A comparison of CardioQ and thermodilution cardiac output during off-pump coronary artery surgery

OBJECTIVE: To compare CardioQ esophageal Doppler cardiac output and thermodilution cardiac output during off-pump coronary artery bypass surgery. DESIGN: Prospective clinical study. SETTING: University-affiliated teaching hospital PARTICIPANTS: Adult patients (n = 20) undergoing elective coronary artery bypass surgery without cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: Three hundred thirty-one comparisons of simultaneous CardioQ and thermodilution cardiac outputs were made. The Pearson correlation coefficient for the pooled data was 0.62. Using a Bland-Altman approach, the overall bias was -0.56 L/min with a precision of 0.64 L/min. The 95% limits of agreement (bias +/- 2 SD) were -0.56 +/- 1.28 L/min. For individual patients, the bias ranged from -1.35 L/min to 0.27 L/min and the precision from 0.24 L/min to 0.74 L/min. CONCLUSION: Because of the wide limits of agreement and the large interpatient differences in both bias and precision, the CardioQ esophageal Doppler cardiac output cannot currently be recommended as an alternative to thermodilution cardiac output during off-pump coronary artery bypass surgery.