Patent Publication Number: US-2023148883-A1

Title: Pressure of blood monitor

Description:
CROSS-REFERENCES 
     The following applications and materials are incorporated herein, in their entireties, for all purposes: U.S. Provisional Patent Application Ser. No. 61/971,947, filed Mar. 28, 2014, and U.S. patent application Ser. No. 14/673,853, filed Mar. 30, 2015. 
    
    
     INTRODUCTION 
     Existing methods of measuring blood pressure on a digit (such as a finger) in outpatient settings typically employ the same underlying technology as used in arm and wrist blood pressure measurement devices. As such, these devices typically require a spacious interior to house an inflatable cuff and multiple batteries or other power sources necessary for cuff inflation. These methods are therefore generally not suitable for frequent, on demand use due to their relatively large size and the time it takes to inflate the cuff. What is needed is a more convenient blood pressure monitoring device that is less cumbersome and more suitable for discrete, frequent use and/or continuous monitoring. Ideally, an improved blood pressure measuring device would also have a reduced cost of manufacturing. 
     SUMMARY 
     The present disclosure may include one or more apparatus, systems, and methods related to monitoring of pressure, including monitoring the pressure of blood. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Advantages and characteristics of one or more embodiments of the present disclosure will become apparent from the description with reference to the figures. 
         FIG.  1    is a schematic diagram showing relationships between components of an illustrative pressure of blood monitoring device. 
         FIG.  2    is an isometric view of an illustrative pressure of blood monitoring device according to aspects of the present disclosure, and a side view of the device mounted on a finger. 
         FIG.  3    is a sectional overhead view of the device of  FIG.  2   , including a portion of a human finger. 
         FIG.  4    is an isometric view of another illustrative pressure of blood monitoring device having a crosswise brace portion. 
         FIG.  5    is a sectional view of an illustrative prior art inflatable cuff-style blood pressure device on a finger. 
         FIG.  6    depicts response curves showing relationships between the quantified change in an outside parameter responsible for pressure changing in the soft tissue surrounding an artery and the corresponding tissue pressure or pressure on the artery. 
         FIG.  7    is a sectional side view of an illustrative critical pressure sensor suitable for use in a pressure of blood monitoring device according to aspects of the present disclosure. 
         FIG.  8    is an isometric view of another illustrative critical pressure sensor suitable for use in a pressure of blood monitoring device according to aspects of the present disclosure. 
         FIG.  9    is a sectional side view of the sensor of  FIG.  8   . 
         FIG.  10    is schematic diagram showing relationships between components of another illustrative pressure of blood monitoring device. 
         FIG.  11    is an isometric view of an illustrative pressure of blood monitoring device according to aspects of the present disclosure. 
         FIG.  12    is a sectional side view of an illustrative proportional sensor suitable for use in a pressure of blood monitoring device according to aspects of the present disclosure. 
         FIG.  13    is an exemplary calibration curve associated with the sensor of  FIG.  12   . 
         FIG.  14    is an illustrative continuous sensor suitable for use in a pressure of blood monitoring device according to aspects of the present disclosure. 
         FIG.  15    is an illustrative method for monitoring pressure of blood suitable for use with pressure of blood monitoring devices according to aspects of the present disclosure. 
         FIG.  16    is another illustrative method for monitoring pressure of blood suitable for use with pressure of blood monitoring devices according to aspects of the present disclosure. 
         FIG.  17    is another illustrative method for monitoring pressure of blood suitable for use with pressure of blood monitoring devices according to aspects of the present disclosure. 
         FIG.  18    is an illustrative data processing system suitable for use with pressure of blood monitoring devices and methods according to aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Overview 
     Various embodiments of pressure of blood monitoring devices, one or more embodiments including a non-inflating, digit-mounted blood pressure of blood monitor, are described below and illustrated in the associated drawings. Unless otherwise specified, a pressure of blood monitor and/or its various components may, but are not required to, contain at least one of the structure, components, functionality, and/or variations described, illustrated, and/or incorporated herein. Furthermore, the structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein in connection with a pressure of blood monitor may, but are not required to, be included in other pressure of blood monitors. The following description of various embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application or uses. Additionally, the advantages provided by the embodiments, as described below, are illustrative in nature and not all embodiments provide the same advantages or the same degree of advantages. 
     This disclosure concerns a monitoring device that measures pressure of blood (interchangeably termed “BP” for blood pressure) non-invasively on a user&#39;s finger. A BP monitor, according to aspects of the present disclosure, includes a non-inflatable cuff and enables BP devices that are much smaller in size, less expensive to make, and potentially more precise than traditional finger-mounted BP devices. In addition, the embodiments described herein can incorporate several types of sensors to measure blood pressure either on demand or continuously, or both. In some examples, systolic and diastolic values may be generated on demand similar to traditional monitors. In some examples, continuous monitoring and alerting of patients of unwanted blood pressure levels may be provided. In one or more embodiments, the BD device readings can be used to generate a heart pulse reading based on one more readings of oscillations of pressure of blood. 
     Definitions 
     Blood pressure is typically stated in terms of two numbers, e.g. “110 over 70” or “115/75.” These two numbers correspond to systolic and diastolic blood pressure, respectively. 
     “Systolic pressure” is the blood pressure caused by a contracting heart, pushing blood through the arteries. Normal systolic blood pressure is less than 120 mm Hg. 
     “Diastolic pressure” is the pressure in the arteries during the time between contractions, i.e., when the heart is resting. Normal diastolic blood pressure is less than 80 mm Hg. 
     A “sphygmomanometer” is a device for measuring blood pressure. 
     SPECIFIC EXAMPLES, MAJOR COMPONENTS, AND ALTERNATIVES 
     Example 1 
     This example describes an illustrative digit-mounted BP monitoring device generally indicated at  100 ; see  FIG.  1   . 
       FIG.  1    is a schematic diagram showing relationships between various components that may be included in BP monitoring device  100 . In this example, BP monitor  100  may include a sensor  102 , a sensor mount  104 , a brace  106 , an indicator  108 , and/or a processor  110 , and may be configured to be applied to a digit  112 , such as a human finger. Sensor  102  may include one or more suitable sensors configured to sense and/or measure one or more desired physical or physiological characteristics when placed adjacent to an area of the body, for example, a digit  112  and convert the information into a useable format such as an electrical and/or digital signal. For example, sensor  102  may include a device sensitive to pressure, pulse, sound, light, motion, temperature, chemical composition or changes, electromagnetic fields, moisture, vibration, oscillation, and/or any combination of these. In some examples, sensor  102  may include an electronic sensor. In some examples, sensor  102  may include a mechanical sensor. In some examples, sensor  102  may include a selectable sensitivity feature. 
     Sensor  102  may be affixed, attached, operatively connected, or otherwise retained by sensor mount  104 . Sensor mount  104  may include any suitable structure configured to ensure sensor  102  is held adjacent to an area of the body to be monitored, such as digit  112 , in a predetermined manner suitable for the sensor type and configuration. For example, many possible sensors will need to be held in a fixed position such that pressure placed on the sensor by the digit does not displace the sensor relative to sensor mount  104 . In other examples, sensor  102  may be mounted to sensor mount  104  in a floating or biased fashion, such that the sensor may move by a certain amount when held against digit  112 . In some examples, an amount of such biasing may be adjustable or selectable. In some examples, sensor  102  may be fixed in one dimension and adjustable in one or more other dimensions, resulting in a predetermined number of degrees of freedom. For example, sensor mount  104  may be configured such that sensor  102  is fixed in a direction normal to digit  112 , but may be adjusted along a path parallel to the digit. 
     Brace  106  may surround, attach piecewise, and/or extend from sensor mount  104 , and may include any suitable structure configured to brace BP monitor  100  against certain portions of the anatomy of digit  112 . Brace  106  may be configured to create a void or space under sensor  102 . For example, brace  106  may include a pair of elongate extensions with one extension on either side of sensor mount  104 . Brace  106  may be sized and configured such that the brace has a long axis aligned with the long axis of digit  112 , and spans the distance between opposite terminal condyles of a phalanx bone in the digit (as shown in  FIG.  3   ). In some examples, brace  106  has a long axis aligned perpendicular to the long axis of the digit, and may be sized to span a portion of the width of the digit (as shown in  FIG.  4   ). In these examples, a functional portion of brace  106  may have a width smaller than an expected diameter of digit  112 . 
     Indicator  108  may include any suitable human-perceptible indicator configured to provide information related to the functioning of BP monitor  100 . For example, indicator  108  may include one or more audible, visual, and/or tactile features. Indicator  108  may include a digital display, a light or LED, a speaker, a positional indicator, a color indicator, a pop-up button, a vibrating component, and/or the like, and/or any combination of these. In some examples, indicator  108  may be excluded from the device. 
     Processor  110  may include any suitable data processing device or controller (as further described below), and may be configured to respond to information provided by sensor  102 . For example, processor  110  may be programmed or configured to respond to pressure above a certain setpoint by turning on an LED indicator  108  and/or displaying a textual or numeric value on a display indicator  108 . Processor  110  may include aspects capable of receiving inputs and/or adjustments from a user through a user interface. For example, processor  110  may be connectable to another device having a graphical user interface and an input device through which various aspects and/or setpoints of BP monitor  100  may be selected and/or adjusted. In some examples, setpoints may be adjusted by mechanical interfaces on BP monitor  100  itself. In some examples, processor  110  may be excluded and an output of sensor  102  may directly control indicator  108 . 
