Method and apparatus for monitoring vital signs remotely

Abstract

A method and apparatus for monitoring vital signs, such as cardiopulmonary activity, using a ballistograph are provided. The method and apparatus may be used to monitor an infant sleeping in a crib, a patient in a hospital, a person with a chronic disease at home or in professional care, or a person in an elder-care setting.

1 . Apparatus for monitoring heart and respiration rates of a human subject at rest, comprising, in operative condition,
 (a) a sensing unit having (i) a fluid or gas-filled pad adapted to be placed on a bed, crib, or chair support, for cushioning at least an upper body portion of a subject lying on or resting against the support, mattress or cushion, and (ii) a pressure sensor in gas or fluid communication with gas or fluid in said unit, for generating electrical signals in response to pressure variations within the gas or fluid in the pad, and   (b) a monitoring unit operatively connected to said pressure sensor, for (i) receiving signals therefrom, (ii) generating from said signals, information about the heart and respiration rates of the subject, and (iii) relaying such information to a monitoring station or individual.   
     
     
         2 . The apparatus of  claim 1 , wherein the pad is a fluid-filled pad. 
     
     
         3 . The apparatus of  claim 1 , wherein the pad is a gas-filled pad. 
     
     
         4 . The apparatus of  claim 1 , which further includes a pressure-control unit comprising a pump in fluid or gas communication with the pad and a controller operatively connected to the pump for maintaining fluid or gas within the pad at a selected pressure or within a defined pressure range. 
     
     
         5 . The apparatus of  claim 1 , wherein said pad comprises a single fluid or gas-filled chamber, having a pressure sensor in fluid or gas communication therewith, for generating electrical signals in response to pressure changes within the chamber. 
     
     
         6 . The apparatus of  claim 1 , wherein said pad includes at least two independent, fluid or gas-filled chambers, each of which has a pressure sensor in fluid communication therewith, for generating electrical signals in response to pressure changes within the associated chamber. 
     
     
         7 . The apparatus of  claim 1 , which further includes an ambient-null device comprising a fluid or gas-filled ambient pad, a weight carried on the ambient pad, for exerting pressure thereon, and an ambient pressure sensor in fluid or gas communication with fluid in the ambient pad, for generating electrical signals in response to pressure changes within the fluid or gas, in response to ambient motion in the vicinity of the subject, wherein said monitoring unit is operatively connected to said ambient pressure sensor, for (i) receiving signals therefrom, and (ii) processing the signals received from the first-mentioned and ambient pressure sensors, to filter such ambient motion from motion related to the subject's heart and respiration rates. 
     
     
         8 . The apparatus of  1 , wherein said monitoring unit includes a processor operative to (i) generate heart-rate information of the subject, based on time-dependent signals having frequency components in the range from about 0.1 to about 10 Hz, and (ii) generate respiration rate information of the subject based on time-dependent signals having frequency components in the range less than about 1 Hz. 
     
     
         9 . The apparatus of  claim 8 , wherein the information generated by the signal processor further includes blood-pressure information. 
     
     
         10 . The apparatus of  claim 9 , wherein said pad includes upper and lower independent, fluid or gas-filled chambers, each of which has a pressure sensor in fluid communication therewith, for generating electrical signals in response to pressure changes within the associated chamber, and the information generated by the processor includes information about the orientation of the individual with respect to the pad, based on a characteristic ventral, dorsal or lateral signals produced by processing the two separate signals generated for the two chambers. 
     
     
         11 . The apparatus of  claim 8 , wherein said monitoring unit includes a remote monitor, and a transmitter for transmitting such heart and respiration rate information from the processor to the monitor. 
     
     
         12 . The apparatus  claim 1 , wherein said pad further includes temperature sensor for measuring the temperature of the individual on the pad. 
     
     
         13 . A sensor unit for use with a monitoring unit, for monitoring heart and respiration rates of a human subject at rest, comprising, in operative condition,
 (a) a fluid or gas-filled pad adapted to be placed on a bed, crib, or chair support, for cushioning at least an upper-body portion of a subject lying on or resting against the support, and   (b) a pressure sensor in fluid communication with fluid in said unit, for generating electrical signals in response to pressure variations within the fluid or gas, and adapted to be operatively connected to such a monitor.   
     
     
         14 . The sensing unit of  claim 13 , wherein said pad includes as single fluid or gas-filled chamber having a pressure sensor in fluid of gas communication therewith, for generating electrical signals in response to pressure changes within the chamber. 
     
     
         15 . The sensing unit of  claim 13 , wherein said pad includes at least two independent, fluid-filled chambers, each of which has a pressure sensor in fluid or gas communication therewith, for generating electrical signals in response to pressure changes within the associated chamber. 
     
     
         16 . The sensing unit of  claim 13 , wherein for the pad is a fluid-filled pad. 
     
     
         17 . The sensing unit of  claim 13 , wherein for the pad is a gas-filled pad. 
     
     
         18 . A method for monitoring vital signs, including heart and respiration rates, of a human subject lying on or resting against a bed, crib, or chair support, comprising
 (a) placing between the subject and the support, a fluid or gas-filled pad positioned for cushioning at least an upper-body area of the subject,   (b) generating electrical signals in response to pressure variations within the fluid or gas by a pressure sensor in fluid communication with fluid or gas in said pad, and   (c) processing the electrical signals received from the pressure sensor to generate information about the heart and respiration rate of the subject.   
     
