Patent Publication Number: US-11026578-B2

Title: Alerting for loss of full skin contact of patient electrodes

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATIONS 
     This patent application is a divisional of U.S. patent application Ser. No. 15/432,811 filed on Feb. 14, 2017, which in turn is a divisional of U.S. patent application Ser. No. 14/956,776 filed on Dec. 2, 2015 and is now abandoned, which in turn is a divisional of U.S. patent application Ser. No. 14/064,468 filed on Oct. 28, 2013 and issued on Jan. 19, 2016 as U.S. Pat. No. 9,237,858, which in turn claims priority from U.S. Provisional Patent Application Ser. No. 61/875,600, filed on Sep. 9, 2013, and which further is a Continuation-In-Part of U.S. patent application Ser. No. 13/024,225, filed on Feb. 9, 2011, and is now abandoned. 
     This patent application may be found to be related with U.S. patent application Ser. No. 14/064,515, filed on Oct. 28, 2013 and issued on Apr. 19, 2016 as U.S. Pat. No. 9,317,729. 
    
    
     BACKGROUND 
     In humans, the heart beats to sustain life. In normal operation, it pumps blood through the various parts of the body. More particularly, the various chambers of the heart contract and expand in a periodic and coordinated fashion, which causes the blood to be pumped regularly. More specifically, the right atrium sends deoxygenated blood into the right ventricle. The right ventricle pumps the blood to the lungs, where it becomes oxygenated, and from where it returns to the left atrium. The left atrium pumps the oxygenated blood to the left ventricle. The left ventricle then expels the blood, forcing it to circulate to the various parts of the body. 
     The heart chambers pump because of the heart&#39;s electrical control system. More particularly, the sinoatrial (SA) node generates an electrical impulse, which generates further electrical signals. These further signals cause the above-described contractions of the various chambers in the heart, in the correct sequence. The electrical pattern created by the sinoatrial (SA) node is called a sinus rhythm. 
     Sometimes, however, the electrical control system of the heart malfunctions, which can cause the heart to beat irregularly, or not at all. The cardiac rhythm is then generally called an arrhythmia. Arrhythmias may be caused by electrical activity from locations in the heart other than the SA node. Some types of arrhythmia may result in inadequate blood flow, thus reducing the amount of blood pumped to the various parts of the body. Some arrhythmias may even result in a Sudden Cardiac Arrest (SCA). In a SCA, the heart fails to pump blood effectively, and, if not treated, death can occur. In fact, it is estimated that SCA results in more than 250,000 deaths per year in the United States alone. Further, a SCA may result from a condition other than an arrhythmia. 
     One type of arrhythmia associated with SCA is known as Ventricular Fibrillation (VF). VF is a type of malfunction where the ventricles make rapid, uncoordinated movements, instead of the normal contractions. When that happens, the heart does not pump enough blood to deliver enough oxygen to the vital organs. The person&#39;s condition will deteriorate rapidly and, if not reversed in time, they will die soon, e.g. within ten minutes. 
     Ventricular Fibrillation can often be reversed using a life-saving device called a defibrillator. A defibrillator, if applied properly, can administer an electrical shock to the heart. The shock may terminate the VF, thus giving the heart the opportunity to resume pumping blood. If VF is not terminated, the shock may be repeated, often at escalating energies. 
     A challenge with defibrillation is that the electrical shock must be administered very soon after the onset of VF. There is not much time: the survival rate of persons suffering from VF decreases by about 10% for each minute the administration of a defibrillation shock is delayed. After about 10 minutes, the rate of survival for SCA victims averages less than 2%. 
     The challenge of defibrillating early after the onset of VF is being met in a number of ways. First, for some people who are considered to be at a higher risk of VF or other heart arrythmias, an Implantable Cardioverter Defibrillator (ICD) can be implanted surgically. An ICD can monitor the person&#39;s heart, and administer an electrical shock as needed. As such, an ICD reduces the need to have the higher-risk person be monitored constantly by medical personnel. 
     Regardless, VF can occur unpredictably, even to a person who is not considered at risk. As such, VF can be experienced by many people who lack the benefit of ICD therapy. When VF occurs to a person who does not have an ICD, they collapse, because blood flow has stopped. They should receive therapy quickly. 
     For a VF victim without an ICD, a different type of defibrillator can be used, which is called an external defibrillator. External defibrillators have been made portable, so they can be brought to a potential VF victim quickly enough to revive them by a rescuer. For a person at extremely high risk of VF, wearable defibrillators have been made 
     A problem with defibrillators is that they have electrodes that could fall off the patient. The electrodes could lose contact with the skin of the patient, which prevents them from acquiring an ECG of the patient, and then guiding an electrical shock for defibrillating the patient. 
     In addition, in the field of sensing, sometimes some locations are not easily accessible. Radio Frequency Identification (RFID) tags offer advantages for labeling items and being sensed remotely, but it is often not economical to produce small numbers of custom RFID tags for very specific purposes. 
     BRIEF SUMMARY 
     The present description gives instances of patient electrodes, patient monitors, defibrillators, wearable defibrillators, software and methods, the use of which may help overcome problems and limitations of the prior art. 
     In one embodiment, a patient electrode includes a pad for attaching to the skin of a patient, a lead coupled to the pad, and a contact detector that can change state, when the pad does not contact fully the skin of the patient. When the detector changes state, an output device may emit an alert, for notifying a rescuer or even the patient. An advantage over the prior art is that embodiments can be made economically. 
     These and other features and advantages of this description will become more readily apparent from the following Detailed Description, which proceeds with reference to the drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of a scene where an external defibrillator is used to save the life of a person according to embodiments. 
         FIG. 2  is a table listing two main types of the external defibrillator shown in  FIG. 1 , and who they might be used by. 
         FIG. 3  is a diagram showing components of an external defibrillator, such as the one shown in  FIG. 1 , which is made according to embodiments. 
         FIG. 4  is a diagram of components of a patient electrode made according to embodiments, in a use context. 
         FIGS. 5A and 5B  are diagrams of embodiments of novel use of RFID technology, applied to embodiments of the novel electrodes and systems of the invention. 
         FIG. 6  is a diagram of a patient electrode according to an embodiment where an output device is coupled to the electrode. 
         FIG. 7  is a flowchart for illustrating methods according to embodiments. 
         FIG. 8  is a diagram of a host device that may use an electrode according to embodiments. 