     Various embodiments of BP monitor  100  are described in detail below, along with related concepts and methods. 
     Example 2 
     This example describes an illustrative BP monitoring device  200  having an elongate brace portion, the device configured to be placed on the side of a finger; see  FIGS.  2 - 3   . 
     In this example, BP monitor  200  may include a brace in the form of a flat panel  1  which may have a sensor mount in the form of a cylindrical chamber  2  screwed or otherwise fixed into the panel. Chamber  2  may house sensors, and a height of the chamber may be adjustable to change position of a sensor relative to the finger. Panel  1  may include a non-stretchable strap  3  affixed to the panel at one end, and a lock mechanism (not shown) for the other end of the strap. Strap  3  may be any suitable strap or other attachment device configured to secure monitor  200  to a finger. Monitor  200  may be used on any finger, and may preferably be used on an index finger as shown in the top drawing of  FIG.  2   . As indicated, monitor  200  may be configured to attach to a side of the finger. 
       FIG.  3    shows a cross-section of the device mounted on a finger, from a lateral view. Panel  1  may be supported by the widening of a phalanx bone  6  in the joint areas of fingers (i.e., at the condyles) and holds cylindrical chamber  2  off the bone, between the joints. In this example, chamber  2  may house a sensor insert  4  with sensors on its surface coming in contact with a skin  10  of the finger. Proximity of sensor insert  4  to the skin can be adjusted via a screw thread  5  on the chamber to accommodate the particular anatomy of a patient. To perform measurement, strap  3  may be wrapped around the finger in a snug but comfortable fashion. Pressure is then created in a soft tissue  9  of the finger, causing the tissue to fill the space under the strap (in this case around a radial artery  7 ). Pressure may be created in soft tissue  9  by bending the finger or otherwise pressing on the surface under the strap. Note that finger-bend can create sufficient enough pressure to occlude finger arteries even for very high systolic levels (e.g., 300 mm Hg). 
     Ulnar artery  8  can also be used to perform measurement, if the device is flipped to the other side of the finger or with sensor installed on the medial side of the finger. Outside pressure does not need to be necessarily provided by bending the finger. If the device is configured to operate in the continuous monitoring mode, constant outside pressure can be provided by a special piston under spring pressure, as further explained below. 
     Example 3 
     This example describes an illustrative BP monitoring device  300  having a short cross-brace portion, the device configured to be placed on a finger similar to a ring; see  FIG.  4   . 
     BP monitor  300  is a variation of monitor  200 , akin to a ring in which sensor housing  2  and strap  3  may be held by a bracket  11  that is smaller in width than the finger, thereby preventing the soft tissue of a finger from filling the space under the bracket. Rather, soft tissue may be allowed to fill the space under the sensors when the finger is bent. In general, monitor  300  may be operated in substantially the same manner as monitor  200 . 
     Example 4 
     This example describes shortcomings of an existing method used in traditional BP monitoring devices; see  FIG.  5   . 
       FIG.  5    illustrates one of the main shortcomings of using a prior art inflatable cuff to measure blood pressure in a finger. In  FIG.  5   , outer  12  and inner  13  surfaces of the cuff are shown with the cuff inflated by a volume of air  14 , where reference number  15  is the surface of the finger. As shown, soft tissue  9  may accumulate in an area spaced from the arteries ( 7  and  8 ), resulting in insufficient soft tissue around the finger arteries, so the arteries are pressed down against the bone. This configuration can result in incorrect measurement of blood pressure, as the pressure applied from the outside via inflation of the cuff may not be equal to the pressure inside the arteries. 
     Example 5 
     This example describes expected response curves when applying pressure to the tissue around an artery; see  FIG.  6   . 
     In addition to the device architecture described throughout this disclosure, sensor designs may also be varied to accommodate various modes of use. Various sensors can be used separately or in combination. In some examples, sensor designs are based on the oscillometric method.  FIG.  6    is a diagram depicting the concept underlying oscillations measured by these sensor designs. 
     Referring to  FIG.  6   , the horizontal, or “X” axis signifies the quantified change in an outside parameter responsible for pressure changing in the soft tissue surrounding an artery. In traditional devices, outside pressure is usually created by pumping air into a cuff, whereas this disclosure teaches, for example, bending of the finger (for on-demand use) or with the help of a biased piston (for continuous use). On the vertical, or “Y” axis is the corresponding tissue pressure or pressure on the artery (and, accordingly, the sensor being used). 
     Various important aspects of the curve will now be described: 
     Curve  1 - 2  depicts how blood pressure would behave if outside pressure were applied on the artery when the artery is full of blood. 
     Curve  3 - 4  depicts how blood pressure would behave if outside pressure is applied on the artery when the artery is empty, i.e., has no blood in it. 
     Curve  1 -A-D- 4  curve indicates how pressure on the sensor would behave if blood pressure is always maintained at the diastolic (i.e., low) level. Note that segment A-D signifies emptying of the artery. 
     Curve  1 -B-C- 4  indicates how pressure on the sensor would behave if blood pressure is always maintained at the systolic (i.e., high) level. 
     There should generally be precise one-to-one dependence between the X and Y parameters except in the area of A-B-C-D, where we observe pressure fluctuations on the Y axis for any given X value. By way of illustration, P S1 , P S2 , and P S3  depict three thresholds. As shown in  FIG.  6   , P S1 &lt;P dia  (diastolic pressure); P dia &lt;P S2 &lt;P sys  (systolic pressure); and P S3 &gt;P sys . For thresholds P S1  and P S3 , corresponding ∂ 1  and ∂ 3  levels would have single, precise values (and could trigger an Off/On switch of the sensor). For P S2 , however, there exists a range of oscillations (between ∂ 2  and ∂ 2 ′)caused by blood pressure changes during the cardiac cycle. Due to these oscillations, the pressure on the sensor would change, from point M below the P S2  threshold (sensor Off) to point K above the P S2  threshold (sensor On). Accordingly, at any point within the P  dia -P sys  range, pressure outside the artery always has a certain range that can be captured by an oscillometric sensor. Both diastolic and systolic blood pressure levels can therefore be identified. In fact, any threshold within P dia -P sys  range can also be identified, making so-called critical pressure sensors possible (as described herein). 
     Example 6 
     This example describes an illustrative critical sensor  400  suitable for use in BP monitoring devices as described in Examples 1-3; see  FIG.  7   . 
     Critical pressure sensor  400  may include any suitable sensor configured to switch between on and off when a critical (pre-specified) blood pressure level is detected. Accordingly, this type of sensor may be used to provide an alert to the patient. Referring back to  FIG.  6   , when outside the P dia -P sys  range (such as at P S1  and P S3 ), pressure applied on the sensor always has a precise value for any corresponding point on the X axis. However, at any point within the P dia -P sys  range, pressure outside the artery has a range that can be captured by an oscillometric sensor. In other words, a critical pressure sensor would turn On-&gt;Off-&gt;On as blood pressure fluctuates. Critical blood pressure devices can therefore be built that would alert patients when a certain pre-specified threshold falls within the P dia -P sys  range. In some examples, such a monitor may be able to accommodate both systolic and diastolic thresholds. In some examples, if pressure around the artery is stabilized by a biased piston (e.g., at level P S2 ), the piston will be displaced between ∂ 2  and ∂ 2 ′ and az during the cardiac cycle. This movement can be detected by a movement sensor, thereby forming a continuous critical pressure monitor. 
     Turning now to  FIG.  7   , sensor  400  may include a top  54  and bottom  16  surface of cylindrical chamber  2 . The top part may have a circular pressure scale (not shown) which has one hand that is attached to a control screw  17 . The position of the hand (corresponding to a certain level on the pressure scale) determines a distance between electrical contact element  18  and electrical contact element  19 . Element  18  may include the extension of a spring  22  that is shaped such that, as screw  17  is turned in one direction (e.g., clockwise), the distance between elements  18  and  19  increases. Spacing elements  18  and  19  farther apart increases a threshold for the sensor to turn on, because element  19 , which is affected by pressure, has farther to travel before making the connection. Likewise, if screw  17  is turned in the other direction (e.g., counterclockwise), the threshold for the sensor is lowered. Element  19  may include a convex, curved spring leaf, and may have a finger-facing surface covered with dielectric layer  20  (e.g., Teflon) and an adhesive  21 . When the adhesive side is pressed against the finger (e.g., by bending the finger), pressure builds in soft tissue  9  of the finger and thus around artery  7 . The distance between elements  18  and  19  determines how much spring pressure must be overcome, and therefore the pressure level at which the sensor is turned on. The greater the distance, the greater the pressure would need to be to turn the sensor on. Additional dielectric layers  23  and  24  provide insulation for elements  18  and  19  when there is no contact between the two. 
     Referring back to  FIG.  6   , there will be a range of thresholds where pressure oscillations would turn the sensor from off to on and back for any pre-specified level between P dia  and P sys . This enables devices that would alert patients when their blood pressure exceeds or drops below a certain pre-specified or selected level. 
