Respiration and movement monitoring system

• US 6,011,477 A
• Filed: 07/21/1998
• Issued: 01/04/2000
• Est. Priority Date: 07/23/1997
• Status: Expired due to Term

• Current Assignee: Sensitive Technologies LLC
• Original Assignee: Sensitive Technologies LLC
• Inventors: Teodorescu, Horia-Nicolai, Mlynek, Daniel J.
• Primary Examiner(s): Hofsass, Jeffery A.
• Assistant Examiner(s): PHAM, TOAN NGOC
• Application Number:
  US09/120,042
• Time in Patent Office: 532 Days
• Field of Search: 340/573.1, 340/573.7, 340/575, 340/572.5
• US Class Current: 340/573.1
• CPC Class Codes: A61B 2503/06 Children, e.g. for attention deficit diagnosis
• CPC Class Codes: A61B 5/0507 using microwaves or terahertz waves
• CPC Class Codes: A61B 5/1126 using a particular sensing technique
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/6892 Mats
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00

Abstract

A monitoring system (10) of this invention includes a first sensor (12) for detecting the respiration and/or movements of an infant (14), and an optional second sensor (18) for detecting the presence and/or movement of the infant or proximal objects (20) surrounding the infant. An optional accelerometric sensor (22) detects movements of a platform (16) supporting the infant and contributes supplementary movement data to the monitoring system. An optional audio sensor (24) detects sounds associated with the infant or proximal objects. None of the sensors are physically attached to the infant. A controller (26) conditions and processes the various sensor signals and generates alarms by interpreting the sensor signals. The controller optionally communicates with a remote control unit (30). In one embodiment the first sensor signal is filtered (112, 114) to extract respiration- and nonrespiration-related signals that are processed by a signal processor (116), which compares the extracted signals to thresholds, and if neither signal exceeds its threshold for a predetermined time, a low signal alarm is generated. In another embodiment, the signal processor determines whether a respiration decay period is less than a threshold value, and if not, generates a respiration decay alarm. In yet another embodiment, the signal processor compares the respiration-related signal pattern to a stored pattern, and if the patterns do not match, a respiration pattern alarm is generated. The signal processor further interprets various combinations of the sensor signals and makes aggregated decisions to generate specific warnings when critical situations occur.

Claims

1. An apparatus for monitoring respiration and movements of an infant positioned adjacent to a supporting platform, comprising:

a first sensor positioned between the infant and the support platform, the first sensor not having a physical attachment to the infant and including a distributed inductance and distributed capacitance device formed as a radially wound spiral flat conductor strip that produces a uniform electric field for sensing the respiration and movements of the infant the first sensor further having an impedance that is a function of a frequency, the impedance having a maximum value when the frequency equals a resonant frequency of the first sensor, the resonant frequency varying as a function of the respiration and movements of the infant;

an oscillator generating a signal having an operating frequency that substantially equals or is close to the resonant frequency of the first sensor;

a high-impedance element coupling the signal from the oscillator to the first sensor, the high-impedance element and the first sensor forming a voltage divider that produces from the signal a sensor voltage that is proportional to the impedance of the first sensor and is, therefore, responsive to the respiration and movements of the infant;

a detector extracting from the sensor voltage a first signal representative of the respiration and movements of the infant;

a controller receiving the first signal and including a band-pass filtering function to extract from the first signal a respiration-related signal and a band-stop filtering function to extract from the first signal a movement-related signal; and

a signal processor processing at least one of the respiration-related signal and the movement-related signal to generate an alarm signal.

2. The apparatus of claim 1 in which the band-pass filter function has a tunable bandwidth and the band-stop filter function has a tunable cutoff frequency, the tunable bandwidth and cutoff frequency being adjustable to account for an age-related average respiration rate of the infant.

3. The apparatus of claim 1 in which the support platform includes at least one of a crib and an incubator.

4. The apparatus of claim 1 in which the first sensor is enclosed in at least one of a comforter, a quilt, a sheet, a bedspread, a pane, a counterpane, and a fancy.

5. The apparatus of claim 1 in which the resonant circuit is formed on a major surface of a thin flexible plastic substrate.

6. The apparatus of claim 1 in which the resonant circuit is formed from a material including at least one of a thin metallic film, a thick conductive film, and a conductive polymeric film.

7. The apparatus of claim 1 in which the resonant circuit includes first and second major surfaces, and a sponge sheet is positioned adjacent to at least one of the first and second major surfaces.

8. The apparatus of claim 1 in which the first sensor includes an array of resonant circuits each formed as a spiral conductor, and in which the array of resonant circuits are electrically connected in at least one of a parallel circuit or a series circuit.

9. The apparatus of claim 1 in which the first sensor includes an array of resonant circuits each formed as a spiral conductor, and in which each resonant circuit in the array has an associated generator and an associated output signal, the output signals being summed combined to form the first signal.

10. The apparatus of claim 1 further including at least one second sensor that is spaced apart from the first sensor, the second sensor defining a safety perimeter around the infant, and in which the controller receives from the second sensor a second signal indicative of at least one of a proximity to the safety perimeter of the infant and a proximity to the safety perimeter of an external object.

11. The apparatus of claim 1 further including at least one accelerometric sensor that generates an acceleration signal indicative of movements of the support platform, the signal processor comparing the acceleration signal and the first sensor signal to increase a reliability of detecting movements of the infant.

12. The apparatus of claim 1 further including an audio detector that generates an audio signal indicative of sounds associated with the infant, the signal processor inhibiting the alarm signal if the audio signal exceeds a predetermined threshold level.

