title: Clinical impact of arterial ammonia levels in ICU patients with different liver diseases.
abstract: OBJECTIVE
  Increased arterial ammonia levels are associated with high mortality in patients with acute liver failure (ALF). Data on the prognostic impact of arterial ammonia is lacking in hypoxic hepatitis (HH) and scarce in critically ill patients with cirrhosis.
  
  
  METHODS
  The patient cohort comprised 72 patients with HH, 43 patients with ALF, 100 patients with liver cirrhosis and 45 patients without evidence for liver disease. Arterial ammonia concentrations were assessed on a daily basis in all patients and the results were compared among these four patient groups and between 28-day survivors and 28-day non-survivors overall and in each group.
  
  
  RESULTS
  Overall 28-day mortality rates in patients with HH, ALF and cirrhosis and in the control group were 54, 30, 49 and 27 %, respectively. Peak arterial ammonia levels differed significantly between transplant-free 28-day survivors and non-survivors in the HH and ALF groups (p < 0.01 for both). Multivariate regression identified peak arterial ammonia concentrations as an independent predictor of 28-day mortality or liver transplantation in patients with HH and ALF, respectively (p < 0.01). There was no association between mortality and arterial ammonia in patients with liver cirrhosis and in the control group. Admission arterial ammonia levels were independently linked to hepatic encephalopathy grades 3/4 in patients with HH (p < 0.01), ALF (p < 0.05) and cirrhosis (p < 0.05), respectively.
  
  
  CONCLUSIONS
  Elevated arterial ammonia levels indicate a poor prognosis in acute liver injury and are associated with advanced HE in HH, ALF and cirrhosis. Arterial ammonia levels provide additional information in the risk assessment of critically ill patients with liver disease.
authors: Intensive Care Unit 13H1, Division of Gastroenterology and Hepatology, Department of Internal Medicine III , Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria. andreas.drolz@meduniwien.ac.at
authors: Andreas
authors: A
authors: Drolz
authors: Bernhard
authors: B
authors: Jäger
authors: Marlene
authors: M
authors: Wewalka
authors: Reinhard
authors: R
authors: Saxa
authors: Thomas
authors: T
authors: Horvatits
authors: Kevin
authors: K
authors: Roedl
authors: Thomas
authors: T
authors: Perkmann
authors: Christian
authors: C
authors: Zauner
authors: Ludwig
authors: L
authors: Kramer
authors: Peter
authors: P
authors: Ferenci
authors: Valentin
authors: V
authors: Fuhrmann
mesh_terms: D000328:Adult; D000368:Aged; D000641:Ammonia / Q000097:blood*; D001317:Austria / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D018572:Disease-Free Survival; D005260:Female; D006505:Hepatitis / Q000175:diagnosis / Q000401:mortality*; D006801:Humans; D008103:Liver Cirrhosis / Q000175:diagnosis / Q000401:mortality*; D017114:Liver Failure, Acute / Q000175:diagnosis / Q000401:mortality*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D000641:Ammonia
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