Thermodilution

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Paul M. Heerdt - One of the best experts on this subject based on the ideXlab platform.

  • flow dependency of error in Thermodilution measurement of cardiac output during acute tricuspid regurgitation
    Journal of Cardiothoracic and Vascular Anesthesia, 2001
    Co-Authors: Paul M. Heerdt, George A. Blessios, Michael L. Beach, Charles W. Hogue
    Abstract:

    Objective: To evaluate the effect of variable degrees of tricuspid regurgitation on Thermodilution cardiac output measurements during changes in venous return. Design: Prospective, controlled animal study. Setting: University laboratory. Participants: Eight anesthetized mongrel dogs instrumented for simultaneous measurement of cardiac output by Thermodilution and ascending aortic electromagnetometry. Interventions: Data were collected before and after induction of moderate and severe tricuspid regurgitation. Under each condition, measurements were obtained at baseline and after opening 2 peripheral arteriovenous shunts to increase venous return. Measurements and Main Results: Baseline electromagnetic flow ranged from 1.74 to 3.62 L/min (median 2.73 L/min). Moderate and severe regurgitation reduced median electromagnetic flow values by 31% and 51%. Applying generalized estimating equations to model Thermodilution cardiac output as a function of electromagnetic flow, arteriovenous shunt, and severity of tricuspid regurgitation revealed that (1) moderate and severe regurgitation changed the slope and intercept of the Thermodilution/electromagnetic regression, but the differences between them were not significant, and (2) arteriovenous shunt alone had no effect under any condition. A simplified model independent of shunt and containing just 2 levels of tricuspid regurgitation (none or present) crossed with electromagnetic flow was applied. This analysis showed that regurgitation caused Thermodilution to significantly underestimate electromagnetic flow at cardiac outputs >2.27 L/min (99 mL/kg/min) and overestimate it at flows <1.02 L/min (44 mL/kg/min). Conclusions: These data show that acute tricuspid regurgitation may produce underestimation of cardiac output by Thermodilution when flow is relatively high, produce overestimation when flow is relatively low, or have minimal effect when flow is in the midrange. Copyright © 2001 by W.B. Saunders Company

  • Flow dependency of error in Thermodilution measurement of cardiac output during acute tricuspid regurgitation.
    Journal of cardiothoracic and vascular anesthesia, 2001
    Co-Authors: Paul M. Heerdt, George A. Blessios, Michael L. Beach, Charles W. Hogue
    Abstract:

    Objective: To evaluate the effect of variable degrees of tricuspid regurgitation on Thermodilution cardiac output measurements during changes in venous return. Design: Prospective, controlled animal study. Setting: University laboratory. Participants: Eight anesthetized mongrel dogs instrumented for simultaneous measurement of cardiac output by Thermodilution and ascending aortic electromagnetometry. Interventions: Data were collected before and after induction of moderate and severe tricuspid regurgitation. Under each condition, measurements were obtained at baseline and after opening 2 peripheral arteriovenous shunts to increase venous return. Measurements and Main Results: Baseline electromagnetic flow ranged from 1.74 to 3.62 L/min (median 2.73 L/min). Moderate and severe regurgitation reduced median electromagnetic flow values by 31% and 51%. Applying generalized estimating equations to model Thermodilution cardiac output as a function of electromagnetic flow, arteriovenous shunt, and severity of tricuspid regurgitation revealed that (1) moderate and severe regurgitation changed the slope and intercept of the Thermodilution/electromagnetic regression, but the differences between them were not significant, and (2) arteriovenous shunt alone had no effect under any condition. A simplified model independent of shunt and containing just 2 levels of tricuspid regurgitation (none or present) crossed with electromagnetic flow was applied. This analysis showed that regurgitation caused Thermodilution to significantly underestimate electromagnetic flow at cardiac outputs >2.27 L/min (99 mL/kg/min) and overestimate it at flows

  • Inaccuracy of cardiac output by Thermodilution during acute tricuspid regurgitation
    The Annals of thoracic surgery, 1992
    Co-Authors: Paul M. Heerdt, George A. Blessios, Charles G. Pond, Michael Rosenbloom
    Abstract:

    We have been comparing cardiac output measured with a novel Doppler pulmonary artery catheter to that measured by Thermodilution and aortic electromagnetometry in cardiac surgical patients. We report here our observation of a nearly twofold increase in Thermodilution cardiac output after the acute intraoperative onset of tricuspid regurgitation that was not confirmed by the novel catheter or direct measurement of aortic blood flow. We conclude that in some patients, acute tricuspid regurgitation may lessen the reliability of Thermodilution cardiac output.

Laurent Bonello - One of the best experts on this subject based on the ideXlab platform.

  • Doppler echocardiography for assessment of systemic vascular resistances in cardiogenic shock patients
    European Heart Journal: Acute Cardiovascular Care, 2020
    Co-Authors: Mélanie Gaubert, Noémie Resseguier, Franck Thuny, Franck Paganelli, Jennifer Cautela, Johan Pinto, Chloé Ammar, Marc Laine, Laurent Bonello
    Abstract:

