure (AoCLF) carry a high mortality. The rationale for extracorporeal systems is to provide an environment facilitating recovery or a window of opportunity for liver transplantation. Recent technologies have used albumin as a scavenging molecule. Two different albumin dialysis systems have been developed using this principle: MARS (Molecular Adsorbent Recirculation System) and SPAD (Single-Pass Albumin Dialysis). A third system, Prometheus (Fractionated Plasma Separation and Adsorption), differs from the others in that the patient's albumin is separated across a membrane and then is run over adsorptive columns. Although several trials have been published (particularly with MARS), currently there is a lack of controlled studies with homogenous patient populations. Many studies have combined patients with ALF and AoCLF. Others have included patients with different etiologies. Although MARS and Prometheus have shown biochemical improvements in AoCLF and ALF, additional studies are required to show conclusive benefit in short- and long-term survival. The appropriate comparator is standard medical therapy rather than head-to-head comparisons of different forms of albumin dialysis

Elevated serum liver-type fatty acid binding protein levels in non-acetaminophen acute liver failure patients with organ dysfunction.

Liver-type fatty acid binding protein (FABP1) has previously been demonstrated to improve prognostic discrimination in acetaminophen (APAP)-induced ALF but has not been investigated in other etiologies of ALF. AIM: To determine whether FABP1 levels (early: admission or late: days 3-5) are associated with 21-day transplant-free survival in non-APAP ALF. METHODS: FABP1 was measured in serum samples from 384 ALF patients (n = 88 transplant-free survivors (TFS), n = 296 died/LT-NTFS) using solid-phase enzyme-linked immunosorbent assay and analyzed with US ALFSG registry data. RESULTS: Of 384 ALF patients (autoimmune hepatitis n = 125, drug-induced liver injury n = 141, Hepatitis B n = 118), 177 (46%) patients received LT. Early FABP1 levels were significantly higher in ALF patients requiring vasopressor support (203.4 vs. 76.3 ng/mL) and renal replacement therapy (203.4 vs. 78.8 ng/mL; p < 0.001 for both). Late FABP1 levels were significantly higher in patients requiring mechanical ventilation (77.5 vs. 53.3 ng/mL), vasopressor support (116.4 vs. 53.3 ng/mL) and in patients with grade 3/4 hepatic encephalopathy (71.4 vs. 51.4 ng/mL; p = 0.03 for all). Late FABP1 levels were significantly lower in TFS patients (TFS 54 vs. NTFS 66 ng/mL; p = 0.049) but not admission (TFS 96 vs. NTFS 87 ng/mL; p = 0.67). After adjusting for significant covariates, serum FABP1 did not discriminate significantly between TFS and patients who died/received LT at day 21 either on admission (p = 0.29) or late (days 3-5, p = 0.087) time points. CONCLUSION: In this first report of FABP1 in non-APAP ALF, FABP1 levels at late time points (days 3-5) were significantly lower in ALF patients who were alive without transplant at day 21 but not after adjusting for covariates reflecting severity of illness. Higher FABP1 levels were associated with the presence of increased organ failure

a cohort study

Funding: This work was supported by grants from the National Institutes of Health (U19AI135964, P30AG059988), with institutional support from UL1TR001422. The funding agency played no role in the study design, collection of data, analysis, or interpretation of data.The impact of multidrug-resistant (MDR) colonization and MDR infection in critically ill cirrhosis patients remains unclear. We assessed the association of MDR colonization and MDR infection with these patients' survival. Observational cohort study including adult cirrhosis patients admitted to 5 intensive care units at Northwestern Memorial Hospital (Chicago, Illinois, USA) on January 1, 2010, to December 31, 2017. Patients admitted for elective liver transplant or with previous liver transplant were excluded. Patients were screened for MDR colonization on intensive care unit admission. Infection diagnoses during the intensive care unit stay were considered. The primary endpoint was hospital transplant-free survival. Among 600 patients included, 362 (60%) were men and median (interquartile range) age was 58.0 (49.0, 64.0) years. Median (interquartile range) Model for End-stage Liver Disease, Sequential Organ Failure Assessment, and Chronic Liver Failure-Acute-on-Chronic Liver Failure scores on intensive care unit day 1 were 28.0 (20.0, 36.0), 9.0 (6.0, 13.0), and 55.0 (48.0, 64.0), respectively. Overall, 76 (13%) patients were transplanted and 443 (74%) survived the hospital stay. Infections were diagnosed in 347 (58%) patients: pneumonia in 197 (33%), urinary tract infection in 119 (20%), peritonitis in 93 (16%), bloodstream infection in 99 (16%), Clostridium difficile colitis in 9 (2%), and catheter tip infection in 7 (1%). MDR colonization and MDR infection were identified in 200 (33%) and 69 (12%) patients, respectively. MDR colonization was associated with MDR infection (p < 0.001). MDR colonization or MDR infection was associated with higher number and duration of antibiotics (p < 0.001). Following adjustment for covariables (age, sex, etiology, portal hypertension, and Sequential Organ Failure Assessment score), MDR colonization [OR (95% CI), 0.64 (0.43, 0.95)] or MDR infection [adjusted OR (95% CI), 0.22 (0.12, 0.40)] were independently associated with lower transplant-free survival. Among critically ill cirrhosis patients, MDR colonization or MDR infection portended a worse prognosis.publishersversionpublishe