     Example 7 
     This example describes another illustrative critical sensor  500  suitable for use in BP monitoring devices as described in Examples 1-3; see  FIGS.  8 - 9   . 
     Sensor  500  may include a linear pressure scale  25 . Thresholds are set with a runner  26  that slides along a channel  27 . The runner has a spring  28  disposed within its cavity that presses on a button  29  that in turn presses on a crossbar  30 . The crossbar rests and pivots on a bearing  31  at one end, and on a button  32  at the opposite end. Another surface of button  32  includes a specific surface area pressing on the finger, representing a part of the total pressure area of panel  33 . Movement of the runner along channel  27  changes the location of a pressure point created by spring  28  and button  29 , and thereby changes the amount of pressure applied on button  32  against panel  33 . 
     When the panel is pressed against the finger (e.g., by bending the finger), button  32  is configured to detach from the panel and trigger an electric contact between elements  34  and  35  when the outside pressure created exceeds the pressure created by the ratio of pressure from the crossbar on the bottom to the surface area of the button against the finger. When elements  34  and  35  come in contact, an LED  37  may turn on, indicating that the pre-specified critical pressure level is reached. A position of element  35  may be adjusted with a screw  36  to ensure elements  34  and  35  are sufficiently close to each other. 
     In order for the patient to see whether the pre-specified critical pressure level is within the area of oscillations (between P dia  and P sys ), the device may incorporate another sensor  38  that detects pulse pressure oscillations. Sensor  38  may require use of another LED. If the critical pressure sensor turns on while sensor  38  is able to detect oscillations (i.e., a pulse), then the pre-specified critical level lies within the P dia  and P sys  range. The converse is also true. Sensor  38  may include piezoelectric components, but may include any suitable mechanism sensitive to pulse pressure oscillations. When used with devices such as described in Example 6, sensor  38  should be located close to leaf spring sensor  19 . 
     Example 8 
     This example describes an illustrative digit-mounted BP monitoring device generally indicated at  210 ; see  FIG.  10   . 
       FIG.  10    is a schematic diagram showing relationships between various components that may be included in BP monitoring device  210 . In this example, BP monitor  210  may include a sensor  212  which may be incorporated into a printed circuit board  214 . The printed circuit board  214  may support other elements, such as a processor  216 , an indicator  218 , and a battery  220 . BP monitor  210  may be configured to be applied to an area of a body, for example a digit  222 , such as a human finger. 
     Sensor  212  may include one or more suitable sensors configured to sense and/or measure one or more desired physical or physiological characteristics when placed adjacent to, for example, digit  222  and convert the information into a useable format such as an electrical and/or digital signal. For example, sensor  212  may include a device sensitive to pressure, pulse, sound, light, motion, temperature, chemical composition or changes, electromagnetic fields, moisture, vibration, oscillation, and/or any combination of these. In some examples, sensor  212  may include an electronic sensor. In some examples, sensor  212  may include a mechanical sensor. In some examples, sensor  212  may include a selectable sensitivity feature. 
     Sensor  212  may be attached to the printed circuit board  214 . Sensor  212  may be incorporated into printed circuit board  214 , so that at least one component of sensor  212  is an inherent component of the printed circuit board itself. 
     The printed circuit board  214  may have a long axis aligned with the long axis of digit  222  and span the distance between opposite terminal condyles of a phalanx bone in the digit. The printed circuit board may be substantially the same size as or smaller than a credit card. The printed circuit board may provide physical support for sensor  212  and may be configured to maintain physical contact between sensor  212  and an area of the body, for example digit  222 . The printed circuit board may comprise one or more components of sensor  212 . 
     Processor  216  may include any suitable data processing device or controller (as further described below), and may be configured to respond to information provided by sensor  212 . For example, processor  216  may be programmed or configured to respond to pressure above a certain setpoint by turning on an LED indicator  218  and/or displaying a textual or numeric value on a display indicator  218 . Processor  216  may include aspects capable of receiving inputs and/or adjustments from a user through a user interface. For example, processor  216  may be connectable to another device having a graphical user interface and an input device through which various aspects and/or setpoints of BP monitor  210  may be selected and/or adjusted. In some examples, setpoints may be adjusted by mechanical interfaces on BP monitor  210  itself. In some examples, processor  216  may be excluded and an output of sensor  212  may directly control indicator  218 . 
     Indicator  218  may include any suitable human-perceptible indicator configured to provide information related to the functioning of BP monitor  210 . For example, indicator  218  may include one or more audible, visual, and/or tactile features. Indicator  218  may include a digital display, a light or LED, a speaker, a positional indicator, a color indicator, a pop-up button, a vibrating component, and/or the like, and/or any combination of these. In some examples, indicator  218  may be excluded from the device. 
     Battery  220  may provide power for processor  216 , sensor  212 , indicator  218 , and/or any other components that require electrical power. 
     Example 9 
     This example describes an illustrative BP monitoring device  310  including a printed circuit board, the device configured to be placed on the side of a finger; see  FIGS.  11 ,  12 , and  13   . 
       FIG.  11    is a schematic isometric view of BP monitoring device  310 . In this example, BP monitor  310  may include a printed circuit board  312 . BP monitor  310  may include a strap  314  affixed to the panel at one end, and a lock mechanism (not shown) for the other end of the strap. Strap  314  may be any suitable strap or other attachment device configured to secure monitor  310  to a finger. Monitor  310  may be used on any appropriate body area, such as a finger, and may be used on an index finger. BP monitor  310  may include a proportional sensor on a first side  316  of the printed circuit board  312 . The proportional sensor may be positioned on the first side  316  of the printed circuit board so that the proportional sensor is in physical contact with the finger when BP monitor  310  is secured to the body area. An example of a proportional sensor attached to a printed circuit board can be seen in  FIG.  12   . 
     As described in Example  8  above and as illustrated in  FIG.  10   , the printed circuit board  312  may support various components of BP monitor  310  on a second side  318  of the printed circuit board. A processor, display, and/or a battery may be connected to printed circuit board  312  on the second side  318 . 
       FIG.  12    is a sectional side view of an illustrative proportional sensor  600  suitable for use in a blood pressure monitoring device. Sensor  600  may include a corrugated leaf spring  39  which flattens out when pressure is applied to sensor  600 .  FIG.  12    depicts leaf spring  39  in an uncompressed state proximate that same spring shown at  40  in a compressed or flattened out state. For example, leaf spring  39  may include a tempered stainless steel foil one half of one millimeter thick formed into a corrugated shape. The distance between adjacent peaks of the corrugation may be approximately 1 millimeter. Leaf spring  39  may be isolated from a conductive layer  42  by an insulating layer  44 . Together, leaf spring  39 , conductive layer  42 , and insulating layer  44  may form a capacitor. As pressure is applied to sensor  600 , leaf spring  39  may compress or flatten out, decreasing the effective distance between leaf spring  39  and conductive layer  42  and, in turn, increasing the capacitance of the capacitor. The layers of the capacitor may be configured so that the capacitance increases linearly with pressure, see  FIG.  13   . Sensor  600  may be said to be a “proportional sensor” in the sense that the capacitance may increase linearly with the applied pressure. Sensor  600  may be said to be a “capacitive sensor” in the sense that it may use a capacitor to measure applied pressure. 
     Sensor  600  may be supported on a base layer  41 . Some or all of the base layer  41 , the conductive layer  42 , and the insulating layer  44  may be component layers of circuit board  312 . The conductive layer  42  may be any layer of metallization comprising, for example, copper or gold and may have a thickness in a range of 1 to 10 microns. The insulating layer  44  may be any insulating layer and may have a thickness in a range of 10 to 20 microns. 
     There may be a first protective layer  45  disposed over leaf spring  39 . The first protective layer may be Teflon tape with a thickness of approximately  50  microns. There may be a second protective layer  55  disposed over the first protective layer  45 . The second protective layer may be adhesive Teflon tape with a thickness of approximately 70 microns. Either of the first or second protective layers may be omitted and there may be additional protective layers not shown in  FIG.  12   . One or both of the first and second protective layers may extend beyond the leaf spring  39  and one or both of the first and second protective layers may make contact with insulating layer  44 . One or both the first and second protective layers may cover one or more of the components described herein and may be attached at any desired point to cover the one or more components. 
     Sensor  600  may be very thin. The total thickness of the conductive layer  42 , the insulating layer  44 , the leaf spring  39 , the first protective layer, and the second protective layer may be as thin as approximately 100 microns. Such a thin sensor would not appreciably increase the thickness of the printed circuit board on which the sensor is mounted. Further, by incorporating sensor  600  into printed circuit board  312 , the electric circuitry required to measure the capacitance of the capacitor may be built in to the printed circuit board. 