         FIG. 9  is a diagram of components of a wearable defibrillator system made according to embodiments. 
         FIG. 10  is a flowchart for illustrating methods according to embodiments. 
         FIG. 11  is a diagram illustrating RFID-based wireless sensing of a changed condition, according to embodiments. 
         FIG. 12  is a diagram illustrating electrical connections for an RFID-based sensor, according to embodiments that can be used to mainly detune the tag antenna as a result of sensing a changed condition. 
         FIG. 13  is a diagram illustrating electrical connections for an RFID-based sensor, according to embodiments that can be used mainly to disrupt the tag chip operation as a result of sensing a changed condition. 
         FIG. 14  is a flowchart for illustrating methods according to embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     As have been mentioned, the present description is about inventions in both fields of defibrillation and RFID, which have overlap. Embodiments of the inventions are now described in more detail. This specification should be interpreted as a whole, and not as separated by the subheadings below. 
     Detecting Loss of Full Skin Contact in Patient Electrodes 
       FIG. 1  is a diagram of a defibrillation scene. A person  82  is lying on their back. Person  82  could be a patient in a hospital, or someone found unconscious, and then turned to be on their back. Person  82  is experiencing a condition in their heart  85 , which could be Ventricular Fibrillation (VF). 
     A portable external defibrillator  100  has been brought close to person  82 . At least two defibrillation electrodes are usually provided with external defibrillator  100 , and are sometimes called electrodes. The first electrode is made of a pad  104  and electrode lead  105 , and the second electrode is made of a pad  108  and electrode lead  109 . At least one of these electrodes has a further component according to embodiments. A rescuer (not shown) has attached pads  104 ,  108  to the skin of person  82 . Defibrillator  100  is administering, via the electrodes, a brief, strong electric pulse  111  through the body of person  82 . Pulse  111 , also known as a defibrillation shock, goes also through heart  85 , in an attempt to restart it, for saving the life of person  82 . 
     Defibrillator  100  can be one of different types, each with different sets of features and capabilities. The set of capabilities of defibrillator  100  is determined by planning who would use it, and what training they would be likely to have. Examples are now described. 
       FIG. 2  is a table listing two main types of external defibrillators, and who they are primarily intended to be used by. A first type of defibrillator  100  is generally called a defibrillator-monitor, because it is typically formed as a single unit in combination with a patient monitor. A defibrillator-monitor is sometimes called monitor-defibrillator. A defibrillator-monitor is intended to be used by persons in the medical professions, such as doctors, nurses, paramedics, emergency medical technicians, etc. Such a defibrillator-monitor is intended to be used in a pre-hospital or hospital scenario. 
     As a defibrillator, the device can be one of different varieties, or even versatile enough to be able to switch among different modes that individually correspond to the varieties. One variety is that of an automated defibrillator, which can determine whether a shock is needed and, if so, charge to a predetermined energy level and instruct the user to administer the shock. Another variety is that of a manual defibrillator, where the user determines the need and controls administering the shock. 
     As a patient monitor, the device has features additional to what is minimally needed for mere operation as a defibrillator. These features can be for monitoring physiological indicators of a person in an emergency scenario. These physiological indicators are typically monitored as signals. For example, these signals can include a person&#39;s full ECG (electrocardiogram) signals, or impedance between two electrodes. Additionally, these signals can be about the person&#39;s temperature, non-invasive blood pressure (NIBP), arterial oxygen saturation/pulse oximetry (SpO2), the concentration or partial pressure of carbon dioxide in the respiratory gases, which is also known as capnography, and so on. These signals can be further stored and/or transmitted as patient data. 
     A second type of external defibrillator  100  is generally called an AED, which stands for “Automated External Defibrillator”. An AED typically makes the shock/no shock determination by itself, automatically. Indeed, it can sense enough physiological conditions of the person  82  via only the shown defibrillation electrodes  104 ,  108  of  FIG. 1 . In its present embodiments, an AED can either administer the shock automatically, or instruct the user to do so, e.g. by pushing a button. Being of a much simpler construction, an AED typically costs much less than a defibrillator-monitor. As such, it makes sense for a hospital, for example, to deploy AEDs at its various floors, in case the more expensive defibrillator-monitor is more critically being deployed at an Intensive Care Unit, and so on. 
     AEDs, however, can also be used by people who are not in the medical professions. More particularly, an AED can be used by many professional first responders, such as policemen, firemen, etc. Even a person with first-aid and CPR/AED training can use one. And AEDs increasingly can supply instructions to whoever is using them. 
     AEDs are thus particularly useful, because it is so critical to respond quickly, when a person suffers from VF. Indeed, the people who will first reach the VF sufferer may not be in the medical professions. 
     Increasing awareness has resulted in AEDs being deployed in public or semi-public spaces, so that even a member of the public can use one, if they have obtained first aid and CPR/AED training on their own initiative. This way, defibrillation can be administered soon enough after the onset of VF, to hopefully be effective in rescuing the person. 
     There are additional types of external defibrillators, which are not listed in  FIG. 2 . For example, a hybrid defibrillator can have aspects of an AED, and also of a defibrillator-monitor. A usual such aspect is additional ECG monitoring capability. A wearable defibrillator is another example. 
       FIG. 3  is a diagram showing components of an external defibrillator  300  made according to embodiments. These components can be, for example, in external defibrillator  100  of  FIG. 1 . These components of  FIG. 3  can be provided in a housing  301 , which is also known as casing  301 . 
     External defibrillator  300  is intended for use by a user  380 , who would be the rescuer. Defibrillator  300  typically includes a defibrillation port  310 , such as a socket in housing  301 . Defibrillation port  310  includes nodes  314 ,  318 . Defibrillation electrodes  304 ,  308 , which can be similar to the electrodes of  FIG. 1 , can be plugged in defibrillation port  310 , so as to make electrical contact with nodes  314 ,  318 , respectively. It is also possible that electrodes can be connected continuously to defibrillation port  310 , etc. Either way, defibrillation port  310  can be used for guiding via electrodes to person  82  an electrical charge that has been stored in defibrillator  300 , as will be seen later in this document. 
     If defibrillator  300  is actually a defibrillator-monitor, as was described with reference to  FIG. 2 , then it will typically also have an ECG port  319  in housing  301 , for plugging in ECG electrode leads  309 . ECG electrode leads  309  can help sense an ECG signal, e.g. a 12-lead signal, or from a different number of leads. Moreover, a defibrillator-monitor could have additional ports (not shown), and an other component  325  for the above described additional features, such as patient signals. 
