Finger blood pressure cuff

Abstract

One aspect of the disclosure relates to a finger blood pressure cuff. The finger blood pressure cuff can include a housing having an opening sized to receive a person's finger, and an inflatable elastomeric bladder disposed about an interior-facing surface of the opening. The inflatable elastomeric bladder can be inflated to pressurize and temporarily occlude blood flow in a user's finger. The finger blood pressure cuff can include a pressure sensor to obtain a blood pressure measurement.

Description

[0001] Case Analysis

[0002] This application is a divisional application of Chinese Invention Patent Application No. 201880076440.1, filed on September 26, 2018.

[0003] Cross-references to related applications

[0004] This application claims priority to U.S. Patent Application No. 15 / 855,932, filed December 27, 2017, entitled “FINGER BLOOD PRESSURE CUFF,” which in turn claims priority to U.S. Provisional Patent Application No. 62 / 566,202, filed September 29, 2017, also entitled “FINGER BLOOD PRESSURE CUFF.” Each of these applications is incorporated herein by reference in its entirety for all purposes. Technical Field

[0005] This application relates to a finger blood pressure cuff. Background Technology

[0006] Blood pressure is an important health indicator measured in both clinical and non-clinical settings. Many automated systems used to measure a user's blood pressure utilize oscillometric blood pressure measurement (OBPM) technology. Traditional OBPM systems inflate a sac with air and squeeze the arteries at varying pressures, and the OBPM system "listens" to the user's heart rate at that pressure. OBPM systems are widely used primarily because they are easier to use than other alternatives and, unlike traditional auscultation methods, do not require trained operators.

[0007] The pressure signal captured by OBPM is affected by static pressure, which is influenced by the placement of the band relative to the heart. Some existing OBPM systems require the measuring device to be placed around the upper arm at heart height so that the static pressure is approximately equal to that at the heart. Other existing OBPM systems can be placed around the wrist; however, such systems may be more susceptible to variations in static pressure, for example, due to the height difference between the heart and the measurement location.

[0008] Armband-based OBPM systems tend to be large, bulky, and uncomfortable. Wrist-worn OBPM systems may be more portable than armband-based systems, but they are less reliable and accurate. Summary of the Invention

[0009] Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the specification, drawings, and claims.

[0010] One aspect of this disclosure relates to a device for estimating a user's blood pressure. The device includes: a housing having an aperture sized to receive a human finger; a pump; an inflatable bladder disposed around an inwardly facing surface of the aperture and at least partially defining a pressurizable volume in fluid communication with the pump; and a pressure sensor in fluid communication with the pressurizable volume and configured to generate pressure data indicating pressure within the pressurizable volume over time. The pump is configured to pressurize the pressurizable volume and cause the inflatable bladder to expand toward the center of the aperture and contact the user's finger when the user's finger is in the aperture and the pump is activated.

[0011] In some implementations, the device further includes an annular structure disposed within the orifice and surrounding the inflatable elastic bladder, the annular structure at least partially defining a pressurizable volume. The annular structure may have a first end and a second end, wherein a generally cylindrical inner surface spans between the first and second ends. The inflatable elastic bladder includes a first sealing shoulder and a second sealing shoulder, wherein a membrane is structurally located between the first and second sealing shoulders. The first sealing shoulder is sealed against the first end of the annular structure, and the second sealing shoulder is sealed against the second end of the annular structure. The annular structure includes one or more ports for fluidly connecting the pressurizable volume to a pump. The one or more ports may extend through the annular structure and may be configured to fluidly connect the pressurizable volume to an annular channel surrounding the annular structure and in fluid communication with the pump. In some implementations, the pressurizable volume has a continuous annular shape. In some implementations, the inflatable bladder includes two or more leaf sections distributed substantially symmetrically about the central axis of the hole, each leaf section including a middle section supported between two end sections, wherein when the pressurizable volume is at zero gauge pressure, the middle section of each leaf section extends closer to the central axis than the corresponding end section of that leaf section. The device may further include a controller configured to control the pump to: increase the pressure within the pressurizable volume from a first pressure to a second pressure, thereby causing the inflatable bladder to expand toward the central axis; and provide a notification in response to an indication from a pressure sensor that the pressurizable volume is at the second pressure, instructing the user to insert their finger into the orifice. The controller is configured to control the pump to further increase the pressure in the pressurizable volume beyond the second pressure. The controller is configured to monitor pressure data from the pressure sensor to determine when the pressure within the pressurizable volume reaches a third pressure, at which pulsating changes in the pressure within the pressurizable volume can be detected in the pressure data. The controller is configured to control the pump to further increase the pressure in the pressurizable volume to a fourth pressure, at which the pulsating changes in the pressure within the pressurizable volume decrease to a first predetermined level. The controller is configured to determine systolic blood pressure data based on the fourth pressure, and the controller is configured to determine diastolic blood pressure data based on the third pressure. The inflatable bladder may have a helical twist about the central axis of the orifice. In some implementations, the inflatable elastic bladder is made of silicone or other elastomers having a Young's modulus selected from about 0.001 GPa to about 0.1 GPa and about 0.003 GPa to about 0.05 GPa. In some implementations, the inflatable elastic bladder includes a membrane segment that transitions to telescopic segments at opposite ends, each telescopic segment extending rearward toward the other telescopic segment from the location where it transitions to the membrane segment, and each telescopic segment terminating in a sealing shoulder surrounding the membrane segment.In some implementations, the housing includes a circumferential lip that: extends around the hole; forms an opening smaller than the hole when viewed along the central axis of the hole; and, when viewed along the central axis and the device is oriented such that the inflatable bladder is located behind the circumferential lip, obscures a portion of the inflatable bladder from view.

[0012] Another aspect of this disclosure relates to an apparatus for estimating a user's blood pressure. The apparatus includes: an inflatable bladder that at least partially defines a pressurizable volume; a pump in fluid communication with the inflatable bladder and configured to: when the pump is activated, pressurize the pressurizable volume and cause the inflatable bladder to inflate and contact the user's appendage; and a pressure sensor in fluid communication with the inflatable bladder and configured to generate pressure data indicating pressure within the pressurizable volume over time. The inflation rate of the pump can be controlled by controlling at least one of a duty cycle, voltage, or drive frequency.

[0013] In some implementations, the inflatable bladder is an inflatable elastic bladder disposed around an inwardly facing surface of an opening in the device, wherein a pump is configured to pressurize the pressurizable volume when a user's finger is positioned within the opening of the device. In some implementations, the pump inflation rate is controlled between approximately 1 mmHg per second and approximately 10 mmHg per second. In some implementations, the device further includes a controller coupled to the pump, wherein the controller is configured to control the pump's duty cycle. The controller may be configured to increase the pump's duty cycle from a first duty cycle to a second duty cycle at a first selected rate. The first duty cycle may be less than 100% and the second duty cycle may be 100%, the first selected rate being between approximately 0.1% and approximately 20% per second of duty cycle increase. The controller may be configured to increase the pump's duty cycle from the second duty cycle to a third duty cycle at a second selected rate. In some implementations, the controller is configured to dynamically change the pump's duty cycle based at least in part on pressure data from the pressurizable volume. In some implementations, the device also includes a controller coupled to the pump, wherein the controller is configured to control the pump's inter-peak voltage (Vp). pp The controller can be configured to increase the pump's inter-peak voltage from a first inter-peak voltage to a second inter-peak voltage at a selected rate. In some implementations, the pump's drive frequency is equal to or greater than approximately 23 kHz.

[0014] Another aspect of this disclosure relates to a method for controlling the inflation rate of an inflatable bladder. The method includes using a pump to inflate the inflatable bladder and bring it into contact with a user's appendage, and increasing the pump's duty cycle from a first duty cycle to a second duty cycle at a first selected rate.

[0015] In some implementations, a first duty cycle is less than 100% and a second duty cycle is 100%, with a first selection rate between approximately 0.1% and approximately 20% per second of duty cycle increase. In some implementations, the method further includes: acquiring pressure data indicating the pressure within the pressurizable volume of the inflatable bladder as it changes over time; and increasing the pump's duty cycle from the second duty cycle to a third duty cycle at a second selected rate. The duty cycle is increased from the second to the third duty cycle when the pressure within the pressurizable volume reaches a threshold pressure. In some embodiments, the method further includes: acquiring pressure data indicating the pressure within the pressurizable volume of the inflatable bladder as it changes over time; and dynamically changing the pump's duty cycle based at least in part on the pressure data of the pressurizable volume.

[0016] Another aspect of this disclosure relates to an apparatus for estimating a user's blood pressure. The apparatus includes: an inflatable bladder that at least partially defines a pressurizable volume; a pump in fluid communication with the inflatable bladder and configured to: when the pump is activated, pressurize the pressurizable volume and cause the inflatable bladder to inflate and contact the user's appendage; a pressure sensor in fluid communication with the inflatable bladder and configured to generate pressure data indicating pressure within the pressurizable volume over time, wherein the pressure data includes oscillometric data in a first pressure curve and pulsation information in a second pressure curve; and a controller coupled to the pump. The controller is configured to cause the pump to pressurize the pressurizable volume to a first pressure greater than the maximum amplitude pressure of the oscillometric data in the first pressure curve.

[0017] In some implementations, the inflatable bladder is an inflatable elastic bladder disposed around an inwardly facing surface of an opening in the device, wherein a pump is configured to pressurize the pressurizable volume when a user's finger is positioned within the opening of the device. In some embodiments, a first pressure curve indicates the pressure within the pressurizable volume over time up to a first pressure, and a second pressure curve indicates the pressure within the pressurizable volume over time after reaching the first pressure. In some implementations, a controller is further configured to cause the pump to deflate the inflatable bladder, such that the pressure within the pressurizable volume reaches a target pressure less than the first pressure after reaching the first pressure. The controller may be configured to cause the pump to inflate the inflatable bladder so that the pressure within the pressurizable volume reaches a second pressure in the second pressure curve from the target pressure, wherein the second pressure is based at least in part on information from oscilloscope data in the first pressure curve. In some implementations, the controller may be configured to hold the pressurizable volume at the second pressure for a duration sufficient to generate pulsating information in the second pressure curve. The duration for which the pressurizable volume is held at the second pressure can be between about 1 second and about 15 seconds. In some implementations, the controller is also configured to hold the pressurizable volume at the target pressure for a duration sufficient to obtain pulsation information in the second pressure curve, wherein the target pressure is based at least in part on information from oscillometric data in the first pressure curve. In some implementations, the controller is also configured to analyze the pulsation information in the second pressure curve to determine one or more of pulse wave analysis (PWA) characteristics, arterial compliance, respiratory activity, and atrial fibrillation.