       FIG.  13    shows an illustrative calibration diagram associated with sensor  600 . The layers of the capacitor may be configured so that the capacitance increases linearly with pressure. Curve  43  in  FIG.  13    is an exemplary calibration curve that may be used with sensor  600 .  FIG.  13    depicts a graph of capacitance on the “y”-axis, measured in picofarads and pressure on the “x”-axis, measured in mmHg. The pressure is the pressure exerted on sensor  600  by the soft tissue in contact with sensor  600  and the capacitance is the capacitance of the capacitor comprised of the leaf spring  39 , the conductive layer  42 , and the insulating layer  44 . The scales of the x and y axes are exemplary and not meant to be limiting in any way. The slope and y-intercept of curve  43  are also meant to be exemplary and not limiting in any way. Indeed, it is not required that curve  43  be strictly linear. All that is required of curve  43  to be an effective calibration curve is that curve  43  is a one-to-one function. Such a calibration curve can be created by applying known pressures to sensor  600  and measuring the corresponding capacitances. This calibration curve can then be stored and later used to determine the applied pressure for a given measured capacitance. If the correspondence between capacitance and pressure is one-to-one, such as with linear curve  43 , then for every measured capacitance there will be exactly one indicated pressure. 
     Example 10 
     This example describes an illustrative BP monitoring device having a continuous sensor  700 ; sensor  700  may also be suitable for use in BP monitoring devices as described in Examples 1-3; see  FIG.  14   . 
       FIG.  14    is a sectional, lateral view of sensor  700  on a finger. The base of a sensor insert  46  may be screwed into a central part of base panel  1  of the device via a threaded chamber  47  such that the base of the sensor comes in contact with the skin of the finger when tape or strap  3  is wrapped around the finger in a snug but comfortable fashion. A loose end of tape or strap  3  may be fixed with a lock mechanism  48  (e.g. a buckle). Inside sensor insert  46 , a spring  49  may be contained from the top with a lid  50 . The base of spring  49  pushes against a sensor insert  51 , which in turn pushes against the surface of the finger. The spring should be sized such that the pressure it exerts when compressed stays roughly constant despite pressure changes created by finger movement. 
     Because the pressure applied by the insert on the skin cannot materially exceed the pressure created by the spring, a roughly constant level of pressure can be created. The base of insert  51  may contain a sensor  52  that tracks movement of sensor insert  51  and thereby detects the presence of oscillations. This sensor can be equipped with an LED  53 , or other indicator, to alert the patient if blood pressure exceeds or drops below a pre-specified level. To facilitate changing the pre-specified level in this configuration, another sensor insert may be used, with a different spring. Alternatively, a different configuration is possible. For example, this device can be configured akin to the device in  FIGS.  8 - 9   , where button  32  is replaced with a piston with a large enough area, movement sensor  52  may be attached to element  35 , and the design of the runner accommodates a larger angular range of motion for the crossbar  30 . 
     Example 11 
     This example describes an illustrative BP monitoring device having a critical sensor, such as the ones illustrated in  FIGS.  7 - 9   , and associated methods. 
     A patient may specify a certain blood pressure level, such as by positioning a runner on a blood pressure scale. This level becomes a setpoint for the critical pressure sensor, which triggers an LED when outside pressure on the artery (e.g., from bending the finger) exceeds the setpoint. The patient then bends his or her finger gradually while crossing the point where the LED is lit. If the setpoint happens to be inside the P dia -P sys  range, the patient will observe oscillations resulting from the pressure pulse. If the setpoint lies outside of this range, the sensor will not register oscillations. 
     This type of BP monitoring device may be simple and inexpensive to make relative to other examples. It is also very reliable, due to its simplicity and low energy use. For example, the device may only use batteries during measurement and does not need to be switched off when not in use. 
     Example 12 
     This example describes an illustrative BP monitoring device having a critical sensor, such as the ones illustrated in  FIGS.  7 - 9   , and a pulse sensor, and associated methods. 
     As in Example 11, a patient may specify a certain blood pressure level, such as by positioning a runner on a blood pressure scale. Here, either diastolic or systolic levels can be set. This level becomes a set-point for the critical pressure sensor which triggers an indicator such as an LED when outside pressure on the artery (e.g., from bending the finger) exceeds the setpoint. This device may also have another sensor which detects pulse pressure oscillations, equipped with its own LED. When the patient bends the finger, pulse pressure is only sensed if within the P dia -P sys  range. If the critical pressure sensor LED turns on prior to the pulse sensor LED, the patient&#39;s diastolic blood pressure is above the pre-specified setpoint. If the critical pressure sensor LED turns on after the pulse sensor LED turns off, the patient&#39;s systolic pressure is below the pre-specified setpoint. If the critical pressure sensor LED turns on while the pulse sensor LED is still lit, the setpoint is within the P dia -P sys  range, informing the patient that blood pressure is either (a) at or above the pre-specified systolic level, and/or (b) at or below the pre-specified diastolic level, depending on which level was pre-specified. 
     This type of device may have advantages in that it does not require the user be trained in gradual finger bending in order to observe oscillations around set-points. The two types of devices may also be used in the same fashion if the user so prefers. 
     The type of device described in this example may include two sensors, and may require an amplifier and a power source for the oscillation sensor. 
     Example 13 
     This example describes an illustrative BP monitoring device having a proportional sensor, such as the one illustrated in  FIGS.  11  and  12   , and associated methods. 
     This device may function similarly to traditional blood pressure monitors in that it has one sensor which registers blood pressure oscillation equal to the mean blood pressure and associated pressure applied on the artery. The device may include a display and an electronic system which enables processing and memory of oscillation signals, and/or may be operatively connected to such a display and/or system. Unlike traditional monitors, this device does not use inflation to generate outside pressure. Rather, the user gradually bends his finger and the device generates P  dia , P  sys  and P mean  values. 
     Example 14 
     This example describes an illustrative BP monitoring device having a critical sensor, such as the ones illustrated in  FIGS.  7 - 9   , and more specifically a continuous sensor as illustrated in  FIG.  14   , and associated methods. 
     This device is capable of continuous monitoring due to a feature that enables a constant pressure level on the artery regardless of the position of the finger (for low pressure levels) and constant pressure on the artery when the finger is bent in high blood pressure areas (but without fixation). The level of constant pressure is specified by the user, such as with a runner on a pressure scale of the device. The device is equipped with a sensor that detects pulse pressure oscillations in the area of the insert where constant pressure is applied. 
     In the areas of low blood pressure, when the set-point is below P dia , this sensor detects no oscillations. However, as soon as blood pressure drops below the setpoint, oscillations are registered and the user can be alerted. In the areas of intermediate blood pressure, when the setpoint is in the P dia -P sys  range, oscillations will be registered. However, as soon as P sys  drops below the pre-specified setpoint, oscillations cease and the user can be alerted. In areas of high blood pressure, the user will need to bend the finger since maintaining constant level at high levels is impractical. If the setpoint is above the P sys  level, as long as P sys  is below the setpoint the device detects no oscillations. However, as soon as P sys  exceeds the set-point, oscillations can be registered and the user can be alerted. Note that this device does not require the user be skilled in gradual finger bending in order to observe oscillations around the set-point as the outside pressure cannot exceed the pre-specified level. 
     Example 15 
     This example describes a method for monitoring blood pressure, such as may be performed using one or more of the devices described above; see  FIG.  15   . 
       FIG.  15    is a flowchart illustrating steps performed in an illustrative method, and may not recite the complete process or all steps of the process.  FIG.  15    depicts multiple steps of a method, generally indicated at  800 , which may be performed in conjunction with devices and methods according to aspects of the present disclosure. Although various steps of method  800  are described below and depicted in  FIG.  15   , the steps need not necessarily all be performed, and in some cases may be performed in a different order than the order shown. 
     At step  802 , a BP monitor may be placed adjacent to an area of a body, such as a finger of a patient. For example, a BP monitor such as those described herein may be strapped or otherwise attached to a patient&#39;s finger. In some examples, the BP monitor may be attached to one side of the finger. In some examples, the BP monitor may be attached across a phalanx bone from side to side. In some examples, the BP monitor may be attached lengthwise to a finger, spanning opposing condyles of a phalanx bone. 
     At step  804 , pressure may be exerted upon an artery, for example, in the finger as well as on a sensor in the BP monitor, without use of an inflatable cuff or other inflatable device. For example, the patient may bend the finger to cause soft tissue to fill a space under the sensor. For example, a biased piston may exert a preset amount of pressure on the soft tissue. In some examples, more than one sensor may be provided. Using a critical sensor, as described above, a patient may, for example, perform a quick, discrete check of blood pressure. This may be performed, for example, to determine if medication is needed. Using a “proportional” sensor, a patient may receive both exact systolic and diastolic pressure readings in one operation but faster and more conveniently than with traditional (inflatable cuff) monitors. In some examples, a continuous sensor may be used and a patient may monitor for low blood pressure. For example, this may be advantageous to predict light-headedness or other symptoms. 
     Step  806  may include sensing oscillations when pressure is in the P dia -P sys  range. Step  806  may include sensing a pulse. Step  806  may include comparing a sensed pulse to a sensed pressure oscillation and/or absence of a pulse and/or absence of a pressure oscillation. 
     At step  806 , an indication or other information corresponding to sensed blood pressure characteristics may be presented to the patient and/or any other user and/or a data processing system. For example, an LED light may be lit if blood pressure is sensed to be above a selected threshold. In some examples, a data processing system (see below) may receive data corresponding to the sensed blood pressure and/or a preselected threshold, and may be configured to respond in any suitable manner. For example, a data processing system may cause numerical, textual, and/or symbolic information corresponding to the BP characteristic(s) to appear on a display. For example, the LED light mentioned above may be driven by an output of the data processing system. For example, the data processing system may store data points for use in a time-based analysis such as a graph, table, or chart. For example, a message may be displayed and/or sound may be generated to alert the user to a potentially dangerous condition. 
