Abstract:
The present invention is an apnea monitor giving alarm when apnea occurs. It uses new designed gas flow sensor and gas differential flow sensor to detect actual airflow from patients nose and mouth. The gas flow sensor and gas differential flow sensor are evolved from a galvanometer utilizing it&#39;s structure for sensitivity. The apnea monitor measures the change of chest volume to detect breathing by a conductive rubber string. The apnea monitor also detects the frequency of baby&#39;s movement to predict possible apnea.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The traditional apnea monitor measures the electrical resistance across the chest to sense breathing. These apnea monitors have both positive and negative false alarms. The reason that it does not give alarm when a baby stops breathing is that noise is too weak to detect (weaker than noise). The reason that alarm goes off when the baby is healthy is the noise is to strong (stronger than the breathing signal). Where the noise comes from? The resistance of the chest is influenced by the liquid flow inside the body and the air flow in the lung. The present invention measures the change of chest volume instead of measuring the resistance of the chest. 
         [0002]    Before an apnea happens, usually a baby moves a lot. It is helpful to have a warning when the baby moves too often. The present invention detects the frequency of movement of a baby and will give a warning if there is too much movement. Measuring the change of chest volume can not detect obstructive apnea. Measuring the actual airflow coming in and going out of the patient&#39;s nose or mouth is an important method to detect apnea including obstructive apnea. 
         [0003]    U.S. Pat. No. 6,849,049 suggests to use a mass airflow sensor AWM2100V manufactured by Honeywell Inc as a sensor capable of accurately measuring a very small flow. How ever, the description of AWM2100V published by Honeywell gives a warning: “DO NO USE these products as safety or emergency stop devices, or in any other application where failure of the product could result in personal injury.” 
         [0004]    The present invention comprises a portion that can detect actual gas flow going in and out of nose and mouth. The critical part is the gas flow sensor and gas differential flow sensor. The present design of gas flow meter and gas differential flow sensor is made extremely sensitive and reliable. 
       REFERENCES CITED [REFERENCED BY] 
     U.S. Patent Documents 
       [0005]      
         [0000]    
       
         
               
               
               
             
           
               
                   
               
             
             
               
                 3924612 
                 December 1975 
                 Dempster et al. 
               
               
                 4083245 
                 April 1978 
                 Osborn 
               
               
                 4170228 
                 October 1979 
                 Elson et al. 
               
               
                 4170899 
                 October 1979 
                 Fujita et al. 
               
               
                 4173891 
                 November 1979 
                 Johnson 
               
               
                 4178919 
                 December 1979 
                 Hall 
               
               
                 4259967 
                 April 1981 
                 Vooren et al. 
               
               
                 4285245 
                 August 1981 
                 Kennedy 
               
               
                 4506553 
                 March 1985 
                 Bruce et al. 
               
               
                 4523481 
                 June 1985 
                 Steen 
               
               
                 4548076 
                 October 1985 
                 Haake et al. 
               
               
                 4599895 
                 July 1986 
                 Wiseman 
               
               
                 4754651 
                 July 1988 
                 Shortridge et al. 
               
               
                 4796651 
                 January 1989 
                 Ginn et al. 
               
               
                 4829449 
                 May 1989 
                 Polesnak 
               
               
                 4905709 
                 March 1990 
                 Bieganski et al. 
               
               
                 4989456 
                 February 1991 
                 Stupecky 
               
               
                 5006109 
                 April 1991 
                 Douglas et al. 
               
               
                 5033312 
                 July 1991 
                 Stupecky 
               
               
                 5038621 
                 August 1991 
                 Stupecky 
               
               
                 5060655 
                 October 1991 
                 Rudolph 
               
               
                 5063938 
                 November 1991 
                 Becket et al. 
               
               
                 5107860 
                 April 1992 
                 Malouvier et al. 
               
               
                 5111827 
                 May 1992 
                 Rantala 
               
               
                 5137026 
                 August 1992 
                 Waterson et al. 
               
               
                 5170798 
                 December 1992 
                 Riker 
               
               
                 5357972 
                 October 1994 
                 Norlien 
               
               
                 5357975 
                 October 1994 
                 Kraemer et al. 
               
               
                 5367910 
                 November 1994 
                 Woodward 
               
               
                 5501231 
                 March 1996 
                 Kaish 
               
               
                 5535739 
                 July 1996 
                 Rapoport et al. 
               
               
                 5546933 
                 August 1996 
                 Rapoport et al. 
               
               
                 5564432 
                 October 1996 
                 Thomson 
               
               
                 5685296 
                 November 1997 
                 Zdrojkowski et al. 
               
               
                 5722417 
                 March 1998 
                 Garbe 
               
               
                 5743270 
                 April 1998 
                 Gazzara et al. 
               
               
                 5803066 
                 September 1998 
                 Rapoport et al. 
               
               
                 6142952 
                 November 2000 
                 Behbehani et al. 
               
               
                 6849049 
                 February 2005 
                 Starr, et al 
               
               
                   
