Evaluation of impedance cardiography: comparison of NCCOM3-R7 with Fick and thermodilution methods

Heart Lung. 1995 May-Jun;24(3):194-206. doi: 10.1016/s0147-9563(05)80037-8.


Objective: To assess the degree of error of the BoMed NCCOM3 model revision seven (R7) impedance cardiograph in determining stroke volume and estimated cardiac output.

Design: Three-group, within-subject, repeated measures design.

Sample: Group 1: patients (n = 17) with heart disease undergoing an elective coronary angiogram; group 2: patients (n = 28) after elective heart surgery; and group 3: healthy volunteers (n = 28).

Measurement: Cardiac output was determined by the BoMed NCCOM3-R7 impedance cardiograph, Fick principle, and thermodilution method. The NCCOM3-R7 was compared with the direct Fick and thermodilution methods in groups 1 and 2, respectively, to estimate validity coefficients. In group 3, repeated measures were obtained with the NCCOM3-R7 to calculate reliability coefficients.

Results: The NCCOM3-R7 underestimated Fick measurements by 1.050 +/- 1.529 L/min at rest and 1.505 +/- 2.214 L/min during exercise. Correlation coefficients of 0.684 at rest (p = 0.001) and 0.219 during exercise (p = 0.248) were obtained. The NCCOM3-R7 underestimated thermodilution values by 0.425 +/- 1.325 L/min in subjects initially after heart surgery and 0.358 +/- 1.235 L/min 2 to 4 hours later. Correlation coefficients of 0.547 (p = 0.002) and 0.505 (p = 0.004) were obtained for the two time periods, respectively. A reliability coefficient of 0.837 was calculated with healthy subjects.

Conclusion: The NCCOM3-R7 has a clinically unacceptable level of error for evaluating cardiac performance in patients with heart disease.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cardiac Output
  • Cardiac Surgical Procedures
  • Cardiography, Impedance / methods*
  • Diagnostic Errors
  • Exercise
  • Female
  • Heart Diseases / physiopathology
  • Humans
  • Indicator Dilution Techniques*
  • Male
  • Middle Aged
  • Postoperative Period
  • Reproducibility of Results
  • Rest
  • Thermodilution*