     The data processing system may be incorporated into the BP monitor. The data processing system may be incorporated (at least in part) in another device or system. For example, a data processing system may be completely or partly disposed in a handheld device such as a smart phone, in a laptop or desktop computer, and/or in a tablet computer, and/or the like, and/or any combination of these. Information, also referred to as data, may be transferred from the sensor(s) to the indicator and/or data processing system in any suitable manner. For example, data may be transferred wirelessly, such as over wi-fi, Bluetooth, and/or Bluetooth Low Energy (BLE). In some examples, data may be transferred over a wired and/or optical connection, and/or the like, and/or any combination of these. In some examples, data may be processed by firmware and/or software such as a computer program or application. For example, data may be processed by a so-called “app” on a smart phone such as an iPhone, Android phone, and/or Windows phone, and/or the like. 
     This method may be performed in a hospital or medical environment. In some examples, the method may be performed in a home or mobile environment. A mobile use is facilitated by the reduced size and wearable nature of the device as compared to typical BP devices. 
     Example 16 
     This example describes a method for monitoring pressure of blood in an artery, such as may be performed using one or more of the devices described above, see  FIG.  16   . 
       FIG.  16    is a flow chart illustrating steps performed in an illustrative method, and may not recite the complete process or all steps of the process.  FIG.  16    depicts multiple steps of a method, generally indicated at  810 , which may be performed in conjunction with devices and methods according to aspects of the present disclosure. Although various steps of method  810  are described below and depicted in  FIG.  16   , the steps need not necessarily all be performed, and in some cases may be performed in a different order than the order shown. 
     At step  812 , a non-invasive sensor of a blood pressure monitoring device may be contacted at an area above an artery of a finger. The sensor could be one or more of the sensors described herein, for example, sensors  400 ,  500 ,  600  or  700 . The pressure monitoring device could be one or more of the monitoring devices described herein, for example, pressure monitoring devices  100 ,  200 ,  300 ,  210 , or  310 . The area above an artery of a finger may be an area on the side of a finger between a metacarpophalangeal (MCP) joint and a proximal inter-phalangeal joint (PIP). 
     At step  814 , one or more pressure data readings from the area may be collected with the non-invasive sensor. The pressure data readings may be other than readings corresponding to an air pressure reading. Standard blood pressure monitors measure the pressure in a volume of air, however, the sensors disclosed herein all measure pressure of soft tissue under the skin, which is not an air pressure. Step  814  may occur after the contacting step  812  and after a pressure is exerted at the area on the sensor. The pressure exerted at the area may be caused by a bending of a finger. The bending may cause a higher pressure in the artery proximate the artery, relative to a lesser bending position. The bending may cause an injection of liquid proximate the area. This injection of liquid may improve the accuracy of any pressure data readings. The bending of the finger may be at a proximal inter-phalangeal (PIP) joint. The sensor may collect a plurality of pressure data readings continuously as the exerted pressure changes between a first pressure value and a second pressure value. The first pressure value may be either a minimum value or a maximum value. The second pressure value may be either a minimum value or a maximum value. A minimum value may be achieved when the finger is in a substantially unbent position. A maximum value may be achieved when the finger is in a bent or bending position. The first pressure value may be approximately 0 mmHg, approximately 300 mmHg, or any value in between 0 and 300 mmHg. For example, the first pressure value may be approximately 40 mmHg and the second pressure value may be approximately 180 mmHg. The sensor may collect pressure data readings continuously over a plurality of time intervals, every approximately 100 milliseconds, as the exerted pressure changes between the first and second pressure values. The pressure change may take place over approximately 30 seconds. 
     At step  816 , one or more pressure data readings are analyzed with a computer device, for example that shown in  FIG.  18   . Analyzing the one or more pressure data readings may include generating at least one of a blood pressure reading and a heart pulse reading. Step  816  does not include analyzing any pressure data readings corresponding to an air pressure reading. Step  816  of analyzing the one or more pressure data readings may occur at the same time as step  814  of collecting the one or more pressure data readings. Both of steps  816  and  814  may occur over a range of time intervals. As discussed previously, the pressure data readings may be collected over an amount of time up to approximately 30 seconds. Step  816  of analyzing the pressure data readings could occur during and after that same amount of time. For example, one or more sensors may be configured to continuously monitor the area and may begin automatically collecting at least one reading after detecting with the non-invasive sensor a change in pressure at the area from a zero mmHg state to a non-zero mmHg state. This change may be in response to a bending of the finger. That is, as the computing device analyzes the pressure data readings and registers a change in pressure from a zero mmHg state, the sensor may automatically begin collecting at least one pressure data reading. The sensor may be configured to continuously monitor the area when the finger is in a position where the exerted force is approximately zero mmHg. 
     Method  810  may further include receiving at least one of the blood pressure reading and the heart pulse reading generated based on the one or more pressure data readings analyzed by the computer system. 
     Method  810  may further include attaching the pressure of blood monitoring device to a finger. The pressure of blood monitoring device may be part of a ring system that includes a printed circuit board coupled to the non-invasive sensor, see for example  FIGS.  10 - 12   . 
     Method  810  may further include measuring changes in capacitance in response to changes in pressure to generate the one or more pressure data readings as discussed in relation to  FIGS.  12  and  13   . 
     Example 17 
     This example describes a method for monitoring pressure of blood in an artery, such as may be performed using one or more of the devices described above, see  FIG.  17   . 
       FIG.  17    is a flow chart illustrating steps performed in an illustrative method, and may not recite the complete process or all steps of the process.  FIG.  17    depicts multiple steps of a method, generally indicated at  820 , which may be performed in conjunction with devices and methods according to aspects of the present disclosure. Although various steps of method  820  are described below and depicted in  FIG.  17   , the steps need not necessarily all be performed, and in some cases may be performed in a different order than the order shown. 
     At step  822 , a sensor of a pressure monitoring device is contacted with an area of a body capable of being monitored for pressure of blood. The sensor could be one or more of the sensors described herein, for example, sensors  400 ,  500 ,  600  or  700 . The pressure monitoring device could be one or more of the monitoring devices described herein, for example, pressure monitoring devices  100 ,  200 ,  300 ,  210 , or  310 . The area of the body capable of being monitored for blood pressure readings may be an area above an artery of a finger. The area above an artery of a finger may be an area on the side of a finger between a metacarpophalangeal (MCP) joint and a proximal inter-phalangeal joint (PIP). 
     At step  824 , one or more pressure readings from the area may be collected with the sensor. For example, the capacitive sensor  600  may be used to collect one or more pressure readings. The one or more pressure readings may be collected after the contacting step  822 . Step  824  of collecting pressure readings may be after a pressure is exerted at the area on the sensor. The sensor may collect a plurality of pressure data readings continuously as the exerted pressure changes between a first pressure value and a second pressure value. The first pressure value may be either a minimum value or a maximum value. The second pressure value may be either a minimum value or a maximum value. The first pressure value may be approximately 0 mmHg, approximately 300 mmHg, or any value in between 0 and 300 mmHg. For example, the first pressure value may be approximately 40 mmHg and the second pressure value may be approximately 180 mmHg. The sensor may collect pressure data readings continuously over a plurality of time intervals, every approximately 100 milliseconds, as the exerted pressure changes between the first and second pressure values. The pressure change may take place over approximately 30 seconds. The sensor may be configured to automatically collect a plurality of readings as the exerted pressure changes from the first pressure value to the second pressure value. Step  824  of collecting one or more pressure of blood readings with a sensor may occur without data generated from an air inflatable element. Indeed, all sensors disclosed herein and all blood pressure monitoring devices disclosed herein are capable of collecting pressure readings without an air inflatable element, for example, an air inflatable cuff. Instead of using an air inflatable element to change the pressure exerted at the area where pressure data readings are to be collected, the sensors disclosed herein measure pressures exerted at the area of the body that are caused by a bending of the finger. 
     At step  826 , one or more pressure readings are analyzed with a computing device, for example see  FIG.  18   . Analyzing the one or more pressure data readings may include generating one or more health data readings based on the analysis of the one or more pressure data readings. The one or more pressure data readings may be analyzed to generate a blood pressure reading as the health data reading. The computing device may be remote or coupled to the sensor. 
     Method  820  may further include measuring an oscillation of pressure of blood readings over time intervals, see step  824 , of the collected plurality of pressure readings to generate a heart pulse rate as the health data reading. Step  826  of analyzing the one or more pressure data readings may occur at the same time as step  824  of collecting the one or more pressure data readings. Both of steps  826  and  824  may occur over a range of time intervals. As discussed previously, the pressure data readings may be collected over an amount of time up to approximately  20  or  30  seconds, or any other time. Step  826  of analyzing the pressure data readings could occur during and after that same amount of time. For example, one or more sensors may be configured to continuously monitor the area and may begin automatically collecting at least one reading after detecting with the capacitive sensor a change in pressure at the area from a zero mmHg state to a non-zero mmHg state. That is, as the computing device analyzes the pressure data readings and registers a change in pressure from a zero mmHg state, the sensor may automatically begin collecting at least one pressure data reading. 