A comparison of early versus late initiation of renal replacement therapy in critically ill patients with acute kidney injury: a systematic review and meta-analysis

Abstract Introduction Our aim was to investigate the impact of early versus late initiation of renal replacement therapy (RRT) on clinical outcomes in critically ill patients with acute kidney injury (AKI). Methods Systematic review and meta-analysis were used in this study. PUBMED, EMBASE, SCOPUS, Web of Science and Cochrane Central Registry of Controlled Clinical Trials, and other sources were searched in July 2010. Eligible studies selected were cohort and randomised trials that assessed timing of initiation of RRT in critically ill adults with AKI. Results We identified 15 unique studies (2 randomised, 4 prospective cohort, 9 retrospective cohort) out of 1,494 citations. The overall methodological quality was low. Early, compared with late therapy, was associated with a significant improvement in 28-day mortality (odds ratio (OR) 0.45; 95% confidence interval (CI), 0.28 to 0.72). There was significant heterogeneity among the 15 pooled studies (I2 = 78%). In subgroup analyses, stratifying by patient population (surgical, n = 8 vs. mixed, n = 7) or study design (prospective, n = 10 vs. retrospective, n = 5), there was no impact on the overall summary estimate for mortality. Meta-regression controlling for illness severity (Acute Physiology And Chronic Health Evaluation II (APACHE II)), baseline creatinine and urea did not impact the overall summary estimate for mortality. Of studies reporting secondary outcomes, five studies (out of seven) reported greater renal recovery, seven (out of eight) studies showed decreased duration of RRT and five (out of six) studies showed decreased ICU length of stay in the early, compared with late, RRT group. Early RRT did not; however, significantly affect the odds of dialysis dependence beyond hospitalization (OR 0.62 0.34 to 1.13, I2 = 69.6%). Conclusions Earlier institution of RRT in critically ill patients with AKI may have a beneficial impact on survival. However, this conclusion is based on heterogeneous studies of variable quality and only two randomised trials. In the absence of new evidence from suitably-designed randomised trials, a definitive treatment recommendation cannot be made

Variation in the Care of Acute Liver Failure: A Survey of Intensive Care Professionals

Introduction: Acute liver failure (ALF) is a rare disease with potentially high mortality. We sought to assess the individual approach to ALF by intensive care unit (ICU) professionals. Methods: Cross-sectional survey of ICU professionals. Web-based survey capturing data on respondents’ demographics, characteristics of patients with ALF admitted to ICU, and their management. Results: Among 204 participants from 50 countries, 140 (68.6%) worked in Europe, 146 (71.6%) were intensivists, 142 (69.6%) admitted &#x3c;25 patients with ALF per year, and 166 (81.8%) reported &#x3c;25% of patients had paracetamol-related ALF. On patients’ outcomes, 126 (75.0%) reported an emergency liver transplantation (ELT) rate &#x3c;25% and 140 (73.3%) a hospital mortality rate &#x3c;50%. The approach to ALF in the ICU varied with age, region, level of training, type of hospital, and etiology (prescribing N-acetylcysteine for paracetamol toxicity, triggers for endotracheal intubation, measurement of and strategies for lowering serum ammonia, extracorporeal device deployment, and prophylactic antibiotics). Conclusions: The management of patients with ALF by ICU professionals differed substantially concerning the relevant clinical measures taken. Further education and high-quality research are warranted

Development and Pilot of a Checklist for Management of Acute Liver Failure in the Intensive Care Unit

