title: Energy expenditure in acetaminophen-induced fulminant hepatic failure.
abstract: OBJECTIVE
  To determine energy expenditure in critically ill patients suffering from acetaminophen-induced fulminant hepatic failure and compare it with values obtained in matched, healthy control subjects and in patients studied during the anhepatic period of elective liver transplantation.
  
  
  METHODS
  Prospective, controlled, observational study.
  
  
  METHODS
  A ten-bed intensive therapy unit and a liver transplant unit at a University teaching hospital.
  
  
  METHODS
  Sixteen patients suffering from acetaminophen-induced fulminant hepatic failure who were sedated, paralyzed, and mechanically ventilated; 16 age-, gender-, and weight-matched, awake, healthy control subjects; and 16 patients with chronic liver disease, undergoing elective liver transplantation, who were studied during the anhepatic period of surgery.
  
  
  METHODS
  None.
  
  
  RESULTS
  The mean energy expenditure was calculated in each case for a 30-min period, using indirect calorimetry. In the patients undergoing liver transplantation, measurements were performed after clamping the hepatic veins and recipient hepatectomy. Energy expenditure was markedly increased in the fulminant hepatic failure group (mean energy expenditure, 4.05 [SD 0.52] kJ x kg(-1) x hr(-1)), in comparison with healthy control subjects (mean, 3.44 [0.27] kJ x kg(-1) x hr(-1); mean difference, 18%; p < .001) and in comparison with patients during the anhepatic period of liver transplantation (mean, 3.15 [0.61] kJ x kg(-1) x hr(-1); mean difference, 29%; p < .001). These differences were even more pronounced when a correction factor for differences in core temperature was included in the calculation. Harris-Benedict predictions of energy expenditure were unreliable in the patients with acute liver failure. No correlations were found among energy expenditure and hemodynamic variables, the requirement for vasoconstrictors, or the presence of renal failure.
  
  
  CONCLUSIONS
  Despite the loss of functioning liver cell mass, the metabolic rate is substantially increased in patients with acetaminophen-induced fulminant hepatic failure. This finding is consistent with the marked systemic inflammatory response, which accompanies acute hepatic failure. The Harris-Benedict equation is unreliable when an estimation of energy expenditure is required in patients with this condition.
authors.affiliation: Department of Anaesthetics, Royal Infirmary of Edinburgh, Scotland, UK.
authors.forename: T S
authors.initials: TS
authors.lastname: Walsh
authors.forename: S J
authors.initials: SJ
authors.lastname: Wigmore
authors.forename: P
authors.initials: P
authors.lastname: Hopton
authors.forename: R
authors.initials: R
authors.lastname: Richardson
authors.forename: A
authors.initials: A
authors.lastname: Lee
mesh_terms: D000082:Acetaminophen / Q000009:adverse effects*; D000293:Adolescent; D000328:Adult; D001481:Basal Metabolism; D002153:Calorimetry, Indirect; D016022:Case-Control Studies; D004734:Energy Metabolism; D005260:Female; D006501:Hepatic Encephalopathy / Q000139:chemically induced* / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012121:Respiration, Artificial
chemical_list: D000082:Acetaminophen