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Impedance cardiographyThe impact of new technology
Author(s) -
Critchley L. A. H.
Publication year - 1998
Publication title -
anaesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.839
H-Index - 117
eISSN - 1365-2044
pISSN - 0003-2409
DOI - 10.1046/j.1365-2044.1998.437-az0550.x
Subject(s) - medicine , impedance cardiography , interfacing , critically ill , cardiac output , gold standard (test) , signal processing , signal (programming language) , electrical impedance , intensive care medicine , hemodynamics , electronic engineering , stroke volume , computer science , cardiology , heart failure , digital signal processing , computer hardware , electrical engineering , ejection fraction , engineering , programming language
The 1990s have witnessed major advances in impedance cardiography technology. Problems existed with the methods used to calculate cardiac output. Excessive lung fluid, as often found in critically ill patients, may also invalidate measurements. The signal processing and measurement techniques used in older systems were deficient. The newer systems, of which there are at least six, incorporate novel and improved signal processing techniques. They also offer analog visual displays, personal computer interfacing, sophisticated analytical software and haemodynamic patient management systems. Evaluation of these systems is difficult because no true ‘gold standard’ method of cardiac output measurement exists. When compared with thermodilution techniques, limits of agreement of ± 20–30% seem acceptable. These limits can be achieved in normal subjects but not in critically ill patients. Validation data are available for only half of the new systems. Until recently, the main application for impedance cardiography has been research but improved accuracy should lead to increased clinical usage.