[0018] Another aspect of this disclosure relates to a method for estimating a user's blood pressure. The method includes: using a pump to inflate an inflatable bladder to contact the user's appendage; obtaining pressure data indicating pressure within a pressurizable volume of the inflatable bladder over time, wherein the pressure data includes oscillometric data from a first pressure curve; maintaining inflation of the inflatable bladder to achieve a first pressure greater than the maximum amplitude pressure of the oscillometric data from the first pressure curve; and deflating the inflatable bladder to achieve a target pressure from the first pressure. The target pressure is based at least in part on information from the oscillometric data from the first pressure curve.

[0019] In some implementations, the method further includes a duration of holding the pressurizable volume at the target pressure between approximately 1 second and approximately 15 seconds. The pressure data may further include pulsation information in a second pressure curve, wherein this pulsation information is obtained while the pressurizable volume is held at the target pressure.

[0020] Another aspect of this disclosure relates to a method for estimating a user's blood pressure. The method includes: using a pump to inflate an inflatable bladder to contact the user's appendage; obtaining pressure data indicating pressure within a pressurizable volume of the inflatable bladder over time, wherein the pressure data includes oscillometric data from a first pressure curve; maintaining inflation of the inflatable bladder to bring the pressure in the pressurizable volume to a first pressure, the first pressure being greater than the maximum amplitude pressure of the oscillometric data from the first pressure curve; deflating the inflatable bladder from the first pressure; and inflating the inflatable bladder to bring the pressure in the pressurizable volume to a second pressure. The second pressure is based at least in part on information from the oscillometric data from the first pressure curve.

[0021] In some implementations, the method further includes maintaining the pressurizable volume at the second pressure for a duration between about 1 second and about 15 seconds. The pressure data may also include pulsation information in the second pressure curve, wherein the pulsation information is obtained while the pressurizable volume is maintained at the second pressure.

[0022] Another aspect of this disclosure relates to an apparatus for estimating a user's blood pressure. The apparatus includes: an inflatable bladder that at least partially defines a pressurizable volume; a pump in fluid communication with the inflatable bladder and configured to: when the pump is activated, pressurize the pressurizable volume and cause the inflatable bladder to inflate and contact the user's appendage; a pressure sensor in fluid communication with the inflatable bladder and configured to generate pressure data indicating pressure within the pressurizable volume over time; and one or more accelerometers. The one or more accelerometers are configured to determine the relative positioning of the apparatus with respect to the user's heart.

[0023] In some implementations, the inflatable bladder is an inflatable elastic bladder disposed around an inwardly facing surface of an opening in the device, wherein a pump is configured to pressurize the pressurizable volume when a user's finger is positioned within the opening of the device. In some implementations, one or more accelerometers are also configured to determine whether the device is in motion or stationary. The device may also include a controller configured to use the pump to initiate inflation of the inflatable bladder when one or more accelerometers determine that the device is within a threshold height relative to the user's heart and the device remains stationary for a threshold duration. The controller may also be configured to shut down the device or enter a power-saving mode when one or more accelerometers determine that the device is not positioned within a threshold height relative to the user's heart and the device remains stationary for a sufficiently long duration. In some implementations, one or more accelerometers are configured to determine the relative positioning of the device with respect to the user's heart by measuring tilt about an axis orthogonal or substantially orthogonal to the vertical axis, the tilt including a roll angle and a pitch angle, wherein each of the roll angle and pitch angle is between about 0 degrees and about 30 degrees when it is determined that the device is at approximately the same height as the user's heart. In some implementations, the device also includes one or more stethoscope sensors configured to acoustically determine the position of the user's heart. In some implementations, the device also includes one or more optical sensors for determining that the user's finger is located within an aperture in the device, wherein an inflatable bladder is disposed around an inwardly facing surface of the aperture. In some implementations, the device also includes one or more feedback devices configured to communicate the device's positioning relative to the user's heart to the user, one or more of which include at least one of: a speaker for audio feedback, a light-emitting diode (LED) for optical feedback, a display for visual feedback, and a motor for haptic feedback.

[0024] Another aspect of this disclosure relates to an apparatus for estimating a user's blood pressure. The apparatus includes: an inflatable bladder that at least partially defines a pressurizable volume; a pump in fluid communication with the inflatable bladder and configured to: when the pump is activated, pressurize the pressurizable volume and cause the inflatable bladder to inflate and contact the user's appendage; a pressure sensor in fluid communication with the inflatable bladder and configured to generate pressure data indicating pressure within the pressurizable volume over time; and one or more proximity sensors configured to determine that the apparatus is located near the user's heart.

[0025] In some implementations, the inflatable bladder is an inflatable elastic bladder disposed around an inwardly facing surface of an opening in the device, wherein a pump is configured to pressurize the pressurizable volume when a user's finger is positioned within the opening. In some implementations, one or more proximity sensors include one or both of a stethoscope sensor and a microphone, configured to acoustically determine the proximity of the user's heart. In some implementations, the device further includes one or more accelerometers configured to determine whether the device is in motion or stationary. The device may also include a controller configured to initiate inflation of the inflatable bladder using the pump when one or more proximity sensors determine that the device is near the user's heart and one or more accelerometers determine a stationary threshold duration for the device.

[0026] These other implementations are described in further detail with reference to the accompanying drawings and the following detailed description. Attached Figure Description

[0027] Figure 1 A perspective view of an example finger blood pressure cuff is shown, based on some implementations.

[0028] Figure 2 A perspective view of the various components of an example finger blood pressure cuff, based on some implementations, is shown.

[0029] Figure 3A A side view of an example finger blood pressure cuff is shown, based on some implementations.

[0030] Figure 3B The section cut along line AA is shown. Figure 3A A cross-sectional perspective view of a finger blood pressure cuff.

[0031] Figure 3C The cut-off line BB is shown. Figure 3A A cross-sectional perspective view of a finger blood pressure cuff.

[0032] Figure 3D The section cut along line AA is shown. Figure 3A A cross-sectional side view of a finger blood pressure cuff.

[0033] Figure 3E The cut-off line BB is shown. Figure 3A A cross-sectional side view of a finger blood pressure cuff.

[0034] Figure 3F It shows Figure 3A Front view of a finger blood pressure cuff.

[0035] Figure 3G It shows the way Figure 3F The cross-sectional view of the finger blood pressure cuff shown is shown in the cross-sectional plane.

[0036] Figure 4A An example inflatable elastic bladder according to some implementations is shown; the front view, side sectional view and isometric view are depicted from left to right.

[0037] Figure 4B An example of an inflatable elastic bladder according to some other implementations is shown; the front view, side section view, isometric view, side view, and front section view are depicted from left to right.

[0038] Figure 5A An example inflatable elastic bladder with three inflatable lobes is shown according to some implementations; a front view, a side sectional view, and an isometric view are depicted from left to right.

[0039] Figure 5B An example inflatable elastic bladder with three inflatable twisted leaves is shown according to some implementations; a front view, a side sectional view, an isometric view and a side view are depicted from left to right, as well as several front sectional views along the right side of the figure.

[0040] Figure 5C An example inflatable elastic bladder with pre-inflated blades is shown according to some implementations; a front view, a side sectional view, and an isometric view are depicted from left to right.

[0041] Figure 6A and Figure 6B The graphs show the inflation curves of the pre-inflated and non-pre-inflated bladders.

[0042] Figure 7 A graph showing the typical waveform of a piezoelectric pump is provided.

[0043] Figure 8 A voltage graph is shown that varies over time, with the duty cycle of the square wave signal driving the piezoelectric pump changing gradually.

[0044] Figure 9 The inflation curve of a finger blood pressure cuff using a piezoelectric pump is shown.

[0045] Figure 10 A graph for blood pressure measurement is shown, depicting a first pressure curve and a subsequent second pressure curve, wherein the second pressure curve is inflated to the target pressure and held at the target pressure.

[0046] Figure 11 A graph for blood pressure measurement is shown, depicting a first pressure curve and a subsequent second pressure curve, wherein the second pressure curve is deflated to the target pressure and held at the target pressure.

[0047] Figure 12 and Figure 13The image shows a sample finger blood pressure cuff, which can be worn during measurement, with the user placing their hand at an angle on their chest.

[0048] Figure 14 and Figure 15 A photograph of an example finger blood pressure cuff is shown, which is placed on a surface and in which a finger is inserted through the opening of the finger blood pressure cuff for blood pressure measurement. Detailed Implementation

[0049] Unlike traditional blood pressure cuffs placed around a user's arm or wrist, this disclosure relates to blood pressure cuffs placed around a user's fingers. Finger blood pressure cuffs can offer advantages over traditional wrist or arm cuffs because they are likely to be less bulky, easier to use, more portable, more compact, less conspicuous, and more comfortable for the user. However, measuring blood pressure at a user's finger is generally not considered accurate and reliable compared to measurements taken at the upper arm or wrist because it is further from the user's heart. As used herein, a finger blood pressure cuff refers to any system, device, or apparatus that is wrapped around a user's finger and configured to estimate the user's blood pressure.

[0050] In one embodiment, a finger blood pressure cuff may include a rigid annular structure and an inflatable elastic bladder configured to inflate inward toward the center of the annular structure and contact a user's finger that has been inserted through the annular structure. The elastic bladder can be inflated to pressurize and squeeze the user's finger, temporarily obstructing blood flow in the user's finger. Some examples of finger blood pressure cuffs may include one or more sensors for detecting when the user's finger is near the user's chest. The finger blood pressure cuff may generate pressure data during use corresponding to the pressure applied to the user's finger; such data can then be analyzed by the finger blood pressure cuff or another device receiving the data from the cuff to obtain measurements of blood pressure and other cardiovascular data, such as heart rate.

[0051] Example structure of a finger blood pressure cuff

[0052] Figure 1A perspective view of an example finger blood pressure cuff 100 according to some implementations is shown. The finger blood pressure cuff 100 may include a housing 102 having an opening or hole 104 through which a user's finger can be inserted. A generally rigid annular structure and an inflatable elastic bladder 110 may be disposed within the opening 104 of the housing 102. The housing 102 may enclose one or more components associated with performing operation of the finger blood pressure cuff 100, such as one or more of the following: a controller or control unit, a pressure sensor, one or more inertial measurement units (e.g., multi-axis accelerometers, gyroscopes, etc.), a piezoelectric pump (or various types of pumps), a battery or other power source, and other circuitry. The housing 102 may be supported on a base 106, which is connected to a power cable 108. Alternatively, the housing 102 may only have a connector port for direct connection to the power cable.

