Method and system for detecting apnea
First Claim
1. A method for detecting and responding to apnea in a human subject comprising:
- measuring in real time the chest impedance signal and heartbeat of a human subject;
converting said chest impedance signal per second to a re-sampled chest impedance signal per heartbeat;
filtering said re-sampled chest impedance signal to provide a filtered chest impedance signal per heartbeat;
renormalizing said filtered chest impedance signal;
calculating in real time the running variance of said filtered chest impedance signal; and
calculating a probability of apnea from a histogram compiled from the running variance of the filtered chest impedance signal for a set of apneic infants;
wherein said histogram is interpreted as a statistical mixture of a first distribution corresponding to apnea events and a second distribution corresponding to regular breathing, and said first distribution divided by the sum of said first distribution and second distribution produces a probability of apnea for each variance; and
wherein said filtered chest impedance signal attenuates the impedance caused by the heartbeat.
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Abstract
Existing monitors for apnea miss many serious events because they do not adequately distinguish the heart signal in chest impedance from the respiratory signal. Described herein is a respiratory monitoring system and method for improved detection and response to apnea, particularly in a NICU setting but also useful in a home setting. This method filters from the chest impedance the part of the impedance that is caused by the beating of the heart in a human subject, and then identifies in real time significant silence in the filtered chest impedance signal, including determining the probability of apnea. If the probability of apnea exceeds a threshold value, the apneic subject can be stimulated using automated interactions such as a vibrating mattress or air blower.
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Citations
2 Claims
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1. A method for detecting and responding to apnea in a human subject comprising:
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measuring in real time the chest impedance signal and heartbeat of a human subject; converting said chest impedance signal per second to a re-sampled chest impedance signal per heartbeat; filtering said re-sampled chest impedance signal to provide a filtered chest impedance signal per heartbeat; renormalizing said filtered chest impedance signal; calculating in real time the running variance of said filtered chest impedance signal; and calculating a probability of apnea from a histogram compiled from the running variance of the filtered chest impedance signal for a set of apneic infants; wherein said histogram is interpreted as a statistical mixture of a first distribution corresponding to apnea events and a second distribution corresponding to regular breathing, and said first distribution divided by the sum of said first distribution and second distribution produces a probability of apnea for each variance; and wherein said filtered chest impedance signal attenuates the impedance caused by the heartbeat. - View Dependent Claims (2)
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Specification