Introduction Acute liver failure (ALF) is an ideal condition for use of a checklist. Our aims were to develop a checklist for the management of ALF in the intensive care unit (ICU) and assess the usability of the checklist among multiple providers. Methods The initial checklist was developed from published guidelines and expert opinion. The checklist underwent pilot testing at 11 academic liver transplant centers in the US and Canada. An anonymous, written survey was used to assess the usability and quality of the checklist. Written comments were used to improve the checklist following the pilot testing period. Results We received 81 surveys involving the management of 116 patients during the pilot testing period. The overall quality of the checklist was judged to be above average to excellent by 94% of users. On a 5-point Likert scale, the majority of survey respondents agreed or agreed strongly with the following checklist characteristics: the checklist was easy to read (99% agreed/agreed strongly), easy to use (97%), items are categorized logically (98%), time to complete the checklist did not interfere with delivery of appropriate and safe patient care (94%) and was not excessively burdensome (92%), the checklist allowed the user the freedom to use his or her clinical judgment (80%), it is a useful tool in the management of acute liver failure (98%). Web-based and mobile apps were developed for use of the checklist at the point of care. Conclusion The checklist for the management of ALF in the ICU was shown in this pilot study to be easy to use, helpful and accepted by a wide variety of practitioners at multiple sites in the US and Canada

Liver transplantation in the critically ill: a multicenter Canadian retrospective cohort study

Introduction: Critically ill cirrhosis patients awaiting liver transplantation (LT) often receive prioritization for organ allocation. Identification of patients most likely to benefit is essential. The purpose of this study was to examine whether the Sequential Organ Failure Assessment (SOFA) score can predict 90-day mortality in critically ill recipients of LT and whether it can predict receipt of LT among critically ill cirrhosis listed awaiting LT. Methods: We performed a multicenter retrospective cohort study consisting of two datasets: (a) all critically-ill cirrhosis patients requiring intensive care unit (ICU) admission before LT at five transplant centers in Canada from 2000 through 2009 (one site, 1990 through 2009), and (b) critically ill cirrhosis patients receiving LT from ICU (n = 115) and those listed but not receiving LT before death (n = 106) from two centers where complete data were available. Results: In the first dataset, 198 critically ill cirrhosis patients receiving LT (mean (SD) age 53 (10) years, 66% male, median (IQR) model for end-stage liver disease (MELD) 34 (26-39)) were included. Mean (SD) SOFA scores at ICU admission, at 48 hours, and at LT were 12.5 (4), 13.0 (5), and 14.0 (4). Survival at 90 days was 84% (n = 166). In multivariable analysis, only older age was independently associated with reduced 90-day survival (odds ratio (OR), 1.07; 95% CI, 1.01 to 1.14; P = 0.013). SOFA score did not predict 90-day mortality at any time. In the second dataset, 47.9% (n = 106) of cirrhosis patients listed for LT died in the ICU waiting for LT. In multivariable analysis, higher SOFA at 48 hours after admission was independently associated with lower probability of receiving LT (OR, 0.89; 95% CI, 0.82 to 0.97; P = 0.006). When including serum lactate and SOFA at 48 hours in the final model, elevated lactate (at 48 hours) was also significantly associated with lower likelihood of receiving LT (0.32; 0.17 to 0.61; P = 0.001). Conclusions: SOFA appears poor at predicting 90-day survival in critically ill cirrhosis patients after LT, but higher SOFA score and elevated lactate 48 hours after ICU admission are associated with a lower probability receiving LT. Older critically ill cirrhosis patients (older than 60) receiving LT have worse 90-day survival and should be considered for LT with caution

Prognosis of cirrhotic patients admitted to intensive care unit: a meta-analysis

and METAREACIR GroupInternational audienceBackgroundThe best predictors of short- and medium-term mortality of cirrhotic patients receiving intensive care support are unknown.MethodsWe conducted meta-analyses from 13 studies (2523 cirrhotics) after selection of original articles and response to a standardized questionnaire by the corresponding authors. End-points were in-ICU, in-hospital, and 6-month mortality in ICU survivors. A total of 301 pooled analyses, including 95 analyses restricted to 6-month mortality among ICU survivors, were conducted considering 249 variables (including reason for admission, organ replacement therapy, and composite prognostic scores).ResultsIn-ICU, in-hospital, and 6-month mortality was 42.7, 54.1, and 75.1%, respectively. Forty-eight patients (3.8%) underwent liver transplantation during follow-up. In-ICU mortality was lower in patients admitted for variceal bleeding (OR 0.46; 95% CI 0.36–0.59; p 19 at baseline (OR 8.54; 95% CI 2.09–34.91; p 26 (OR 3.97; 95% CI 1.92–8.22; p < 0.0001; PPV = 0.75), and hepatorenal syndrome (OR 4.67; 95% CI 1.24–17.64; p = 0.022; PPV = 0.88).ConclusionsPrognosis of cirrhotic patients admitted to ICU is poor since only a minority undergo liver transplant. The prognostic performance of general ICU scores decreases over time, unlike the Child–Pugh and MELD scores, even recorded in the context of organ failure. Infection-related parameters had a short-term impact, whereas liver and renal failure had a sustained impact on mortality