Physiological and fluid-dynamic investigations of the transthoracic impedance plethysmography method for measuring cardiac output: Part I—A fluid-dynamic approach to the theory using an expansible tube model

1976 ◽  
Vol 14 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Ken-Ichi Yamakoshi ◽  
Hiroshi Ito ◽  
Akio Yamada ◽  
Shigeru Miura ◽  
Tetsuo Tomino
Keyword(s):  
Cardiac Output ◽  
Fluid Dynamic ◽  
Impedance Plethysmography ◽  
Tube Model ◽  
Dynamic Approach ◽  
Transthoracic Impedance

Comparison of two noninvasive techniques for estimating cardiac output during exercise

1986 ◽  
Vol 61 (1) ◽  
pp. 155-159 ◽  
Author(s):  
D. D. Hatcher ◽  
O. D. Srb
Keyword(s):  
Cardiac Output ◽  
Large Range ◽  
Impedance Plethysmography ◽  
Cycle Ergometer ◽  
O2 Consumption ◽  
Noninvasive Techniques ◽  
Transthoracic Impedance ◽  
The Mean ◽  
The Difference ◽  
Male Subjects

This study presents the comparison of two different noninvasive techniques for the estimation of cardiac output (Q). The two techniques used were transthoracic impedance plethysmography (Z) and the indirect Fick CO2 rebreathing (RB) method. Paired estimates of Q were made on 60 different male subjects at rest and during graded increments of work on a cycle ergometer. The mean resting Q as measured by the Z technique (COZ) was 7.46 +/- 0.35 and 5.96 +/- 0.43 l/min using the RB (CORB) technique. At 200 W the mean COZ was 18.67 +/- 0.72 l/min and the CORB was 23.73 +/- 0.84 l/min. Both the techniques were linearly correlated (R) with O2 consumption; i.e., RZ = 0.752, RRB = 0.855. The difference between these two R values is statistically significant (P less than 0.001). A linear relationship was found between the Z and RB techniques at all work loads (R = 0.75). This study suggests that both techniques are equally as reliable over a large range of work loads, with the Z technique being the simplest and most efficient to implement. It was also found that lung volume had no effect on the calculated COZ.

Non-Invasive Monitoring of Hemodynamic Parameters during Hemodialysis

1995 ◽  
Vol 18 (9) ◽  
pp. 499-503 ◽  
Author(s):  
F. Pizzarelli ◽  
P. Dattolo ◽  
M. Piacenti ◽  
M.A. Morales ◽  
T. Cerrai ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Blood Volume ◽  
Impedance Cardiography ◽  
Hemodynamic Parameters ◽  
Non Invasive ◽  
Transthoracic Impedance ◽  
Cardiac Output Index ◽  
On Line ◽  
Two Parameters

We studied in 13 hemodialysis patients intradialytic variations of blood volume (BV) and cardiac output, by means of non-invasive methods. We found a weak correlation, r 0.2 or less, between BV variations and intradialysis blood pressure variations. The sensitivity of the former in describing the variations of the latter was only 32%. During the 30 min preceeding the hypotensive crisis the percent BV variations did not show any predictive trend. On the contrary, refilling increased as blood pressure dropped and a weak inverse relation (r -0.35) was found between these two parameters. Unstable patients had predialytic blood volume values significantly lower than stable ones and comparable to healthy subjects. On the contrary, the correlation between percent variations of cardiac output index and MAP was 0.68 with a sensitivity and specificity of 90% and 59%, respectively. Unfortunately these promising results were obtained only with an estimate of cardiac output obtained by echocardiography and not by transthoracic impedance cardiography, which is much more feasible than the former as on-line monitoring of cardiac output. On-line monitoring of hemodynamic parameters is an appealing but still unsolved task.

OPTIMIZATION OF TRAFFIC ON ROAD NETWORKS

2007 ◽  
Vol 17 (10) ◽  
pp. 1587-1617 ◽  
Author(s):  
CASCONE ANNUNZIATA ◽  
CIRO D'APICE ◽  
PICCOLI BENEDETTO ◽  
RARITÀ LUIGI
Keyword(s):  
Road Network ◽  
Fluid Dynamic ◽  
Distribution Coefficients ◽  
Dynamic Approach ◽  
Urban Network ◽  
Traffic Distribution ◽  
Cost Functionals ◽  
Traffic Behavior ◽  
Velocity Average

This paper focuses on the optimization of traffic flow on a road network, modeled by a fluid-dynamic approach. Three cost functionals that measure average velocity, average traveling time, and total flux of cars, are considered. First, such functionals are optimized for two simple networks that consist of a single junction: one with two incoming and one outgoing roads (junctions of 2 × 1 type), and the other with one incoming and two outgoing roads (junctions of 1 × 2 type). The optimization is made with respect to right of way parameters and traffic distribution coefficients, obtaining an explicit solution. Then, through simulations, the traffic behavior for complex networks is studied. The main result is that the local optimization ensures a very good result also for the complete network. This is shown by the case study of Re di Roma Square, a big traffic circle of the urban network of Rome.

scholarly journals Sonoelectrochemical hydrogenation of safrole: A reactor design, statistical analysis and computational fluid dynamic approach

2020 ◽  
Vol 63 ◽  
pp. 104949 ◽  
Author(s):  
Josinete Angela da Paz ◽  
Frederico Duarte de Menezes ◽  
Thiago Matheus Guimarães Selva ◽  
Marcelo Navarro ◽  
José Ângelo Peixoto da Costa ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Reactor Design ◽  
Dynamic Approach
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