     Defibrillator  300  also includes a measurement circuit  320 . Measurement circuit  320  receives physiological signals from ECG port  319 , and also from other ports, if provided. These physiological signals are sensed, and information about them is rendered by circuit  320  as data, or other signals, etc. 
     If defibrillator  300  is actually an AED, it may lack ECG port  319 . Measurement circuit  320  can obtain physiological signals through nodes  314 ,  318  instead, when defibrillation electrodes  304 ,  308  are attached to person  82 . In these cases, a person&#39;s ECG signal can be sensed as a voltage difference between electrodes  304 ,  308 . Plus, impedance between electrodes  304 ,  308  can be sensed for detecting, among other things, whether these electrodes  304 ,  308  have been inadvertently disconnected from the person, above and beyond the present invention, or in combination with the present invention. 
     Defibrillator  300  also includes a processor  330 . Processor  330  may be implemented in any number of ways. Such ways include, by way of example and not of limitation, digital and/or analog processors such as microprocessors and digital-signal processors (DSPs); controllers such as microcontrollers; software running in a machine; programmable circuits such as Field Programmable Gate Arrays (FPGAs), Field-Programmable Analog Arrays (FPAAs), Programmable Logic Devices (PLDs), Application Specific Integrated Circuits (ASICs), any combination of one or more of these, and so on. 
     Processor  330  can be considered to have a number of modules. One such module can be a detection module  332 , which senses outputs of measurement circuit  320 . Detection module  332  can include a VF detector. Thus, the person&#39;s sensed ECG can be used to determine whether the person is experiencing VF. 
     Another such module in processor  330  can be an advice module  334 , which arrives at advice based on outputs of detection module  332 . Advice module  334  can include a Shock Advisory Algorithm, implement decision rules, and so on. The advice can be to shock, to not shock, to administer other forms of therapy, and so on. If the advice is to shock, some external defibrillator embodiments merely report that to the user, and prompt them to do it. Other embodiments further execute the advice, by administering the shock. If the advice is to administer CPR, defibrillator  300  may further issue prompts for it, and so on. 
     Processor  330  can include additional modules, such as module  336 , for other functions. In addition, if other component  325  is indeed provided, it may be operated in part by processor  330 , etc. 
     Defibrillator  300  optionally further includes a memory  338 , which can work together with processor  330 . Memory  338  may be implemented in any number of ways. Such ways include, by way of example and not of limitation, nonvolatile memories (NVM), read-only memories (ROM), random access memories (RAM), any combination of these, and so on. Memory  338 , if provided, can include programs for processor  330 , and so on. The programs can be operational for the inherent needs of processor  330 , and can also include protocols and ways that decisions can be made by advice module  334 . In addition, memory  338  can store prompts for user  380 , etc. Moreover, memory  338  can store patient data. 
     Defibrillator  300  may also include a power source  340 . To enable portability of defibrillator  300 , power source  340  typically includes a battery. Such a battery is typically implemented as a battery pack, which can be rechargeable or not. Sometimes, a combination is used, of rechargeable and non-rechargeable battery packs. Other embodiments of power source  340  can include AC power override, for where AC power will be available, and so on. In some embodiments, power source  340  is controlled by processor  330 . 
     Defibrillator  300  additionally includes an energy storage module  350 . Module  350  is where some electrical energy is stored, when preparing it for sudden discharge to administer a shock. Module  350  can be charged from power source  340  to the right amount of energy, as controlled by processor  330 . In typical implementations, module  350  includes one or more capacitors  352 , and so on. 
     Defibrillator  300  moreover includes a discharge circuit  355 . Circuit  355  can be controlled to permit the energy stored in module  350  to be discharged to nodes  314 ,  318 , and thus also to defibrillation electrodes  304 ,  308 . Circuit  355  can include one or more switches  357 . Those can be made in a number of ways, such as by an H-bridge, and so on. 
     Defibrillator  300  further includes a user interface  370  for user  380 . User interface  370  can be made in any number of ways. For example, interface  370  may include a screen, to display what is detected and measured, provide visual feedback to the rescuer for their resuscitation attempts, and so on. Interface  370  may also include a speaker, to issue voice prompts, etc. Interface  370  may additionally include various controls, such as pushbuttons, keyboards, and so on. In addition, discharge circuit  355  can be controlled by processor  330 , or directly by user  380  via user interface  370 , and so on. 
     Defibrillator  300  can optionally include other components. For example, a communication module  390  may be provided for communicating with other machines. Such communication can be performed wirelessly, or via wire, or by infrared communication, and so on. This way, data can be communicated, such as patient data, incident information, therapy attempted, CPR performance, and so on. 
       FIG. 4  is a diagram of components of a patient electrode  410  made according to embodiments, in a use context. Patient electrode  410  includes a pad  404 , which is configured to be attached to a skin  483  of a patient  482 . Patient electrode  410  may also include an electrode lead  405  that is coupled to pad  404 . A plug (not shown) may optionally be provided, coupled to electrode lead  405 , and configured to be plugged into a socket, such as defibrillation port  310  or ECG port  319  of  FIG. 3 . 
     In some embodiments, patient electrode  410  is configured to detect an ECG signal of patient  482 , when attached to skin  483 . In some embodiments, patient electrode  410  is configured to deliver a defibrillation pulse to patient  482  through skin  483 . In some embodiments, patient electrode  410  can do both. In other words, patient electrode  410  may be an ECG electrode, or a defibrillation electrode, or both. 
     Pad  404  can be flexible, to conform to the curvature of the body of patient  482 . Pad  404  may include a backing layer  422 , and a conductive layer  424  attached to backing layer  422 . Conductive layer  424  is electrically coupled to electrode lead  405 . 
     Conductive layer  424  typically has adhesive, for adhering to skin  483 . Even though adhesives are good and help the entire pad  404  remain attached to skin  483 , sometimes there is loss of full contact  460 . Loss of full contact means that pad  404  does not contact skin  483  in part, or fully. Either only a portion, or the entire pad  404 , may come off skin  483 , neither of which is desirable. Defibrillating through a pad that has partially come off can increase the current density through the portion of the pad that has not come off, which can harm the patient. Alternately, some of the energy might not reach the patient depending on the electrode. And, if the pad has only partially come off, an ECG might still be received, thus possibly not alerting a user that the pad has partially come off. 