               
             
          
         
       
     
       Foreign Patent Documents 
       [0006]      
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 0 086 259 
                 August, 1983 
                 EP 
               
               
                   
                 0 772 026 
                 May, 1997 
                 EP 
               
               
                   
                 60-168433 
                 August, 1985 
                 JP 
               
               
                   
                 63-99841 
                 May, 1988 
                 JP 
               
               
                   
                 3-39140 
                 February, 1991 
                 JP 
               
               
                   
                 WO 97/18752 
                 May, 1997 
                 WO 
               
               
                   
                   
               
             
          
         
       
     
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  shows the gas flow sensor. Item  1  is a sail to sense the difference of gas pressure. Item  2  is a sail support. Item  10  is a balance weight. Item  4  is a light emitting diode. Item  3  is a photo diode sensing the light from item  4 . Item  5  is a light path controller. Item  6  is an axle. Item  7  and Item  8  are bearings. Item  9  is a gossamer. The output of photo diode  3  will be sent to logic circuit  2 . (  FIG. 5 ) 
           [0008]      FIG. 2  is a side view of the gas flow sensor 
           [0009]      FIG. 3  shows a body moving sensor. Item  21  and  24  are conductive rubber strings or rubber bends. Item  22  and  23  are resistances. Item  26  is a battery. Item  27  is a capacitor. 
           [0010]      FIG. 4  shows the diagram of a logic circuit  1  that will give an alarm if the input rate is greater than a predetermined threshold. Item  31  is an AC amplifier. Item  31  takes the input analog signal and amplifies it. Item  32  re-shapes the signal and generates pulses that can trigger a counter. Item  33  is a counter. When counter exceeds a predetermined threshold, it will send a signal to trigger flip-flop  34 . Then the flip-flop will send signal to the driver  35  and activate the warning buzzer  38 . Item  36  is a clock circuit which is periodically sending reset signal to counter  33 . If the input rate does not exceed the threshold before the counter gets reset, there will be no warning. Item  37  is a push button to clear the flip-flop. 
           [0011]      FIG. 5.0  shows a diagram for chest volume sensor. Item  501  is a conductive rubber string or rubber bend. Item  502  is a resistance. They are in series. Item  503  is a capacity. The top of the circuit is connected to positive. The bottom of the circuit is grounded. The output will be sent to logic circuit  2  ( FIG. 5 ). 
           [0012]      FIG. 5  shows logic circuit  2  that will give an alarm if the input has not come for a predetermined period (let&#39;s say 20 second). Item  41  is an AC amplifier. Item  42  is a re-shaper. Item  43  is a counter. Item  45  is a flip-flop. Item  44  is a clock circuit, periodically (let&#39;s say every one second) sending a pulse to increase counter  43 . If counter has exceeded threshold (20) since last input came, it will send output to trigger flip-flop  45 . Then flip-flop will send signal to driver  46  and buzzer  47  will be activated. When there is an input to  41  before the predetermined period expires, counter  43  is reset to zero to prevent alarm. Item  48  is a push button to deactivate alarm. 
           [0013]      FIG. 6  shows a diagram of a gas differential flow sensor. Item  61  is a sail. Item  62  and  63  are sail supports secured on item  67 . Item  64  and  65  are balance weights. Item  67  is a coil frame. Item  66  is coil on the coil fame  67 . Item  68  and  69  are axles secured on the coil frame  67 . Item  670  and  671  are bearings. Item  672  and  673  are gossamers. Item  674  is a magnet. Coil  66 , gossamer  672 , and gossamer  673  are electrically connected in series. The output will be sent to logic circuit  2  ( FIG. 5 ) 
           [0014]      FIG. 7  is a side view of the gas differential flow sensor. Item  675  is a magnet cylinder. Item  676  and  677  are magnet supports for item  674 . 
           [0015]      FIG. 8  shows moving monitor using a motion detector. Item  81  is a motion detector. Item  82  is logic circuit  1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    The present invention has three portions. 
         [0017]    The first portion of the present invention is a chest volume monitor. It measures the change of the chest volume to detect breathing by measuring the change of resistance of the rubber string  501 . The rubber string  501  is in series with resistance  502 . A constant voltage V+ is applied to the two resistances circuit. The sensor is a tiny conductive rubber string  501  around the chest of the patent. A change of length of rubber string  501  causes a change of resistance of the rubber string. The voltage at the connection of two components will change if the resistance of the rubber string  502  (see  FIG. 5.0 ) changes, which is amplified and processed by a logic circuit  2  (see  FIG. 5 ) or a microprocessor (was not shown in figures) after amplified. 