[0053] Figure 2 Perspective views of various components of an example finger blood pressure cuff 100 according to some implementations are shown. The finger blood pressure cuff 100 includes: a housing 102 having an opening 104 for receiving an annular structure 112; and an inflatable bladder 110 within the opening 104, such that the inflatable bladder 110 is positioned around an inwardly facing surface of the hole or opening 104 (thus, when viewed by a user, the inflatable bladder 110 appears to provide an inner surface of the hole or opening 104). The annular structure 112 may include a rigid, stiff, or semi-rigid outer ring circumferentially disposed around the inflatable bladder 110. The annular structure 112 may have a size based on the size of a user's finger. In some implementations, the inflatable bladder 110 may include a continuous, inflatable, generally annular volume 114. Alternatively, in some embodiments, the inflatable bladder may include two or more inflatable volumes 112 surrounding the center of the opening 104 (which may be spaced apart or alternatively define a continuous internal bladder volume, as in the depicted example). The two or more inflatable volumes 112 may be two or more inflatable leaflets symmetrically distributed about the center of the opening. However, it will be understood that in some implementations, the two or more inflatable leaflets may be asymmetrically distributed about the center of the opening. In some implementations, the inflatable bladder 110 may include three inflatable leaflets. Upon inflation, for example, when the pressurizable volumes are pressurized using a pump, the inflatable bladder 110 may expand inward toward the center of the hole or opening 104 and press against the user's finger inserted into the opening 104, providing sufficient arterial clamping to at least temporarily obstruct blood flow to the user's finger.

[0054] As described above, the annular structure 120 and the inflatable bladder 110 can be combined to define a pressurizable volume that can be pressurized to cause the inflatable bladder 110 to expand toward the center of the annular structure 120. In many implementations, the annular structure 120 and the inflatable bladder 110 can be substantially radially or axially symmetrical (it should be understood that such substantially radial or axial symmetry relative to the annular structure 120 can be applied to "inward-facing" surfaces, such as those facing the interior of the annular shape, and the remainder of the annular structure can exhibit a lack of symmetry and not be annular), wherein the central axes of the two components are substantially aligned, and wherein the annular structure 120 surrounds the inflatable bladder 110. In other words, the annular structure 120 can provide a rigid frame that supports or helps support the inflatable elastic bladder 110, and can also provide an annular rigid surface that defines a portion of the pressurizable volume of the bladder 110, wherein the majority of the remaining pressurizable volume of the bladder 110 is provided by the inflatable elastic bladder 110.

[0055] Several components can be enclosed within the housing 102 of the finger blood pressure cuff 100. For example... Figure 2 As shown, the finger blood pressure cuff 100 may include a pump 130, such as a piezoelectric pump fluidly connected to a pressurizable volume (also referred to as a "bladder volume") of an inflatable elastic bladder 110, so that the pump 130 can pressurize the pressurizable volume and inflate the inflatable elastic bladder 110. The pump 130 may be fluidly connected to the inflatable elastic bladder 110 via a pump inlet / outlet 132 in the housing 102 and via one or more ports 122 of the annular structure 120. The ports 122 may be holes or openings in the annular structure 120, wherein the holes or openings may be positioned within an annular channel 124 of the annular structure 120. Although in Figure 2 Two alternative inflatable bladders 110 are shown—but only one is used in a particular finger blood pressure cuff 100, although both are shown in this example figure. The various inflatable bladders 110 are interchangeable and thus can be installed in and removed from the housing 102. The finger blood pressure cuff 100 may also include a pressure sensor 140, which is also fluidly connected to the pressurizable volume of the inflatable bladder 110 to allow measurement of pressure within the pressurizable volume over a period of time. The finger blood pressure cuff 100 may also include a controller or control unit configured to control the pump 130 and to receive and process data from the pressure sensor 140, wherein the controller or control unit, along with other circuitry, may be mounted on one or more printed circuit boards (PCBs) 150. The finger blood pressure cuff 100 may also include a battery 152 for powering the finger blood pressure cuff 100. Figure 2As shown, the charger can be configured to recharge the battery 152, for example, via inductive charging or other charging technologies, and the charger can be integrated into the base 106 where the blood pressure cuff 100 can be housed. The blood pressure cuff 100 may also include one or more communication interfaces, such as USB, Bluetooth, etc., which can be used to send data directly or via one or more intermediate devices from the device to another device (e.g., a smartphone, computer, or remote server). This data can be processed using one or more processors within the housing 102, one or more processors in another device (e.g., a server or smartphone), or a combination of such options.

[0056] Figure 3A A side view of an example finger blood pressure cuff is shown. Figure 3B The section cut along line AA is shown. Figure 3A A cross-sectional perspective view of a finger blood pressure cuff. Figure 3C The cut-off line BB is shown. Figure 3A A cross-sectional perspective view of a finger blood pressure cuff. Figure 3D The section cut along line AA is shown. Figure 3A A cross-sectional side view of a finger blood pressure cuff. Figure 3E The cut-off line BB is shown. Figure 3A A cross-sectional side view of a finger blood pressure cuff.

[0057] exist Figures 3B-3E In the finger blood pressure cuff 100, the opening 104 of the housing 102 accommodates an inflatable elastic bladder 110. The inflatable elastic bladder 110 occupies a volume within the opening 104. In some implementations, the inflatable elastic bladder 110 may have a generally triangular shape along a portion of its length to provide a trefoil design. Figures 3B-3E As shown, the inflatable bladder 110 includes three leaves, each configured to expand towards the center of the opening 104 upon inflation. Using two or more leaves provides a centering effect for the finger and promotes finger movement towards the center of the opening 104, thereby promoting uniform inflation of the leaves and applying pressure more evenly to the finger radially through the bladder 110. Furthermore, using two or more leaves reduces inaccuracies that may arise due to the user's finger being relatively small compared to the inflatable bladder 110. Without multiple leaves, the bladder would stretch, and the tensile strength of the bladder 110 would support some of the internal pressure, thereby reducing pressure on the finger. This effect is more pronounced for smaller fingers and is minimized by the application of multiple leaves.

[0058] Inflation air can be supplied from pump 130 (e.g., a piezoelectric pump) through multiple holes or ports 122 in the annular structure 120 to inflate the inflatable leaflets of the bladder 110. It should be understood that alternative designs may use liquids (e.g., water or oil) instead of air (or, if desired, gases other than air), and pumps designed for use with liquids instead of gases may be utilized—in which case a reservoir, such as another inflatable bladder, may be used to store working fluid not within the inflatable bladder mechanism. One or more pressure sensors 140 of the finger blood pressure cuff 100 may be configured to measure pressure within the pressurizable volume of the inflatable bladder 110, which is typically proportional to the pressure actually applied by the bladder 110 to the user's finger located in the opening 104. Accordingly, pressure sensors 140 may be used to generate pressure data indicating the pressure within the pressurizable volume of the inflatable bladder 110. The pressure sensed within the pressurizable volume is typically proportional to the pressure applied to the user's finger located in the opening 104. This pressure data can be used to provide a "pressure profile," which visually represents the pressure measured over a period of time within the pressurizable volume of the inflatable bladder 110. For example... Figure 3B and Figure 3D As shown, pressure sensors 140 can be housed within housing 102 and adjacent to annular structure 120 and inflatable bladder 110. Each pressure sensor (one or more) of pressure sensors 140 and pressurization pumps (one or more) 130 can be electrically coupled to a controller. The controller can include at least one of the following: a general-purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. In some implementations, the controller includes a processor, wherein the processor can be controlled by computer-executable instructions stored in memory to provide the functions described herein. The processor and other circuitry can be disposed on one or more PCBs 150 surrounded by housing 102.

[0059] In some implementations, the inflatable bladder 110 may be sealed or attached to the annular structure 120, wherein the seal or attachment may form an opposing airtight volume. Although the inflatable bladder 110 and the annular structure 120 may form an airtight volume, it is to be understood that in some implementations, the inflatable bladder 110 and the annular structure 120 may include leakage points (e.g., designed to leak) to reduce inflation rate and / or provide a controlled or “automatic” deflation mode. In some implementations, the inflatable bladder 110 may be welded or bonded to the annular structure 120 via a thermoplastic material or thermoplastic coating on the inflatable bladder 110. In some implementations, the inflatable bladder 110 may be attached to the annular structure 120 by adhesive or using suitable chemical bonding techniques.

[0060] Conventional OBPM systems use inflatable bladders made of flexible but generally inelastic materials such as vinyl. However, the finger blood pressure cuff 100 of this disclosure uses an inflatable bladder 110 made of an elastic material. In some implementations, the elastic material comprises silicone or other elastomers having a Young's modulus between about 0.001 GPa and about 0.1 GPa, or between about 0.003 GPa and about 0.05 GPa, which is several orders of magnitude lower than the Young's modulus of similar vinyl materials currently used in conventional blood pressure cuffs. For example, the elastomer may have a Young's modulus of about 0.005 GPa. In the case of a finger cuff device, the pressure loss is less when using an elastic material compared to using an inelastic material. Without being limited by any theory, the elastic material can provide flexibility to ensure that the pressure inside the inflatable bladder 110 is optimally transmitted to the user's finger, thereby minimizing pressure loss. Furthermore, non-elastic materials can have more creases and wrinkles, which allow the bladder material to fold and press against itself, thus introducing an additional source of pressure loss from the material itself. As used herein, pressure loss refers to the difference between the internal pressure of the inflatable bladder (i.e., the pressure used to inflate and stretch the bladder 110) and the external pressure applied to the blood vessels of the user's finger. The reduced pressure loss achieved by using elastic materials allows the finger blood pressure cuff 100 to be used on fingers of various sizes with negligible differences in signal output.

[0061] In some embodiments, the inflatable bladder 110 can be relatively thin, for example, with a thickness between about 0.1 mm and about 0.75 mm, or between about 0.25 mm and about 0.5 mm. A thin inflatable bladder 110 can reduce pressure loss while allowing the inflatable bladder 110 to expand.