     Patient electrode  410  may also include a contact detector  444 . Contact detector  444  may be coupled to pad  404  or electrode lead  405 . Contact detector  444  may be configured to be in one of a plurality of detector states. In some embodiments, contact detector  444  can change from one state to another, when pad  404  does not contact fully skin  483 . In some embodiments, the detector states are different values of an electrical property of the contact detector. The electrical property can be impedance, or generation of electrical current or voltage, and so on. 
     In some instances, a determination is made from the current detector state that pad  404  does not fully contact patient skin  483 . This can be accomplished in a number of ways, which depend on the type of contact detector  444 . Some examples are described, which are not limiting. In addition, more than one detection techniques can be used. 
     In some embodiments, contact detector  444  is a temperature sensor, and the detector state indicates a detected temperature. Normally, the detected temperature would be that of the patient&#39;s skin  483 . However, if there is loss of contact  460 , the temperature sensor will sense the temperature of the environment of skin  483 , instead of that of skin  483  itself. Accordingly, the determination of loss of full contact  460  can then be made if the detected temperature changes beyond a threshold, or changes beyond a threshold within a preset time. Adjustments should be made for the event that the patient is being cooled, as will be obvious to a person skilled in the art in view of the present description. 
     In some embodiments, contact detector  444  is an optical sensor, and the detector state indicates a detected illumination. The optical sensor can be placed so that, when the pad is normally attached to skin  483 , it prevents any light from reaching it. However, if there is loss of full contact  460 , the optical sensor may detect illumination, which is the same phenomenon as lifting a curtain in an otherwise dark room. Accordingly, the determination of loss of full contact  460  can then be made if the detected illumination changes beyond a threshold. 
     In some embodiments, contact detector  444  is a capacitive sensor, and the detector state indicates a detected capacitance. The capacitive sensor can be placed so that, when the pad is normally attached to skin  483 , the capacitive sensor detects capacitance from the mass of the patient  482 . However, if there is loss of full contact  460 , the capacitive sensor may detect a lot less capacitance, as it will not be detecting the capacitance from the mass of the patient  482 . Accordingly, the determination of loss of full contact  460  can then be made if the detected capacitance changes beyond a threshold. 
     Patient electrode  410  is intended for use with an output device  470 . Output device  470  is configured to emit an alert  477 , when it is determined from the current detector state that pad  404  does not contact fully skin  483  of patient  482 . The types of alert  477  are described later in this document. 
     Output device  470  may be implemented in any number of ways. It may be attached to patient electrode  410  or not. In some embodiments, output device  470  is coupled to a monitor that has a module configured to measure a physiological parameter of patient  482 . In those cases, output device  470  can be used to emit another alert, if the physiological parameter exceeds a threshold or rescuers are to be notified. 
     In some embodiments, a sense signal is generated that encodes the current detector state. Output device  470  can be configured to receive a version of the sense signal, for example along path  468  in  FIG. 4 . 
     In some of those embodiments, patient electrode  410  further has a power source (not shown). The power source can be configured to query the contact detector about its current state, and generate the sense signal accordingly. 
     The sense signal can be implemented in any number of ways. It can be wired, in which case path  468  includes at least one wire. The wire can be implemented as a pair of sense leads, an example of which is shown later. Alternately, the wire can be implemented via electrode lead  405 , by multiplexing its function between receiving ECG and sensing the detector. Moreover, the sense signal can be wireless, in which case path  468  includes the air. A number of wireless technologies may be used, such as Bluetooth and so on. 
     This description also includes inventions in the field of Radio Frequency IDentification (RFID) technology, which can be applied in many fields of remote sensing. Such inventions are described more fully later in this document, while some of their particular applications for the patient electrodes and systems of the invention are now described. 
       FIGS. 5A and 5B  are diagrams of embodiments of novel use of RFID technology, applied to embodiments of the novel electrodes and systems of the invention. They are also an example where a sense signal is transmitted wirelessly according to embodiments. A patient electrode according to embodiments has a pad  504 , a contact detector  544  shown only in  FIG. 5B , and an RFID tag  555  coupled to contact detector  544 . 
     In  FIG. 5A , an RFID reader/interrogator  500  is configured to interrogate RFID tag  555 . Reader  500  could be, for example, communication module  390  of  FIG. 3 . Reader  500  has an antenna  501 , and transmits an interrogation wave  531 . Tag  555  backscatters a backscattered wave  532 , with information from tag  555 . In such embodiments, backscattered wave  532  can encode the sense signal. 
       FIG. 5B  shows more detail for pad  504 . RFID tag  555  is located on the top side of pad  504 , which does not contact the patient skin. Contact detector  544  is located on the bottom side of pad  504 , which is why it is shown in dashed lines. Moreover, contact detector  544  is coupled to RFID tag  555  with jumper wires  596 , which can go through pad  504 , or around an edge of it. Briefly, as contact detector  544  detects that the pad does not contact fully the skin of the patient, its electrical properties will change, and thus operation of RFID tag  555  will be impacted. Accordingly, reader  500  may be able to detect the loss of contact, by comparing backscattered wave  532  with what it expected to receive. More detailed embodiments and explanations are provided later in this description. 
     As mentioned above, in some embodiments, the output device is coupled to the electrode. An example is now described. 
       FIG. 6  is a diagram of a patient electrode  610  according to embodiments. Electrode  610  has a pad  604 , an electrode lead  605 , and a contact detector  644 . Electrode  610  also includes an output device  670  is coupled to pad  604 . Alternately, output device  670  can be coupled to electrode lead  605 . 
     The output device, such as output device  670 , is made according to the alert that is desired. For example, the alert can be auditory, and output device  670  can include a sound producing device, such as a speaker. Or, the alert may be visual, and output device  670  can include a light producing device, such as a screen that can produce a message, an LED that can light next to appropriate writing, or picture, and so on. Or, the alert may be tactile, and output device  670  can include a vibrating mechanism. 
       FIG. 7  shows a flowchart  700  for describing methods according to embodiments. The methods of flowchart  700  may also be practiced by embodiments described above, such as the patient electrode of  FIG. 6 . 
     According to an optional operation  710 , the contact detector of the patient electrode is queried about its current state. Optionally, a sense signal is generated responsive to the current detector state. 
