title: Effects of changes in vascular tone on the agreement between pulse contour and transpulmonary thermodilution cardiac output measurements within an up to 6-hour calibration-free period.
abstract: OBJECTIVE
  To examine whether the agreement between pulse contour and transpulmonary thermodilution cardiac index (CI) measurements is altered by changes in vascular tone within an up to 6-hr calibration-free period.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Medical intensive care unit of a university hospital.
  
  
  METHODS
  Fifty-nine critically ill patients.
  
  
  METHODS
  None.
  
  
  RESULTS
  Data from 59 critically ill patients equipped with a PiCCO device were retrospectively analyzed. The database contained the transpulmonary thermodilution CI (CI(T)) value obtained at each time point the device was calibrated and the pulse contour CI (CI(PC)) value recorded immediately before this time point. Seven subsets of CI pairs were defined according to intervals of time elapsed from the previous calibration (within the first 30 mins, between 30 mins and 1 hr, and every hour up to 6 hrs). In the whole set of 400 CI pairs, CI(PC) correlated with CI(T) (r2 = .68, p < .001). The bias +/- SD was 0.12 +/- 0.61 L/min/m2, and the percentage error was 35%. Among the seven time-interval subsets, the percentage error was <30% only in the two first ones (27% and 26%, respectively). When changes in systemic vascular resistance by >15% occurred (129 times), CI(PC) correlated with CI(T) (r2 = .64), the bias +/- SD was 0.12 +/- 0.62 L/min/m2, and the percentage error was 36%. In the subset of CI pairs recorded within the 1-hr calibration-free period while vascular resistance changed by >15% (n = 32), the bias +/- SD was 0.04 +/- 0.47 L/min/m and the percentage error was 29%.
  
  
  CONCLUSIONS
  Our study in critically ill patients suggests that the agreement between pulse contour cardiac output and transpulmonary thermodilution cardiac output was not significantly influenced by changes in vascular tone. However, after a 1-hr calibration-free period, recalibration may be encouraged. Such a procedure provides helpful information drawn from other thermodilution-derived variables.
authors: Service de réanimation médicale, Centre Hospitalo-Universitaire de Bicêtre, Assistance Publique-Hôpitaux de Paris, EA 4046, Université Paris 11, Le Kremlin-Bicêtre, France.
authors: Olfa
authors: O
authors: Hamzaoui
authors: Xavier
authors: X
authors: Monnet
authors: Christian
authors: C
authors: Richard
authors: David
authors: D
authors: Osman
authors: Denis
authors: D
authors: Chemla
authors: Jean-Louis
authors: JL
authors: Teboul
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002138:Calibration; D002302:Cardiac Output / Q000502:physiology*; D015331:Cohort Studies; D016638:Critical Illness; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013815:Thermodilution / Q000295:instrumentation*; D013997:Time Factors; D014655:Vascular Resistance / Q000502:physiology*