title: Therapeutic plasma exchange does not reduce vasopressor requirement in severe acute liver failure: a retrospective case series.
abstract: BACKGROUND
  In acute liver failure (ALF) therapeutic plasma exchange (TPE) improves laboratory measures of liver function. In patients with ALF requiring minimal vasoactive support TPE has also been shown to provide haemodynamic benefits including an increase in systemic blood pressure. However the haemodynamic effects of TPE in patients with severe ALF requiring moderate or high dose vasopressor therapy has not been reported. We retrospectively examined the haemodynamic effects of TPE in a cohort of patients with severe ALF requiring vasopressor therapy.
  
  
  METHODS
  Physiological, laboratory and treatment data were collected on all patients with ALF who received TPE between January 2000 and December 2012. All patients were managed in the intensive care unit of a tertiary referral centre for ALF and liver transplantation. The primary outcome measures were changes in mean arterial pressure (MAP), vasopressor score and the ratio of vasopressor score to MAP (vasopressor dependency index (VDI)) from baseline prior to TPE through to 12 hours after completion of TPE. Secondary outcome measures were changes in other routinely collected physiological variables and laboratory results. Results are presented as median (interquartile range (IQR)). Outcome measures were evaluated using a mixed effect model.
  
  
  RESULTS
  Thirty nine TPE were performed in 17 patients with ALF (13 paracetamol poisoning). All TPE were performed with a centrifugal apheresis system (duration 130 minutes (IQR 115 - 147.5), plasma volume removed 5.1% body weight (IQR 4.6 - 5.5). Baseline values for primary outcome measures were: MAP 82 mmHg (IQR 72 - 92.5), vasopressor score 8.35 (IQR 3.62 - 24.6) and VDI 0.10 (IQR 0.05 - 0.31). MAP was significantly higher immediately after TPE compared to baseline (p = 0.039), however when corrected for change in vasopressor requirement there was no significant change in VDI with TPE (p = 0.953). Twelve hours after TPE the MAP, vasopressor score and VDI were not significantly different from baseline (p = 0.563, p = 0.317 and p = 0.214 respectively).
  
  
  CONCLUSIONS
  In this cohort of patients with severe ALF centrifugal TPE did not significantly affect vasopressor requirements.
authors.affiliation: Department of Critical Care Medicine, Flinders Medical Centre, Bedford Park, South Australia Australia.
authors.forename: Ubbo F
authors.initials: UF
authors.lastname: Wiersema
authors.affiliation: Flinders Centre for Epidemiology and Biostatistics, School of Medicine, Flinders University, Bedford Park, South Australia Australia.
authors.forename: Susan W
authors.initials: SW
authors.lastname: Kim
authors.affiliation: SA Pathology Transfusion Service, Flinders Medical Centre, Bedford Park, South Australia Australia.
authors.forename: David
authors.initials: D
authors.lastname: Roxby
authors.affiliation: Department of Critical Care Medicine, Flinders Medical Centre, Bedford Park, South Australia Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Holt
mesh_terms: D000328:Adult; D003131:Combined Modality Therapy; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D017114:Liver Failure, Acute / Q000188:drug therapy* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D010951:Plasma Exchange; D012189:Retrospective Studies; D014662:Vasoconstrictor Agents / Q000627:therapeutic use*
chemical_list: D014662:Vasoconstrictor Agents
keywords: Acute liver failure; Haemodynamic; Plasmapheresis; Shock; Therapeutic plasma exchange; Vasopressor