The level of cardiac output affects the relationship and agreement between pulmonary artery and transpulmonary aortic thermodilution measurements in an animal model.
OBJECTIVE
The authors investigated the relationship between pulmonary artery and transpulmonary aortic thermodilution cardiac output measurements under conditions of increasing cardiac output (CO).


METHODS
Animal study with repeated simultaneous measurements comparing 2 cardiac output measurement techniques.


METHODS
Experimental animal facility of a university hospital.


METHODS
Ten female pigs.


METHODS
In anesthetized pigs, an aortic thermistor catheter and a pulmonary artery catheter (PAC) were inserted. Then dobutamine was infused under continuous cardiac output (CCO) monitoring to target different levels of CO. After each L/min increase of CCO simultaneous aortic and PAC thermodilution, CO measurements were performed by using a bolus injection of cooled normal saline and the amount of thermal indicator loss (TL) was calculated.


RESULTS
Pooled analysis of CO data with the method of Bland and Altman showed that aortic thermodilution CO was higher than PAC thermodilution CO with a bias of 3.8% +/- 11.1%. The range of TL was 30.4% to -10.1%. Differential analysis according to the range of CO revealed that, in each animal under conditions of low CO, aortic thermodilution CO was higher than PAC thermodilution CO, whereas results were inverse under conditions of high CO.


CONCLUSIONS
The authors concluded that the amount of CO differentially affects the relationship between aortic and PAC thermodilution CO. TL and recirculation may be the explanation for this finding.
Hüter
Lars
L
Department of Anaesthesiology and Intensive Care Medicine, University of Jena, Jena, Germany. Lars.Hueter@med.uni-jena.de
Schwarzkopf
Konrad R
KR
Preussler
Niels P
NP
Schubert
Harald
H
Schreiber
Torsten
T
D000818:Animals; D001011:Aorta / Q000502:physiology; D001831:Body Temperature; D002302:Cardiac Output / Q000187:drug effects / Q000502:physiology*; D002316:Cardiotonic Agents; D002407:Catheterization, Swan-Ganz / Q000379:methods*; D004280:Dobutamine; D005260:Female; D023421:Models, Animal; D011651:Pulmonary Artery / Q000502:physiology; D016008:Statistical Distributions; D013552:Swine; D013815:Thermodilution / Q000379:methods*
D002316:Cardiotonic Agents; D004280:Dobutamine