[0062] In some implementations, the elastic material can be treated or coated to reduce the stickiness of the elastic bladder. For example, the elastic material can be treated with ultraviolet (UV) oxidation to reduce its stickiness or coefficient of friction, thereby allowing a person's fingers to be more easily inserted into the opening 104. For example, subjecting a silicone-based inflatable elastic bladder to UV radiation, corona discharge, or plasma, combined with introducing polar groups into the surface regions of the silicone, can induce oxidation, resulting in a vitrified silica-like surface layer. In other cases, the inflatable elastic bladder can be treated with a chemical coating, such as NuSil's R-2182 low-friction silicone coating, which provides such low stickiness and / or coefficient of friction upon curing.

[0063] In some implementations, such as Figure 3E The others shown Figures 3A-3D , Figure 3F and Figure 3G (This implementation is not shown), the housing 102 may be equipped with a stretchable textile-based cap or tube 107 that covers the inflatable elastic bladder and prevents the inflatable elastic bladder from directly contacting the skin during insertion and measurement. The cap may be made of, for example, a thin, stretchable fabric material, such as Lycra. TM Or Spandex TM This allows the cover to stretch to accommodate the expansion of the inflatable bladder 110 without applying excessive compressive force to the inflatable bladder 110.

[0064] In some implementations, the elastic material of the sac 110 may be substantially transparent to allow light of certain wavelengths to pass through. Therefore, an optical sensor may be incorporated (e.g., within the inflatable elastic sac 110) to perform additional functions via the finger blood pressure cuff 100. In some such implementations, flexible printed circuitry may be incorporated into or otherwise attached to the surface of the sac 110, partially defining the sac volume. Such circuitry may include, for example, a photodetector and a photoemitter forming a photoplethysmography (PPG) sensor. The photoemitter may be configured to direct light through the sac 110 and into the dermis of the finger during measurement, and then the photoemitter may measure the amount of light diffusely reflected back out of the dermis and back through the sac 110. The PPG sensor may also operate in the usual manner for PPG sensors. In other such implementations, a transmissive PPG sensor may be used, wherein the photoemitter is located within the sac volume on one side of the opening 104, and the photodetector is located within the sac volume on the other side of the opening 104, either directly through or in a position therebetween. Even when a person's finger is inserted into the opening 104, light emitted from the photoelectric emitter, if bright enough, can still pass through the finger or at least a portion of it, thus being modulated by the blood flow through the finger, and enter the photodetector, where the detected signal can be used as input to the PPG sensor. Such a PPG sensor can be configured to measure heart rate, blood oxygenation, SpO2 levels, and other cardiovascular parameters.

[0065] In some implementations, the inflatable bladder 110 may include creases and other non-uniformities with varying flexibility to reduce pressure loss. For example, the inflatable bladder 110 may include leaflets as described above to reduce pressure loss.

[0066] In some implementations, the inflatable elastic bladder 110 may be molded from a single material. In other implementations, the inflatable elastic bladder 110 may be molded from more than one material.

[0067] The length of the inflatable bladder 110 (where the length is measured along the axis of the finger inserted into the bladder 110) can be sized based on the length of the user's finger. A longer inflatable bladder 110 can provide improved arterial clamping. In some implementations, the length of the inflatable bladder 110 can be between approximately 0.5 inches and approximately 1.5 inches, or between approximately 0.75 inches and approximately 1.25 inches. In testing, a length approximately 80% of the adult phalanx length was found to work well for adult test subjects with a variety of finger and hand sizes, while still providing sufficient arterial clamping and thus good blood pressure measurement.

[0068] In some embodiments, the volume of the fully inflated bladder 110 can be between about 1 cubic centimeter and about 20 cubic centimeters, or between about 3 cubic centimeters and about 10 cubic centimeters. This volume is significantly smaller than that of a conventional inflatable bladder in a conventional OBPM system.

[0069] Figure 3F It shows Figure 3A Front view of a finger blood pressure cuff. Figure 3G The CC section along the line is shown. Figure 3F A cross-sectional side view of a finger blood pressure cuff. Figure 3G The inflatable bladder 110 also includes a pair of telescopic portions 116 located at each end of the bladder 110. As used herein, "telescopic portion" can refer to a portion of the inflatable bladder 110 that wraps around, bends, or folds back from, for example, from, the membrane of the inflatable bladder 110 to allow the rest of the inflatable bladder 110 to expand or contract. Here, the telescopic portion 116 may be arranged in a ring around the inflatable bladder 110, and the telescopic portion 116 is configured to reduce inflation resistance by allowing the bladder 110 to expand inward toward the center of the opening 104 without requiring too much stretching of the bladder membrane. Figure 3F The diagram shows a three-lobed capsule, arrows indicating how these lobes inflate, and dashed lines indicating the outline of the lobes when pressurized. Some implementations may have more than three lobes, such as four or five lobes. Some implementations may have fewer than three lobes, such as two lobes. Figure 3GAs shown, the telescopic portion 116 can be folded, bent, shaped, or configured to reduce the inflation resistance of the inflatable elastic bladder 110 during inflation. The telescopic portion 116 may be disposed in the opening 104 of the housing 102 and attached to the housing 102 via one or more O-rings or sealing shoulders 118 integral with the bladder 110. The O-rings or sealing shoulders 118 may be compressed between the annular structure 120 and the housing 102 to clamp the bladder 110 to the annular structure 120 and form an airtight seal of the bladder volume or pressurizable volume 112. Therefore, for example, the annular structure 120 can be considered to have a first end and a second end, wherein a substantially cylindrical inner surface spans between the first end and the second end (the overall shape of this surface can be cylindrical, but can have discontinuities, such as pressure ports; or be slightly elliptical; or can have an irregular shape matching the cross-sectional profile of an average human finger); the inflatable elastic bladder 110 can have a first sealing shoulder and a second sealing shoulder, each of which is sized and shaped to abut the first end and the second end, respectively. By compressing the first and second sealing shoulders against the first and second ends of the annular structure 120, the inflatable elastic bladder 110 can be sealed to the annular structure 120, thereby forming a pressurizable volume or bladder volume 112. Figure 3G Also visible is an annular channel 124, which is disposed between the annular structure 120 and the housing 102, and provides a fluid communication path between the orifice / port 122 leading to the bladder volume 112 and the inlet / outlet ports 132, 142 for the pump 130 and / or pressure sensor 140.

[0070] In some embodiments, housing 102 may include a circumferential lip 102' surrounding a hole or opening 104 (if the hole is a through hole, the circumferential lip may optionally be located on both sides of the hole; if the hole is a blind hole, the circumferential lip is located only on one side of the housing where the hole is located). (Although the depicted implementation does not have such a prominent circumferential lip, the dashed outline 102' indicates how such a circumferential lip may appear.) The circumferential lip may extend around the hole or opening 104 and may form an opening smaller than the hole 104 (or at least smaller than the hole or opening through which the circumferential lip passes), and the lip may obscure some or all of the inflatable elastic bladder 110 as viewed along the central axis of the hole or opening 104 (and at least when the inflatable blood pressure cuff is at zero atmosphere). In some such implementations, the circumferential lip may obscure the crease of the telescopic portion 116, for example, the area where the telescopic membrane transitions to the telescopic portion 116, when viewed along the central axis. Therefore, the circumferential lip can help protect the inflatable elastic bladder 110 (especially the telescopic crease) from abrasion or other wear and tear that may be caused by repeated insertion of fingers into the finger blood pressure cuff.

[0071] Figure 4A An example of an inflatable elastic bladder 410 according to some implementations is shown. As described above, this implementation of the inflatable elastic bladder 410 is axially symmetrical about an axis, such as the central axis of a hole, and is characterized by a pair of telescopic portions 416. The inflatable elastic bladder 410 includes a bladder membrane 411 for defining a bladder volume or pressurizable volume, and the inflatable elastic bladder 410 also includes one or more sealing shoulders 418 integral with the bladder membrane 411 and configured to attach to a finger blood pressure cuff. This inflatable elastic bladder 410 can be used to provide a pressurizable volume having a continuous annular shape.

[0072] It is to be understood that, as used herein, the term "central axis" includes axes that may not necessarily pass through the center of a particular structure or geometry, but may be located very close to it (e.g., if the opening is slightly asymmetrical, the central axis may be a central axis passing through the centroid of the opening, or it may pass through the center of the circle surrounding the opening). However, in general, the central axis of a structure or feature may lie within a first distance of the "true" central axis of that structure or feature, for example, a central axis passing through the centroid or an axis of symmetry forming the structure or feature. This first distance may, for example, be ±10% of the maximum dimension of the feature defining the central axis. For example, if the opening is generally circular but not actually circular, the central axis may pass through a point within ±10% of the maximum dimension of the opening's centroid.

[0073] Figure 4B Another example of an inflatable elastic bladder 420 according to some other implementations is shown. In addition to the inflatable elastic bladder 420, it also includes multiple (e.g., four) longitudinal ribs 421, which may be included to provide some stiffness to the bladder 420 and potentially promote the formation of creases / pleats within the bladder 420 outside of predetermined locations. Figure 4B Inflatable elastic bladder 420 and Figure 4A The inflatable elastic bladder is the same. The longitudinal ribs 421 may extend in a direction parallel to the central axis of the hole (or the axis of axial or radial symmetry of the inflatable elastic bladder), and the longitudinal ribs 421 may be arranged in a circular array centered on the central axis. Figure 4A and Figure 4B Each of the inflatable elastic bladders 410 and 420 is depicted as an inflatable elastic bladder having an axially uniform annular inflatable volume.

[0074] Figure 5A An example inflatable elastic bladder 510 with three inflatable leaves 511 is shown according to some implementation. It is important to understand that... Figure 5AThe shape depicted in the example is that of example bladder 510 at rest, i.e., without undergoing pressurization (and thus, for example, the shape of the bladder at zero gauge pressure—the pressure inside the bladder equals the ambient atmospheric pressure outside the bladder). Therefore... Figure 5A The molded shape of the sac 510 includes visible leaf-like features. When the sac 510 is pressurized, the leaves 511 expand inward from the point that is closest to the center, thereby applying pressure to the finger at approximately evenly spaced locations around the circumference of the finger.

[0075] Figure 5B An example inflatable elastic sac 520 with three helically twisted leaflets 521 is shown according to some implementations. Helically twisting can be included in the leaflets 521 to cause folds to form between the leaflets 521 following a helical path, rather than a path normally aligned with the central axis of the phalanx / sac 520. As can be seen from section JJ to section MM, the triangular opening in the middle of the membrane undergoes a helical twist of approximately 40° along the length of the sac 520 (as indicated by the dotted-dotted reference axis in these figures). This reduces the chance that a larger artery in the finger (which typically extends in a direction aligned with the finger bones) might align with one of the folds and therefore experience less clamping pressure than the area of ​​the finger in contact with the middle of the leaflet 521.

