发明名称 |
ESTIMATION OF CARDIAC EJECTION FRACTION AND END DIASTOLIC VOLUME |
摘要 |
The invention estimates a cardiac performance value such as cardiac output (CO) and cardiac ejection fraction (EF) by sensing a downstream indicator concentration signal y(t) that corresponds to an indicator (preferably heat) signal x(t) injected upstream in a patient's blood channel. The signal x(t) is preferably generated as a series of alternating transitions between a high state and a low state, such as a PRBS signal. The signal y(t) is then divided into at least one sub-signal that is synchronous with x(t). A decay parameter .tau. that minimizes a cost function that includes a time-domain channel relaxation model is then calculated. The cardiac performance value is then calculated based on this value for .tau.. For each transition of the injected indicator signal, a corre-sponding segment of the indicator concentration signal is preferably isolated, and a segment relaxation parameter is then calculated. The decay parameter .tau. is then estimated as a predetermined function of the segment relaxation parameters. In embodiments of the invention in which x(t) is periodic, the invention also generates estimates of .tau. by finding the minimum of a cost function between a model of the channel and an average of several cycles of y(t), each corresponding to one period of x(t).
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申请公布号 |
CA2388980(C) |
申请公布日期 |
2011.03.15 |
申请号 |
CA20002388980 |
申请日期 |
2000.12.01 |
申请人 |
EDWARDS LIFESCIENCES CORPORATION |
发明人 |
ROTELIUK, LUCHY D.;MCKOWN, RUSSELL |
分类号 |
A61B5/01;A61B5/028;A61B5/0275 |
主分类号 |
A61B5/01 |
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