Method and apparatus for deriving a respiration signal and/or artifact signal from a physiological signal
First Claim
1. A method of deriving an output signal from a physiological signal having at least a respiration signal component and a cardiac artifact signal component, said output signal indicative of a respiration signal and/or a cardiac artifact signal, the method comprising the steps of:
- (a) detecting a heartbeat moment;
(b) measuring and storing the amplitude of a signal with an impedance pneumograph at approximately the time of said heartbeat moment;
(c) measuring an instantaneous amplitude of said signal at a time after the time of the heartbeat moment;
(d) calculating the difference between the instantaneous amplitude of the signal and the stored amplitude thereof;
(e) calculating and storing a learning signal related to the heartbeat moment, said learning signal calculated as a function of a previous learning signal and the difference between the instantaneous amplitude of the signal and the stored amplitude thereof; and
(f) performing at least one of the following steps;
(f1) generating an output signal indicative of a cardiac artifact signal by reading out said learning signal, and(f2) calculating the difference between the instantaneous amplitude of the signal and the learning signal, and generating an output signal indicative of a respiration signal from said difference between the instantaneous amplitude of the signal and the learning signal.
4 Assignments
0 Petitions
Accused Products
Abstract
A method for deriving a respiration signal and/or a cardiac artifact signal from a physiological signal, in particular an impedance pneumography signal, includes detection of a heartbeat moment, storing the amplitude of the physiological signal at the heartbeat moment, and calculating and storing a learning signal, the learning signal being a function of a previous learning signal and the difference between the instantaneous amplitude of the physiological signal and the stored amplitude thereof. The learning signal is either read out starting each time with the particular heartbeat moment, for deriving the cardiac artifact signal, or subtracted from the physiological signal at each heartbeat moment for deriving the respiration signal.
31 Citations
13 Claims
-
1. A method of deriving an output signal from a physiological signal having at least a respiration signal component and a cardiac artifact signal component, said output signal indicative of a respiration signal and/or a cardiac artifact signal, the method comprising the steps of:
-
(a) detecting a heartbeat moment; (b) measuring and storing the amplitude of a signal with an impedance pneumograph at approximately the time of said heartbeat moment; (c) measuring an instantaneous amplitude of said signal at a time after the time of the heartbeat moment; (d) calculating the difference between the instantaneous amplitude of the signal and the stored amplitude thereof; (e) calculating and storing a learning signal related to the heartbeat moment, said learning signal calculated as a function of a previous learning signal and the difference between the instantaneous amplitude of the signal and the stored amplitude thereof; and (f) performing at least one of the following steps; (f1) generating an output signal indicative of a cardiac artifact signal by reading out said learning signal, and (f2) calculating the difference between the instantaneous amplitude of the signal and the learning signal, and generating an output signal indicative of a respiration signal from said difference between the instantaneous amplitude of the signal and the learning signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. An apparatus for deriving an output signal from a physiological signal having at least a respiration signal component and a cardiac artifact signal component, said output signal indicative of a respiration signal and/or a cardiac artifact signal, said apparatus comprising:
-
(a) means for detecting a heartbeat moment; (b) an impedance pneumograph means for measuring and storing the amplitude of a signal at approximately the time of said heartbeat moment; (c) means for measuring an instantaneous amplitude of said signal at a time after the time of the heartbeat moment; (d) means for calculating the difference between the instantaneous amplitude of the signal and the stored amplitude thereof; (e) means for calculating and storing a learning signal related to the heartbeat moment, said learning signal calculated as a function of a previous learning signal and the difference between the instantaneous amplitude of the signal and the stored amplitude thereof; and (f) means for deriving said output signal, including means for reading out said learning signal and means for calculating the difference between the instantaneous amplitude of the signal and the learning signal and deriving the output signal from said difference between the instantaneous amplitude of the signal and the learning signal.
-
-
12. A system for deriving an output signal from a physiological signal having at least a respiration signal component and a cardiac artifact signal component, said output signal indicative of a respiration signal and/or a cardiac artifact signal, said apparatus comprising:
-
(a) monitor means for measuring a physiological condition of a patient and generating a physiological signal on the basis of said physiological condition, and for detecting a heartbeat moment and EKG means for providing a QRS signal indicative of said heartbeat moment; (b) A/D means coupled to said monitor means for digitalizing said physiological signal; (c) means, coupled to said A/D means, for storing the amplitude of the digitalized physiological signal at approximately the time of said heartbeat moment; (d) means for calculating and storing a learning signal related to the heartbeat moment, including means for calculating the difference between the instantaneous amplitude of the physiological signal and the stored amplitude thereof and for calculating said learning signal as a function of a previous learning signal and the difference between the instantaneous amplitude of the physiological signal and the stored amplitude thereof; and (e) means for deriving said output signal, including means for reading out said learning signal and means for calculating the difference between the instantaneous amplitude of the physiological signal and the learning signal. - View Dependent Claims (13)
-
Specification