[0076] Figure 5C An example inflatable elastic bladder 530 with a central leaflet 531 is shown according to some implementations, the central leaflet being... Figure 5A The trefoil design extends further toward the center of the opening, so that the inserted finger will be more actively "centered" through the leaf 531.

[0077] Figures 5A-5C Each of them shows a perspective view, a front view, and a sectional view based on the front view. Figure 5B A side view of an inflatable elastic bladder 520 with a spirally twisted leaf 521 is also shown, which has multiple cross-sectional views cut along lines JJ, KK, LL and MM to depict the twisted leaf 521.

[0078] In some implementations, such as Figure 5A As shown, introducing multiple leaves 511 into the inflatable elastic bladder 510 can improve the compliance of the inflatable elastic bladder 510 with various finger sizes. In some implementations, such as Figure 5B As shown, introducing a twisted leaflet 521 into the inflatable elastic bladder 520 can improve arterial clamping and further reduce pressure loss. In some implementations, such as Figure 5C As shown, a central leaflet 531 is used in the inflatable elastic bladder 530, or the leaves are pre-inflated to make them appear similar to Figure 5AThe leaf-like structure can provide benefits such as improved contact with the user's fingers during insertion, and thus reduced pressure loss.

[0079] Conventional OBPM systems do not inflate the inflatable bladder until blood pressure measurement is initiated. However, the finger blood pressure cuff of this disclosure may include a pre-inflation mechanism, for example, maintaining a small amount of air in the bladder sufficient to expand it to a similar size to that shown in the image, prior to further inflation of the elastic bladder for blood pressure measurement. Figure 5C The configuration of the elastic bladder shown is inflated. Before initiating blood pressure measurement, the elastic bladder can occupy the desired volume in the opening, such as... Figure 3F The diagram shows the partial inflatable volume. Pre-inflated bladders reduce pressure loss that could result from inflating the bladder to a specific volume to achieve contact with the user's fingers. A pre-inflated bladder can contact or nearly contact the user's fingers positioned within the opening, regardless of the size of the fingers. Pre-inflation reduces the volume required to inflate the bladder to achieve contact with the user's fingers. While conventional OBPM systems may require wrapping and tightening the inflatable bladder around the user's appendage to achieve a "close" or "fitting" contact, pre-inflated bladders introduce volume within the bladder to achieve contact without altering the diameter of the opening or the outer diameter of the bladder.

[0080] In some implementations, the finger blood pressure cuff of this disclosure may include a controller configured to control a pump to pre-inflate an inflatable bladder from a first pressure (e.g., atmospheric pressure) to a second predicted pressure or second pressure as described above before finger insertion. Upon finger insertion, the controller may cause the pump to further inflate the inflatable bladder to a third pressure, at which a pressure sensor detects pulsation in the pressure, for example, pulsation consistent with pulsation caused by a heartbeat (e.g., pulsation periodically between approximately 50 cycles per minute and 200 cycles per minute), and then reach a fourth pressure at which the pulsation in the pressure decreases to a first predetermined level, for example, the observed maximum pulsation is 0, or less than 5% of the observed maximum pulsation. Alternatively, the controller may cause the pump to pressurize the inflatable bladder to the fourth pressure, for example, after reaching the second pressure, by pressurizing the inflatable bladder to a pressure higher than the maximum expected measurement pressure, and then allowing said pressure to decrease in a controlled manner until pulsation in the pressure signal is detectable. In this implementation, the pressure can then be further reduced in a controlled manner to reach a third pressure.

[0081] Figure 6A and Figure 6B The inflation curves (pressure curves during inflation) of pre-inflated and non-pre-inflated airbags were compared. Figure 6AThe inflation curve of the pre-inflated airbag was depicted, and Figure 6B The inflation curves of the non-pre-inflated airbags were depicted. Figure 6A and Figure 6B Each of these plots depicts an inflation curve for: (1) the pressure sensed by the pressure sensor (described by pressures 601, 611), (2) the pressure actually applied to the medium finger (described by pressures 602, 612), and (3) the pressure applied to the small finger (described by pressures 603, 613). One or more pressure pulses are recorded to estimate blood pressure. One or more pulses in the inflation curve may be part of oscillometric data used to estimate the user's blood pressure. Figure 6A In the context of pre-inflated airbags, at a given time during which one or more pulses are recorded, a first pressure difference between the actual applied pressure 602 and the observed pressure 601 on the medium-sized finger is represented by ΔP1, and a second pressure difference between the actual applied pressure 603 and the observed pressure 601 on the small finger is represented by ΔP2. Figure 6B In the context of an uninflated bladder, at a given time when one or more pulses are recorded, a third pressure difference between the actual applied pressure 612 and the observed pressure 611 on a medium-sized finger is represented by ΔP3, and a fourth pressure difference between the actual applied pressure 613 and the observed pressure 611 on a small finger is represented by ΔP4. Figure 6A and Figure 6B The results show that with a pre-inflated airbag, the actual applied pressures 602 and 603 are closer to the observed pressure 601, and show less variation for different finger sizes. Therefore, the final estimate of blood pressure will generally be more accurate. Without a pre-inflated airbag, the actual applied pressures 612 and 613 are significantly smaller than the observed pressure 611, and this difference is even more pronounced for smaller finger sizes.

[0082] Pump control of blood pressure cuff

[0083] A pressure pump can be used to control the inflation / deflation of the inflatable bladder of a blood pressure cuff. The pressure pump can be fluidly connected to the pressurizable volume of the inflatable bladder, wherein the pressure pump is configured to: when the pressure pump is activated, pressurize the pressurizable volume and inflate the inflatable bladder to contact the user's appendage (e.g., the user's finger). When the pump is activated, the pressurizable volume is inflated under the drive of the pressure pump and expands toward the user's appendage to contact the user's appendage. When the user's appendage is inserted into the opening of the blood pressure cuff, and the pump is activated to pressurize the pressurizable volume and contact the user's appendage, blood pressure measurement can occur. The blood pressure cuff may include a pressure sensor for generating pressure data indicating the pressure in the pressurizable volume over time, wherein this pressure data can be used to obtain the user's blood pressure measurement result.

[0084] In some implementations, the pressurizing pump may be a piezoelectric pump. A typical piezoelectric pump used to control inflation may pressurize the bladder too quickly, making it impossible to detect a pulsation wave in blood pressure measurement. For example, a typical pump may pressurize the bladder at an inflation rate greater than 20 mmHg per second, greater than 50 mmHg per second, greater than 80 mmHg per second, or greater than 100 mmHg per second. Such a high inflation rate is too fast to pressurize the volume surrounding the user's finger. Therefore, a pulsation wave is not detected in the blood pressure measurement. However, the blood pressure cuff of this disclosure includes a pump and control hardware that controls the inflation rate to allow for the detection of a pulsation wave in blood pressure measurement. In some implementations, the pump's inflation rate (or more precisely, pressurizing rate) is less than about 20 mmHg per second, less than about 10 mmHg per second, or less than about 5 mmHg per second. For example, the pump's inflation rate may be controlled between about 1 mmHg and about 10 mmHg per second. Furthermore, the pump inflation rate can be modulated to maintain a linear or near-linear pressure-time history of the bladder pressure, thereby eliminating arbitrary nonlinear relationships from the oscilloscope waveform. For example, at inflation rates between approximately 1 mmHg per second and approximately 10 mmHg per second, such as approximately 4 mmHg per second, the pressure rise in the bladder can be maintained in an approximately linear manner.

[0085] The blood pressure cuff of this disclosure may include a controller or control unit coupled to a pump. The control unit or controller may include at least one of the following: a general-purpose single-chip or multi-chip processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, or discrete hardware components. In some embodiments, the controller is capable of controlling the pump according to instructions (e.g., software) stored on one or more non-transitory computer-readable media. Such non-transitory media may include the blood pressure cuff's memory. The controller is configured to input control signals to drive the pump based on various parameters.

[0086] Additional control hardware can be coupled to the controller to control various operations of the pump, or more generally, the blood pressure cuff. The controller can be coupled to, for example, a DC-DC boost circuit to change the pump's drive voltage. The controller can optionally be coupled to an exhaust valve to deflate and deflate the pressurizable volume of the inflatable cuff. For example, in some implementations (such as...) Figure 3E As depicted in the text; Figures 3A-3D , Figure 3F and Figure 3G(These additional features are not described in the text), valve 105 may be fluidly connected to the pressurizable volume, for example, via an annular channel 124. Valve 105 may be, for example, a controllable valve operated by a controller, or it may be a mechanically ejected valve that automatically allows pressure exceeding a preset point (e.g., 275 mmHg to 300 mmHg gauge pressure) to be released. In the case of controllable valve 105, the controller may monitor data from a pressure sensor and may cause valve 105 to release pressure exceeding a preset threshold (e.g., 275 mmHg to 300 mmHg gauge pressure). In some implementations, housing 102 may also or alternatively include a mechanical plug 103 that can be accessed by a user from outside the device; the mechanical plug 103 may be configured to be easily removed by the user if the pressure within the inflatable bladder 110 exceeds a comfortable level (and / or, for example, if a fault preventing pump shutdown exists).

[0087] The blood pressure cuff disclosed herein includes a controller for changing one or more parameters to affect the inflation rate of the pump. The parameters for controlling the inflation rate may be fixed during blood pressure measurement, or the parameters for controlling the inflation rate may be continuously changed during blood pressure measurement. For example, the rate of change of the duty cycle may be fixed during blood pressure measurement (e.g., set according to a preset sequence of duty cycle lengths), or the rate of change of the duty cycle may be dynamically changed, at least in part, based on pressure readings from the blood pressure measurement (e.g., the duty cycle length may be changed based on feedback from a pressure sensor).

[0088] The controller can be configured to control at least one of the pump's drive frequency, voltage, or duty cycle. Controlling one or more of the aforementioned characteristics of the pump can control the pump's charging rate.

