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Does bronchial thermodilution allow estimation of cardiac output?
S A Loer1, J K Wietasch, T W Scheeren
1Institut für Experimentelle Anaesthesiologie, Heinrich-Heine-Universität, Düsseldorf, Germany.
Intensive Care Medicine
|April 8, 1999
Summary
Bronchial thermodilution, using cold saline injections, provides cardiac output estimates comparable to traditional aortic thermodilution methods in dogs. This suggests potential for a less invasive approach to measuring blood flow.
Area of Science:
- Physiology
- Cardiovascular Research
- Medical Instrumentation
Background:
- Transcapillary heat transfer can create thermodilution curves.
- Bronchial thermodilution curves can resemble aortic curves.
Purpose of the Study:
- To test if flow rates from bronchial thermodilution curves are similar to aortic curves.
- To evaluate bronchial thermodilution for cardiac output estimation.
Main Methods:
- A comparative study was conducted on five anesthetized dogs.
- Cardiac output was manipulated by blood withdrawal and fluid/drug infusion.
- Thermistors were placed in a bronchiole and the ascending aorta.
Main Results:
- Bronchial and aortic thermodilution curves were recorded after right atrial injection of cold saline.
- Bronchial thermodilution yielded flow estimates similar to aortic curves.
- Correlation was acceptable (r=0.84) with a mean difference of <2%.
Conclusions:
- The Stewart-Hamilton equation can be applied to bronchial temperature-time curves for cardiac output estimation.
- Bronchial thermistors are not currently recommended as routine alternatives to pulmonary artery catheters.