Patent ID: 7630763
Filing Date: 2009-12-08
Classification: A61B,A61N

Abstract:
1. A method comprising: measuring a first impedance signal between at least first and second electrodes, which define a first electrode configuration, in a subject's thorax; extracting a first cardiac stroke signal from the first impedance signal; extracting a first respiration signal from the first impedance signal; extracting a first cardiac amplitude measurement from the first cardiac stroke signal; extracting a first respiration amplitude measurement from the first respiration signal; computing a first comparative measurement between the first cardiac amplitude measurement and the first respiration amplitude measurement; measuring a second impedance signal between at least third and fourth electrodes, which define a second electrode configuration, in a subject's thorax, wherein at least one of the third and fourth electrodes is a different electrode from at least one of the first and second electrodes; extracting a second cardiac stroke signal from the second impedance signal; extracting a second respiration signal from the second impedance signal; extracting a second cardiac amplitude measurement from the second cardiac stroke signal; extracting a second respiration amplitude measurement from the second respiration signal; computing a second comparative measurement between the second cardiac amplitude measurement and the second respiration amplitude measurement; and using the first and second comparative measurements as a basis for selecting one of the first and second electrode configurations for subsequent extraction of at least one of the respiration and cardiac stroke signals.