title: Mean cardiac output by thermodilution with a single controlled injection.
abstract: OBJECTIVE
  A new method to estimate mean cardiac output by thermodilution with a single duration-controlled injection was evaluated in patients.
  
  
  METHODS
  Prospective criterion standard study.
  
  
  METHODS
  University hospital cardiac surgical intensive care unit and cardiac operation room.
  
  
  METHODS
  Of 33 patients, 24 underwent coronary bypass graft surgery, four had a valve replacement, and five were treated in the intensive care unit.
  
  
  METHODS
  Interventions consisted of thermodilution cardiac output measurements. One single duration-controlled injection of cold fluid was used to calculate cardiac output. This controlled injection was performed with a duration equal to one whole ventilation cycle of the ventilator. An algorithm adapted to this duration-controlled injection calculated cardiac output. Moreover, this algorithm has properties to reduce errors caused by artificial ventilation and thermal noise.
  
  
  RESULTS
  In 33 patients, the averaged values of four measurements equally spread over the ventilatory cycle (phase-controlled) were compared with the values of two single duration-controlled measurements. The measurements were performed during periods of stable respiration and circulation. No significant difference was observed between the mean of four phase-controlled measurements and the mean of the two duration-controlled measurements. The cardiac output values in the intensive care patients were significantly higher compared with the two other patient groups (p <.05). The difference between the two methods could not be subdivided for the three patient groups (p >.05). The coefficient of variation of the single duration-controlled thermodilution measurements was significantly lower than the single phase-controlled measurements, 3% vs. 6% (p <.01).
  
  
  CONCLUSIONS
  One single duration-controlled injection thermodilution measurement is as accurate and repeatable as the mean of four phase-controlled measurements and is clinically feasible.
authors.affiliation: Department of Intensive Care, Leiden University Medical Center, The Netherlands. JRCJansen@LUMC.nl
authors.forename: J R
authors.initials: JR
authors.lastname: Jansen
authors.forename: J J
authors.initials: JJ
authors.lastname: Schreuder
authors.forename: K D
authors.initials: KD
authors.lastname: Punt
authors.forename: P C
authors.initials: PC
authors.lastname: van den Berg
authors.forename: O
authors.initials: O
authors.lastname: Alfieri
mesh_terms: D000328:Adult; D000368:Aged; D002302:Cardiac Output; D003325:Coronary Care Units; D003327:Coronary Disease / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D006349:Heart Valve Diseases / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D011336:Probability; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013815:Thermodilution / Q000379:methods*