title: Copeptin and arginine vasopressin concentrations in critically ill patients.
abstract: BACKGROUND
  Determination of arginine vasopressin (AVP) concentrations may be helpful to guide therapy in critically ill patients. A new assay analyzing copeptin, a stable peptide derived from the AVP precursor, has been introduced.
  
  
  OBJECTIVE
  Our objective was to determine plasma copeptin concentrations.
  
  
  METHODS
  We conducted a post hoc analysis of plasma samples and data from a prospective study.
  
  
  METHODS
  The setting was a 12-bed general and surgical intensive care unit (ICU) in a tertiary university teaching hospital.
  
  
  METHODS
  Our subjects were 70 healthy volunteers and 157 ICU patients with sepsis, with systemic inflammatory response syndrome (SIRS), and after cardiac surgery.
  
  
  METHODS
  There were no interventions.
  
  
  METHODS
  Copeptin plasma concentrations, demographic data, AVP plasma concentrations, and a multiple organ dysfunction syndrome score were documented 24 h after ICU admission.
  
  
  RESULTS
  AVP (P < 0.001) and copeptin (P < 0.001) concentrations were significantly higher in ICU patients than in controls. Patients after cardiac surgery had higher AVP (P = 0.003) and copeptin (P = 0.003) concentrations than patients with sepsis or SIRS. Independent of critical illness, copeptin and AVP correlated highly significantly with each other. Critically ill patients with sepsis and SIRS exhibited a significantly higher ratio of copeptin/AVP plasma concentrations than patients after cardiac surgery (P = 0.012). The American Society of Anesthesiologists' classification (P = 0.046) and C-reactive protein concentrations (P = 0.006) were significantly correlated with the copeptin/AVP ratio.
  
  
  CONCLUSIONS
  Plasma concentrations of copeptin and AVP in healthy volunteers and critically ill patients correlate significantly with each other. The ratio of copeptin/AVP plasma concentrations is increased in patients with sepsis and SIRS, suggesting that copeptin may overestimate AVP plasma concentrations in these patients.
authors.affiliation: Department of Anesthesiology, Innsbruck Medical University, Anichstrasse 35, 6020 Innsbruck, Austria. Stefan.Jochberger@uibk.ac.at
authors.forename: Stefan
authors.initials: S
authors.lastname: Jochberger
authors.forename: Nils G
authors.initials: NG
authors.lastname: Morgenthaler
authors.forename: Viktoria D
authors.initials: VD
authors.lastname: Mayr
authors.forename: Günter
authors.initials: G
authors.lastname: Luckner
authors.forename: Volker
authors.initials: V
authors.lastname: Wenzel
authors.forename: Hanno
authors.initials: H
authors.lastname: Ulmer
authors.forename: Siegfried
authors.initials: S
authors.lastname: Schwarz
authors.forename: Walter R
authors.initials: WR
authors.lastname: Hasibeder
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Friesenecker
authors.forename: Martin W
authors.initials: MW
authors.lastname: Dünser
mesh_terms: D000328:Adult; D000368:Aged; D001127:Arginine Vasopressin / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D016638:Critical Illness; D005260:Female; D006020:Glycopeptides / Q000097:blood*; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D018805:Sepsis / Q000097:blood; D018746:Systemic Inflammatory Response Syndrome / Q000097:blood; D013903:Thoracic Surgery
chemical_list: D006020:Glycopeptides; C048197:copeptins; D001127:Arginine Vasopressin; D002097:C-Reactive Protein