Abstract:
The medical equipment warning device is employed in combination with a power operated medical treatment machine such as a sleep apnea treatment machine. The warning device includes a DC relay with contacts that are open when the relay is connected to an AC source. A signal generator is connected to a battery by the DC relay when the AC source is interrupted and contacts close the DC circuit. The signal generator produces an audible, visual or physical signal that warns a person that the AC power source has failed. Restoration of the AC power source activates the DC relay and opens the DC circuit thereby deactivating the signal generator.

Description:
The disclosure incorporates the medical equipment warning device disclosed in provisional patent application No. 60/108,723, filed on Nov. 17, 1998, whose priority is claimed for this application. 
    
    
     TECHNICAL FIELD 
     This invention relates to a medical equipment warning device and more particularly to a warning device that provides an audible warning if a medical device such as a sleep apnea treatment device fails or the devices power source fails. 
     BACKGROUND OF THE INVENTION 
     Sleep apnea is a transient cessation of respiration while a person is sleeping. The symptoms are varied and the cause of sleep apnea is unknown. Some individuals with sleep apnea may merely snore. Others reduce air intake and the oxygen level in their hemoglobin decreases. A reduction in hemoglobin oxygen level may be fatal if it is not corrected quickly. 
     Apnea is associated with restriction of the upper passages of the human respiratory system. The methodology for treating sleep apnea is to supply air to the respiratory system under pressure. The air under pressure tends to expand the air passages and thereby increase the flow of oxygen to the lungs. The air under pressure may be supplied by elaborate machines in a hospital for treatment of sleep apnea. The air under pressure may also be supplied to some individuals in their homes any time they sleep. The machines used in hospitals may supply air during inspiration at one pressure and during expiration at a lower pressure. These machines have central processing units that sense air flow rates, leakage, pressure, humidity and vibrations due to snoring. The measurements sensed may be recorded in the central processing unit. Some processing units make appropriate adjustments in air flow and pressure after each breath. The recorded measurements and the adjustments help doctors determine future treatment. These elaborate machines are relatively expensive. Individuals that require pressurized air when sleeping use less elaborate machines. Such machines are much less expensive. However, they are modified as required to meet the requirements of each individual with sleep apnea that requires such a machine. Some individuals for example, cannot tolerate pressurized air during expiration. Such individuals require a machine that supplies air at a lower pressure during expiration. 
     Hospitals generally have auxiliary power sources that supply electricity if the primary source fails for any reason. Auxiliary power systems provide electric power within seconds if there is an interruption in the primary system. Individual homes generally do not have auxiliary power sources and even if they do it takes at least a few minutes to disconnect the primary power source, connect the auxiliary power source and place the auxiliary power source in operation. A person that relies upon a medical device for assistance in the case of a life threatening disorder such as some forms of sleep apnea may not be able to wait for a repair crew to repair an electric power line, a transformer or a generator. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a warning device that produces a warning if the power to a medical device is interrupted. 
     Another object of the invention is to provide an audible warning when there is an interruption of power to a medical device. 
     A further object of the invention is to provide a warning device that produces a warning if the medical device has a malfunction. 
     A still further object of the invention is to provide a temporary power source that powers a medical device if the primary source is interrupted. 
     The medical equipment warning device has a relay that is deenergized when the primary power source is interrupted. Upon being deenergized, the relay connects an audio device to a storage battery and an audible signal is generated. The relay also connects the storage battery to the medical device to continue operation of the device. 
     At least one sensor senses an important operating parameter of the medical device. The sensor is preferably one that can determine if the medical device is not functioning properly. Upon detecting a malfunction, the sensor connects the storage battery to the audio device and an audible signal is generated. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The presently preferred embodiments of the invention are disclosed in the following description and in the accompanying drawings, wherein: 
     FIG. 1 is a circuit diagram of an alternating current interruption detector with an alarm signal generator; 
     FIG. 2 is a circuit diagram of a continuous positive air pressure medical device control system with an auxiliary direct current power source; 
     FIG. 3 is a circuit diagram of a continuous positive air pressure medical device control system with an alternating current interruption detector, an audible alarm and an auxiliary direct current power source; and 
     FIG. 4 is a circuit diagram of a continuous positive air pressure medical device control system including an alternating current interruption detector, an air pressure sensor, an audible alarm and an auxiliary direct current power source. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The alternating current interruption detector  10 , shown in FIG. 1, includes an AC power source  12 , a relay  14 , a battery  16  and a signal generator  18 . The relay  14  is energized by a 120 volt alternating current and has contacts that are opened when the relay is connected to a 120 volt Ac source by lines  20  and  22 . The signal generator  18  for individuals with the ability to hear is a sound generator. The sound generator  18  can be a bell or a buzzer but is preferably a solid state sound device. For individuals with impaired hearing, the signal generator  18  can be a flashing light, a vibrator or other device that will alert a person. Combinations of signal generators  18  can also be employed. One terminal on the relay  14  is connected to the sound generator  18  by a line  24 . The battery  16  has one terminal connected to the relay  14  by a line  26  and another terminal connected to the sound generator  18  by a line  28 . An interruption of current to the relay  14  from a power source  12  will allow the contacts in the relay to close and connect the battery  16  to the sound generator  18 . The sound generator  18  will produce sound until the power source  12  resumes the supply of current to the relay  14  and opens the relay contact. The sound generator  18  will also stop producing sound if the battery  16  runs down or if the circuit connecting the battery to the sound generator  18  is opened by a switch provided for that purpose. The current interruption detector  10  can be used with or without a medical device. 
     The continuous positive air pressure medical device  30  shown in FIG. 2 is connected to an AC interruption detector and an auxiliary. direct current power source as shown in FIG.  2 . The device  30  includes an electric motor  32  and a compressor or fan  34 . The compressor  34  supplies air under pressure to a mask  36  through a supply tube  38 . A band  40  holds the mask  36  over a person&#39;s nose. An air discharge  42  is attached to the mask  36  for discharging air from the lungs of a person wearing the mask during expiration. 
     The electric motor  32 , as shown in FIG. 2, is a DC motor. The motor  32  is connected to an AC power source  44  by lines  46  and  48  through an AC to DC converter  50 . 
     A relay  52  is connected to the AC power source  44  by lines  54  and  56 . A battery  58  is connected to the relay  52  by a line  60  and to the electric motor  32  by a line  62 . A line  64  connects the relay  52  to the motor  32 . When the AC power source  44  is supplying current to the relay  52 , contacts in the relay are held open. An interruption of current from the AC power source  44  will allow contacts in the relay  52  to close and connect the battery  58  to the motor  32 . Upon the resumption of the supply of current from the AC power source  44  to the relay  52 , the contacts in the relay are opened and the battery  58  is disconnected from the motor  32 . With the control circuit of FIG. 2 the compressor  34  will automatically continue to supply compressed air to the mask  36  when there is an interruption in current from the AC power source  44 . 
     A continuous positive air pressure sleep apnea treatment device  66  with an auxiliary power source battery  68  and an audible alarm  70  is shown in FIG.  3 . The treatment device includes a DC motor  72  that drives a compressor  74 . The compressor  74  supplies air under pressures through a supply tube  75  to a mask  76  that covers the nose of a person using the device. A strap  80  holds the mask  76  in place. An air discharge  82  permits the discharge of used air during expiration by the person wearing the mask  76 . 
     The DC motor  72  is connected to an AC power source  90  by lines  84  and  86 . An AC to DC converter  88  mounted on the motor  72  converts the AC voltage to a DC voltage to run the motor. A switch  92  is provided for turning the motor  72  off. 
     An interruption in power to the power source  90  will cause the normally open contacts in the relay  94  to close. When the relay  94  is closed, the battery  68  has one terminal connected to the motor  72  by a line  96  and another terminal connected to the motor by a line  98 , the relay  94  and a line  100 . A line  102  connects the battery  68  to the audible alarm  70  and to line  96 , which runs to the motor  72 . The circuit to the relay  94  is completed by line  104  to the alarm and by line  100  to the motor. An interruption in current from the AC power source  90  allows contacts in the relay  94  to close and connect the battery  68  to the alarm  70  and motor  72 . A switch  106  is provided to turn off the motor  72  when it is connected to the battery  68 . A switch  108  is provided to disable the audible alarm  70  when it is not required. 
