Abstract
Purpose
To evaluate the performance of two different continuous cardiac output monitoring systems based on the thermodilution principle in critically ill patients.
Methods
Nineteen cardiac surgical patients were randomly assigned to continuous cardiac output monitoring using one of the two systems under study (group I, IntelliCath™ catheter, n=9; group II, Opti-Q™ catheter,n = 10). Each patient was studied over a period of three hours. Conventional bolus thermodilution cardiac output measurements were carried out every 15 min leading to 13 measurements in each patient. The continuous cardiac output values were compared with the bolus thermodilution measurements. Bias (mean difference between continuous and bolus thermodilution) and precision (SD of differences) were calculated as a measure of agreement between the respective continuous method and conventional bolus thermodilution.
Results
The range of measured cardiac outputs was 3.8–15.4 L·min−1 (IntelliCath™) and 3.5–8.3 L·min−1 (OptiQ™). Bias and precision was 0.06 ± 0.76 L·min−1 (IntelliCath™) and −0.04 ± 0.74 L·min−1 (OptiQ™), respectively. There was no difference in bias between the two systems (P=0.38). ± 2 SD of the differences (i.e., 95% of the differences) did not fall within the predetermined limits of agreement of ± 0.5 L·min−1.
Conclusions
There was no difference between the two systems regarding the agreement with conventional bolus thermodilution as the standard. A discrepancy between bolus and continuous thermodilution cardiac output measurement techniques above the clinically acceptable limits suggest that they are not interchangeable.
Résumé
Objectif
Évaluer, chez des patients gravement malades, la performance de deux systèmes de monitorage continu du débit cardiaque fondés sur le principe de la thermodilution.
Méthode
Dixneuf patients de cardiochirurgie ont été répartis de façon aléatoire en deux groupes de monltorage continu du débit cardiaque: le groupe I, avec une sonde IntelliCath™, n = 9; le groupe II, avec une sonde Opti- Q™, n = 10). Chaque patient a été observé pendant trois heures. Les mesures traditionnelles du débit cardiaque par thermodilution d’un bolus ont été faites toutes les 15 min, pour un total de 13 mesures par patient. Les valeurs continues du débit cardiaque ont été comparées aux mesures par thermodilution d’un bolus. Le biais (différence moyenne entre la thermodilution continue et celle d’un bolus) et la précision (écart type des différences) ont été calculés comme mesure de concordance entre la méthode continue et la thermodilution traditionnelle d’un bolus.
Résultats
Les limites des débits cardiaques mesurés ont été de 3,8 – 15,4 L·min− 1 (IntelliCath™ et de 3,5 – 8,3 L·min− 1 (OptiQ™). Le biais et la précision ont été de 0,06 ± 0,76 L·min− 1 (IntelliCath™) et de − 0,04 ± 0,74 L·min− 1 (OptiQ™), respectivement. Le biais a été comparable entre les deux sondes (P = 0,38); et ± 2 écarts types des différences (95 % des différences) n’étaient pas compris dans les limites de concordance prédéterminées de ± 0,5 L·min− 1.
Conclusion
Les deux systèmes n’ont pas présenté de différence entre eux quant à la concordance avec la norme traditionnelle de la thermodilution d’un bolus. Une divergence entre les mesures du débit cardiaque par themodilution d’un bolus et thermodilution continue au delà des limites acceptables en pratique permet d’affirmer que ces deux techniques ne sont pas interchangeables.
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Zöllner, C., Goetz, A.E., Weis, M. et al. Continuous cardiac output measurements do not agree with conventional bolus thermodilution cardiac output determination. Can J Anesth 48, 1143–1147 (2001). https://doi.org/10.1007/BF03020382
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DOI: https://doi.org/10.1007/BF03020382