[0089] When an alternating current is applied, a piezoelectric pump typically discharges air at a flow rate in response to an alternating drive signal. Typical piezoelectric pumps are designed to operate in response to alternating drive signals of a specific frequency and voltage (e.g., a square wave signal with a nominally constant frequency and voltage). It will be understood that a sinusoidal signal can be applied, a square wave signal can be applied, and so on. Figure 7 As shown, a typical piezoelectric pump can be operated using a square wave signal; however, it will be understood that other piezoelectric pumps can be operated using a sine wave signal or other alternating drive signals. The alternative drive signal can be characterized by its amplitude V0 and drive frequency f0. The pump's charging rate can be determined at least in part by controlling characteristics such as the pump's amplitude and drive frequency. When discussing the voltage applied to the pump, the peak-to-peak voltage V0 can be used. pp Where the amplitude V0 is the peak-to-peak voltage V pp Half the value. The signal driving frequency can be, for example, 23kHz, and the driving voltage can be, for example, 5V. pp -30Vpp .

[0090] While the drive frequency is typically not adjustable, some degree of adjustment is possible within the design limits of the drive signal. Accordingly, in some implementations, the pump's drive frequency can be adjusted to control the pump speed, thereby controlling its inflation rate. However, reducing the drive frequency below the design lower limit of the acceptable drive signal frequency may cause the pump to malfunction, and the pump may fail to provide sufficient arbitrary pressurization. However, in some embodiments, a controller coupled to the pump can be configured to modify the drive frequency to change the pump's inflation rate. In some embodiments, the pump's drive frequency is equal to or greater than about 23 kHz. The pump's drive frequency can be modified to an externally audible noise level.

[0091] Additionally or alternatively, the inflation rate of the piezoelectric pump can be controlled by controlling the pump voltage. Also known as "amplitude modulation," this allows the voltage applied to the pump to be controlled within a given desired amplitude range. In some implementations, the voltage applied to the pump can be increased within the desired amplitude range. If the peak-to-peak potential difference V... pp From approximately 12V pp Approximately 40V pp The amplitude range is from approximately 6V to approximately 20V. Higher voltages or amplitudes typically correspond to larger volumetric displacements in the piezoelectric pump. In some implementations, the controller can be configured to increase the pump's inter-peak voltage from a first inter-peak voltage to a second inter-peak voltage at a selected rate. For example, the first inter-peak voltage could be approximately 5V. pp With approximately 20V pp Between (e.g., 10V) pp Furthermore, the second interpeak voltage can be around 40V. pp With approximately 80V pp Between (e.g., 60V) pp This corresponds to an amplitude range of 2.5V-10V (e.g., 5V) to 20V-40V (e.g., 30V). The amplitude can be gradually increased according to a selected rate. In some implementations, the amplitude increases at a selected rate between about 2V / second and about 10V / second (e.g., about 5V / second). Changing the amplitude of the drive signal can cause a change in the amount of noise heard from the pump. In some implementations, amplitude modulation can reduce the noise transmitted from the piezoelectric pump.

[0092] Alternatively, the pump's charging rate can be controlled by adjusting the pump's duty cycle. The duty cycle guides the charge time (T). on The percentage of the sum of the on-time and off-time, where in a given period, T = T on +T offThe duty cycle can be gradually increased at a selected rate to achieve the desired duty cycle. In some implementations, the selected rate can be fixed during blood pressure measurement, and the duty cycle can be increased at the selected rate from a first duty cycle (e.g., less than 100% duty cycle) to a second duty cycle (e.g., 100% duty cycle). In some implementations, the selected rate can be between about 0.1% and about 20% of the duty cycle increase per second. For example, the duty cycle can be increased from 40% to 100% duty cycle at a rate of about 1% of the duty cycle increase per second.

[0093] In some implementations, the selected rate can be dynamically changed during blood pressure measurement, and the duty cycle can be increased at a first rate from a first duty cycle (e.g., less than 100% duty cycle) to a second duty cycle (e.g., greater than the first duty cycle), and the duty cycle can be increased at a second rate from the second duty cycle to a third duty cycle (e.g., greater than the second duty cycle). The first rate differs from the second rate, wherein each of the first and second rates is between approximately 0.1% and approximately 20% of the duty cycle increase per second. For example, the duty cycle can be increased from 20% to 30% at a rate of approximately 1% per second, and the duty cycle can subsequently be increased from 30% to 50% at a rate of approximately 5% per second. The duty cycle can be increased until 100% duty cycle is reached, or in some cases, until a lower duty cycle level is reached.

[0094] Figure 8 The graph shows the voltage change over time, where the duty cycle of the square wave signal driving the piezoelectric pump gradually changes. Clearly, the duty cycle signal is used to modulate the pump's fixed-frequency drive signal; when the duty cycle signal is 100%, a fixed-frequency drive signal is provided to the pump; when the duty cycle signal is 0%, no fixed-frequency drive signal is provided to the pump. Therefore, the pump is driven at a constant frequency during the "on" duty cycle phase, and is not driven during the "off" duty cycle phase. Figure 8 In this context, the piezoelectric pump is being driven by a duty cycle signal with a pulsating wave frequency of approximately 5000 Hz. For example... Figure 8 As shown, the duty cycle gradually increases from 70% to 100% at a rate of 10% per second. Figure 7 The square wave signal in it is continuous. Figure 8 The square wave signal in the piezoelectric pump is discontinuous or "chopped." As mentioned above, this causes the piezoelectric pump to operate intermittently and to inflate the bladder at a slower rate than at full speed. This slower inflation rate is suitable for inflating smaller volumes.

[0095] As described below, the controller can also be coupled to a pressure sensor in fluid communication with the inflatable bladder, and the pressure sensor is configured to generate pressure data indicating the pressure within the pressurizable volume over time. In some implementations, the controller is configured to change the rate of increase of the duty cycle from a first rate to a second rate when the pressure within the pressurizable volume reaches a threshold pressure. This allows the increase of the duty cycle to slow down or accelerate when a specific pressure level is reached, thereby controlling the pump's inflation rate. For example, the first rate could be an increase of 1% per second and the second rate could be an increase of 0.5% per second, or the first rate could be an increase of 0.5% per second and the second rate could be an increase of 1% per second. In some implementations, the threshold pressure could be a pressure between about 50 mmHg and about 250 mmHg, or a pressure between about 100 mmHg and about 180 mmHg. In some implementations, the controller is configured to dynamically change the pump's duty cycle based at least in part on the pressure data from the pressurizable volume. The power of certain duty cycles may not be sufficient to pressurize the pressurizable volume to a level exceeding a specific pressure, and therefore the duty cycle can be dynamically tuned based on pressure data.

[0096] Modifying the pump's duty cycle can distort the linearity of the inflation profile, potentially interfering with the accurate reading and recording of pulsation information in blood pressure measurements. Accordingly, the duty cycle and its selected rate of change can be optimized to achieve a linear or near-linear inflation profile. In other words, the duty cycle can be gradually increased at a desired rate to make the inflation profile substantially linear. Figure 9 The inflation curve of a finger blood pressure cuff using a piezoelectric pump is shown. (Example) Figure 9 As shown, the inflation rate of the inflation curve is approximately linear. For example, increasing the duty cycle from 20% to 40% by 1% per second, and then increasing the duty cycle from 40% to 60% by 0.5% per 0.1 seconds, can achieve a substantially linear inflation curve.

[0097] The controller of a piezoelectric pump adjusts one or more of the pump's drive frequency, voltage, and duty cycle to control the pump's inflation rate. Adjusting parameters such as duty cycle, voltage, and / or drive frequency not only reduces the inflation rate but also allows for a more linear inflation rate.

[0098] Pressure curve and measurement results of blood pressure cuff

[0099] OBPM systems measure a user's blood pressure by observing and analyzing oscillometric patterns in a pressure curve. In a conventional OBPM system, the pressure curve is obtained by inflating a blood pressure cuff to the desired pressure to at least temporarily obstruct blood flow in the underlying vessel, then deflating the cuff, noting the cuff pressure at the first recorded heartbeat (systolic pressure) and at the recorded cessation of heartbeat (diastolic pressure). Typical blood pressure measurements may involve inflating to an initial pressure greater than the systolic blood pressure and then deflating to a final pressure lower than the diastolic blood pressure. During blood pressure measurement, a pressure curve can be recorded including one or more pulses occurring during inflation and deflation. These pulses are caused by the user's heartbeat. Techniques known in the art for determining blood pressure from one or more pulses recorded in the pressure curve can be used.

[0100] In this disclosure, a blood pressure cuff, such as a finger cuff, can be inflated to an initial pressure at least slightly above systolic blood pressure using a first pressure curve. At some point during inflation, the cuff and dermis will come into contact with sufficient pressure to transmit blood pulsations from the dermis to the cuff, manifesting as pressure pulsations measurable by a pressure sensor. These pulsations typically increase in intensity as the dermis and cuff are pressed more firmly together, resulting in better coupling between the dermis and cuff, until the cuff applies such pressure through the dermis to the artery that blood flow ceases (at which point the pulsations also cease). Generally, the pressure at which the pulsations in the dermis are first detected by the pressure sensor is associated with a person's diastolic blood pressure, while the higher pressure at which blood flow stops and the pulsations end is generally associated with a person's systolic blood pressure. More specifically, conventional oscillometric measurements can use the first and last pulsations of a specific amplitude normalized to their maximum value to determine the measurements of diastolic and systolic blood pressure. Therefore, measurements can typically involve inflating the cuff to a pressure above systolic blood pressure and recording the pressure data measured during this inflation. Systolic pressure can then be estimated based on the pressure data obtained during inflation. Diastolic pressure can be estimated based on the pressure data obtained during deflation.

[0101] The blood pressure cuff of this disclosure can more reliably and accurately determine a person's blood pressure, including systolic and diastolic pressure, by causing a pump to pressurize a pressurizable volume of an inflatable bladder to a first pressure greater than the maximum amplitude pressure in a first pressure curve, and subsequently causing the pump to maintain the pressurizable volume at a second pressure in a second pressure curve for a period of time, wherein the second pressure is at least partially based on information from the first pressure curve. The blood pressure cuff may include a controller coupled to a pump in fluid communication with the inflatable bladder, and the controller is also coupled to a pressure sensor in fluid communication with the inflatable bladder. The inflatable bladder at least partially defines the pressurizable volume. The pump is configured to pressurize the pressurizable volume and, when the pump is activated, cause the inflatable bladder to contact the user's limb. The pressure sensor is configured to acquire and generate pressure data indicating the pressure within the pressurizable volume over time, wherein the pressure data includes oscillometric data from the first pressure curve and pulsation information from the second pressure curve. A first pressure curve can indicate the pressure within the pressurizable volume over time up to a first pressure, and a second pressure curve can indicate the pressure within the pressurizable volume over time after the first pressure has been reached. In some embodiments, the second pressure curve indicates the pressure within the pressurizable volume when the pressurizable volume is held at a second pressure.