         [0018]    The second portion of the present invention is a moving monitor. There are two conductive rubber strings  21  and  24  connected to the patient&#39;s (baby) body. Let&#39;s say, one end of item  21  is connected to a foot of the baby. The other end of item  21  is connected to the left side of the bed. One end of item  24  is connected to the same foot and the other end of item  24  is connected to the right side of the bed. The movement of the body will cause a change of resistance of the conductive rubber strings. Two conductive rubber strings and two resistances  22  and  23  combine a Wheatstone bridge. The output of the Wheatstone bridge is the input to the logic circuit  1  (see  FIG. 4 ) The alternative moving sensor is a motion detector that used to turn on lights outside the doors when people go close to it. 
         [0019]    The third portion is an obstructive apnea monitor. The obstructive apnea monitor comprises a gas flow sensor or gas movement sensor, a logic circuit  2  ( FIG. 5 ) or microprocessor. The gas flow sensor is mounted in a mouth mask (not shown in figures). 
         [0020]    How the gas flow sensor works? 
         [0021]    The sail  1  is secured to the sail support  2 . The sail support  2  is secured to the axle  6 . The axle  6  is held by bearings  7  and  8 . Bearings  7  and  8  are secured to the frame of case of the gas flow meter. One end of the gossamer  9  is secured to the axle  6 . The other end of gossamer  9  is item  10 , which is secured to frame of the case of the gas flow sensor case. The light emitter diode  4  is secured to the frame of the case. The light emitter diode  4  sends light to photo diode  3  which is also secured to the frame of the case. When there is no gas flow, the light path controller  5  is in an initial position (relative to the frame of the case). In the initial position the light path controller  5  shall completely block the light to the photo diode if the initial position is well adjusted. When there is gas flow, the sail will be pushed and the axle will rotate, which will cause the light path controller  5  move away from the light path. This will allow some light from the light emitter diode  4  reach the photo diode  3 . The more gas flow will be, the more light will reach the photo diode  3 . The output of the photo diode is the output of the gas flow sensor. The angle that the assembly (including the sail, the support beam, the axle, the light path controller, and the gossamer) rotates is proportional to torque applied to the assembly by the gas flow. The torque is a function of the gas flow (volume/second). The amount of light that reaches the photo diode  3  is a function of the angle the assembly rotates. So the output (I) of the photo diode  3  is a function of gas flow: 
         [0000]        I=f (volume/second) 
         [0022]    It is possible to use the gas flow sensor for as a gas flow meter. In this case, a DC amplifier will be used. 
         [0023]    The light path controller can be a mirror that reflect the light from light source to light sensor when the light source and light sensor are on the same side of the mirror. 
         [0024]    How to adjust the gas flow sensor? 
         [0025]    The position of gossamer end  10 , relative to the frame of case, can be adjusted to change the initial position of the light path controller so that the light path controller completely blocks the light path when there is no gas flow. The central gravity of the whole rotating assembly shall be adjusted to the central line of the axle so that no matter how the gas flow sensor is positioned, the initial position of the light path controller will not change. The adjustment of position of the central gravity of the assembly is accomplished by changing the weight and the position of central gravity of the balance weight  11 . If two photo sensors are used, the gas flow sensor can detect gas flow from two directions. How a gas differential flow sensor works? 
         [0026]    The structure of the gas differential flow sensor is the same as a galvanometer except that the pointer is replaced by a sail. The method is similar to using a motor as a generator. The sail  61  is supported by sail supports  62  and  63 . The sail supports  62  and  63  are secured to coil fame  67 . The axles  68  and  69  are secured to the coil frame and supported by bearing  670  and  671 . The coil  66  is surrounds the coil frame  67 . The bearing  670  and  671  are secured to the frame of the gas differential flow sensor. The gossamers  672  and  673  keep the sail in the initial position when there is no gas flow. The balance weights  64  and  65  are used to make the central gravity of the movement assembly (including the sail  61 , the sail supports  62  and  63 , the coil frame  67 , the coil  66 , the axles  68  and  69 , and the gossamers  672  and  673 ) on the central line of axles  68  and  69 . The magnet  674  generates magnetic field through the coil  66 . When the position of sail  61  is changed by a change of gas flow, the assembly will rotate. This will change the magnetic flux through the coil  66  and generate some electrical potential. The electrical potential will be passed through the gossamers  672  and  673  and become output of the sensor. The output of the sensor will be amplified and processed by a logic circuit  2 . When there is no change of gas flow, there is no output from the gas differential flow sensor.