The Measurement Of Cardiovascular Parameters Using The ICG Indicator Dilution Method; A Comparison Of Invasive Measurements With Pulse Dye Densitometry.

     M. Reekers, M.J.G. Simon, R. Mooren, F. Boer, A.G.L. Burm, J. Vuyk

Department of Anesthesiology, Leiden University Medical Centre, The Netherlands

Introduction:

In the field of minimal invasive measurements of cardiac output and other cardiovascular parameters, a transcutaneous method has been developed based on pulse spectrophotometry of indocyanine green (ICG); pulse dye densitometry (PDD). In this study, cardiac output (CO) and the elimination constant of ICG (k) are compared when measured by PDD or intravascularly. For intravascular measurements, arterial blood samples were taken at high frequency; the ICG concentration was determined by HPLC.

Patients and Methods:

Three males and six females were included, age 21-86 yr. A maximum of three simultaneous experiments were performed in each patient. The CO and k values derived from the arterial and PDD curves were compared by method of Bland-Altman analysis.

Results:

Conclusions:

The mean difference in cardiac output measurements in this small group is 1.6% ± 21%; this relates well to other studies comparing PDD to other methods of cardiac output measurement. Differences may be due to the discrepancy in vascular bed at the detection site.  The difference in measurement of k is 4% ± 17%. Motion artefacts easily disturb the value of k. For the measurement of cardiac output by PDD, use of the nose probe is recommended.