title: Comparison of cardiac output measurements by arterial trans-cardiopulmonary and pulmonary arterial thermodilution with direct Fick in septic shock.
abstract: OBJECTIVE
  The aim of this study was to compare cardiac output (CO) measurements by arterial trans-cardiopulmonary thermodilution (ATD) and pulmonary arterial thermodilution (PATD) with CO estimated on the basis of the Fick calculation via a metabolic monitor in septic shock.
  
  
  METHODS
  In a prospective animal study 20 anaesthetized, ventilated pigs (20.9 +/- 1.9 kg) were investigated. Septic shock was induced with faecal peritonitis. A pulmonary artery catheter was used for conventional measurement of CO. Simultaneously ATD was measured with a thermistor tipped catheter inserted into right carotid artery. Whole body oxygen consumption was measured by indirect calorimetry. Eighty data pairs of simultaneous CO measurements were analysed.
  
  
  RESULTS
  CO measured with Fick and that measured with PATD were significantly correlated (r = 0.94, r = 0.87, P < 0.001). Mean CO measured by PATD was 94.3 +/- 40.1 mL min(-1) kg(-1). Bias was 10.1 mL min(-1) kg(-1) (95% confidence interval (CI): 6.0-14.2 mL min(-1) kg(-1)) with limits of agreement of -26.8 to 47.0 mL min(-1) kg(-1). Correlation between Fick derived CO estimation and ATD CO was similar (r = 0.91, r2 = 0.83, P < 0.001). Mean CO measured by trans-cardiopulmonary thermodilution was 104.3 +/- 43.2 mL min(-1) kg(-1). Bias was 0.75 mL min(-1) kg(-1) (95% CI: -3.8 to 5.3 mL min(-1) kg(-1)) with limits of agreement of -39.7 to 41.2 mL min(-1) kg(-1).
  
  
  CONCLUSIONS
  Even during haemodynamic instability in septic shock the correlation of arterial trans-cardiopulmonary thermodilution and PATD derived CO with direct Fick was good. As arterial trans-cardiopulmonary thermodilution is less invasive than PATD, the former may offer practical advantages.
authors.affiliation: Friedrich-Schiller University, Department of Anaesthesiology and Intensive Care Medicine, Jena, Germany. Gernot.Marx@med.uni-jena.de
authors.forename: G
authors.initials: G
authors.lastname: Marx
authors.forename: T
authors.initials: T
authors.lastname: Schuerholz
authors.forename: R
authors.initials: R
authors.lastname: Sümpelmann
authors.forename: T
authors.initials: T
authors.lastname: Simon
authors.forename: M
authors.initials: M
authors.lastname: Leuwer
mesh_terms: D000465:Algorithms; D000818:Animals; D002153:Calorimetry, Indirect; D002302:Cardiac Output / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D010101:Oxygen Consumption; D010538:Peritonitis / Q000503:physiopathology; D011651:Pulmonary Artery / Q000502:physiology*; D012772:Shock, Septic / Q000503:physiopathology*; D013552:Swine; D013815:Thermodilution