Thermodilution and esophageal Doppler ultrasound in the assessment of blood flow changes induced by endotoxin and dobutamine.
BACKGROUND
Intermittent (IT) and continuous (CT) thermodilution and esophageal Doppler (ED), are all used for hemodynamic monitoring. The aim of this study was to test the agreement between these methods during endotoxin (ET) and dobutamine infusion.


METHODS
Twenty-two pigs (39 +/- 1.8 kg body weight) were randomized to general anesthesia and either continuous ET (n = 9) or placebo (PL, n = 13) infusion. After 18 hours of ET or PL infusion, the animals were further randomized to receive dobutamine (n = 3 in ET, n = 5 in PL) or PL. A set of measurements using the three methods were obtained every hour, and the relative blood flow changes between two subsequent measurements were calculated.


RESULTS
Bias or limits of agreement for flows were 0.73 L/min or 1.80 L/min for IT and CT, -0.33 L/min or 4.29 L/min for IT and ED, and -1.06 or 3.94 for CT and ED (n = 515, each). For flow changes they were 1% or 44%, 2% or 59%, and 3% or 45%, respectively. Bias and limits of agreement did not differ in ET- and PL-treated animals or in animals with or without dobutamine. Despite significant correlation between any two methods, the respective correlation coefficients (r) were small (IT vs. CT: 0.452; IT vs. ED: 0.042; CT vs. ED: 0.069; all p < 0.001). The same directional changes were measured by any two methods in 49%, 40%, and 50%. When IT flows >5 L/min were compared with IT flows </=5 L/min, the latter had 49% (p < 0.001), 23% (p < 0.001), and 24% smaller limits of agreement than the former (p = 0.012).


CONCLUSIONS
IT and CT cardiac output agree only to a moderate level, and agreement between the respective relative blood flow changes is even worse. ED has poor agreement with both thermodilution methods, especially when cardiac output is >5 L/min.
Taniguchi
Yoshie
Y
Departments of Anesthesiology, Bern University Hospital, University of Bern, Bern, Switzerland.
Bracht
Hendrik
H
Porta
Francesca
F
Krejci
Vladimir
V
Ali
Sayed Z
SZ
Beck
Mario
M
Mettler
Daniel
D
Takala
Jukka
J
Jakob
Stephan M
SM
D000818:Animals; D002302:Cardiac Output / Q000187:drug effects / Q000502:physiology*; D002316:Cardiotonic Agents / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D004731:Endotoxins / Q000494:pharmacology; D004926:Escherichia coli; D008070:Lipopolysaccharides; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D015203:Reproducibility of Results; D013152:Splanchnic Circulation / Q000187:drug effects / Q000502:physiology*; D013552:Swine; D013815:Thermodilution; D018608:Ultrasonography, Doppler
D002316:Cardiotonic Agents; D004731:Endotoxins; D008070:Lipopolysaccharides; D004280:Dobutamine