     According to another operation  720 , it is determined from the current state whether the pad contacts fully the skin of the patient. If a sense signal has been generated, the determination may be made from the sense signal. If the determination of operation  720  results in “yes”, execution returns to operation  710 . 
     If the determination of operation  720  results in “no”, then according to another operation  730 , an alert is emitted by the output device. In some embodiments, the output device receives a version of the sense signal, and emits the alert. In some embodiments, the alert signal is null unless operation  720  results in “no”. Then the output device only operates based on the sense signal being non-zero. 
       FIG. 8  is a diagram of a host device  800  made according to embodiments, which may use an electrode  810  according to embodiments. Host device  800  may be a patient monitor, a defibrillator, a wearable defibrillator, a device such as that of  FIG. 3 , and so on. Patient electrode  810  includes a pad  804 , an electrode lead  805  and a contact detector  855 . 
     Host device  800  includes an electrode port  811 . Electrode port  811  is configured to receive electrode lead  805 . As electrode port  811  can be repeated for the proper number of electrodes, it will become similar to port  310  or port  319  of  FIG. 3 . Optionally, host device  800  could also have a module configured to measure an ECG of the patient through electrode port  811 , such as module  320  of  FIG. 3 . 
     Host device  800  also includes a sense port  812 . Sense port  812  is configured to receive a sense signal from contact detector  855 . 
     In the embodiment of  FIG. 8 , electrode  810  includes sense leads  868 , and sense port  812  is a physical port for receiving sense leads  868 . The sense signal is thus transferred from electrode  810  via sense leads  868  to host device  800 . Equivalently, the sense signal could be transferred wirelessly as seen in  FIG. 5A , in which case sense port  812  is a wireless receiver such as reader  500  or communication module  390  of  FIG. 3 . 
     Host device  800  further includes an output device  870 . Output device  870  is configured to emit an alert, if it is detected from the sense signal that pad  804  does not contact fully the skin of the patient. 
     Optionally, host device  800  may also include other components. For example, it may include a processor  830 . Processor  830  may be configured to detect from the sense signal whether electrode  810  does not contact fully the skin of the patient. 
     Host device  800  may further include a memory  838 , which can work together with processor  830 . Memory  838  may be implemented in any number of ways. Such ways include, by way of example and not of limitation, volatile memories, nonvolatile memories (NVM), read-only memories (ROM), random access memories (RAM), magnetic disk storage media, optical storage media, smart cards, flash memory devices, any combination of these, and so on. Memory  838  is thus a non-transitory storage medium. Memory  838 , if provided, can include programs for processor  830  to execute. Executing is performed by physical manipulations of physical quantities, and may result in the functions, processes and/or methods to be performed, and/or the processor to cause other devices or components or blocks to perform such functions, processes, actions and/or methods. The programs can include sets of instructions. The programs can be operational for the inherent needs of processor  830 . 
     In addition, memory  838  can store prompts for a user. Moreover, memory  838  can store data. The data can include patient data, system data and environmental data. The data can be stored in memory  838  before it is transmitted out of host device  800 . 
     Plus, host device  800  may further be configured to make an entry in the memory, if it is detected that the electrode does not contact fully the skin of the patient. The entry can be of the date, time, other available data including patient data, and efforts to emit the alert. 
     Moreover, host device  800  may include another module  825 . Other module  825  can be configured to measure a physiological parameter of the patient, which can be other than the patient&#39;s ECG. In some embodiments, the local parameter is a trend that can be detected in a monitored physiological parameter of the patient. A trend can be detected by comparing values of parameters at different times. 
     Additionally, host device  800  may include a defibrillator  888 . Defibrillator  888  can be configured to transmit an electrical defibrillation pulse through electrode port  811 , in the event that electrode  810  is a defibrillation electrode. 
     As described above, the alert can be auditory, visual or tactile. In some embodiments, the alert identifies the electrode that is coming off the skin, thus distinguishing it from another electrode. The alert could include a picture of the electrode in question. The picture could also be in a context, such as indicating the location of the electrode. 
     Host device  800  may also emit the alert electronically to a remote care giver, as a transmitted message. The message may be transmitted over a communication network wirelessly or not. 
     In some embodiments, host device  800  is part of a wearable defibrillation system. Embodiments are now described in more detail, also with reference to  FIG. 9 . 
     A wearable defibrillator system made according to embodiments has a number of components. One of these components is a support structure, which is configured to be worn by the patient. The support structure can be any structure suitable for wearing, such as a harness, a vest, one or more belts, another garment, and so on. The support structure can be implemented in a single component, or multiple components. For example, a support structure may have a top component resting on the shoulders, for ensuring that the defibrillation electrodes will be in the right place for defibrillating, and a bottom component resting on the hips, for carrying the bulk of the weight of the defibrillator. A single component embodiment could be with a belt around at least the torso. Other embodiments could use an adhesive structure or another way for attaching to the person, without encircling any part of the body. There can be other examples. 
       FIG. 9  is a diagram of components of a wearable defibrillator system made according to embodiments, as it might be worn by a patient  982 . Patient  982  may also be referred to as person  982 , and/or wearer  982  since he or she wears components of the wearable defibrillator system. 
     In  FIG. 9 , a generic support structure  950  is shown relative to the body of person  982 , and thus also relative to his or her heart  985 . Structure  950  could be a harness, a vest, one or more belts, a garment, as per the above; it could be implemented in a single component, or multiple components, and so on. Structure  950  is wearable by person  982 , but the manner of wearing it is not depicted, as structure  950  is depicted only generically in  FIG. 9 . 
     A wearable defibrillator system is configured to defibrillate the patient, by delivering electrical charge to the patient&#39;s body in the form of an electric shock or one or more pulses.  FIG. 9  shows a sample external defibrillator  900 , and sample defibrillation electrode pads  904 ,  908 , which are coupled to external defibrillator  900  via electrode leads  905 . Defibrillator  900  can be made as device  300  of  FIG. 3 , or in other ways. Defibrillator  900  is coupled to support structure  950 . As such, all components of defibrillator  900  can be therefore coupled to support structure  950 . When defibrillation electrode pads  104 ,  108  make good electrical contact with the body of person  982 , defibrillator  900  can administer a brief, strong electric pulse  911  through the body, similar to pulse  111  of  FIG. 1 . 
