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Cardiac output by Portapres.
Marjorie S Pitt1, Paul Marshall, Jonathan P Diesch
1Institute for Cardiovascular Research, University of Leeds, Leeds LS2 9JT, U.K.
Clinical Science (London, England : 1979)
|December 16, 2003
Summary
Portapres provides continuous cardiac output estimates from pulse, but tends to overestimate values. Its precision limits use to detecting large changes, like during exercise, not small ones during orthostatic stress.
Area of Science:
- Physiology
- Cardiovascular Research
- Medical Technology Assessment
Background:
- Continuous cardiac output (CO) monitoring is valuable for physiological and clinical assessment.
- The Portapres device offers non-invasive CO estimation from peripheral pulse analysis.
- Evaluating the accuracy and precision of novel CO monitoring tools is crucial.
Purpose of the Study:
- To assess the accuracy and precision of Portapres for continuous cardiac output estimation.
- To compare Portapres CO estimates with a rebreathing method in healthy subjects.
- To determine the utility of Portapres during rest, maximal exercise, and orthostatic stress.
Main Methods:
- Portapres device used for continuous peripheral pulse analysis.
- Cardiac output estimated via Portapres and compared to a rebreathing method.
- Healthy subjects underwent assessments at rest, during maximal treadmill exercise, and during orthostatic stress.
Main Results:
- Portapres demonstrated a tendency to overestimate cardiac output compared to the rebreathing method.
- Random errors (precision) ranged from +/- 1.2 to 2.6 L/min (2 S.D. of differences).
- Overestimation and error margins were more pronounced during smaller physiological changes (orthostasis).
Conclusions:
- Portapres's precision limitations restrict its use to detecting substantial CO changes, such as during exercise.
- The method's errors preclude reliable individual subject data analysis for small CO variations, like those in orthostatic stress.
- Group average data may be examined for smaller changes, but individual monitoring is unreliable.