Comparison of a New Cardiac Output Ultrasound Dilution Method With Thermodilution Technique in Adult Patients Under General Anesthesia

Objective: The purpose of this study was to investigate the reliability of cardiac output (CO) measured by a new ultrasound dilution method (COud) in comparison with CO by pulmonary artery thermodilution (COtd) in adult patients undergoing surgery. Design: A prospective study. Setting: A university hospital, single institutional. Participants: Twenty-nine adult patients undergoing abdominal surgery. Measurements and Main Results: After approval of the institutional ethics review board, 29 adult patients were evaluated. After induction, radial and pulmonary artery catheters were inserted. A disposable extracorporeal AV loop was connected between existing arterial and central venous catheters. Reusable ultrasound sensors that measure changes in blood ultrasound velocity after dilution by isotonic saline were clamped onto the arterial and venous limbs of the loop. Ultrasound dilution (UD) measurements (COstatus; Transonic Systems, Inc, Ithaca, NY) were obtained by injecting 30 mL of body-temperature isotonic saline into the venous limb of the AV loop. An average of 3 COud and 5 COtd was obtained for comparison. Bland-Altman plot and correlation analysis were used for statistical comparison. A total of 142 comparison measurements were obtained. The correlation coefficient between the 2 techniques was r = 0.91. Bland-Altman analysis did not produce any significant bias (bias = 0.02, standard deviation = 0.56). The percentage error of these data was 23.53%. Conclusions: COud measurements agreed well with COtd. The results of this study indicated that COud might be interchangeable with conventional COtd in perioperative adult patients. (C) 2009 Elsevier Inc. All rights reserved.