[0102] To obtain a clearer signal and a more reliable estimate of a person's blood pressure, in some implementations, the first pressure curve may be approximately linear at a specific rate, such as between approximately 1 mmHg per second and approximately 10 mmHg per second. In some implementations, the first pressure curve may be non-linear, where, based on sensing pressure fluctuations, the first pressure curve may be flatter as it approaches systolic and diastolic pressure. In some implementations, the first inflation curve may include a stepped and / or flat inflation curve, where the stepped and / or flat inflation curve may measure one or more of pulsatility wave analysis (PWA) characteristics, arterial compliance, respiration, atrial fibrillation, and other physiological parameters.

[0103] In this disclosure, the blood pressure cuff can undergo a process to record pressure data during inflation / deflation onto a second pressure curve following the first pressure curve. For example... Figure 10 As shown, in the second pressure curve, the blood pressure cuff can be reduced from the first pressure to zero gauge pressure or another lower pressure, and then inflated back to the second pressure. Alternatively, as... Figure 11As shown, the blood pressure cuff can deflate from a first pressure to a second pressure. During the second pressure curve, the cuff can be maintained at the second pressure for a sufficient duration to record multiple oscillations or pulsations originating from the pulsating behavior in the user's blood vessels. In some implementations, the applied pressure can be maintained at the second pressure for a duration between approximately 1 second and approximately 15 seconds, approximately 3 seconds and approximately 10 seconds, or approximately 5 seconds and approximately 10 seconds. The second pressure for the second pressure curve can be obtained from information in the first pressure curve. For example, the second pressure can be the maximum amplitude pressure from oscillometric data (oscillometric data refers to oscillation data generated in the first pressure curve due to pulsation in the subject's blood vessels). Unlike continuous deflation or inflation beyond the second pressure after the first inflation process, the second inflation / deflation process can maintain the applied pressure at the second pressure to obtain pulsation information in the second pressure curve. Pulsation information can be used to extract and characterize one or more of PWA features, arterial compliance, respiration, atrial fibrillation, and other physiological indicators. Since the pressure is constant during the second inflation / deflation process, pulsations with similar amplitudes can be easily averaged to reduce noise and thus extract more robust features. This provides better data for pulsation wave analysis. In some implementations, pulsation information from maintaining the applied pressure at the second pressure can be used to verify information obtained from the first pressure curve.

[0104] Figure 10A graph for blood pressure measurement is shown, depicting a first pressure curve followed by a second pressure curve, where the second pressure curve is inflated to and maintained at a target pressure; the target pressure (in this example) is the maximum amplitude pressure seen in the oscillometric data, which may correspond to the user's mean arterial pressure. The first pressure curve shows a substantially linear inflation curve with oscillometric data recorded during inflation. The pressure applied in the first pressure curve exceeds the maximum amplitude pressure recorded from the oscillometric data. This maximum amplitude pressure corresponds to the pressure at the point of change of maximum amplitude pressure (reproduced below the first pressure curve). The pressure is released to deflate the cuff to zero gauge pressure or near zero gauge pressure. A second inflation is then performed, in which the cuff is inflated to reach the target pressure, which corresponds to the maximum amplitude pressure determined according to the oscillometric data in the first pressure curve. This pressure is maintained or held at the target pressure, which may be the user's mean arterial pressure. This pressure is maintained for a duration sufficient to produce pulsation information in the second pressure curve. The second pressure curve is recorded and shown as a substantially linear inflation curve, where additional oscillometric data (referred to as pulsation information in this example) is recorded while the pressure is maintained at the target pressure. In some implementations, systolic and diastolic blood pressure can be determined based on pulsation information in a second pressure curve. Inflection points, peaks, and other features from additional oscillometric data or pulsation information can be analyzed to extract more pulsation characteristics.

[0105] Figure 11 A graph for blood pressure measurement is shown, depicting a first pressure curve followed by a second pressure curve, where the second pressure curve deflates to a target pressure and remains at that target pressure. Figure 10 Similarly, the first pressure curve shows a substantially linear inflation curve with oscillometric data recorded during inflation, where the pressure exceeds the maximum amplitude pressure recorded from the oscillometric data. The blood pressure cuff is then deflated to reach a target pressure, which corresponds to the maximum amplitude pressure determined from the oscillometric data in the first pressure curve. This pressure is maintained or sustained at the target pressure, which may be the user's mean arterial pressure. This pressure is maintained for a duration sufficient to generate pulsation information in the second pressure curve. The second pressure curve is recorded, where additional oscillometric data (referred to as pulsation information in this example) is recorded while the pressure is maintained at the target pressure.

[0106] Blood pressure cuff position detection

[0107] The blood pressure cuff of this disclosure may be equipped with one or more sensors to determine: the relative position of the cuff to the user's heart, and / or, in some cases, the angular orientation of the user's limb inserted into the cuff relative to the Earth's gravitational field. One or more sensors may be coupled to a controller or control unit to receive data from one or more sensors and determine whether the blood pressure cuff is correctly positioned. For accurate blood pressure measurements with a finger cuff, it is preferable to position the finger with the cuff attached at approximately the same height as the user's heart. This allows for the determination of static pressure, which would otherwise lead to inaccurate measurements.

[0108] In some implementations of this disclosure, the blood pressure cuff may include one or more accelerometers. These accelerometers can be used to estimate the relative position of the blood pressure cuff to the user's heart, and can also determine whether the cuff is in motion. When the user's finger is positioned within the finger cuff, the angle of the finger cuff can be determined to help determine if the user is holding the finger cuff in the correct position. In some implementations, the one or more accelerometers are configured to measure the angle of the blood pressure cuff relative to gravity. In some implementations, the one or more accelerometers can be used to measure tilt angles about an axis orthogonal or substantially orthogonal to a vertical axis, including tilt and pitch angles. The tilt and pitch angles can be within thresholds to help determine if the blood pressure cuff is positioned near the user's heart. For example, when the finger cuff is at approximately the same height as the user's heart, each of the pitch and tilt angles can be between about 0 degrees and about 30 degrees. The one or more accelerometers can be configured to measure acceleration in at least two or three orthogonal directions. An acceleration output (A) can be generated. x A y and A z ), and acceleration output (A x A y and A z The acceleration output is provided to the controller, and the controller can use the acceleration output to determine the tilt of the finger blood pressure cuff, wherein the tilt can be correlated with the position of the user's hand / finger at the height of the user's heart.

[0109] For example, Figure 12 and Figure 13The photograph depicts an example finger blood pressure cuff as shown in the previous illustration, where the cuff is worn during measurement and the user places their hand at an angle on their chest. This positioning typically results in the finger blood pressure cuff being at the same height as the person's heart. In some implementations, a triaxial accelerometer can be used to assess the orientation of the finger blood pressure cuff relative to the Earth's gravitational field. The finger blood pressure cuff can be examined for angular orientation relative to all three axes to determine whether the user's forearm (or more precisely, the user's finger) is at an angle between 15° and 45° to the horizontal axis, and whether the base of the finger blood pressure cuff (or other predetermined reference surface) is approximately parallel to the vertical axis. For example, determining whether the base is approximately parallel to the vertical axis could mean that the base is parallel to a plane at an angle between approximately 75° and approximately 105° to the vertical axis. In other words, the range of angular orientation of the finger blood pressure cuff can be considered within acceptable limits to determine that it is at approximately the same height as the user's heart, for example, where the bottom or base of the device is within ±15° vertically, and the centerline of the device (the centerline of the sac / opening) is at 30° ±15° horizontally. When such a determination is made via an accelerometer, the finger blood pressure cuff can activate a pump to inflate the inflatable bladder, thus initiating the process for obtaining blood pressure measurements.

[0110] Additionally or alternatively, the blood pressure cuff may include one or more altimeters. These altimeters can detect changes in altitude and can be configured to determine the height of the cuff relative to the user's heart. In some implementations, the altimeters can measure changes in altitude in response to changes in the angle of the cuff, and can be used to instruct the user to reach the correct height (e.g., "lower your hand by 2 inches").

[0111] Additionally or alternatively, the blood pressure cuff may include one or more stethoscope sensors to acoustically determine the location of the user's heart. In some implementations, the one or more stethoscope sensors include microphones to listen to the user's heartbeat and determine proximity to the user's heart accordingly. Thus, the one or more stethoscope sensors can function as one or more proximity sensors to determine whether the blood pressure cuff is positioned near the user's heart.

[0112] Additionally or alternatively, the blood pressure cuff may include one or more optical sensors for determining whether a user's finger is inside the cuff's opening. As mentioned above, the material of the inflatable bladder may be transparent or substantially transparent to certain wavelengths of light. The one or more optical sensors may be integrated within the finger cuff, or more specifically, the one or more optical sensors may be integrated within the inflatable bladder. The one or more optical sensors may be configured to detect whether a user's finger has been inserted through the opening of the cuff. In some implementations, the one or more optical sensors may include one or more photoplethysmography (PPG) sensors. The one or more PPG sensors may be used to determine at least one of the user's heart rate, respiratory rate, skin condition, or other physiological parameters.

[0113] In some implementations, one or more accelerometers or other motion sensors can be used to determine whether the blood pressure cuff is in motion. The blood pressure cuff can be configured not to initiate blood pressure measurement and not to inflate the cuff's elastic bladder when the finger cuff is in motion. Blood pressure measurement can be initiated when the cuff is properly positioned at the user's heart height and the measured motion is slow enough to last for a sufficient duration. The controller can automatically initiate inflation of the inflatable bladder when one or more motion sensors (e.g., one or more accelerometers) determine that the finger cuff is within a threshold height of the user's heart or near the user's heart for a sufficient duration. The sufficient duration can be between about 0.5 seconds and about 5 seconds, or between about 1 second and about 3 seconds. For example, the threshold height can be within ±2 inches of the user's heart, or within the target angular orientation as described above.