     Method  820  may further include analyzing a change in capacitance of the capacitive sensor to generate the one or more pressure data readings. The capacitance of the capacitive sensor may change due to a change in configuration between conductive materials of the capacitive sensor. For example, in the capacitive sensor shown in  FIG.  12   , the configuration of conductive materials  39  and  42  may change as pressure is applied to the sensor and the conductive materials become closer together. 
     Method  820  may further include providing a pressure monitoring device that includes the capacitive sensor, the capacitive sensor being configured to be in contact with the area of skin above an artery. The capacitive sensor may include a conductive element disposed on a bottom side adjacent a printed circuit board, such as conductive layer  42  shown in  FIG.  12   . The capacitive sensor may include a resilient member, such as leaf spring  39  shown in  FIG.  12   . The capacitive sensor may include an insulation layer separating the conductive element from the resilient member, such as insulating layer  44  shown in  FIG.  12   , and an adhesive layer covering the resilient member, such as the first or second protective layers  45  and  55  shown in  FIG.  12   . The capacitive sensor may be configured to collect one or more pressure of blood data readings while in contact with the area. Providing the pressure monitoring device may include a data processing device, in communication with the capacitive sensor, configured to analyze data readings produced by the sensor, the data processing device including a processor, a memory, and a set of instructions stored in the memory and executed by the processor to determine whether the information provided by the sensor meets selected criteria, and providing an alert to a user if the information meets the criteria. 
     Method  820  may further include providing the pressure monitoring device with an attachment portion that houses the sensor, see for example,  FIG.  11   . The pressure exerted on the sensor from the finger may be caused by the bending of the finger. 
     Example 18 
     This example describes a data processing system  900  in accordance with aspects of the present disclosure. In this example, data processing system  900  is an illustrative data processing system for implementing methods, measurement systems, and/or data handling portions of the devices and methods described above and shown in  FIGS.  1 - 13   ; See  FIG.  18   . 
     In this illustrative example, data processing system  900  includes communications framework  902 . Communications framework  902  provides communications between processor unit  904 , memory  906 , persistent storage  908 , communications unit  910 , input/output (I/O) unit  912 , and display  914 . Memory  906 , persistent storage  908 , communications unit  910 , input/output (I/O) unit  912 , and display  914  are examples of resources accessible by processor unit  904  via communications framework  902 . Processor unit  904  serves to run instructions for software that may be loaded into memory  906 . Processor unit  904  may be a number of processors, a multi-processor core, or some other type of processor, depending on the particular implementation. Further, processor unit  904  may be implemented using a number of heterogeneous processor systems in which a main processor is present with secondary processors on a single chip. As another illustrative example, processor unit  904  may be a symmetric multi-processor system containing multiple processors of the same type. 
     Memory  906  and persistent storage  908  are examples of storage devices  916 . A storage device is any piece of hardware that is capable of storing information, such as, for example, without limitation, data, program code in functional form, and other suitable information either on a temporary basis or a permanent basis. 
     Storage devices  916  also may be referred to as computer readable storage devices in these examples. Memory  906 , in these examples, may be, for example, a random access memory or any other suitable volatile or non-volatile storage device. Persistent storage  908  may take various forms, depending on the particular implementation. 
     For example, persistent storage  908  may contain one or more components or devices. For example, persistent storage  908  may be a hard drive, a flash memory, a rewritable optical disk, a rewritable magnetic tape, or some combination of the above. The media used by persistent storage  908  also may be removable. For example, a removable hard drive may be used for persistent storage  908 . 
     Communications unit  910 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit  910  is a network interface card. Communications unit  910  may provide communications through the use of either or both physical and wireless communications links. 
     Input/output (I/O) unit  912  allows for input and output of data with other devices that may be connected to data processing system  900 . For example, input/output (I/O) unit  912  may provide a connection for user input through a keyboard, a mouse, and/or some other suitable input device. Further, input/output (I/O) unit  912  may send output to a printer. Display  914  provides a mechanism to display information to a user. 
     Instructions for the operating system, applications, and/or programs may be located in storage devices  916 , which are in communication with processor unit  904  through communications framework  902 . In these illustrative examples, the instructions are in a functional form on persistent storage  908 . These instructions may be loaded into memory  906  for execution by processor unit  904 . The processes of the different embodiments may be performed by processor unit  904  using computer-implemented instructions, which may be located in a memory, such as memory  906 . 
     These instructions are referred to as program instructions, program code, computer usable program code, or computer readable program code that may be read and executed by a processor in processor unit  904 . The program code in the different embodiments may be embodied on different physical or computer readable storage media, such as memory  906  or persistent storage  908 . 
     Program code  918  is located in a functional form on computer readable media  920  that is selectively removable and may be loaded onto or transferred to data processing system  900  for execution by processor unit  904 . Program code  918  and computer readable media  920  form computer program product  922  in these examples. In one example, computer readable media  920  may be computer readable storage media  924  or computer readable signal media  926 . 
     Computer readable storage media  924  may include, for example, an optical or magnetic disk that is inserted or placed into a drive or other device that is part of persistent storage  908  for transfer onto a storage device, such as a hard drive, that is part of persistent storage  908 . Computer readable storage media  924  also may take the form of a persistent storage, such as a hard drive, a thumb drive, or a flash memory, that is connected to data processing system  900 . In some instances, computer readable storage media  924  may not be removable from data processing system  900 . 
     In these examples, computer readable storage media  924  is a physical or tangible storage device used to store program code  918  rather than a medium that propagates or transmits program code  918 . Computer readable storage media  924  is also referred to as a computer readable tangible storage device or a computer readable physical storage device. In other words, computer readable storage media  924  is a media that can be touched by a person. 
     Alternatively, program code  918  may be transferred to data processing system  900  using computer readable signal media  926 . Computer readable signal media  926  may be, for example, a propagated data signal containing program code  918 . For example, computer readable signal media  926  may be an electromagnetic signal, an optical signal, and/or any other suitable type of signal. These signals may be transmitted over communications links, such as wireless communications links, optical fiber cable, coaxial cable, a wire, and/or any other suitable type of communications link. In other words, the communications link and/or the connection may be physical or wireless in the illustrative examples. 
     In some illustrative embodiments, program code  918  may be downloaded over a network to persistent storage  908  from another device or data processing system through computer readable signal media  926  for use within data processing system  900 . For instance, program code stored in a computer readable storage medium in a server data processing system may be downloaded over a network from the server to data processing system  900 . The data processing system providing program code  918  may be a server computer, a client computer, or some other device capable of storing and transmitting program code  918 . 
     The different components illustrated for data processing system  900  are not meant to provide architectural limitations to the manner in which different embodiments may be implemented. The different illustrative embodiments may be implemented in a data processing system including components in addition to and/or in place of those illustrated for data processing system  900 . Other components shown in  FIG.  9    can be varied from the illustrative examples shown. The different embodiments may be implemented using any hardware device or system capable of running program code. As one example, data processing system  900  may include organic components integrated with inorganic components and/or may be comprised entirely of organic components excluding a human being. For example, a storage device may be comprised of an organic semiconductor. 
     In another illustrative example, processor unit  904  may take the form of a hardware unit that has circuits that are manufactured or configured for a particular use. This type of hardware may perform operations without needing program code to be loaded into a memory from a storage device to be configured to perform the operations. 
     For example, when processor unit  904  takes the form of a hardware unit, processor unit  904  may be a circuit system, an application specific integrated circuit (ASTC), a programmable logic device, or some other suitable type of hardware configured to perform a number of operations. With a programmable logic device, the device is configured to perform the number of operations. The device may be reconfigured at a later time or may be permanently configured to perform the number of operations. Examples of programmable logic devices include, for example, a programmable logic array, a programmable array logic, a field programmable logic array, a field programmable gate array, and other suitable hardware devices. With this type of implementation, program code  918  may be omitted, because the processes for the different embodiments are implemented in a hardware unit. 
     In still another illustrative example, processor unit  904  may be implemented using a combination of processors found in computers and hardware units. Processor unit  904  may have a number of hardware units and a number of processors that are configured to run program code  918 . With this depicted example, some of the processes may be implemented in the number of hardware units, while other processes may be implemented in the number of processors. 
     In another example, a bus system may be used to implement communications framework  902  and may be comprised of one or more buses, such as a system bus or an input/output bus. Of course, the bus system may be implemented using any suitable type of architecture that provides for a transfer of data between different components or devices attached to the bus system. 
     Additionally, communications unit  910  may include a number of devices that transmit data, receive data, or both transmit and receive data. Communications unit  910  may be, for example, a modem or a network adapter, two network adapters, or some combination thereof. Further, a memory may be, for example, memory  906 , or a cache, such as that found in an interface and memory controller hub that may be present in communications framework  902 . 
     The flowcharts and block diagrams described herein illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various illustrative embodiments. In this regard, each block in the flowcharts or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function or functions. It should also be noted that, in some alternative implementations, the functions noted in a block may occur out of the order noted in the drawings. For example, the functions of two blocks shown in succession may be executed substantially concurrently, or the functions of the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. 
