Effects of cardiac output levels on the measurement of transpulmonary thermodilution cardiac output in patients with acute respiratory distress syndrome.
BACKGROUND
Transpulmonary thermodilution cardiac output (CO) correlates closely with pulmonary artery (PA) thermodilution CO. Levels of CO may contribute to varying amounts of thermal indicator loss and recirculation during thermodilution CO measurement. This study aimed to investigate the effects of CO levels on the agreement between transpulmonary and PA thermodilution CO in patients with acute respiratory distress syndrome (ARDS).


METHODS
Twenty-two patients with ARDS were prospectively enrolled. Paired bolus transpulmonary thermodilution cardiac index (BCItp) and continuous PA thermodilution cardiac index (CCIpa) data were recorded at baseline and repeated immediately and at 2, 4, and 6 hours after volume expansion with a 500-mL infusion of 10% pentastarch (HES 200/0.5).


RESULTS
One hundred and ten paired cardiac index measurements were recorded and divided into 4 quartiles from the lowest to the highest CCIpa. The mean BCItp was higher than CCIpa, and the Bland and Altman analysis revealed a mean (SD) bias of 0.57 (0.75) L L min(-1) m(-2). The limits of agreement (2SD) were +2.07 to -0.93 L min(-1) m(-2). BCItp correlated closely with CCIpa (R = 0.887). CCIpa negatively correlated with the difference between BCItp and CCIpa (R = -0.26). The bias of quartile 1 with the least CCIpa was significantly greater than those of the three other quartiles.


CONCLUSIONS
In patients with ARDS, transpulmonary thermodilution is a clinically acceptable and interchangeable alternative to PA thermodilution for CO measurement. Levels of CO weakly and negatively correlate with the difference between BCItp and CCIpa. There is greater overestimation of BCItp over CCIpa in low than in high CO states.


METHODS
Diagnostic study, level II.
Division of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
Chung-Chi
CC
Huang
Ning-Hung
NH
Chen
Li-Fu
LF
Li
Cheng-Ta
CT
Yang
Hsiu-Feng
HF
Hsiao
Yen-Huey
YH
Chen
Hui-Ling
HL
Lin
Kuo-Chin
KC
Kao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002302:Cardiac Output / Q000502:physiology*; D002405:Catheterization, Central Venous; D002407:Catheterization, Swan-Ganz; D005260:Female; D005263:Femoral Artery; D005440:Fluid Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery; D015203:Reproducibility of Results; D012128:Respiratory Distress Syndrome / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D012769:Shock / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D013815:Thermodilution / Q000379:methods*; D055815:Young Adult