Respiration monitor
First Claim
1. Apparatus for monitoring the respiration activity of a patient and for suppressing disturbing signals comprising:
- first means connectable to a patient for providing a variable thorax impedance signal;
second means connectable to the patient for providing a heart rate signal;
trigger level means coupled to said first means for providing an adjustable threshold value, said trigger level means having control input means for raising said threshold value;
reference trigger means coupled to said trigger level means and said first means for producing a trigger pulse in response to the amplitude of said thorax impedance signal exceeding a level related to said threshold value;
comparator means coupled to said reference trigger means and said second means for providing an output signal to the control input means of said trigger level means in response to said trigger pulse and said heart rate signal having substantially equal periods, thereby to raise said threshold value; and
output means coupled to said trigger level means and said first means for producing a respiration signal in response to the amplitude of said thorax impedance signal and said threshold value.
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Accused Products
Abstract
A respiration monitor for measuring the variations of the thorax impedance of a patient due to respiration activity includes circuitry for suppressing the indication of unwanted signals caused by the activity of the heart. This circuitry is connected to receive separate signals corresponding to the heart beat rate and compare the periods of these signals to those of the signals measured at the thorax of the monitored person. If the periods of both signals are substantially equal, i.e. the signals measured at the thorax are actually due to heart activity rather than to respiration, the trigger threshold value of the monitor is automatically and stepwise raised so that the monitor does no longer respond to heart beat related signals but indicates that no respiration signals are measured.
43 Citations
7 Claims
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1. Apparatus for monitoring the respiration activity of a patient and for suppressing disturbing signals comprising:
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first means connectable to a patient for providing a variable thorax impedance signal; second means connectable to the patient for providing a heart rate signal; trigger level means coupled to said first means for providing an adjustable threshold value, said trigger level means having control input means for raising said threshold value; reference trigger means coupled to said trigger level means and said first means for producing a trigger pulse in response to the amplitude of said thorax impedance signal exceeding a level related to said threshold value; comparator means coupled to said reference trigger means and said second means for providing an output signal to the control input means of said trigger level means in response to said trigger pulse and said heart rate signal having substantially equal periods, thereby to raise said threshold value; and output means coupled to said trigger level means and said first means for producing a respiration signal in response to the amplitude of said thorax impedance signal and said threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification