Abstract:
A patient monitor has an information processor, an information display, a control or selector, at least two sensor sockets, and at least two patient sensors. The information processor is programmable and re-programmable according to a user&#39;s requirements. The sockets are substantially identical with a number of socket connectors and are electrically connected in parallel with one another. One of the sensors monitors one aspect of a patient&#39;s condition and generates a signal to the information processor accordingly. A second sensor monitors a second aspect of a patient&#39;s condition and generates a signal to the information processor accordingly. Each of the patient sensors plugs into any of the sensor sockets. The sensor sockets and the sensors have connectors that connect when the sensors are plugged into the sockets. Not all of the connectors are used by a sensor, however, so the patient monitor identifies and differentiates each sensor not by which socket it is plugged into, but by which plug and socket connectors are used.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This is a continuing application of co-pending United States provisional Patent Application Serial No. 60/156,856, entitled Patient Monitor and filed on Sep. 30, 1999 by Leland L. Ladd, the disclosure of which is incorporated here by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     The invention relates generally to patient care and more particularly to the monitoring of a patient&#39;s condition. and the issue of an alarm when a predetermined criteria is met. 
     A variety of personal condition indicators may require monitoring in various patient care settings, including home care, nursing home, and hospital environments. Consistent quality monitoring is frequently compromised, however, in each setting. In a home setting, trained personnel are typically not available or affordable, for example, and care can easily be overlooked. Similarly, trained nursing care personnel are commonly limited in a nursing home setting. This may result from limited funding or cost reduction pressures. This may also result from unusual or unforeseen circumstances in which more patients require attention from trained personnel at a given time than was expected or forecasted. That is to say, merely the inherent unpredictability of nursing care may result in a personnel short fall. 
     Even in a hospital setting, personnel resources may fall short for some, if not all, of the same reasons as noted above. Further, the demands of an operating theatre can cause a lapse in patient monitoring. To say the very least, any effective assistance that may facilitate or enhance the work of an operating room nurse is clearly desirable. Even the smallest detail can make a life or death difference in surgery, including not requiring the time to identify which of several sockets on a piece of equipment is the correct socket, for example. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, a patient monitor of the invention has an information processor, an information display, a control or selector, at least two sensor sockets, and at least two patient sensors. The sockets are substantially identical with a number of socket connectors and are electrically connected in parallel with one another. One of the sensors monitors one aspect of a patient&#39;s condition and generates a signal to the information processor accordingly. A second sensor monitors a second aspect of a patient&#39;s condition and generates a signal to the information processor accordingly. Each of the patient sensors plugs into any of the sensor sockets. The sensor sockets and the sensors have connectors that connect when the sensors are plugged into the sockets. Not all of the connectors are used by a sensor, however, so the patient monitor identifies and differentiates each sensor not by which socket it is plugged into, but by which plug and socket connectors are used. 
    
    
     These and other features, objects, and benefits of the invention will be recognized by one having ordinary skill in the art and by those who practice the invention, from the specification, the claims, and the drawing figures. 
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is a front perspective view of a cabinet of a patient monitor according to the invention; 
     FIG. 2 is an exploded view thereof; 
     FIG. 3 is a projection of the front panel thereof, showing a preferred user interface; 
     FIG. 4 is a block diagram of a power circuit for the patient monitor; 
     FIG. 5 is a pump control diagram for the patient monitor; 
     FIG. 6 is a block diagram of a circuit therefor; 
     FIG. 7 is the view of FIG. 6 showing an alternative circuit; 
     FIG. 8 is a block diagram of a processor circuit for the patient monitor; 
     FIG. 9 is a software flow diagram for the patient monitor; 
     FIG. 10 is a schematic view of a mass level sensor for the patient monitor; 
     FIG. 11 is a schematic view of a fluid level sensor for the patient monitor; 
     FIG. 12 is a schematic view of a patient movement pad for the patient monitor; and 
     FIG. 13 is a schematic view of an array of connectors and input devices for the patient monitor. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of a patient monitor according to the invention is generally shown in the drawing figures and discussed below. The patient monitor may be generally housed in a cabinet  50  as shown in drawing FIGS. 1-3. The cabinet may have a front panel  52  with an alpha-numeric display panel  54 , status indicators  56   a - 56   d , and user input switches  58   a - 58   f . The cabinet  50  may be of various constructions and configurations, as will be understood by one having ordinary skill in the art. Some exemplary cabinet materials may include, without limitation, stainless steel, powder coated metals, and engineering plastics. 
     The alpha-numeric display panel  54  is preferably a liquid crystal display (LCD) although other display devices may be used depending upon a manufacturer&#39;s or user&#39;s preferences. More particularly, the inventor has found a 16×2 character LCD to perform well in the patient monitor. 
     Likewise, light emitting diodes have been found to perform well for the various status indicators  56   a - 56   d , although other indicators may be substituted. Presently, indicators for monitor power status (on/off)  56   a , for batter power source charging status  56   b , and for an alarm condition  56   c  and  56   d  relative to a patient monitor have been found to be sufficient and minimally required indicators. Additional indicators may be added and desired by various users, although potential users are cautioned against the inherent confusion that comes with a plethora of indicators. 
     A sufficient and minimal array of input switches is also shown in the drawings and includes switches for menu access  58   a , power  58   b , menu scrolling  58   c  and  58   d , menu choice entry  58   e , and alarm toggle  58   f . Membrane tactile switching or the like is preferred if only because of the ease with which the front panel may be wiped clean. Other switching may also be used with compromises in the ability to clean the front panel around the switches, however. While most of the switches are most preferably accessible on the front panel, the power switch  58   b  may alternatively be relocated on the back panel, for example. 
     The monitor is preferably provided with an alternative choice between wall plug, also commonly known as line power, and an onboard battery power supply (FIG.  4 ). A power cord with an integral transformer and plug may be used as is commonly known to provide an about six volt battery current to the patient monitor. By providing onboard battery power, the patient monitor may operate a nominal twenty-five hours during a power failure or patient transportation, for example. 
     A circuit for the ability to choose alternative power sources is schematically shown in FIG.  4 . The transformer power cord  62  feeds through a circuit breaker  64  to the battery  66 . The battery  68  then feeds to an air pump  70 , a power regulator  72 , and a voltage sensor  74 . The power regulator may be a switching type regulator of about five volts output, for example. The output of the regulator is then used for the electronics  80  of the patient monitor. A loop from the battery  68  to the voltage sensor  74  provides monitoring of the power supply and may send a low power signal to the control electronics  80  when battery power drops below a preselected value, as will be understood by one having ordinary skill in the art. This may occur after an extended period of being disconnected from wall power. A low power signal alarm may be interpreted as a flashing power indicator  56   a  or an audible voice alert. The low power alarm will preferably activate at power levels of about twenty-five percent, at fifteen percent, and again at five percent remaining charge. These power levels may be reflected in the power indicator  56   a  as increasing flashing frequency. The voice alarm may be programmed to state the power level that remains. 
     The patient monitor is preferably provide with an air pressure pump  70  and may also have a vacuum pump  80  (FIGS.  5 - 7 ). Alternatively, a manufacturer or user may prefer to omit the vacuum pump  80  or the pressure pump  70 , depending upon their monitoring requirements (FIG.  7 ). 
     The pressure pump  70  is useful with infusion bags and may provide a capacity of about 500 mm Hg pressure by connection of an infusion bag air pressure tube with an air pressure connector of the patient monitor. Dual redundant air pressure sensors  82  are preferably used to monitor selected and used air pressure within about five percent of a predetermined setting. The patient monitor may further be programmed to facilitate a pressure tubing alarm. The pressure tubing alarm may sense a blocked or kinked tube when a set pressure is achieved too quickly. Conversely, an open or leaking pressure tube may be sensed when a set pressure takes too long to achieve. Further, a pressure tubing alarm may be set for when either an infusion bag fluid tube or a pressure tube becomes blocked or kinked after a set pressure is properly achieved. 
