Validation of the Cardiac Output Calculation
80 simultaneous measurements on 46 heart patients with Thermodilution (•), Doppler (¤) or Fick’s method (×) and CardioScreen® (niccomo™) from medis.
r=0.857
CO in l/min reference methods
CO in l/min CardioScreen® System
The measurements were carried out at ICUs and in heart catheter labs (also with exercise on bicycle) in following clinics (all located in Germany and Austria):
| Klinikum Bamberg |
Klinikum Augsburg |
Herzzentrum Bad Krozingen |
| 2. Med. Klinik Erlangen |
Waldkrankenhaus Erlangen |
Herzchirugie Freiburg |
| Klinikum Nürnberg Süd |
Klinikum Nürnberg Nord |
Klinikum Ingolstadt |
| Bezirskrankenhaus Salzburg |
Klinikum Fürth |
|
| LVA-Klinik für Lungenkrankheiten Bad Reichenhall |
|
|
Some of the measurements are published (German language):
Stark, H. J., Schultz, K., Krieger, V., Korn, V., Petro, W.: Nichtinvasive Ermittlung des Herzzeitvolumens mit der Impedanzkardiographie. Hohe Korrelation mit der invasiven Fickschen Methode; Atemwegs- und Lungenkrankheiten 22 (1996). S. 73-75
Other studies comparing impedance cardiography with invasive methods
Impedance cardiography was developed for NASA in the 70’s. In the meantime many validation studies have been published. The following table gives a selection:
| Author/Year |
Patients |
Correlation |
Reference method |
|
| Edmunds/1982 |
23 |
0.94 |
Fick |
healthy probands |
| Hetherington/1985 |
20 |
0.93 |
Fick |
various heart diseases |
| Teo/1985 |
20 |
0.93 |
Fick |
Angina Pectoris |
| Goldstein/1986 |
45 |
0.85 |
Thermodilution |
healthy and ICU |
| Appel/1986 |
16 |
0.83 |
Thermodilution |
ICU |
| Bernstein/1986 |
17 |
0.88 |
Thermodilution |
ICU |
| Mattar/1986 |
5 |
0.95 |
Thermodilution |
ICU |
| Appel/1987 |
28 |
0.83 |
Thermodilution |
ICU |
| McKinley/1987 |
7 |
0.93 |
Thermodilution |
children |
| Shellok/1987 |
19 |
0.95 |
Thermodilution |
ICU |
| Spinale/1987 |
10 |
0.77 |
Thermodilution |
various heart diseases |
| Könn/1988 |
20 |
0.71 |
Thermodilution |
CHD |
| Jakob/1988 |
11 |
0.73 |
Thermodilution |
various heart diseases |
| Introna/1988 |
8 |
0.94 |
Thermodilution |
children in ICU |
| Shoemaker/1988 |
17 |
0.83 |
Thermodilution |
ICU |
| Saladin/1988 |
24 |
0.83 |
Thermodilution |
various heart diseases |
| |
24 |
0.82 |
Fick |
|
| |
24 |
0.77 |
Fick vs. Thermodilution |
|
| Robert/1988 |
59 |
0.94 |
Thermodilution |
children with various heart diseases |
| Castor/1989 |
1966 |
0.95 |
Thermodilution |
|
| Castor/1990 |
641 |
0.93 |
Thermodilution |
|
| Castor/1990 |
155 |
0.91 |
Thermodilution |
OR |
| |
155 |
0.93 |
Thermodilution |
OR |
| Klocke/1990 |
109 |
0.82 |
Fick |
various heart diseases |
| |
109 |
0.90 |
Thermodilution |
various heart diseases |
| |
109 |
0.87 |
Thermodilution |
with exercise |
Selected from V. Korn following an overview of R. K. Klocke (1994)
Please note the study of Saladin1988: He found a correlation of 0.83 comparing impedance cardiography with thermodilution and of 0.82 compared to Fick’s method. But, the correlation between both invasive methods was only 0.77.
Finally, if the limitations of impedance cardiography (not suitable for some heart diseases and high level of arteriosclerosis) are considered, impedance measurements - combined with high level signal evaluation, such as the PASA-algorithms - are comparable with established invasive methods.
| 