[0114] In some implementations, the controller can be configured to turn off the blood pressure cuff or enter a power-saving mode when the cuff is stationary or remains still for a threshold duration and one or more motion sensors determine that the device is not positioned within a threshold height of the user's heart. When the one or more motion sensors determine that the finger cuff has been stationary for a threshold duration, the controller can automatically turn off the cuff or enter a power-saving mode, where the threshold duration can be between about 5 seconds and about 1 minute or between about 10 seconds and about 30 seconds. In some implementations, the sufficient duration and / or threshold duration can be defined by the user. In some implementations, the blood pressure cuff can be configured to turn off or enter a power-saving mode when the finger cuff is oriented relative to gravity to indicate that the finger cuff is not in use. For example, when one or more motion sensors determine that the base or flat surface (e.g., the base) of the cuff is orthogonally oriented relative to gravity, the controller can automatically turn off the finger cuff or enter a power-saving mode.

[0115] Figure 14 and Figure 15A photograph of an example finger blood pressure cuff placed on a surface is shown, in which a finger is inserted through the opening of the cuff for blood pressure measurement. Figure 14 As shown, when the finger cuff is placed on the surface, the pump is not activated to inflate the inflatable bladder. In some implementations, the finger cuff can be configured to shut off or enter a power-saving mode after being placed on the surface for a sufficiently long period. Regardless of whether the finger cuff is placed on the surface, the user's finger can be inserted through the opening in the finger cuff, as... Figure 15 As shown. In some implementations, a pump is activated to inflate an inflatable bladder, thereby contacting the user's finger. The finger cuff can be configured to take a blood pressure measurement when the user's finger is inserted through the opening and the inflatable bladder is inflated to contact the user's finger. Although a finger cuff can be used to take blood pressure measurements with the cuff placed on a surface, it will be understood that a finger cuff can also be used to take blood pressure measurements without the cuff placed on a surface. In some implementations, a more accurate blood pressure measurement can be taken when the finger cuff is at the same or substantially the same height as the user's heart or near the user's heart.

[0116] In some implementations of this disclosure, the blood pressure cuff may include one or more proximity sensors. These proximity sensors may be configured to determine whether the blood pressure cuff is located near the user's heart. Additionally or alternatively, the proximity sensors may be configured to determine whether the user's appendages (e.g., the user's fingers) are properly positioned within the blood pressure cuff. Examples of proximity sensors may include capacitive sensors, optical sensors, and photoelectric sensors. These proximity sensors may be used to detect the presence of the user's chest, skin, body, or fingers. In some implementations, the blood pressure cuff also includes one or more motion sensors to determine whether the device is in motion or stationary. In some implementations, the blood pressure cuff also includes a controller configured to initiate inflation of the inflatable bladder using a pump when one or more proximity sensors determine that the blood pressure cuff is located near the user's heart and when one or more motion sensors determine that the device has been stationary for a sufficient duration.

[0117] In some implementations, the one or more proximity sensors include one or more stethoscope sensors configured to acoustically determine proximity to the user's heart. The one or more stethoscope sensors function as stethoscopes to listen to the user's heartbeat and determine proximity to the user's heart. The one or more stethoscope sensors may include a microphone that functions as a proximity sensor to acoustically determine the position of the user's heart, thereby aiding in the proper positioning of the blood pressure cuff prior to blood pressure measurement.

[0118] In some implementations of this disclosure, the blood pressure cuff may also include one or more feedback devices. These one or more feedback devices may be configured to communicate the positioning of the blood pressure cuff relative to the user's heart and / or the positioning of the user's fingers relative to the opening of the blood pressure cuff. Feedback from these one or more feedback devices may include informing the user that a blood pressure measurement is in progress; the blood pressure measurement is complete; the bladder is inflating; the bladder is deflating; whether the blood pressure cuff is properly positioned; whether the user's fingers are properly positioned; and information regarding physiological data associated with the user, such as systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, respiratory rate, and blood pressure risk zones / information. These one or more feedback devices may include, but are not limited to, speakers for audio feedback, light-emitting diodes (LEDs) for optical feedback, displays for visual feedback, and motors / vibration motors for haptic feedback. In some implementations, the one or more feedback devices may include a display to present visual feedback to the user. The display (e.g., a screen) may show the user instructions, user information, connectivity data, biostatistics, and / or blood pressure results. In some implementations, the one or more feedback devices may include speakers and / or microphones for audio control and guidance. In some implementations, the blood pressure cuff includes an interface for receiving any or all of the aforementioned feedback via one or more intermediate devices (from one device to another), such as a smartphone, wearable device, computer, or remote server. In some implementations, a remote device, such as a smartphone, wearable device, computer, or remote server, can directly provide any or all of the aforementioned feedback to the user.

[0119] Other implementation methods

[0120] This document describes and illustrates numerous concepts and implementations. While certain implementations, features, attributes, and advantages have been described and illustrated herein, it should be understood that many other, as well as different and / or similar, implementations, features, attributes, and advantages will be apparent from the description and illustration. Similarly, the above-described implementations are provided by way of example only. They are not intended to be exhaustive or to limit this disclosure to the precise forms, techniques, materials, and / or configurations disclosed. Many modifications and variations are possible according to this disclosure. It should be understood that other implementations may be utilized and operational changes may be made without departing from the scope of this disclosure. Likewise, the scope of this disclosure is not limited to the above description, as the description of the above implementations is presented for illustrative and descriptive purposes.

[0121] As used herein, unless otherwise indicated, terms such as “approximately,” “approximately,” “nominally”, etc., relating to numerical values ​​or relationships (e.g., perpendicularity or parallelism) should be understood to include a representation of the value or relationship within ±10% of that value or relationship (e.g., for approximate parallelism, the value could be 90° ± 9°).

[0122] This disclosure is not limited to any single aspect or implementation, nor to any combination and / or arrangement of such aspects and / or implementations. Furthermore, each aspect and / or implementation of any aspect of this disclosure may be used alone or in combination with one or more other aspects and / or implementations of that aspect. For the sake of brevity, many of these permutations and combinations will not be discussed and / or shown separately herein.

Claims

1. An apparatus for estimating a user's blood pressure, the apparatus comprising: An inflatable airbag, the inflatable airbag at least partially defining a pressurizable volume; A pump, which is in fluid communication with the inflatable bladder and is configured to pressurize the pressurizable volume and cause the inflatable bladder to inflate, wherein the inflation rate of the pump can be controlled by controlling the duty cycle of the pump. as well as A controller, coupled to the pump, is configured to change the duty cycle of the pump from a first duty cycle to a second duty cycle at a first selected rate of change and to change the duty cycle from the second duty cycle to a third duty cycle at a second selected rate of change different from the first selected rate of change, such that the inflation curve of the inflatable bladder is substantially linear.

2. The apparatus according to claim 1, wherein, The inflatable bladder is an inflatable elastic bladder disposed around the inward-facing surface of the hole in the device, and The pump is configured to pressurize the pressurizable volume when the user's appendage is positioned in the orifice of the device.

3. The apparatus according to claim 1, wherein the inflation rate of the pump is controlled to be between 1 mmHg per second and 10 mmHg per second.

4. The apparatus of claim 1, further comprising: A pressure sensor is in fluid communication with the inflatable bladder and is configured to generate pressure data indicating the pressure within the pressurizable volume as it changes over time.

5. The apparatus of claim 4, wherein, The controller is configured to receive the pressure data from the pressure sensor and is configured to change the duty cycle of the pump from the first duty cycle to the second duty cycle when the pressure data indicates that the pressure in the pressurizable volume reaches a threshold pressure.

6. The apparatus of claim 1, wherein, The first selected rate of change and the second selected rate of change are between 0.1% and 20% per second of duty cycle increase, respectively.

7. The apparatus according to claim 6, wherein, The first selected rate of change is a 1% increase in duty cycle per second, while the second selected rate of change is a 5% increase in duty cycle per second.

8. The apparatus according to claim 1, wherein, The controller is also configured to change the rate of change of the duty cycle from the first selected rate of change to the second selected rate of change when the pressure in the pressurizable volume reaches a threshold pressure.

9. The apparatus according to claim 8, wherein, The threshold pressure is a value between 100 mmHg and 180 mmHg.

10. The apparatus according to claim 1, wherein, The controller is further configured to control a peak-to-peak voltage V pp .

11. The apparatus according to claim 10, wherein, The controller is also configured to increase the inter-peak voltage of the pump from a first inter-peak voltage to a second inter-peak voltage at a selected rate of change.

12. The apparatus according to claim 11, wherein, The first peak-to-peak voltage is between 5 Vpp and 20 Vpp, and the second peak-to-peak voltage is between 40 Vpp and 80 Vpp. The selected rate of change from the first inter-peak voltage to the second inter-peak voltage is between 2 V per second and 10 V per second.

13. The apparatus according to claim 1, wherein, The controller is also configured to modify the pump's drive frequency to change the pump's inflation rate.

14. The apparatus according to claim 1, wherein, The pump's drive frequency is equal to or greater than 23 kHz.

15. A method for controlling the inflation rate of an inflatable bladder, comprising: A pump is used to inflate the inflatable bladder having a pressurizable volume, causing the inflatable bladder to expand. as well as Controlling the duty cycle of the pump and a selected rate of change of the duty cycle via a controller to achieve a substantially linear inflation curve for the inflatable bladder, wherein controlling the duty cycle and the selected rate of change of the duty cycle to achieve the substantially linear inflation curve includes: The duty cycle of the pump is changed from a first duty cycle to a second duty cycle at a first selected rate of change; and The duty cycle of the pump is changed from the second duty cycle to the third duty cycle at a second selected rate of change, which is different from the first selected rate of change.

16. The method according to claim 15, wherein, The first selected rate of change and the second selected rate of change are between 0.1% and 20% per second of duty cycle increase, respectively.

17. The method of claim 15, further comprising: Pressure data is generated using a pressure sensor in fluid communication with the inflatable bladder, the pressure data indicating the pressure within the pressurizable volume of the inflatable bladder as it changes over time.

18. The method of claim 17, further comprising: Obtain pressure data indicating the pressure within the pressurizable volume of the inflatable bladder, wherein when the pressure within the pressurizable volume reaches a threshold pressure, the duty cycle is changed from the second duty cycle to the third duty cycle.

19. The method of claim 17, further comprising: Obtain the pressure data indicating the pressure within the pressurizable volume of the inflatable bladder, and The duty cycle of the pump is dynamically changed, at least in part, based on the pressure data.

20. The method of claim 17, further comprising: While changing the duty cycle of the pump from the first duty cycle to the second duty cycle at the first selected rate of change, and while changing the duty cycle from the second duty cycle to the third duty cycle at the second selected rate of change, the user's blood pressure is measured based on oscillometric data included in the pressure data.

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