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Measurement of cardiac output without right heart catheterization: reliability, advantages, and limitations of a
Insights
Accurate cardiac output measurement is possible using indocyanine green injected into the left ventricle. However, introducing the indicator into the ascending aorta provides unreliable results for cardiac output determination.
Area of Science:
- Cardiology
- Medical Devices
- Physiology
Background:
- Cardiac output (CO) is a critical hemodynamic parameter.
- Accurate CO measurement is essential for patient management.
- Existing methods for CO assessment have limitations.
Purpose of the Study:
- To evaluate the accuracy and reliability of left ventricle-to-systemic artery indocyanine green (ICG) for CO measurement.
- To compare this method with standard indicator dilution techniques.
- To assess the utility of ascending aorta-to-systemic artery ICG for CO determination.
Main Methods:
- CO was measured in 40 patients using left ventricle-to-systemic artery ICG and standard indicator dilution (thermodilution or pulmonary artery-to-systemic artery ICG).
- In 28 patients, CO was also measured via ascending aorta-to-systemic artery ICG.
- Statistical analysis included correlation (r) and standard error of estimate (SEE).
Main Results:
- Excellent agreement was found between left ventricle-to-systemic artery ICG and standard indicator dilution (r = 0.98, SEE = 0.12 L/min).
- Ascending aorta-to-systemic artery ICG showed significant discrepancies compared to standard methods (difference = 0.72 +/- 0.55 L/min, p < 0.001).
- In 22/28 patients, ascending aorta-to-systemic artery ICG overestimated CO compared to standard methods.
Conclusions:
- Left ventricle-to-systemic artery ICG provides accurate and reliable cardiac output measurements.
- Ascending aorta-to-systemic artery ICG is not a reliable method for quantifying cardiac output.
- The left ventricle-to-systemic artery ICG technique is suitable for patients undergoing left heart catheterization.
Abstract:
This study was done to determine the accuracy and reliability of cardiac output measurements by the injection of indocyanine green into the left ventricle, with simultaneous sampling from a systemic artery. In 40 patients (18 men, 22 women, aged 34 to 74 years), cardiac output was measured in close temporal proximity by (a) standard indicator dilution (right atrium-to-pulmonary artery thermodilution in 11, pulmonary artery-to-systemic artery indocyanine green in 29) and (b) left ventricle-to-systemic artery indocyanine green. There was excellent agreement between the two techniques (r = 0.98, SEE = 0.12 liters/minute). In 28 of the patients, cardiac output also was measured by ascending aorta-to-systemic artery indocyanine green. In these individuals, this technique yielded results that were disparate from those obtained by standard indicator dilution (difference between standard indicator dilution and left ventricle-to-systemic artery indocyanine green = 0.18 +/- 0.13 [mean +/- SD] liters/minute; difference between standard indicator dilution and ascending aorta-to-systemic artery indocyanine green = 0.72 +/- 0.55 liters/minute; p less than 0.001), and in 22 of the 28, the ascending aorta-to-systemic artery indocyanine green cardiac outputs were greater than those obtained by standard indicator dilution. Thus, cardiac output can be measured accurately by injecting indocyanine green into the left ventricle, with simultaneous sampling from a systemic artery, but it cannot be quantified reliably by introducing indicator into the ascending aorta. The left ventricle-to-systemic artery indocyanine green technique can be used in patients undergoing only left heart catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)