title: Cardiac output measurement by pulse dye densitometry: comparison with pulmonary artery thermodilution in post-cardiac surgery patients.
abstract: OBJECTIVE
  Pulse-dye densitometry (PDD) could be a suitable, low-invasive alternative to thermodilution using a pulmonary artery catheter (PAC) for monitoring cardiac output. The aim of our study was to assess the reproducibility and validity of PDD compared to PAC-thermodilution.
  
  
  METHODS
  In 43 post-cardiac surgery patients, the mean of triplicate readings of cardiac output was assessed using both methods. In a subgroup of 26 patients, a second set of measurements was obtained on average 2 h later.
  
  
  RESULTS
  Reproducibility of consecutive measurements was slightly better for PAC-thermodilution than for PDD (median coefficient of variation of the triplicate measurements: 3.5% versus 5.4%, P < 0.01). Both methods correlated well (r = 0.84, p < 0.001). Using Bland and Altman analyses with PAC-thermodilution as the reference method, PDD showed a bias of -0.68 +/- 0.82 L/min, mainly due to differences in higher ranges of cardiac output (>6.5 L/min). Measured changes in cardiac output were 81% concordant (i.e. <1 L/min different) between both methods.
  
  
  CONCLUSIONS
  PDD correlates well with PAC-thermodilution and thus deserves consideration as a low-invasive alternative for measurement and follow-up of cardiac output.
authors.affiliation: Department of Internal Medicine, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: Kroon
authors.forename: A B Johan
authors.initials: AB
authors.lastname: Groeneveld
authors.forename: Yvo M
authors.initials: YM
authors.lastname: Smulders
mesh_terms: D000368:Aged; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures; D002407:Catheterization, Swan-Ganz; D003720:Densitometry; D004395:Dye Dilution Technique; D005260:Female; D006801:Humans; D008297:Male; D011674:Pulse; D015203:Reproducibility of Results; D013815:Thermodilution