title: Assessment of the accuracy of continuous cardiac output and pulse contour cardiac output in tracking cardiac index changes induced by volume load.
abstract: OBJECTIVE
  To assess the ability to track changes in cardiac index (Delta CI) induced by volume loading using continuous pulsed heat thermodilution (CCO), and pulse contour (PCCO) cardiac output (CO) with transpulmonary thermodilution (TD(tp)) CO as reference.
  
  
  METHODS
  Prospective observational clinical trial.
  
  
  METHODS
  Intensive care unit.
  
  
  METHODS
  Twelve ventilated and sedated post-operative cardiac surgery patients.
  
  
  RESULTS
  Each patient had a 7.5F CCO pulmonary artery catheter (Edwards Lifesciences) and a 5F, 20 cm PCCO femoral artery catheter (Pulsion Medical Systems). Forty-five data sets were taken before and after 25 volume loadings of 5 mL/kg of 4% albumin. Volume loading resulted in an increase in CI (2.84 L/(min m(2)) versus 3.12L/(min m(2)), p<.05) although only nine volume loadings changed CI (Delta CI)> or =14%. The change in CI using PCCO (Delta PCCI) was correlated with Delta CI (TD(tp)) (R(2)=.50, p<.0001), whilst Delta CI using CCO (Delta CCI) was not (R(2)=.14). The bias and limits of agreement (LOA) between Delta TD(tp)CI and Delta PCCI was 6.2% (95% CI, +/-5.8%) and 28.4% (95% CI, +/-38.2%) respectively. Delta TD(tp)CI and Delta CCI has a bias of 2.6% (95% CI, +/-8.3%) and LOA of 39.6% (95% CI, +/-63%). Both Delta PCCI and Delta CCI reliably tracked Delta CI> or =14%.
  
  
  CONCLUSIONS
  In this small group of patients the continuous cardiac output methods tracked changes in CI, although, in individual cases they did not change in the same direction as the thermodilution method. Critical care nurses need to critically appraise the accuracy and clinical relevance of continuous CO data within the clinical context.
authors.affiliation: Intensive Care Unit, Prince of Wales Hospital, NSW, Australia.
authors.forename: Martin
authors.initials: M
authors.lastname: Boyle
authors.forename: Margherita
authors.initials: M
authors.lastname: Murgo
authors.forename: John
authors.initials: J
authors.lastname: Lawrence
authors.forename: Andrew
authors.initials: A
authors.lastname: Belessis
authors.forename: Yahya
authors.initials: Y
authors.lastname: Shehabi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002302:Cardiac Output / Q000502:physiology; D006348:Cardiac Surgical Procedures; D002407:Catheterization, Swan-Ganz; D003422:Critical Care; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013815:Thermodilution