Cardiac Output Measurements In Patients Research Articles

Precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation

The precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation (AF) has not previously been determined. A priori we suspected that the precision would be lower in patients with AF than in patients with sinus rhythm (SR). Consequently, we also determined if the precision could be improved by injecting the thermal indicator into the right ventricle instead of the right atrium. Cardiac output was determined as the average result of four injections of 10 ml of iced saline. Replicate measurements were performed with thermal indicator injections into the right atrium and ventricle. The coefficients of variation and the precisions were calculated. In the 25 patients with AF, mean cardiac output was 3.96 l min(-1) (range 2.4-7.4), the coefficient of variation 0.073 (95% CI +/- 0.011), and the precision 0.38 l min(-1) (95% CI +/- 0.14) with injection into the right atrium. In the 25 patients with SR, mean cardiac output was 4.73 l min(-1) (range 2.4-7.3), the coefficient of variation 0.047(95% CI +/- 0.006), and the precision 0.38 l min(-1) (95% CI +/- 0.14). In both groups, an agreement analysis demonstrated that the injection of indicator into the right ventricle resulted in a significantly higher cardiac output [AF+0.25 (95% CI +/- 0.15) l min(-1), SR+0.29 ( +/- 0.20) l min(-1)]. The coefficient of variation for cardiac output determinations is 55% higher in patients with AF. Two measurements, separated by time or intervention, must differ by 15% in AF patients and 9% in SR patients before one can be 95% confident that a real change has taken place.

Comparison of continuous cardiac output measurements in patients after cardiac surgery

Objective: To investigate in a direct comparison accuracy and precision of continuous cardiac output measurements assessed by continuous pulmonary artery thermodilution technique (TDCCO), continuous pulse contour analysis (PCCO), and noninvasive partial CO2-rebreathing technique (NICO) in patients after coronary artery bypass grafting (CABG) during the postoperative period. Design: Prospective, controlled clinical study. Setting: University hospital. Participants: Twenty-two patients undergoing elective CABG surgery. Interventions: Hemodynamic measurements were performed after admission to the ICU and in sequence every 2 hours during the subsequent 6-hour period. Simultaneously, cardiac output (CO) was measured using a TDCCO, PCCO, and NICO. After the continuous cardiac output measurements were read, bolus thermodilution-derived cardiac output was obtained from thermodilution curves detected in the pulmonary artery (TDBCOpa). Four intermittent consecutive boli consisting of 10 mL of ice-cold saline were randomly injected over the ventilatory cycle. Measurements and Main Results: The comparison between the continuous cardiac output measurement methods TDCCO versus PCCO showed a bias of −0.12 L/min, between TDCCO versus NICO −0.17 L/min, and between PCCO versus NICO −0.44 L/min. The comparison to the reference technique between TDBCOpa versus TDCCO revealed a bias of −0.28 L/min, between TDBCOpa versus PCCO −0.40 L/min, and between TDBCOpa versus NICO −0.64 L/min. Conclusions: The results of this clinical investigation show agreement between TDCCO and PCCO to satisfy clinical requirements in a setting of postoperative patients after cardiac surgery. In contrast, the NICO monitor is of very limited use in these patients. © 2003 Elsevier Inc. All rights reserved.

Comparison of continuous, stat, and intermittent cardiac output measurements in patients undergoing minimally invasive direct coronary artery bypass surgery

Objective: To compare intermittent cardiac output (ICO) with continuous cardiac output (CCO) and stat cardiac output (SCO) measurements in patients undergoing minimally invasive direct coronary artery bypass (MIDCAB) surgery. Design: Prospective, clinical study. Setting: Single, tertiary referral center. Participants: Twenty adult patients undergoing off-pump MIDCAB surgery from January through June 2000. Interventions: Each patient had a 7.5F 5-lumen pulmonary artery thermodilution catheter (CCO catheter, Baxter Healthcare Corporation, Irvine, CA) inserted for measurement of cardiac output (CO). ICO, CCO, and SCO were compared at 10 predefined time points. Results: A total of 400 data pairs for CO were obtained. ICO values ranged from 1.8 to 8.4 L/min; CCO, 1.9 to 7.5 L/min; and SCO, 2.25 to 6.35 L/min. Correlation between ICO and CCO was significant (correlation coefficient, r = 0.78, p < 0.001), accompanied by a bias of −0.095 L/min and precision of 0.729 L/min. Similarly, the correlation between ICO and SCO was significant (r = 0.79, p < 0.001), accompanied by good accuracy (bias, 0.084 L/min) and precision (0.843 L/min). There were statistically significant decreases in mean arterial pressure, CO, cardiac index, stroke volume, stroke volume index, and left and right ventricular stroke work indices during anastomosis of the left internal mammary artery to left anterior descending artery. These parameters returned to baseline preinduction values 1 minute after completion of the anastomosis. Conclusion: Excellent correlation, accuracy, and precision were found among the 3 methods of measuring CO in patients undergoing MIDCAB surgery. Further studies are needed to assess their accuracy in multivessel off-pump coronary artery bypass graft surgery and in patients with poor left ventricular function.

Continuous and intermittent cardiac output measurement: pulmonary artery catheter versus aortic transpulmonary technique

Cardiac output (CO) can be measured intermittently by bolus thermodilution methods in the pulmonary artery (COpa) or in the aorta (COart). A continuous thermodilution method (CCO) and a method for continuous estimation using the arterial pulse wave (PCCO) are also available. We compared two methods of intermittent CO measurements in patients during liver transplantation: COpa, regarded as the current clinical standard, and an aortic transpulmonary thermodilution technique (COart) performed with the PiCCO system. We also compared CCO and PCCO. Measurements were made in 62 patients at three stages: after the induction of anaesthesia, after caval clamping phase, and at the end of surgery. We used Bland-Altman and correlation analysis. We found close agreement between the techniques. Mean bias between COart and COpa and PCCO and CCO was 0.15 (2SD of differences between methods=1.74) litre min(-1) and -0.03 (1.75) litre min(-1), respectively. Mean bias between CCO and COpa and PCCO and COpa was 0.02 (1.48) litre min(-1) and 0.04 (1.69) litre min(-1), respectively. Measurement with the aortic transpulmonary thermodilution technique gives continuous and intermittent values that agree with the pulmonary thermodilution method.

Cardiac output determination during experimental hemorrhage and resuscitation using a transesophageal Doppler monitor

Transesophageal Doppler (TED) has been considered a noninvasive and accurate alternative to pulmonary artery catheter for volume replacement and cardiac output measurement in patients undergoing major surgeries.

Effect of tricuspid regurgitation on the reliability of the thermodilution cardiac output technique in congestive heart failure

The accuracy of the thermodilution cardiac output technique in the presence of tricuspid regurgitation (TR) has been challenged. 1 TR is common in patients with advanced congestive heart failure (CHF), for whom baseline cardiac output and changes in cardiac output frequently influence therapy. To establish the reliability of the thermodilution method in this setting, we compared simultaneous thermodilution and Fick oximetric cardiac output measurements in patients with advanced CHF before and after acute vasodilator therapy.