     Numbered Paragraphs 
     This section describes additional aspects and features of pressure monitoring devices and methods, presented without limitation as a series of numbered paragraphs. 
     Each of these paragraphs can be combined with one or more other paragraphs, and/or with disclosure from elsewhere in this application, including the materials incorporated by reference, if any, in any suitable manner. Some of the paragraphs below expressly refer to and further limit other paragraphs, providing without limitation examples of some of the suitable combinations. 
     A0. An apparatus for monitoring blood pressure, comprising: 
     a brace portion configured to span an anatomical feature of a human finger; 
     a sensor mount portion operatively connected to the brace portion such that the sensor mount portion is disposed over a target portion of soft tissue of the human finger when the brace portion spans the anatomical feature; 
     a sensor operatively connected to the sensor mount such that the sensor is adjacent to the target portion of soft tissue when the brace portion spans the anatomical feature; 
     an attachment portion operatively connected to the brace portion and configured to secure the apparatus to the finger with the brace portion spanning the anatomical feature. 
     A1. The apparatus of paragraph A0, wherein the anatomical feature is a phalanx bone and the brace portion spans a length of the phalanx bone. 
     A2. The apparatus of paragraph A0, wherein the sensor mount portion is centered in the brace portion. 
     A3. The apparatus of paragraph A0, wherein the sensor is configured to sense a parameter associated with blood pressure. 
     A4. The apparatus of paragraph A3, wherein the sensor is an oscillometric sensor. 
     A 5 . The apparatus of paragraph A0, wherein the attachment portion and brace are configured such that bending the finger with the device attached causes pressure to be exerted on an artery in the finger. 
     A6. The apparatus of paragraph A5, wherein the artery is a radial artery. 
     A7. The apparatus of paragraph A0, wherein the sensor is a critical pressure sensor. 
     A8. The apparatus of paragraph A7, wherein the sensor has a selectable setpoint. 
     A9. The apparatus of paragraph A0, wherein the sensor is a proportional sensor. 
     A10. The apparatus of paragraph A9, wherein the sensor includes a corrugated leaf spring deformable by pressure. 
     A10b. The apparatus of claim A10, wherein the proportional sensor measured changes in capacitance in response to changes in pressure. 
     A10c. The apparatus of claim A10, wherein the corrugated leaf spring forms a component of a capacitor. 
     A11. The apparatus of paragraph A0, wherein the sensor is a continuous sensor. 
     A12. The apparatus of paragraph A11, wherein the sensor is biased to apply a selected amount of pressure on the target soft tissue. 
     A13. The apparatus of paragraph A0, further including an indicator in communication with the sensor, the indicator providing a signal when sensed blood pressure meets a selected criterion. 
     A14. The apparatus of any other paragraph, further including a data processing system in communication with the sensor. 
     B0. A method for monitoring blood pressure, the method including: 
     attaching a blood pressure monitor to a finger of a patient; 
     exerting pressure on an artery in the finger without using an inflatable mechanism; and 
     providing information corresponding to a sensed characteristic of the blood pressure. 
     B1. The method of paragraph B0, wherein attaching the blood pressure monitor includes strapping a blood pressure monitor to a side of the finger. 
     B2. The method of paragraph B0, wherein attaching the blood pressure monitor includes attaching a monitor having a flat panel and a strap, the flat panel having a void under an attached sensor, the void being placed over a portion of soft tissue on the finger. 
     B3. The method of paragraph B0, wherein exerting pressure includes bending the finger. 
     B3b. The method of paragraph B3, wherein the pressure has a first value of 0 mmHg when the finger is in a straight position and a second value of 300 mmHg when the finger is in a bent position. 
     B4. The method of paragraph B0, wherein exerting pressure includes exerting a predetermined amount of pressure using a biased sensor attached to the monitor. 
     B5. The method of paragraph B0, wherein providing information includes turning on a light. 
     B6. The method of paragraph B0, wherein providing information includes sensing an oscillometric characteristic of the finger. 
     B7. The method of paragraph B0, wherein providing information includes analyzing data from a sensor using a data processing system. 
     B8. The method of paragraph B0, further including continuously monitoring the blood pressure of the patient using a biased sensor attached to the monitor and in contact with soft tissue of the finger. 
     C0. A blood pressure monitor system comprising: 
     a blood pressure monitoring device having a rigid brace portion configured to span a phalanx bone of a human finger, a sensor operatively connected to the brace portion, and an attachment strap for securing the device to a finger; and a data processing device for analyzing information provided by the sensor, the data processing device including a processor, a memory, and a set of instructions stored in the memory and executed by the processor to (a) determine whether the information provided by the sensor meets selected criteria, and (b) providing an alert to a user if the information meets the criteria. 
     C1. The system of paragraph C0, wherein the blood pressure monitoring device is configured to create pressure on an artery in the finger when a user bends the finger. 
     C2. The system of paragraph C0, wherein the instructions further include steps for storing historical data related to blood pressure. 
     D1. A method for monitoring pressure of blood in an artery, comprising: 
     contacting a capacitive sensor of a pressure monitoring device at an area of a body capable of being monitored for pressure of blood readings, 
     collecting with the capacitive sensor one or more pressure data readings from the area after the contacting and after a pressure is exerted at the area on the sensor; and 
     analyzing with a computing device the one or more pressure data readings to generate one or more health data readings based on an analysis of the one or more pressure data readings. 
     D2. The method of paragraph D1, further comprising collecting a plurality of pressure data readings continuously as the exerted pressure changes between 0 millimeters of mercury (mmHg) and 300 mmHg. 
     D3. The method of paragraph D2, further comprising continuously collecting readings over a plurality of time intervals as the pressure changes between zero mmHg and 300 mmHg. 
     D4. The method of paragraph D3, further comprising collecting pressure data readings at time intervals every approximately 100 milliseconds. 
     D5. The method of paragraph D2, wherein changing the exerted pressure continuously between zero mmHg and 300 mmHg occurs over approximately 30 seconds. 
     D6. The method of paragraph D2, further comprising analyzing the plurality of pressure readings to generate a blood pressure reading as the health data reading. 
     D7. The method of paragraph D2, further comprising measuring an oscillation of pressure of blood readings over time intervals of the collected plurality of pressure readings to generate a heart pulse rate as the health data reading. 
     D8. The method of paragraph D1, further comprising automatically collecting a plurality of readings continuously as the exerted pressure changes between zero millimeters mercury (mmHg) and 300 mmHg. 
     D9. The method of paragraph D1, further comprising 
     continuous monitoring by the sensor of the area, and 
     automatically collecting at least one reading after detecting with the capacitive sensor a change in pressure at the area from a zero mmHg state to a non-zero mmHG state. 
     D10. The method of paragraph D1, further comprising analyzing a change in capacitance of the capacitive sensor to generate the one or more pressure data readings. 
     D11. The method of paragraph D10, wherein analyzing a change in capacitance includes measuring a change in a configuration between conductive materials of the capacitive sensor. 
     D12. The method of paragraph D10, wherein measuring the one or more pressure of blood readings occurs without data generated from an air inflatable element. 
     D13. The method of paragraph D1, wherein contacting a capacitive sensor of a blood pressure monitoring device at an area of a body capable of being monitored for pressure of blood readings includes contacting the area above an artery of a finger. 
     D14. The method of paragraph D13, wherein the pressure exerted at the area is caused by a bending of the finger. 
     D15. The method of paragraph D13, wherein the pressure exerted at the area is caused by the finger bent at a proximal inter-phalangeal (PIP) joint. 
     D16. The method of paragraph D13, further comprising collecting at continuous time intervals one or more pressure of blood readings while the finger is bending from an unbent position to a bent position. 
     D17. The method of paragraph D13, further comprising collecting at continuous time intervals one or more pressure of blood readings while the finger is bending from a bent position to another bending or an unbent position. 
     D18. The method of paragraph D13, further comprising automatically activating the sensor to collect one or more pressure of blood readings in response to a bending of the finger. 
     D19. The method of paragraph D1, further comprising continuously monitoring with the sensor the area when the finger is in a position where the exerted force is zero mmHg. 
     D20. The method of paragraph D1, wherein contacting a capacitive sensor of a blood pressure monitoring device at an area of a body capable of being monitored for pressure of blood readings includes contacting the area above an artery on a side of a finger between a metacarpophalangeal (MCP) joint and a proximal inter-phalangeal joint (PIP) joint. 
     D21. The method of paragraph D1, further comprising sending data from the monitoring device to a computer system, the data including the one or more pressure of blood readings. 
     D22. The method of paragraph D21, further comprising receiving a health data reading generated from the one or more pressure of blood readings by the computer system. 
     D23. The method of paragraph D1, further comprising attaching the pressure of blood monitor to a finger, the pressure of blood monitor being part of a ring system that includes a printed circuit board coupled to the pressure of blood monitor. 
     E1. A method for monitoring pressure of blood in an artery, comprising: 
     contacting a non-inflatable sensor of a blood pressure monitoring device at an area above an artery of a finger, 
     collecting with the non-inflatable sensor one or more pressure of blood data readings from the area after the contacting and after a pressure is exerted at the area on the sensor; and 
     analyzing with a computer device one or more pressure data readings to generate at least one of a blood pressure reading and a heart pulse reading. 