     Similarly, the vacuum pump  80  is useful with suction canisters by connection of a canister suction tube with a suction connector of the patient monitor. A vacuum sensor  84  monitors the selected and used vacuum level within about five percent of a predetermined setting. The patient monitor may also be programmed to facilitate vacuum tubing alarms. The vacuum tubing alarm may sense a blocked or kinked tube when a set vacuum is achieved too quickly. Conversely, an open or leaking tube may be sensed when a set vacuum takes too long to achieve. Further, a vacuum alarm may be set if either a suction canister tube or a vacuum tube becomes block or kinked after a set pressure is properly achieved. 
     Infusion bag fluid level monitoring may be provided with a mass differential unit  90  such as is shown in FIG.  10 . This type of sensor may also be used for any consumable. The fluid bag level sensor  90  preferably has a generally cylindrical housing  92 . The housing  92  may be constructed of any suitable structural material, including metals, ceramics, and plastics, for example. The housing  92  may further be constructed by any appropriate method that is suitable for the material selected. The use of a cylindrical housing  92  may facilitate manufacture by extrusion, for example. Further, the cylindrical shape facilitates cleaning of the sensor. 
     As shown, the sensor  90  includes a plunger  94  that has a stop  96 , a shaft  98 , and a connector  100 . The fluid sensor  90  will commonly be used by hanging the sensor on an I.V. pole or the like as is commonly known. The plunger  94  is slideably mounted in the cylinder  92  and slides between extended and retracted positions. A helical scale spring  102  or other scalable bias device urges the plunger  94  toward the retracted position. Further, a micro switch  104  or the like is preferably mounted to close a sensor circuit when the plunger  94  is in the retracted position. The plunger  94  extends when a mass, which may include an infusion fluid bag, is connected with the plunger by connecting the bag with the connector  100 , which may be a hook, for example. Conversely, the bias  102  retracts the plunger  94  when the mass diminishes, indicating consumption of the infusion fluid or other consumable. 
     A trip level of the sensor  90 , where the switch  104  is actuated, may be made adjustable. As shown, a position of the switch  104  may be adjustable relative to the spring  102  at 200 ml and 500 ml of infusion fluid, for example. The trip level of the sensor  90  relative to the content level of the infusion fluid is adjustable by relocating the position of the switch  104  along the cylinder  92 , as will be understood by one having ordinary skill in the art. 
     Conversely, the structure of the sensor  90  may be inverted to sense an accumulation of a used fluid, for example, by either having the switch close when the plunger extends away from the switch  104  or by reprogramming the processor to accept an open switch  104  as a signal criteria. Further yet, the switch  104  may alternatively be placed to contact the plunger stop  96  and close the switch when the plunger is in the extended position. One having ordinary skill in the art will understand that these are only a few of many variations that may be used within the concept of the invention. 
     Another fluid accumulation sensor  120  that is useful with suction canisters and the like is shown in FIG.  11 . The suction canister level sensor  120  has a plug or stopper  122  that cooperates with an opening in a top or cap of a suction canister. A pair of probes  124  and  126  extend in the same general direction from the stopper  122  and extend into a suction canister when the sensor is mounted for use. As fluid is accumulated in the suction canister, the fluid will make contact with the probes  124  and  126  and make a closed circuit condition that the processor may be programmed to interpret. The sensor  120  is connected with the processor by a cord  128 , which may be removable from the stopper  122 . Thus, the stopper  122  and probes  124  and  126  may be provided as a disposable part, while the cord  128  may be reusable. 
     The processor may be programmed to identify a variety of conditions relative to the position of the fluid along the probes  124  and  126 . A full condition may be interpreted when the probes  124  and  126  are both first contacted by the fluid. Alternatively, the probes  124  and  126  may extend relatively far into the suction canister and a varying resistance between the probes as the fluid level rises may be interpreted by the processor as progressively greater quantities of fluid in the canister. 
     Another useful sensor  130  may include a patient motion sensor. The patient motion sensor  130  shown in FIG. 12 comprises a piezoelectric coaxial cable  132 , for example. The cable  132  is threaded through a pad  134  that is placed under a patient. Electrical signals are generated by the piezoelectric cable  132  because of changes in pressure applied to the piezoelectric cable as the patient moves while laying upon the pad  134  and cable. Alternatively, if a more sophisticated motion sensor report is desired, a pad that has a touch sensitive grid may be used. Such a sensor may report specific body position and may be useful in a sleep study, for example. 
     The use of a wide variety of sensors is provided in the patient monitor by using keyed input sockets  140   a - 140   e  and plugs  142   a - 142   e  (FIG.  13 ). The cooperating input sockets  140   a - 140   e  and plugs  142   a - 142   e  are not sensor specific in that a different socket and plug combination are designated for each sensor. Rather, a socket  140   a - 140   e  and plug  142   a - 142   e  combination that has a plethora of connectors or contacts  144   a - 144   e  and  146   a - 146   e , respectively, is used and a pattern or set of the contacts is identified with a particular sensor, resulting in a smart plug connection of the sensor with the processor. An exemplary schematic of five plugs  142   a - 142   e  and five sockets  140   a - 140   e  is shown in FIG.  13 . Each plug  142   a - 142   e  and socket  140   a - 140   e  arbitrarily has five contacts  144   a - 144   e  and  146   a - 146   e , respectively, as shown in FIG.  13 . Significantly, any of the plugs  142   a - 142   e  can mate with any of the sockets  140   a - 140   e . The sockets  140   a - 140   e  are conventionally connected in parallel, so the sockets are electrically identical. The distinction comes in how the socket contacts  144   a - 144   e  are connected with the processor and how the processor is programmed to interpret various signals from the contacts. One having ordinary skill in the art will understand that the processor may be programmed to discern and report as desired virtually any combination of contact input. Thus, a programming of the processor may dictate a plug wiring of the sensors or vice versa, a predetermined plug wiring of the sensors may dictate a programming of the processor. 
     As shown, the processor may be programmed to accommodate a plug  142   a  that has contacts  146   a  wired for a sensor  90  such as an infusion bag level empty sensor signal, while also accommodating a plug  142   c  that has contacts  146   c  wired for a sensor  120  such as a suction canister level full signal, for example. A plug  142   b  that has contacts  146   b  wired for a sensor  130  such as a piezoelectric motion sensor input may also be accommodated, for example. Other desired sensors may further be accommodated by differentiated wiring of contacts  146   d  and  146   e  of plugs  142   d  and  142   e . Thus, the wiring of the sensor with the plug  142   a - 142   e , and more particularly with the plug contacts  146   a - 146   e  and so with the processor through the socket contacts  144   a - 144   e  differentiates or identifies the particular sensor. A significant feature of this cooperating socket  140   a - 140   e  and plug  142   a - 142   e  arrangement is that the sensors and the processor may be configured so a preselected sensor can be plugged into any socket  140   a - 140   e  without a user wasting time or being distracted or otherwise being confused or making a mistake with regard to identifying the correct socket before plugging in a sensor. 
     It will be understood by one having ordinary skill in the art and by those who practice the invention, that various modifications and improvements may be made without departing from the spirit of the disclosed concept. Various relational terms, including left, right, front, back, top, and bottom, for example, are used in the detailed description of the invention and in the claims only to convey relative positioning of various elements of the claimed invention. The scope of protection afforded is to be determined by the claims and by the breadth of interpretation allowed by law.