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Cardiac output and circulating blood volume analysis by pulse dye-densitometry
1Department of Anesthesiology, School of Medicine Kyorin University, Tokyo, Japan.
Journal of Clinical Monitoring
|March 1, 1997
Summary
Pulse dye-densitometry (PDD) accurately measures cardiac output (CO) and circulating blood volume (CBV) non-invasively. This new method offers a less invasive alternative to traditional techniques for assessing cardiovascular function.
Area of Science:
- Cardiovascular Physiology
- Medical Instrumentation
- Diagnostic Techniques
Background:
- Cardiac output (CO) and circulating blood volume (CBV) are critical hemodynamic parameters.
- Traditional methods for measuring CO, such as thermodilution, often require invasive procedures like pulmonary artery catheterization.
- There is a need for less invasive and accurate methods to monitor these vital parameters in clinical settings.
Purpose of the Study:
- To evaluate the clinical accuracy of Pulse Dye-Densitometry (PDD) for determining cardiac output (CO) and circulating blood volume (CBV).
- To compare the PDD method with established techniques like dye dilution cuvette and thermodilution for CO measurement.
- To assess the reliability of PDD in estimating circulating blood volume (CBV) against body size estimations.
Main Methods:
- Non-invasive optical probes (805 and 890 nm) were applied to the finger of 7 patients under general anesthesia to monitor indocyanine green (ICG) concentration.
- Arterial blood samples were concurrently drawn to measure ICG concentration photometrically for comparison with PDD readings.
- CO was validated against dye dilution cuvette and thermodilution methods in 8 patients undergoing coronary artery bypass grafting, and CBV was compared to body size estimates in 30 patients.
Main Results:
- PDD demonstrated a strong correlation with blood dye concentration measurements (r = 0.953, p < 0.01).
- Mean bias for PDD-derived CO compared to the cuvette method was +0.15 +/- 0.72 min L-1 (not significant).
- The average CBV measured by PDD (3.81 +/- 1.39 L) was comparable to the estimated value (3.72 +/- 0.77 L), with no significant difference.
Conclusions:
- Pulse Dye-Densitometry (PDD) provides accurate measurements of cardiac output, comparable to cuvette densitometry.
- While PDD-derived CO showed good agreement, it was slightly less precise than thermodilution.
- The PDD method is less invasive as it avoids pulmonary artery catheterization and additionally provides circulating blood volume measurements.