     F1. A system to monitor the pressure of blood, comprising: 
     a monitoring device that includes a capacitive sensor, the capacitive sensor being configured to be in contact with an area of skin above an artery, the capacitive sensor including:
         a conductive element disposed on a bottom side adjacent a printed circuit board,   a resilient member,   an insulation layer separating the conductive element from the resilient member, and   an adhesive layer covering the resilient member,       

     wherein the capacitive sensor is configured to collect one or more pressure of blood data readings while in contact with the area; and 
     a data processing device, in communication with the capacitive sensor, configured to analyze data readings produced by the sensor, the data processing device including a processor, a memory, and a set of instructions stored in the memory and executed by the processor to determine whether the information provided by the sensor meets selected criteria, and providing an alert to a user if the information meets the criteria. 
     F2. The system of paragraph F1, wherein the sensor is configured to sense a pressure parameter associated with at least one of a blood pressure rate and a heart pulse rate. 
     F3. The system of paragraph F1, wherein the monitoring device includes an attachment portion that houses the sensor, the attachment portion being configured such that bending a finger causes pressure to be exerted on the sensor from the finger. 
     F4. The system of paragraph F1, wherein the sensor is a proportional sensor. 
     F5. The system of paragraph F1, wherein the resilient member is a spring deformable by pressure. 
     F6. The system of paragraph F5, wherein the capacitive sensor measures changes in capacitance in response to changes in pressure. 
     F7. The system of paragraph F5, wherein the corrugated leaf spring forms a component of a capacitor. 
     F8. The system of paragraph F1, wherein the conductive elements comprises copper and gold. 
     F9. The system of paragraph F1, further including an indicator in communication with the sensor, the indicator providing a signal when sensed blood pressure meets a selected criterion. 
     F10. The system of paragraph F9, wherein the monitoring device is configured to create pressure on an artery in the finger when a user bends the finger. 
     G1. A method for monitoring pressure of blood in an artery, comprising: 
     contacting a non-invasive sensor of a pressure of blood monitoring device at an area above an artery of a finger, 
     collecting with the sensor one or more pressure data readings, other than readings corresponding to an air pressure reading, from the area after the contacting and after a pressure is exerted at the area on the sensor; and 
     analyzing with a computer device one or more pressure data readings to generate at least one of a blood pressure reading and a heart pulse reading. 
     G2. The method of paragraph G1, wherein analyzing with a computer device one or more pressure data readings does not include analyzing any pressure data readings corresponding to an air pressure reading. 
     G3. The method of paragraph G1, wherein the pressure exerted at the area is caused by a bending of the finger, the bending causing a high pressure in the artery, relative to a lesser bending position, and the bending causing a liquid injection adjacent the area. 
     G4. The method of paragraph G1, wherein the pressure exerted at the area is caused by the finger bending at a proximal inter-phalangeal (PIP) joint. 
     G5. The method of paragraph G1, further comprising collecting at continuous time intervals one or more pressure readings while the finger is bending from a first position to a bent position. 
     G6. The method of paragraph G1, further comprising collecting at continuous time intervals one or more pressure data readings while the finger is bending from a bent position to another bending or an unbent position. 
     G7. The method of paragraph G1, further comprising automatically activating the sensor to collect one or more pressure data readings in response to a bending of the finger. 
     G8. The method of paragraph G1, further comprising continuously monitoring with the sensor the area when the finger is in a position where the exerted force is zero mmHg. 
     G9. The method of paragraph G1, wherein contacting a non-invasive sensor of a pressure of blood monitoring device at an area above an artery of a finger includes contacting the area above the artery on a side of a finger between a metacarpophalangeal (MCP) joint and a proximal inter-phalangeal (PIP) joint. 
     G10. The method of paragraph G1, further comprising receiving at least one of the blood pressure reading and the heart pulse reading generated based on the one or more pressure data readings analyzed by the computer system. 
     G11. The method of paragraph G1, further comprising attaching the pressure of blood monitoring device to a finger, the pressure of blood monitoring device being part of a ring system that includes a printed circuit board coupled to the non-invasive sensor. 
     G12. The system of paragraph G1, wherein the non-invasive sensor is a proportional sensor. 
     G13. The system of paragraph G1, wherein the non-invasive sensor is a capacitive sensor, and further comprising measuring changes in capacitance in response to changes in pressure to generate the one or more pressure data readings. 
     G14. The method of paragraph G1, further comprising: providing a sensor capable of detecting the exerted pressure such that the sensor is in an inactive state when the exerted pressure is less than a first level and is in an active state when the exerted pressure is at a second level, higher than the first level, and generating an indicator when the exerted pressure is between a diastolic pressure and a systolic pressure. 
     H1. A method for monitoring pressure of blood in an artery, comprising: 
     contacting a capacitive sensor of a pressure monitoring device at an area of a body capable of being monitored for pressure of blood readings, 
     collecting with the capacitive sensor one or more pressure data readings from the area after the contacting and after a pressure is exerted at the area on the sensor; and 
     analyzing with a computing device the one or more pressure data readings to generate one or more health data readings based on an analysis of the one or more pressure data readings. 
     H2. The method of paragraph H1, further comprising collecting a plurality of pressure data readings continuously as the exerted pressure changes between 0 millimeters of mercury (mmHg) and 300 mmHg. 
     H3. The method of paragraph H1, further comprising continuously collecting readings over a plurality of time intervals, every approximately  100  milliseconds, as the exerted pressure changes between approximately 40 mmHg and approximately 180 mmHg, further wherein changing the exerted pressure continuously between zero mmHg and 300 mmHg occurs over approximately 30 seconds. 
     H4. The method of paragraph H1, further comprising analyzing the plurality of pressure data readings to generate a blood pressure reading as the health data reading. 
     H5. The method of paragraph H1, further comprising measuring an oscillation of pressure data readings over time intervals of the collected plurality of pressure readings to generate a heart pulse rate as the health data reading. 
     H6. The method of paragraph H1, further comprising automatically collecting a plurality of pressure data readings continuously as the exerted pressure changes while in the range of greater than zero millimeters mercury (mmHg) and less than or equal to 300 mmHg. 
     H7. The method of paragraph H1, further comprising: 
     monitoring the area continuously with the capacitive sensor, and 
     automatically collecting at least one reading after detecting with the capacitive sensor a change in pressure at the area from a zero mmHg state to a non-zero mmHG state. 
     H8. The method of paragraph H1, further comprising analyzing a change in capacitance of the capacitive sensor to generate the one or more pressure data readings, wherein analyzing a change in capacitance includes measuring a change in a configuration between conductive materials of the capacitive sensor. 
     H9. The method of paragraph H1, wherein measuring the one or more pressure of blood readings occurs without data generated from an air inflatable element. 
     H10. The method of paragraph H1, wherein contacting a capacitive sensor of a blood pressure monitoring device at an area of a body capable of being monitored for pressure of blood readings includes contacting the area above an artery of a finger. 
     H11. The method of paragraph H1, further comprising providing the capacitive sensor configurable to be in contact with the area of skin above an artery, the capacitive sensor including: 
     a conductive element disposed on a bottom side adjacent a printed circuit board, 
     a resilient member, 
     an insulation layer separating the conductive element from the resilient member, and 
     an adhesive layer covering the resilient member, 
     wherein the capacitive sensor is configured to collect one or more pressure of data readings while in contact with the area; and 
     a data processing device, in communication with the capacitive sensor, configured to analyze data readings produced by the sensor, the data processing device including a processor, a memory, and a set of instructions stored in the memory and executed by the processor to determine whether the information provided by the sensor meets selected criteria, and providing an alert to a user if the information meets the criteria. 
     H12. The system of paragraph H11, further comprising 
     providing the pressure monitoring device with an attachment portion that houses the sensor, and 
     bending of a finger causes pressure to be exerted on the sensor from the finger. 
     Advantages, Features, Benefits 
     The different embodiments of the blood pressure monitor described herein provide several advantages over known solutions for monitoring and measuring blood pressure. For example, the illustrative embodiments of a pressure of blood monitor, such as a finger-mounted pressure of blood monitor, described herein allow pressure to be exerted on an artery without use of cumbersome inflatable cuffs and associated equipment and power sources. Any of the one or more embodiments may be configured to monitor any area of the body capable of being monitored for pressure of blood. Additionally, and among other benefits, illustrative embodiments of the pressure of blood monitor described herein allow both on-demand and continuous monitoring of pressure of blood, and may be more accurate than previous methods. No known system or device can perform these functions, particularly in a finger-mounted, low-cost fashion. Thus, the illustrative embodiments described herein are particularly useful for patients needing continuous, low-cost monitoring, particularly in the home. However, not all embodiments described herein provide the same advantages or the same degree of advantage. 
     CONCLUSION 
     The disclosure set forth above may encompass multiple distinct inventions with independent utility. Although each of these inventions has been disclosed in its preferred form(s), the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. The subject matter of the inventions includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. Inventions embodied in other combinations and subcombinations of features, functions, elements, and/or properties may be claimed in applications claiming priority from this or a related application. Such claims, whether directed to a different invention or to the same invention, and whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the inventions of the present disclosure. Furthermore, explicit reference is hereby made to all inventions shown in the drawings, whether or not described further herein.