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Assessment of cardiac preload by indicator dilution and transoesophageal echocardiography
1Klinik für Anaesthesiologie, Medizinische Fakultät, Rheinisch Westfälische Technische Hochschule Aachen, Pauwelstrasse 30, 5204 Aachen, Germany.
Insights
Cardiac preload assessment is crucial for critically ill patients. Both intrathoracic blood volume and left ventricular end-diastolic area effectively indicate preload, showing a close relationship with stroke volume index changes.
Area of Science:
- Critical care medicine
- Cardiovascular physiology
- Hemodynamic monitoring
Background:
- Accurate assessment of cardiac preload is vital for managing critically ill patients.
- Left ventricular end-diastolic area (echocardiography) and intrathoracic blood volume (indicator dilution) are common preload surrogates.
- Controlled studies comparing these surrogates with stroke volume index are lacking.
Purpose of the Study:
- To investigate the relationship between induced changes in cardiac preload surrogates and stroke volume index.
- To compare the utility of left ventricular end-diastolic area and intrathoracic blood volume as preload indicators.
Main Methods:
- The study involved 10 anesthetized patients.
- Changes in body position were used to induce variations in preload.
- Echocardiography and indicator dilution techniques were employed to measure relevant variables.
Main Results:
- A change in body position led to significant decreases in intrathoracic blood volume (18%) and end-diastolic area (27%).
- Stroke volume index decreased concurrently by 19%.
- Strong correlations were observed between stroke volume index and both intrathoracic blood volume (r=0.75) and end-diastolic area (r=0.76).
Conclusions:
- Intrathoracic blood volume and left ventricular end-diastolic area serve as equivalent indicators of cardiac preload within the studied range.
- These findings support the use of both echocardiographic and indicator dilution methods for preload assessment in critically ill patients.
Background And Objective:
Assessment of cardiac preload is of major importance in the management of critically ill patients. Echocardiographic determined left ventricular end-diastolic area and indicator dilution derived intrathoracic blood volume are used as surrogates for cardiac preload. However, no controlled comparison studies on the relationship between induced changes in end-diastolic area and intrathoracic blood volume and concomitant changes in stroke volume index are available.
Methods:
The effects of a change in body position on these variables were investigated in 10 anaesthetized patients.
Results:
Intrathoracic blood volume and end-diastolic area decreased by 18 +/- 11% and 27 +/- 13% respectively. Stroke volume index concomitantly decreased by 19 +/- 11%. Correlation analysis revealed a close relation between stroke volume index and intrathoracic blood volume (r=0.75) and end-diastolic area (r=0.76).
Conclusions:
Within the observed range of data, intrathoracic blood volume and end-diastolic area are equivalent indices of cardiac preload.