Cardiac output monitoring: comparison of a new arterial pressure waveform analysis to the bolus thermodilution technique in patients undergoing off-pump coronary artery bypass surgery.

OBJECTIVE: To analyze the clinical agreement between the conventional intermittent bolus thermodilution (TD) technique and a new arterial pressure waveform analysis (APCO) technique (FloTrac; Edward Lifesciences, Irvine, CA) for cardiac output (CO) estimation. DESIGN: Prospective observational clinical study. SETTING: Cardiac surgery operating room of a tertiary care cardiac center. PARTICIPANTS: Twelve patients undergoing elective off-pump coronary artery bypass (OPCAB) surgery. MEASUREMENTS AND MAIN RESULTS: CO was determined by 2 different methods: TD and APCO at 8 time points (preinduction, postinduction, poststernotomy, left internal mammary artery to left anterior descending artery anastomosis, left [obtuse marginal/diagonal] anastomosis, right [right coronary/posterior descending coronary artery] anastomosis, postprotamine administration, and poststernal closure) in 12 patients undergoing elective OPCAB surgery. The mean bias and limits of agreement (2 standard deviations) expressed in liters per minute at respective points of measurement were -0.54 +/- 1.12, -0.37 +/- 1.0, -0.42 +/- 1.50, -0.25 +/- 1.18, -0.31 + 1.28, +/-0.41 +/- 1.0, 0.06 +/- 1.50, and 0.09 +/- 1.40. CONCLUSION: Good agreement was found between the CO values obtained by the APCO and TD techniques throughout the intraoperative period including the period of coronary artery graft surgery.

Hemodynamic measurements after cardiac surgery: transesophageal Doppler versus pulmonary artery catheter.

OBJECTIVE: The purpose of this study was to compare hemodynamic data derived from the transesophageal Doppler monitor (Medicina TECO, Berkshire, United Kingdom) against those obtained from a pulmonary artery catheter after coronary artery bypass grafting (CABG). DESIGN: Prospective, nonrandomized, clinical study. SETTING: Single, tertiary referral center. PARTICIPANTS: Thirty-five adult patients. INTERVENTIONS: Cardiac output and hemodynamic variables were measured and compared at 4 predefined time points in patients undergoing elective off-pump CABG surgery from January 2003 through June 2003. MEASUREMENT AND MAIN RESULTS: A total of 140 pairs for cardiac output (CO) data were obtained. Transesophageal cardiac output (TECO) values ranged from 1.9 to 8.7 L/min. Thermodilution cardiac output (TDCO) values ranged from 2.7 to 7.6 L/min. Matched measurements were made with each patient at intervals of 30 minutes. Bland-Altman analysis revealed a mean bias of 1.18 +/- 1.36 L/min, with a correlation (r) of 0.593 (p < 0.000) between TECO and TDCO. Similarly poor correlation was observed among cardiac index (r = 0.523), stroke volume (r = 0.615), systemic vascular resistance (r = 0.595), left ventricular stroke work index (r = 0.594), and right ventricular stroke work index (r = 0.590) measured by an esophageal Doppler monitor against a pulmonary artery catheter. CONCLUSION: A transesophageal Doppler device (Medicina TECO) cannot be relied on as a sole method for monitoring cardiac output and derived hemodynamic variables in patients after CABG surgery.