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- Bak, Zoltan, et al.
(författare)
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Transesophageal echocardiographic hemodynamic monitoring during preoperative acute normovolemic hemodilution
- 2000
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Ingår i: Anesthesiology. - : Ovid Technologies (Wolters Kluwer Health). - 0003-3022 .- 1528-1175. ; 92:5, s. 1250-1256
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Tidskriftsartikel (refereegranskat)abstract
- Background: Preoperative acute normovolemic hemodilution may compromise oxygen transport. The aims of our study were to describe the hemodynamic effects of normovolemic hemodilution and to determine its effect on systolic and diastolic cardiac function by multiplane transesophageal echocardiography.Methods: In eight anesthetized patients (aged 13-51 yr) without heart disease, hemoglobin was reduced in steps from 123 ± 8 (mean ± SD) to 98 ± 3 and to 79 ± 5 g/l. Hemodynamic measurements (intravascular pressures, thermodilution cardiac output, and echocardiographic recordings) were obtained during a stabilization period and at each level of hemodilution. Left ventricular wall motion was monitored continuously, and Doppler variables, annular motion, and changes in ejection fractional area were analyzed off-line.Results: During hemodilution, cardiac output by thermodilution increased by 16 ± 7% and 26 ± 10%, corresponding well to the increase in cardiac output as measured by Doppler (difference, 0.32 ± 1.2 l/min). Systemic vascular resistance fell 16 ± 14% and 23 ± 9% and pulmonary capillary wedge pressure increased slightly (2 ± 2 mmHg), whereas other pressures, heart rate, wall motion, and diastolic Doppler variables remained unchanged. Ejection fractional area change increased from 44 ± 7% to 54 ± 10% and 60 ± 9% as a result of reduced end-systolic and increased end-diastolic left ventricular areas.Conclusions: A reduction in hemoglobin to 80 g/l during acute normovolemic hemodilution does not normally compromise systolic or diastolic myocardial function as determined by transesophageal echocardiography. Preload, left ventricular ejection fraction, and cardiac output increase with a concomitant fall in systemic vascular resistance.
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- Chew, Michelle, et al.
(författare)
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Pediatric cardiac output measurement using surface integration of velocity vectors : an in vivo validation study
- 2000
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Ingår i: Critical Care Medicine. - : Ovid Technologies (Wolters Kluwer Health). - 0090-3493 .- 1530-0293. ; 28:11, s. 3664-3671
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To test the accuracy and reproducibility of systemic cardiac output (CO) measurements using surface integration of velocity vectors (SIVV) in a pediatric animal model with hemodynamic instability and to compare SIVV with traditional pulsed-wave Doppler measurements.Design: Prospective, comparative study.Setting: Animal research laboratory at a university medical center.Subjects: Eight piglets weighing 10-15 kg.Interventions: Hemodynamic instability was induced by using inhalation of isoflurane and infusions of colloid and dobutamine.Measurements: SIVV CO was measured at the left ventricular outflow tract, the aortic valve, and ascending aorta. Transit time CO was used as the reference standard.Results: There was good agreement between SIVV and transit time CO. At high frame rates, the mean difference ± 2 sd between the two methods was 0.01 ± 0.27 L/min for measurements at the left ventricular outflow tract, 0.08 ± 0.26 L/min for the ascending aorta, and 0.06 ± 0.25 L/min for the aortic valve. At low frame rates, measurements were 0.06 ± 0.25, 0.19 ± 0.32, and 0.14 ± 0.30 L/min for the left ventricular outflow tract, ascending aorta, and aortic valve, respectively. There were no differences between the three sites at high frame rates. Agreement between pulsed-wave Doppler and transit time CO was poorer, with a mean difference ± 2 sd of 0.09 ± 0.93 L/min. Repeated SIVV measurements taken at a period of relative hemodynamic stability differed by a mean difference ±2 sd of 0.01 ± 0.22 L/min, with a coefficient of variation = 7.6%. Intraobserver coefficients of variation were 5.7%, 4.9%, and 4.1% at the left ventricular outflow tract, ascending aorta, and aortic valve, respectively. Interobserver variability was also small, with a coefficient of variation = 8.5%.Conclusions: SIVV is an accurate and reproducible flow measurement technique. It is a considerable improvement over currently used methods and is applicable to pediatric critical care.
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| 6. |
- Fraser, AG, et al.
(författare)
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Feasibility and reproducibility of off-line tissue Doppler measurement of regional myocardial function during dobutamine stress echocardiography
- 2003
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Ingår i: European Journal of Echocardiography. - 1525-2167 .- 1532-2114. ; 4:1, s. 43-53
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Off-line post-processing of colour tissue Doppler from digital loops may allow objective quantification of dobutamine stress echocardiography. We assessed the reproducibility of off-line measurements of regional myocardial velocities. Methods and Results: Nine observers analysed 10 studies, each making 2400 observations. Coefficients of variation in basal segments from apical windows, at rest and maximal stress, were 9-14% and 11-18% for peak systolic velocity, 16-18% and 17-19% for time-to-peak systolic velocity, 9-17% and 18-24% for systolic velocity time integral, and 18-23% and 21-27% for systolic acceleration. Coefficients of variation for diastolic velocities in basal segments at rest were 11-40%. Coefficients of variation for peak systolic velocity were 10-24% at rest and 14-28% at peak in mid segments, and 19-53% and 29-69% in apical segments. From parasternal windows coefficients of variation for peak systolic velocity were 14-16% in basal posterior, and 19-29% in mid-anterior segments. High variability makes measurement unreliable in apical and basal anterior septal segments. The feasibility of obtaining traces was tested in 92 subjects, and >90% in all basal and mid segments apart from the anterior septum. Conclusion: Quantification of myocardial functional reserve by off-line analysis of colour tissue Doppler acquired during dobutamine stress is feasible and reproducible in 11 segments of the left ventricle. The most reliable measurements are systolic velocities of longitudinal motion in basal segments.
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| 7. |
- Fyrenius, Anna, 1969-, et al.
(författare)
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Major and minor axes of the normal mitral annulus
- 2001
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Ingår i: Journal of Heart Valve Disease. - 0966-8519 .- 2053-2644. ; 10:2, s. 146-152
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Tidskriftsartikel (refereegranskat)abstract
- Background and aim of the study: A dilated or abnormally shaped mitral annulus is a common cause of mitral valve regurgitation, and may be cured by annuloplastic surgery. Multiplane transesophageal echocardiography (TEE) is the diagnostic technique of choice. Our aim was to evaluate and suggest two-dimensional TEE reference values from a standardized procedure of measuring the mitral annular major and minor axes, and their cyclic changes. Methods: The annulus was approximated elliptic in the horizontal plane. The intercommissural (IC, major axis) and anteroposterior (AP, minor axis) distances were measured at end-systole (ES), at maximal valve opening (MO), and at end-diastole (ED) from a mid-esophageal view, in 13 men and eight women with normal echocardiographic findings. Indexed values and reproducibility were calculated. Results: The success rate was 100% at ES, 90% at MO, and 29% at ED. ES distances were largest (p <0.001) and most reproducible (5-5.9%). Body weight, but not height or age, had a significant impact. ES 95% prediction intervals for IC were 27 to 46 mm (16-23 mm/m2) and 22 to 36 mm (13-18 mm/m2) for AP (p <0.001). Corresponding body weight-corrected intervals were 0.39 to 0.59 (IC) and 0.32 to 0.48 (AP) mm/kg. No subject had IC:AP <1.1 together with an AP >0.45 mm/kg. Conclusion: Among measurements made at ES, MO and ED, those at ES provided the most reproducible results, and high-quality images were obtained in normal, non-obese subjects. The distances should be judged in relation to body weight or surface area and each other. The largest IC distance and the most elliptic shape were at ES, while the annulus was minimal at ED. The procedure and normal ranges presented may contribute to the evaluation of patients with mitral regurgitation.
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| 9. |
- Janerot-Sjöberg, Birgitta, 1958-, et al.
(författare)
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Effect of contrast on systolic myocardial ultrasound color-Doppler velocity.
- 2001
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Ingår i: Proceedings to IEEE Engineering Med & Biol(CD skiva),2001. - : IEEE. - 0780372115 ; , s. 3289-3291
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Konferensbidrag (refereegranskat)abstract
- Intravenously distributed ultrasound contrast increases echoes from the normally low echogenic bloodpool and myocardial perfusion imaging is developing. However the microspheres used are potential endothelial stimulators as well as nonlinear scatterers. Tissue Doppler is developed to detect velocities of myocardial motion, which are in the same range as perfusion flow velocities. The effect of contrast is not evaluated. We performed echocardiography in 12 patients with ischemic heart disease before and immediately after a slow intravenous infusion of 27 ml Optison® using color myocardial Doppler imaging (GE Vingmed systemV). Longitudinal basal systolic velocities and their integrals were analyzed in digitally stored cineloops. Peak mean velocity increased 10% by contrast from mean 5.2 ± 1.8 (SD) to 5.7 ± 2.3 cm/s (p=0.02, confidence interval 2-16%) but integral did not change (0.8 ± 0.4 cm). Contrast has no effect on blood pressure or heart rate in used dose. It is therefore of interest to further evaluate if this increase in velocity; a) is a methodological effect that may be used to detect contrast within myocardium (and thereby perfusion/blood volume), or b) is secondary to increased flow and motion caused by endothelial and vascular effects from the contrast microspheres. Either have important methodological, physiological and clinical impact.
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