     
         19 . Apparatus for remotely monitoring heart and respiration rates of a human subject lying on or resting against a bed, crib, or chair support, comprising
 (a) a pad adapted to the placed between the subject and the support, for cushioning at least an upper body portion of the individual,   (b) a sensor on said pad for generating motion-related signals caused by the subject's heartbeat and breathing,   (c) a processor operatively connected to said sensor, for (i) receiving time-dependent signals therefrom, and (ii) generating heart-rate information of the subject, based on received time-dependent signals in the range from about 0.1 to about 10 Hz, and respiration rate information of the subject, based on received timed-dependent signals in the range less than about 1 Hz,   (d) a remote monitor for use by an individual in monitoring said subject, and   (e) a transmitter for transmitting such subject information from the processor to the individual.   
     
     
         19 . The apparatus of  claim 18 , which further includes an ambient-motion device for generating signals related to ambient motion in the vicinity of the subject, and said processor is operatively connected to said device, for processing the signals received from the device, to filter such ambient motion from motion related to the subject's heart and respiration rates. 
     
     
         20 . Apparatus for monitoring vital signs, including heart and respiration rates, of a human subject lying on or resting against a bed, crib, or chair support, comprising
 (a) a pad adapted to the placed between the subject and the support, for cushioning at least an upper body portion of the individual, said pad comprising   (i) a pair of confronting plates, one adapted to be supported on the mattress, and the other adapted for contact with the chest area of the individual, said plates being spaced apart for relative lateral movement in an XY plane and relative vertical movement in the Z direction,   (iii) connecting the two plates, an L-shaped connector attached at opposite ends to the opposing plates and having a pair of laterally extending, orthogonally disposed arms, a strain gauge carried on each arm, in an XY plane, and a strain gauge carried on one of the arms, in a vertical plane, and   (b) a monitoring unit operative to transmit to a remote user, information about the heart rate of the individual, based on signals received from the pad's lateral-movement strain gauge devices, and about the respiration rate of the individual, based on signals received from the pad's vertical-movement strain gauge(s).   
     
     
         21 . The apparatus of  claim 20 , wherein said two opposing plates are substantially rectangular, and connected by said L-shaped connectors in the region of each of the four corners of the two plates. 
     
     
         22 . The apparatus of  claim 21 , which further includes a vertical-movement strain gauge connecting the two plates, for generating information about the weight applied by the individual on the pad. 
     
     
         23 . The apparatus of  claim 21 , wherein said monitoring unit includes a processor operative to (i) wherein said monitoring unit includes a signal processor operative to (i) generate heart-rate information of the subject, based on time-dependent signals received from each of the plural lateral-movement strain-gauge devices, and having frequency components in the range from about 0.1-10 Hz, and (ii) generate respiration rate information of the subject based on timed-dependent signals having frequency received from the at least one of the vertical-movement strain gauge(s), and having frequency components in the range less than about 1 Hz. 
     
     
         24 . The apparatus of  claim 23 , wherein said monitoring unit includes a remote monitor, and a transmitter for transmitting such heart rate and respiration rate information from the processor to the monitor. 
     
     
         25 . The apparatus  claim 24 , wherein said pad further includes temperature sensor for measuring the temperature of the individual on the pad. 
     
     
         26 . The apparatus of  claim 24 , which further includes a weighted strain gauge adapted for attachment to the bed or crib, independent of said pad, for detecting movement of the bed or crib, independent of movement within the pad, and the monitoring unit is operative to remove such independent movement from pad movement detected by the pad strain gauges. 
     
     
         27 . Apparatus for determining the presence of a subject, comprising:
 (a) a sensing unit having (i) a fluid or gas-filled pad adapted to be placed on a bed, crib, or chair support, for cushioning at least an upper body portion of a subject lying on or resting against the support, mattress or cushion, and (ii) a pressure sensor in fluid communication with fluid in said unit, for generating electrical signals in response to pressure variations within the fluid in the pad, and   (b) a monitoring unit operatively connected to said pressure sensor, for (i) receiving signals therefrom, (ii) generating from said signals, information about the presence of the subject and (iii) relaying such information to a monitoring station or individual.   
     
     
         28 . A sensor unit for use with a monitoring unit, for detecting the presence of a subject, comprising:
 (a) a fluid or gas-filled pad adapted to be placed on a bed, crib, or chair support, for cushioning at least an upper-body portion of a subject lying on or resting against the support, and   (b) a pressure sensor in fluid communication with fluid in said unit, for generating electrical signals in response to pressure variations within the fluid or gas, and adapted to be operatively connected to such a monitor.   
     
     
         29 . A method for detecting the presence of a subject on or in a bed, crib, or chair support, comprising:
 (a) placing on or in the bed, crib, or chair support a fluid or gas-filled pad positioned for cushioning at least an upper-body area of the subject,   (b) generating electrical signals in response to pressure variations within the fluid or gas by a pressure sensor in fluid communication with fluid or gas in said pad, and   (c) processing the electrical signals received from the pressure sensor to generate information about the presence of the subject.   
     
     
         30 . Apparatus for monitoring the presence of a subject lying on or resting against a bed, crib, or chair support, comprising:
 (a) a pad adapted to the placed between the subject and the support, for cushioning at least an upper body portion of the individual, said pad comprising   (i) a pair of confronting plates, one adapted to be supported on the mattress, and the other adapted for contact with the chest area of the individual, said plates being spaced apart for relative lateral movement in an XY plane and relative vertical movement in the Z direction,   (iii) connecting the two plates, an L-shaped connector attached at opposite ends to the opposing plates and having a pair of laterally extending, orthogonally disposed arms, a strain gauge carried on each arm, in an XY plane, and a strain gauge carried on one of the arms, in a vertical plane, and   (b) a monitoring unit operative to transmit to a remote user, information about the presence of the subject, based on signals received from the pad's strain gauge devices.