    Objective: Impaired vascular tone plays an important role in cardiogenic shock. Doppler echocardiography provides a non-invasive estimation of systemic vascular resistance. The aim of the present study was to compare Doppler echocardiography with the transpulmonary Thermodilution method for the assessment of systemic vascular resistance in patients with cardiogenic shock. Methods: This prospective monocentric comparison study was conducted in a single cardiology intensive care unit (Hopital Nord, Marseille, France). We assessed the systemic vascular resistance index by both echocardiography and transpulmonary Thermodilution in 28 patients admitted for cardiogenic shock, on admission and after the introduction of an inotrope or vasopressor treatment. Results: A total of 35 paired echocardiographic and transpulmonary Thermodilution estimations of the systemic vascular resistance index were compared. Echocardiography values ranged from 1309 to 3526 dynes.s.m(2)/cm(5) and transpulmonary Thermodilution values ranged from 1320 to 3901 dynes.s.m(2)/cm(5). A statistically significant correlation was found between echocardiography and transpulmonary Thermodilution (r=0.86, 95% confidence interval (CI) 0.74, 0.93; P

Margaret-mary Mcewen - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of Fick and Thermodilution cardiac output determinations in standing horses
    Research in veterinary science, 2008
    Co-Authors: Mauricio Loría Lépiz, Robert D. Keegan, Warwick M. Bayly, Stephen A. Greene, Margaret-mary Mcewen
    Abstract:

    Abstract The Fick and Thermodilution (TD) methods are two currently popular techniques for determination of cardiac output (CO) in adult horses. To our knowledge, a comparison of these two techniques has not been reported. Six healthy, resting, fit, adult horses of either sex and weighing 516.5 ± 33.2 kg (mean ± SD) were instrumented to enable measurement of cardiac output. Resting CO was determined by the Fick method and by Thermodilution while the horses stood quietly in the stocks. Fick and Thermodilution CO measurements were repeated under conditions of increased cardiac output achieved with the use of a dobutamine infusion (5 μg kg−1 min−1, IV), and again under conditions of decreased CO induced by administration of xylazine (0.5 mg/kg, IV). Fick and Thermodilution cardiac outputs were compared using Bland–Altman analysis for repeated measures. The mean of the differences ± 1.96SD (bias and precision) between the two techniques was 1.88 ± 24.17 L/min. Variability between measurements with the two techniques was decreased to 3.41 ± 46.78 mL kg−1 min−1 when CO was normalized for body size by calculation of cardiac index.

Fred A. Crawford - One of the best experts on this subject based on the ideXlab platform.

  • Placement considerations for measuring Thermodilution right ventricular ejection fractions.
    Critical care medicine, 1991
    Co-Authors: Francis G. Spinale, James L. Zellner, Rupak Mukherjee, Fred A. Crawford
    Abstract:

    BACKGROUND AND METHODS Clinical examination of right ventricular (RV) performance has been hampered by the inability to measure easily RV volumes and ejection fraction. This study was performed to examine the effects of catheter position on Thermodilution RVEF measurements. Six pigs (80 to 100 kg) were instrumented with an RV Thermodilution catheter in the pulmonary artery, an injectate catheter in the right atrium, an atrial pacing electrode, and a systemic arterial catheter. RVEF measurements were determined using Thermodilution in two ways: a) with incremental increases in pulmonary valve to thermistor distance; and b) with incremental increases in injectate port to tricuspid valve distance. These measurements were obtained at a paced rate of 102 +/- 2 beats/min and then repeated with pacing-induced tachycardia (140 beats/min). RESULTS There was no significant difference in Thermodilution RVEF measurements with the thermistor positioned 0 to 10 cm from the pulmonary valve at either heart rate. A significant reduction in RVEF occurred with the injection port located 5 to 7 cm proximal to the tricuspid valve, with this decrease becoming more pronounced during tachycardia. CONCLUSIONS These results demonstrate that RVEF measurements can be reliably obtained using Thermodilution. In these large hearts, Thermodilution RVEF measurements appear to be independent of thermistor position within the pulmonary artery. However, large distances from injectate port to tricuspid valve reduced RVEF measurements.

John Hess - One of the best experts on this subject based on the ideXlab platform.

  • cardiac index monitoring by pulse contour analysis and Thermodilution after pediatric cardiac surgery
    The Journal of Thoracic and Cardiovascular Surgery, 2007
    Co-Authors: Ullrich Fakler, Ch Pauli, Gunter Balling, H P Lorenz, Andreas Eicken, M Hennig, John Hess
    Abstract:

    Objectives To validate a new device (PiCCO system; Pulsion Medical Systems, Munich, Germany), we compared cardiac index derived from transpulmonary Thermodilution and from pulse contour analysis in pediatric patients after surgery for congenital heart disease. We performed a prospective clinical study in a pediatric cardiac intensive care unit of a university hospital. Methods Twenty-four patients who had had cardiac surgery for congenital heart disease (median age 4.2 years, range 1.4-15.2 years) were investigated in the first 24 hours after admission to the intensive care unit. A 3F Thermodilution catheter was inserted in the femoral artery. Intracardiac shunts were excluded by echocardiography intraoperatively or postoperatively. Cardiac index derived from pulse contour analysis was documented in each patient 1, 4, 8, 12, 16, 20, and 24 hours after admission to the intensive care unit. Subsequently, a set of three measurements of Thermodilution cardiac indices derived by injections into a central venous line was performed and calculated by the PiCCO system. Results The mean bias between cardiac indices derived by Thermodilution and those derived by pulse contour analysis over all data points was 0.05 (SD 0.4) L · min · m −2 (95% confidence interval 0.01-0.10). A strong correlation between Thermodilution and contour analysis cardiac indices was calculated (Pearson correlation coefficient r = 0.93; coefficient of determination r 2 = 0.86). Conclusions Pulse contour analysis is a suitable method to monitor cardiac index over a wide range of indices after surgery for congenital heart disease in pediatric patients. Pulse contour analysis allows online monitoring of cardiac index. The PiCCO device can be recalibrated with the integrated transpulmonary Thermodilution within a short time frame.