     A wearable defibrillator system according to embodiments includes an output device  970 . In some embodiments, output device  970  is coupled to support structure  950 . In some of these embodiments, output device  970  is coupled such that it is positioned near the patient&#39;s shoulder. This way, an alert that is intended for wearer  982  can be heard more reliably, if it is audible. 
     It should be remembered that a wearable defibrillator system according to embodiments may include electrodes that can have another output device on the pad, or the output device only on the pad. This way a tactile alert will be perceived at the location of the worn electrode. 
     The above-mentioned devices and/or systems perform functions, processes and/or methods, as described in this document. The functions, processes and/or methods may be implemented by one or more devices that include logic circuitry. The logic circuitry may include a processor that may be programmable for a general purpose, or dedicated, such as processor  830 . 
     Moreover, methods and algorithms are described below. These methods and algorithms are not necessarily inherently associated with any particular logic device or other apparatus. Rather, they are advantageously implemented by programs for use by a computing machine, such as a general-purpose computer, a special purpose computer, a microprocessor, etc. 
     Often, for the sake of convenience only, it is preferred to implement and describe a program as various interconnected distinct software modules or features, individually and collectively also known as software. This is not necessary, however, and there may be cases where modules are equivalently aggregated into a single program, even with unclear boundaries. In some instances, software is combined with hardware, in a mix called firmware. 
     This detailed description includes flowcharts, display images, algorithms, and symbolic representations of program operations within at least one computer readable medium. An economy is achieved in that a single set of flowcharts is used to describe both programs, and also methods. So, while flowcharts described methods in terms of boxes, they also concurrently describe programs. 
     A method is now described. 
       FIG. 10  shows a flowchart  1000  for describing methods according to embodiments. The methods of flowchart  1000  may also be practiced by embodiments described above, such as host device  800 . 
     According to an operation  1010 , an electrode lead is received through the electrode port. The electrode lead is of an electrode having a pad for contacting a patient&#39;s skin, and a contact detector. 
     According to another operation  1020 , a sense signal is received through the sense port. The sense signal is received from the contact detector, either via sense leads or wirelessly. 
     According to another operation  1030 , it is determined whether the pad contacts fully the skin of the patient. The determination may be from the received sense signal, which informs of the state of the contact detector. In some embodiments, the sense signal is null unless operation  1030  results in “no”. In some embodiments, the sense signal is nonzero. Depending on the design, there can be an affirmative operation of determining from the sense signal whether the electrode does not contact fully the skin of the patient. If the determination of operation  1030  results in “yes”, execution returns to operation  1010 . 
     If the determination of operation  1030  results in “no”, then according to another operation  1040 , an alert is emitted by the output device. In some embodiments, the alert signal is null unless operation  1030  results in “no”. Then the output device only operates based on the sense signal being non-zero. The alert may be emitted as mentioned above. 
     According to another, optional operation  1050 , an entry is made in a memory. The entry can be made if it is detected that the electrode does not contact fully the skin of the patient. 
     There can be further other optional operations. For example, an ECG of the patient can be measured through the electrode port. Or a physiological parameter of the patient, other than the patient&#39;s ECG, can be measured. Or, an electrical defibrillation pulse can be transmitted through the electrode port. 
     Moreover, the output device may be used also for other notifications. For example, another condition of the patient may be detected, such as from measuring their physiological parameters. The condition may be that a parameter is trending in a way that causes concern, and so on. When the other condition is detected, the output device may emit an alert. 
     The invention also includes methods for processor  830 . Processor  830  receives inputs and causes devices, modules and components to execute functions. Some of the resulting methods are those of  FIG. 10 . 
     In some embodiments, a processor may decode a sense signal. The sense signal may have been received through the sense port. The sense signal may be from a contact detector of an electrode that has a pad for contacting a patient&#39;s skin. Then it may be determined from the sense signal whether the pad does not contact fully the skin of the patient and, if so, the output device can be caused to emit an alert. The alerts can be as above. 
     RFID-Based Sensing 
       FIG. 11  is a diagram illustrating RFID-based wireless sensing of a changed condition, according to embodiments. It will be appreciated that the sensing can be in any number of frequencies, such as 13.56 MHz, 900 MHz, 2.4 GHz and so on. Moreover, where two RFID tags are shown, it is preferred and advantageous that they work in the same frequency, but that is not necessary. 
     A changed condition  1172  is shown in  FIG. 11  at a location  1171 . The condition that could change is illumination, temperature, available mass, capacitance, sound, pressure, humidity, and so on, and the desire is to have a system that detects it without the need for inspection, for example whether a basement leaks water, electrodes losing full contact, etc. A person skilled in the art will find many more uses. 
     Embodiments include an RFID-based sensor  1110 . Sensor  1110  includes a base  1173  that is optional and highly preferred. One or all the other components of sensor  1110  can be coupled to base  1173 . Base  1173  can be made in any way suitable for the described functions such as, for example, from plastic that is hard or flexible. 
     If the change of condition needs to be detected at a specific location such as location  1172 , then base  1173  could be configured to be placed at that location. For example, base  1173  may further have provisions for its attachment, such as a clear flap suitable for gluing or nailing to a place of interest. It is also recommended that base  1173  have a clear area to accommodate writing, for better identification of the sensors at their locations. 
     Sensor  1110  also includes a sensing RFID tag  1155 . Sensing RFID tag  1155  may be coupled to base  1173 , if provided. The word “sensing” in the name of sensing RFID tag  1155  is only for distinguishing from the other RFID tag, if provided. Advantageously, sensing RFID tag  1155  can be procured from commercially available RFID tags. 
     Sensor  1110  additionally includes a detector  1144 . Detector  1144  has an electrical property that may change responsive to a change in the condition, which is why an arrow is shown from changed condition  1172  to detector  1144 . The detector can be of the technology applicable for the condition to be detected. As such, the detector can be a light detector, a temperature sensor, a capacitance sensor, a sound detector, a pressure sensor such as piezoelectric technology, a humidity detector, and so on. Depending on the operation of the detector, the electrical property that changes when the condition changes can be a generated voltage, a generated current, a changed impedance, and so on. 
     In addition, detector  1144  is electrically coupled to sensing RFID tag  1155 . Coupling can be by manufacturing detector  1144  suitably close to the RFID tag. Alternately, detector  1144  can be electrically coupled via jumper wires  1196 . If used, jumper wires  1196  are preferably kept short. Changed condition  1172  will generate a change in the electrical property of detector  1144 , which in turn will impact an operation of sensing RFID tag  1155 . The change in operation can be detected by an interrogating RFID reader, which will thus know about the changed condition  1172 . 