     The continuous positive air pressure sleep apnea treatment device  110 , shown in FIG. 4, has an auxiliary power source  112 , an audible alarm  114  and an air pressure sensor  116 . The pressure sensor  116  can, however, be any one of a variety of sensors usable in analysis or treatment devices. The device  110  includes a compressor  118  driven by a DC motor  120 . The compressor  118  supplies compressed air to the mask  124  through a flexible tube  126 . The mask  124  covers the nose of the wearer and is held in place by a strap  124 . An air discharge  128  permits the discharge of air due to expiration by a person wearing the mask  124 . The compressor  118  can also supply air under pressure to nose tubes rather than a mask  124 . 
     The DC motor  120  has an AC to DC converter  130 . The converter  130  is connected to an AC power source  132  by lines  134  and  136 . An AC motor could be used in place of the DC motor  120  if desired. A DC to AC converter could then be used when supplying current to the AC motor from a battery. The compressor  118  could also be connected to an AC motor and a DC motor and driven by either the AC motor or the DC motor depending upon the power source available. 
     A relay  138  is connected to the AC power source  132  by lines  140  and  142 . When current is supplied to the relay  138  from the AC power source  132 , the contacts in the relay are held open. An interruption in current from the power source  132  will allow the contacts in the relay  138  to close. Closing the relay  138  connects one terminal of the battery to the motor  120  through the line  144 , the relay and line  146 . The other terminal of the battery  112  is connected to the motor  120  by a line  148 . With this arrangement, if current to the power source  132  is interrupted, the battery  112  runs the motor  120 . As soon as current from the AC power source  132  is restored, the relay  138  opens and the battery  112  is disconnected from the motor  120 . 
     The audible alarm  114  is connected to one terminal of the battery  112  by a line  150 . The alarm  114  is also connected to the line  146  by a line  152 . With this arrangement the alarm  114  sounds any time there is an interruption in current from the power source  132 . Some individuals with sleep apnea must be awakened if there is any interruption in the supply of compressed air to their mask  124 . The system described above is intended to insure that the motor  120  receives current all the time and to provide an audible warning if there is any interruption in current from the power source  132 . 
     A failure in the motor  120 , the compressor  118  or the flexible tube  126  will result in a decrease in the pressure of air supplied to the mask  124 . This decrease in pressure may reduce blood oxygen level and could be fatal for individuals with sleep apnea. Such a failure would not necessarily cause the relay  138  to close and activate the alarm  114 . A pressure transducer  116  connected to the mask  124 , the flexible tube  126  or the discharge of compressor  118  would permit detection of a failure other than a failure of the AC power source  132 . The pressure transducer  116  may be connected to lines  140  and  142  by lines  154  and  156 . Upon detection of an abnormal pressure, the pressure transducer  116  energizes the audible alarm  114  through lines  158  and  160 . To operate the pressure transducer  116  when there is a failure in the power supply  132 , the transducer is connected to the battery  112  through lines  162  and  164 . The pressure transducer  116  could, if desired, be connected to. the line  144 .and the lines  154  and  156  can be eliminated. With the lines  154  and  156  eliminated as suggested, the transducer  116  and audible alarm  114  are operated by the DC battery  112  only. Such an arrangement increases the load on the battery  112  and reduces the time between battery charges. However, with a system as shown in FIG. 4, the pressure transducer  116  and the audible alarm  114  would operate on AC as well as DC. 
     The medical equipment warning devices described above can be used with devices for the treatment of medical conditions other than sleep apnea. If a medicine in a gas or vapor form was to be supplied to the mask  36 ,  76  or  124 , it could be added to the intake of the compressor  34 ,  74  or  118  or to the supply tube  38 ,  75  or  126  without changing the warning devices as described. The warning device shown in FIG. 1 can be used in combination with any electrical treatment or analytical device. A suitable container is provided for housing the warning device. The warning device of FIG. 1 can be housed in a small easy to transport case. The complete device shown in FIG. 4 may be packaged in multiple containers. 
     The disclosed embodiments are representative of presently preferred forms of the invention, but are intended to be illustrative rather than definitive thereof. The invention is defined in the claims.