13. The apparatus of claim 1 further including a remote control unit for two-way communicating with the controller control information, and at least one of the alarm signal and an audio signal.

14. The apparatus of claim 13 in which the communicating employs at least one of a radio frequency link, an infrared link, an ultrasound link, and an electrical cable.

15. The apparatus of claim 1 further including a radio frequency generator mechanically coupled to the infant, the radio frequency generator producing a radio frequency signal that is received by the first sensor and having multiple signal strengths that are dependent on a varying distance between the generator and the first sensor and are, therefore indicative of multiple body positions of the infant, at least one of the signal strengths being interpreted by the controller as a prone body position.

16. The apparatus of claim 15 further including at least one of an electrocardiogram ("ECG") sensor and a blood oxygen saturation sensor coupled to the infant for generating at least one of an ECG signal and a blood oxygen saturation signal that modulates the radio frequency generator such that the radio frequency signal includes modulation that is interpreted by the controller as at least one of an ECG pattern and a blood oxygen saturation level of the infant.

17. The apparatus of claim 16 further including a temperature sensor that provides a temperature signal indicative of an ambient temperature in the vicinity of the infant, the controller receiving the radio frequency signal, the ECG signal, the blood oxygen saturation signal, and the temperature signal and determining on the basis of an overall signal pattern whether to generate a warning signal.

18. A method for monitoring respiration and movements of an infant positioned adjacent to a supporting platform, the method comprising:

positioning a first sensor between the infant and the support platform, the first sensor not physically attached to the infant and including a distributed inductance and distributed capacitance device formed as a radially wound spiral flat conductor strip that produces a uniform electric field for sensing the respiration and movements of the infant, the first sensor further having an impedance that is a function of a frequency, the impedance having a maximum value when the frequency equals a resonant frequency of the first sensor, the resonant frequency varying as a function of the respiration and movements of the infant;

generating a signal having an operating frequency that substantially equals or is close to the resonant frequency of the first sensor;

coupling the signal to the first sensor with a high-impedance element, the high-impedance element and the first sensor forming a voltage divider that produces from the signal a sensor voltage that is proportional to the impedance of the first sensor and is, therefore, responsive to the respiration and movements of the infant;

detecting the sensor voltage to produce a first signal representative of the respiration and movements of the infant;

band-pass filtering the first signal to extract a respiration-related signal;

band-stop filtering the first signal to extract a movement-related signal; and

processing at least one of the respiration-related signal and the movement-related signal to generate an alarm signal.

19. The method of claim 18 further including positioning at least one second sensor spaced apart from the first sensor for sensing a safety perimeter around the infant, the second sensor generating a second signal indicative of movements proximal to the safety perimeter of at least one of the infant and an external object.

20. The method of claim 19 in which the processing includes interpreting that the infant is laying down adjacent to the first sensor if the second signal does not exceed a predetermined threshold level.

21. The method of claim 26 in which the processing includes generating a safety perimeter intrusion alarm if the second signal does not exceed a predetermined threshold and the second signal is not substantially correlated with the movement-related signal extracted from the first signal.

22. The method of claim 19 in which the processing includes generating an abnormality alarm if the second signal is substantially correlated with the movement-related signal extracted from the first signal, the abnormality alarm being indicative of at least one of a vibration of the supporting platform, an agitated movement of the infant, and a malfunction.

23. The method of claim 18 further including mechanically coupling a radio frequency generator to the infant, the radio frequency generator producing a radio frequency signal that is received by the first sensor at multiple signal strengths that are dependent on a varying distance between the generator and the first sensor and are, therefore, indicative of multiple body positions of the infant and interpreting at least one of the signal strengths as a prone body position.

24. The method of claim 23 further including generating a monitoring signal indicative of at least one of an electrocardiogram ("ECG") pattern and a blood oxygen saturation level of the infant, modulating the radio frequency signal with the monitoring signal, and detecting from the modulated radio frequency signal at least one of the ECG pattern and the blood oxygen saturation level of the infant.

25. The method of claim 24 further including generating a temperature signal indicative of an ambient temperature in the vicinity of the infant, and determining whether to generate a warning signal by analyzing an overall signal pattern established by the modulated radio frequency signal, the monitoring signal, and the temperature signal.

26. The method of claim 25 further including awakening the infant with at least one of a loud sound and a movement in response to at least one of the alarm signal and the warning signal.

27. The method of claim 25 further including ventilating the infant with an artificial respirator in response to at least one of the alarm signal and the warning signal.

28. The method of claim 23 further including producing a signal strength pattern from the multiple signal strengths, and extracting a secondary respiration signal from the signal strength pattern.

29. The method of claim 18 in which the processing further includes classifying and deciding processes that are based on a medical and family history of the infant, the medical and family history including at least one of an age, a sex, a birthweight, a drug therapy history, a respiratory state, and an infectious state of the infant, and at least one of an age and a smoking status of a mother of the infant.

30. The method of claim 29 in which the classifying and deciding processes employ at least one of a binary logic process, a fuzzy logic process, and a neural network process.

31. The method of claim 18 in which the processing further includes:

determining from the respiration-related signal sets of respiration rates and associated respiration waveform patterns;

storing the sets of respiration rates and associated respiration waveform patterns in a memory;

comparing a subsequently received respiration rate and an associated respiration waveform pattern to at least one of the previously stored sets of respiration rates and associated respiration waveform patterns, and

generating a respiration rate pattern alarm if the subsequently received respiration rate pattern does not substantially match at least one of the previously stored respiration rate patterns.