     Sensor  1110  optionally also includes a reference RFID tag  1156 . Reference RFID tag  1156  may be coupled to base  1173 , if provided. Again, reference RFID tag  1156  can be procured from commercially available RFID tags. If reference RFID tag  1156  will be used for dynamically writing to it periodic information such as received signal strength, then it should be the type that can be written. 
     Reference RFID tag  1156  is not electrically coupled to detector  1144  as is sensing RFID tag  1155 . This means that reference RFID tag  1156  is coupled to detector differently than sensing RFID tag  1155 , or not at all. As such, while the changed condition will impact the operation of sensing RFID tag  1155 , it will not impact that of reference RFID tag  1156 . 
     In fact, it should be considered that in location  1171 , if there is a changed condition  1172 , the operation of both tags may be affected. That is why, in some embodiments, sensor  1110  also includes a shield that is configured to shield reference RFID tag  1156  differently than sensing RFID tag  1155 , so that the latter will not be impacted by changed condition  1172 . Shielding differently means that sensing RFID tag  1155  may be shielded in part, or not at all, by the shield. 
     More can be done by exploiting the Electronic Product Codes (EPCs) that can be stored in the memories of RFID tags  1155 ,  1156 . For example, sensing RFID tag  1155  can have a first memory that stores a first EPC (“EPC1”), and reference RFID tag  1156  can have a second memory that stores a second EPC (“EPC2”). EPC2 can be related to EPC1, so that an RFID reader will know the relationship of the two RFID tags, and it will be easier to select them for interrogation while quieting any other tags in location  1171 . In fact, the first EPC could include a string in common with the second EPC. 
     Embodiments include an RFID reader  1100 , which can be configured to sense the impacted operation of sensing RFID tag  1155 . RFID reader  1100  may have an antenna  1101 , a processor  1130 , and a memory  1138  that could store reader software applications (“apps”)  1139  according to embodiments. Antenna  1101  can transmit and receive waves at the desired frequency for the RFID application. In some embodiments, a different antenna transmits, while antenna  1101  receives. A Received Signal Strength Indicator (RSSI) module may also be provided with reader  1100 , which is configured to measure a strength of the backscattered signal. 
     RFID reader  1100  may transmit an interrogation wave  1131  towards location  1171 , where sensor  1110  is at. Antenna  1101  may receive a backscattered wave  1132  in response to the transmitted wave. Backscattered wave  1132  will include response  1141  from sensing RFID tag  1155 , and response  1142  from reference RFID tag  1156 , if provided. As can be seen from  FIG. 11 , response  1141  can be code EPC1, and response  1142  can be code EPC2. Moreover, if reader  1100  follows a protocol that singulates the RFID tags, it will be able to discern code EPC1 from code EPC2. However, response  1141  may be received at a different strength, also known as signal strength, if changed condition  1172  has caused detector  1144  to impact the operation of sensing RFID tag  1155 . And, as will be seen in embodiments, response  1141  might be too weak to be received, or it might not be received at all, and that is why it is drawn as a “whisper”. 
     Accordingly, from the strength of backscattered wave  1132 , processor  1130  may be able to determine that condition  1172  has changed. Processor  1130  may be further configured to transmit an alert to an operator or a monitoring service, if condition  1172  has changed. 
     The determination can be made in a number of ways. In one embodiment, the determination can be made by comparing the strength of response  1141  to a strength of a previously received backscatter from the location. A value of that strength may have been stored in memory  1138  for future comparison. If the strength of the presently backscattered wave has become less, then the condition may be changing. 
     In an additional embodiment, the determination is made if the strength of the backscattered wave is lower than a threshold. The threshold can be set appropriately. This type of embodiment also takes care of the possibility that backscattered wave  1132  reaching antenna  1101  is too weak to be measured, or that response  1141  is not generated at all. 
     In another embodiment, the backscattered wave includes a stored value of a previously measured signal strength from the location. In other words, once that signal strength was measured previously, its value stored back in the memory of sensing RFID tag  1155 , for future comparison. The determination can then be made by comparing the strength of the presently backscattered wave to the stored value. Also, memory  1138  can be configured to store the value of present response  1141 , for future comparison. 
     In one more embodiment, the determination is made by effectively comparing the signal strength of response  1141 , which is presumed to be backscattered by sensing RFID tag  1155 , to that of response  1142 , which is presumed to be backscattered by reference tag  1156 . In an ideal situation, when there is no changed condition, the signal strengths of responses  1141  and  1142  could be identical. Due to jumper wires  1196 , however, they might not be. Still, their ratio can provide good guidance—if it deteriorates in the future, that could mean there is changed condition  1172 . So, the determination can be made by comparing a detected ratio of the strength of the first response to that of the second response, against that of a previously detected ratio. Plus, performance values of sensing RFID tag  1155  can be stored in the memory of the reference tag  1156  that is less prone to loss due to changed condition  1172 . The strength of this technique is that changes in other conditions are not automatically misinterpreted as changed condition  1172 , because the backscatter signal strength of the reference tag  1156  will also be affected. An example of another such condition is if reader  1100  subsequently transmits at lesser power. 
     As has been mentioned, sensor  1110  is specially made such that the change in the electrical property of detector  1144  will impact the performance of sensing RFID tag  1155 . Moreover, it is very economical to achieve this by procuring a commercially available RFID tag as sensing RFID tag  1155 , and generally electrically coupling it to detector  1144  via jumper wires  1196 . Particular examples of such coupling are now described with reference to  FIGS. 12 and 13 . 
       FIG. 12  is a diagram illustrating electrical connections for an RFID-based sensor according to embodiments. Sensing RFID tag  1255  has a substrate  1291  and a sensing antenna  1292  on substrate  1291 . The term “sensing” in the name of sensing antenna  1292  is only to distinguish from the antenna of any other RFID tag, if provided. The sensing antenna can be any shape. The specific shape of sensing antenna  1292  in the example of  FIG. 12  is from U.S Design Pat. D543,9765 to Impinj for the 900 MHz range, and chosen here so that the simplicity of its pattern would not unnecessarily confuse the description, but many other antenna designs may work just as well, or even better. 
