| 摘要 |
Apparatus and methods are provided for monitoring cardiac output using bioelectrical impedance techniques in which three orthogonal pairs of sense electrodes are placed in the trachea or esophagus in the vicinity of the aorta, while an excitation current is injected into the intervening tissue mass via a current electrode, so that bioelectrical impedance measurements based on the voltage drop sensed by the sense electrodes reflect voltage changes induced primarily by blood flow dynamics. Methods are provided for computing cardiac output from bioelectrical impedance values using a multi-parameter algorithm derived using stepwise multiple linear regression or other optimization techniques. Apparatus and methods are also provided so that the measured cardiac output may be used to control administration of intravenous fluids or medication to an organism or to optimize a heart rate controlled by a pacemaker. |
