Respiration monitoring method and apparatus including cardio-vascular artifact detection
AssigneeSquibb Vitatek Inc.
InventorCharles H. Logan
Life of this patent
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Abstract
A respiration monitor for measuring the variations of the thorax impedance of a patient due to respiration is described. The monitor includes circuitry for suppressing the indication of unwanted signals caused by cardio-vascular activity of the patient. The circuitry receives trigger signals immediately following the QRS complex of the patient's ECG waveform. If a certain negative-going slope is detected in the thorax impedance waveform following the QRS complex, it is counted as a cardio-vascular artifact and not respiration activity. After a predetermined number of cardio-vascular artifact are detected and counted, the respiration monitor is disabled so that this cardio-vascular activity will not reset an apnea counter.
Claims14
Apparatus for monitoring the respiration and heartbeat activity of a patient and for producing an indication whenever respiration is absent for a predetermined number of successive heartbeats, said apparatus being for use with a first and second input signal producing means for producing a first and second input signal respectively
- said first input signal having a first component indicative of patient respiration and a second component indicative of patient heartbeat;
- said first signal having a slope;
- said second input signal indicative of patient heartbeat alone said apparatus comprising:
- (a) processor means responsive to said first signal and said slope of said first signal for producing a third signal whenever the slope of said first signal exceeds a predetermined value;
- (b) comparator enable means for producing an enable pulse, said comparator enable means being responsive to said second input signal;
- (c) comparison means associated with said processor means for producing an output signal whenever said third signal begins within a predetermined period of time, determined by said comparator enable means, after the receipt of said enable pulse by said comparison means and for producing a reset signal whenever said third signal does not begin within said predetermined period of time;
- and
- (d) counter means for producing a disable signal whenever a predetermined number of output signals are produced without the intermediate production of a reset signal, said disable signal being indicative of an absence of respiration for a predetermined number of successive heartbeats.
A method of monitoring the respiration and heartbeat activity of a patient and of providing an indication whenever respiration is absent for a predetermined number of successive heartbeats, said method comprising the steps of:
- (a) providing a first input signal having a slope and a first component indicative of patient respiration and a second component indicative of patient heartbeat;
- (b) providing a second input signal indicative of patient heartbeat alone;
- (c) providing a comparator means;
- (d) producing a third signal whenever the slope of said first input signal exceeds a predetermined value;
- (e) enabling said comparator means for a period of time after the receipt by said comparator means of said second signal;
- (f) producing an output signal whenever said third signal begins within a predetermined period of time after the receipt by said comparator means of said second signal, and producing a reset signal whenever said third signal does not begin within said predetermined period of time,
- (g) producing a disable signal whenever a predetermined number of output signals are produced without the intermediate production of a reset signal, said disable signal being indicative of an absence of respiration for a predetermined number of successive heartbeats.
Dependencies are inferred from the claim text.