     Sensing RFID tag  1255  also has a tag chip  1293  on substrate  1291 . Tag chip  1293  is a rectangle that is much smaller than sensing antenna  1292 , and has conductive pads at its corners. Antenna  1292 , as well as many other antennas, terminates in four edges that are contacted by the conductive pads of tag chip  1293 . 
     A detector  1244  is electrically coupled to sensing antenna  1292 , by jumper wires  1296  that are electrically connected at nodes  1297 . Coupling can be by soldering. If antenna  1292  is covered by a plastic cover, that cover may have to be removed first at the location of nodes  1297 . 
     The connections of  FIG. 12  can be used so that the performance of sensing RFID tag  1255  will be impacted mainly by detuning the sensing antenna. Indeed, when the electrical property of detector  1244  changes because of the changed condition, the impact on sensing antenna  1292  will be felt from nodes  1297 , which are “in the middle” of sensing antenna  1292 , and “far” from where it contacts tag chip  1293 . The antenna properties will likely change, and thus its reflectivity will change. 
     If a commercially available RFID tag  1255  has been used that was already tuned to optimum reflectivity, then the changing property of detector  1244  will detune it and diminish the reflectivity. That is why response  1141  may be weak. 
     Not all detectors work the same way. In general, a meshing circuit  1245  can be coupled between detector  1244  and sensing antenna  1292 . In the example of  FIG. 12 , meshing circuit  1245  is coupled in parallel. 
     Meshing circuit  1245  can be designed so that the particular changing property of detector  1244  becomes an important effect that impacts the operation of tag chip  1255 , and in this case its reflectivity. For example, meshing circuit  1245  could have a resistor, a capacitor, both, etc. If detector  1244  changes impedance due to the changed condition, then meshing circuit  1245  can provide impedance of a suitable value that is added in parallel. 
     The connections of  FIG. 12  can be also used to disrupt the tag chip operation. For example, if detector  1244  generates current due to the changed condition, then meshing circuit  1245  can be a high resistance resistor that creates a DC voltage, some of which can be applied to tag chip  1293 . 
       FIG. 13  is a diagram illustrating electrical connections for an RFID-based sensor according to embodiments. Sensing RFID tag  1355  has a substrate  1391  and a sensing antenna  1392  on substrate  1391 . Sensing antenna  1392  is the same as antenna  1292 , to further illustrate the difference. Sensing RFID tag  1355  also has a tag chip  1393  on substrate  1391 . 
     A detector  1344  is electrically coupled to sensing antenna  1392 , by jumper wires  1396  that are electrically connected at nodes  1397 . Coupling can be by soldering. 
     A meshing circuit  1345  can be coupled between detector  1344  and sensing antenna  1392 . In the example of  FIG. 13 , meshing circuit  1345  is coupled in series. 
     The connections of  FIG. 13  are intended so that the performance of sensing RFID tag  1355  will be impacted mainly by disrupting the operation of tag chip  1393 . Indeed, when the electrical property of detector  1344  changes because of the changed condition, the impact will be felt from nodes  1397 , which are near tag chip  1393 . For example, if detector  1344  generates current due to the changed condition, then meshing circuit  1345  can be a high resistance resistor that creates a DC voltage, some of which can be applied to tag chip  1393 . Depending on the design of tag chip  1393 , the DC voltage may impact the operation of the demodulator and/or the modulator of tag chip  1393 , perhaps preventing it from sensing properly the reader signal, or responding properly. This will be achieved more easily if an antenna design is chosen, and nodes are chosen that are not shorted to each other by the antenna itself. 
     An advantage is that, while it was intended to impact tag chip  1393 , this was accomplished without having to solder to its pads, but by choosing nodes  1397  near it. Reasons to use a commercially available RFID tag are both that it is cheap, and that the low cost already incorporates the made connection between antenna  1392  and tag chip  1393  that requires high precision to make. 
     Other options include making custom antenna designs for such chips, and designing the detector in the tag chip, especially if the latter can be implemented in CMOS. 
       FIG. 14  shows a flowchart  1400  for describing methods according to embodiments. The methods of flowchart  1400  may also be practiced by embodiments described above, such as by reader  1100  or one of its components, for example by reader software. 
     According to an optional operation  1410 , an interrogation wave is transmitted towards the location of interest. Preferably, a sensor such as sensor  1110  has been placed there, and which has one or more RFID tags. 
     According to another operation  1420 , a backscattered wave is received. The backscattered wave may be received in response to the interrogation wave. The backscattered wave may have encoded information that identifies the sensor that is responding this way. 
     According to another, optional operation  1430 , the strength of the received backscattered wave is detected. The detected strength may also be recorded, both locally in the reader and also in an RFID tag on the responding sensor. 
     According to another operation  1440 , it is determined whether a condition has changed at the location. The determination can be made from the strength of the backscattered wave, and also as described above. If not, then execution may return to operation  1410 . 
     If yes, then according to another operation  1450 , an alert is transmitted. The alert can be transmitted by proper messaging to a different module in the host or a different device. 
     In the methods described above, each operation can be performed as an affirmative step of doing, or causing to happen, what is written that can take place. Such doing or causing to happen can be by the whole system or device, or just one or more components of it. In addition, the order of operations is not constrained to what is shown, and different orders may be possible according to different embodiments. Moreover, in certain embodiments, new operations may be added, or individual operations may be modified or deleted. The added operations can be, for example, from what is mentioned while primarily describing a different system, device or method. 
     This description includes one or more examples, but that does not limit how the invention may be practiced. Indeed, examples or embodiments of the invention may be practiced according to what is described, or yet differently, and also in conjunction with other present or future technologies. 
     A person skilled in the art will be able to practice the present invention in view of this description, which is to be taken as a whole. Details have been included to provide a thorough understanding. In other instances, well-known aspects have not been described, in order to not obscure unnecessarily the present invention. 
     Other embodiments include combinations and sub-combinations of features described herein, including for example, embodiments that are equivalent to: providing or applying a feature in a different order than in a described embodiment; extracting an individual feature from one embodiment and inserting such feature into another embodiment; removing one or more features from an embodiment; or both removing a feature from an embodiment and adding a feature extracted from another embodiment, while providing the advantages of the features incorporated in such combinations and sub-combinations. 
     The following claims define certain combinations and subcombinations of elements, features and steps or operations, which are regarded as novel and non-obvious. Additional claims for other such combinations and subcombinations may be presented in this or a related document.