Scandinavian journal of clinical and laboratory investigation
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Scand. J. Clin. Lab. Invest. · Oct 1982
Cardiac output in normal pregnancy measured by impedance cardiography.
Impedance cardiography was used to study cardiodynamic changes throughout normal pregnancy. Stroke volume, heart rate and cardiac output were determined in fourteen normal primigravidae from early pregnancy until 6-25 weeks after delivery. To elucidate the influence of the patient's position on cardiac output, measurements were made in the supine as well as in the left and right lateral positions. ⋯ No significant differences in cardiac output were found between right and left lateral position. However, during pregnancy as well as after delivery, cardiac output measured by impedance cardiography was significantly higher in the supine position than in the lateral positions. Thus, the impedance method does not seem to be reliable in measuring absolute values of stroke volume and cardiac output but may be used for relative measurements during pregnancy.
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Scand. J. Clin. Lab. Invest. · Sep 1980
Comparative StudyDetermination of cardiac output from pulse pressure contour during intra-aortic balloon pumping.
The reliability of cardiac output determinations from radial pulse pressure contour during intra-aortic balloon pumping (IABP) has been tested and compared with thermodilution measurements. During IABP the pulse pressure curve is distorted by preset volume changes in the aorta. The pressure decrease following balloon deflation was compared with pressure increase following systolic ejection to determine stroke volume and cardiac output. ⋯ This made the algorithmic calculation of cardiac output useless in the care of the individual patients. In thirteen patients on IABP seventy-seven comparisons were obtained, and a fair covariation (r = 0.86) was found. The ratio between the two methods of cardiac output measurements did not change significantly with increasing cardiac output.
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Scand. J. Clin. Lab. Invest. · Jun 1980
Comparative StudyDetermination of functional residual capacity with 133-xenon radiospirometry. Comparison with body plethysmography and helium spirometry. Effect of body position.
This study was undertaken to estimate the accuracy of 133-xenon radiospirometry for determination of FRC in healthy subjects. Forty healthy volunteers, both smokers and non-smokers, were examined. The FRC of each subject was concurrently determined with radiospirometric, He-dilution in closed circuit, and body plethysmographic methods. ⋯ The results indicate that the FRC determined radiospirometrically is significantly larger than the FRC determined with He-spirometry. The difference is systematic, suggesting that it is caused by 133-xenon dissolved in blood and accumulated in tissues of the thoracic cage and by dissimilar representation of trapped air in FRCRS and FRCHe. With eventual correction of the systematic error, the FRC obtained as a by-product of radiospirometry may be used, e.g. for clinical purposes.
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Scand. J. Clin. Lab. Invest. · Oct 1979
Comparative StudyMeasurements of cardiac stroke volume in various body positions in pregnancy and during Caesarean section: a comparison between thermodilution and impedance cardiography.
A total of 220 simultaneous pairs of measurements of cardiac stroke volume were made in twelve women before and during Caesarean section in order to compare impedance cardiography with the thermodilution method. A significantly higher coefficient of correlation was found before (r = 0.77) than during anaesthesia (r = 0.55). ⋯ When the uterus was displaced upwards and to the left from the 15 degrees tilt position the stroke volume and the cardiac output were increased when measured by both methods to nearly the same values as in the left lateral position. It is concluded that the impedance method is reliable for measuring cardiac stroke volume in late pregnancy under physiological conditions in the conscious patient, but that it cannot replace the thermodilution method in pharmacological studies.
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Scand. J. Clin. Lab. Invest. · Jun 1977
Comparative StudyEffect of sites of blood sampling in determination of the galactose elimination capacity.
The galactose elimination capacity was calculated from both arterial and capillary or peripheral venous curves in twenty patients. The capillary curves on the average were delayed 1.4 min in relation to the arterial curves. ⋯ Galactose elimination capacity calculated from venous curves was smaller than those calculated from arterial curves, especially in patients with a high galactose elimination capacity. Capillary blood sampling may replace arterial puncture for routine use, whereas venous blood sampling introduces a significant bias.